Dan Luo

Bone, as a mineralized composite of inorganic (mostly carbonated hydroxyapatite) and organic (mainly type I collagen) phases, possesses a unique combination of remarkable strength and toughness. Its excellent mechanical properties are related to its hierarchical structures and precise organization of the inorganic and organic phases at the nanoscale: Nanometer-sized hydroxyapatite crystals periodically deposit within the gap zones of collagen fibrils during bone biomineralization process. This hierarchical arrangement produces nanomechanical heterogeneities, which enable a mechanism for high energy dissipation and resistance to fracture. The excellent mechanical properties integrated with the hierarchical nanostructure of bone have inspired chemists and material scientists to develop biomimetic strategies for artificial bone grafts in tissue engineering (TE). This critical review provides a broad overview of the current mechanisms involved in bone biomineralization, and the relationship between bone hierarchical structures and the deformation mechanism. Our goal in this review is to inspire the application of these principles toward bone TE.

Abstract Surface enhanced Raman scattering (SERS) is a trace detection technique that extends even to single molecule detection. Its potential application to the noninvasive recognition of lung malignancies by detecting volatile organic compounds (VOCs) that serve as biomarkers would be a breakthrough in early cancer diagnostics. This application, however, is currently limited by two main factors: (1) most VOC biomarkers exhibit only weak Raman scattering; and (2) the high mobility of gaseous molecules results in a low adsorptivity on solid substrates. To enhance the adsorption of gaseous molecules, a ZIF‐8 layer is coated onto a self‐assembly of gold superparticles (GSPs) in order to slow the flow rate of gaseous biomarkers and depress the exponential decay of the electromagnetic field around the GSP surfaces. Gaseous aldehydes that are released as a result of tumor‐specific tissue composition and metabolism, thereby acting as indicators of lung cancer, are guided onto SERS‐active GSPs substrates through a ZIF‐8 channel. Through a Schiff base reaction with 4‐aminothiophenol pregrafted onto gold GSPs, gaseous aldehydes are captured with a 10 ppb limit of detection, demonstrating tremendous prospects for in vitro diagnoses of early stage lung cancer.

Natural bone is a mineralized biological material, which serves a supportive and protective framework for the body, stores minerals for metabolism, and produces blood cells nourishing the body. Normally, bone has an innate capacity to heal from damage. However, massive bone defects due to traumatic injury, tumor resection, or congenital diseases pose a great challenge to reconstructive surgery. Scaffold-based tissue engineering (TE) is a promising strategy for bone regenerative medicine, because biomaterial scaffolds show advanced mechanical properties and a good degradation profile, as well as the feasibility of controlled release of growth and differentiation factors or immobilizing them on the material surface. Additionally, the defined structure of biomaterial scaffolds, as a kind of mechanical cue, can influence cell behaviors, modulate local microenvironment and control key features at the molecular and cellular levels. Recently, nano/micro-assisted regenerative medicine becomes a promising application of TE for the reconstruction of bone defects. For this reason, it is necessary for us to have in-depth knowledge of the development of novel nano/micro-based biomaterial scaffolds. Thus, we herein review the hierarchical structure of bone, and the potential application of nano/micro technologies to guide the design of novel biomaterial structures for bone repair and regeneration.

The host immune response to bone biomaterials is vital in determining scaffold fates and bone regeneration outcomes. The nanometer-scale interface of biomaterials, which independently controls physical inputs to cells, regulates osteogenic differentiation of stem cells and local immune response. Herein, we fabricated biomimetic hierarchical intrafibrillarly mineralized collagen (HIMC) with a bone-like staggered nanointerface and investigated its immunomodulatory properties and mesenchymal stem cell (MSC) recruitment during endogenous bone regeneration. The acquired HIMC potently induced neo-bone formation by promoting CD68+CD163+ M2 macrophage polarization and CD146+STRO-1+ host MSC recruitment in critical-sized bone defects. Mechanistically, HIMC facilitated M2 macrophage polarization and interleukin (IL)-4 secretion to promote MSC osteogenic differentiation. An anti-IL4 neutralizing antibody significantly reduced M2 macrophage-mediated osteogenic differentiation of MSCs. Moreover, HIMC-loaded-IL-4 implantation into critical-sized mandible defects dramatically enhanced bone regeneration and CD68+CD163+ M2 macrophage polarization. The depletion of monocyte/macrophages by clodronate liposomes significantly impaired bone regeneration by HIMC, but did not affect MSC recruitment. Thus, in emulating natural design, the hierarchical nanointerface possesses the capacity to recruit host MSCs and promote endogenous bone regeneration by immunomodulation of macrophage polarization through IL-4.

Tactile perception includes the direct response of tactile corpuscles to environmental stimuli and psychological parameters associated with brain recognition. To date, several artificial haptic-based sensing techniques can accurately measure physical stimuli. However, quantifying the psychological parameters of tactile perception to achieve texture and roughness identification remains challenging. Here, we developed a smart finger with surpassed human tactile perception, which enabled accurate identification of material type and roughness through the integration of triboelectric sensing and machine learning. In principle, as each material has different capabilities to gain or lose electrons, a unique triboelectric fingerprint output will be generated when the triboelectric sensor is in contact with the measured object. The construction of a triboelectric sensor array could further eliminate interference from the environment, and the accuracy rate of material identification was as high as 96.8%. The proposed smart finger provides the possibility to impart artificial tactile perception to manipulators or prosthetics.

Increasing global population and decreasing arable land pose tremendous pressures to agricultural production. The application of conventional chemical fertilizers improves agricultural production, but causes serious environmental problems and significant economic burdens. Biochar gains increasing interest as a soil amendment. Recently, more and more attentions have been paid to biochar-based slow-release of fertilizers (SRFs) due to the unique properties of biochar. This review summarizes recent advances in the development, synthesis, application, and tentative mechanism of biochar-based SRFs. The development mainly undergoes three stages: (i) soil amendment using biochar, (ii) interactions between nutrients and biochar, and (iii) biochar-based SRFs. Various methods are proposed to improve the fertilizer efficiency of biochar, majorly including in-situ pyrolysis, co-pyrolysis, impregnation, encapsulation, and granulation. Considering the distinct features of different methods, the integrated methods are promising for fabricating effective biochar-based SRFs. The in-depth understanding of the mechanism of nutrient loading and slow release is discussed based on current knowledge. Additionally, the perspectives and challenges of the potential application of biochar-based SRFs are described. Knowledge surveyed from this review indicates that applying biochar-based SRFs is a viable way of promoting sustainable agriculture.

Virtual reality is a brand-new technology that can be applied extensively. To realize virtual reality, certain types of human-computer interaction equipment are necessary. Existing virtual reality technologies often rely on cameras, data gloves, game pads, and other equipment. These equipment are either bulky, inconvenient to carry and use, or expensive to popularize. Therefore, the development of a convenient and low-cost high-precision human-computer interaction device can contribute positively to the development of virtual reality technology. In this study, a gesture recognition wristband that can realize a full keyboard and multicommand input is developed. The wristband is convenient to wear, low in cost, and does not affect other daily operations of the hand. This wristband is based on physiological anatomy as well as aided by active sensor and machine learning technology; it can achieve a maximum accuracy of 92.6% in recognizing 26 letters. This wristband offers broad application prospects in the fields of gesture command recognition, assistive devices for the disabled, and wearable electronics.

Effective treatment of emerging organic contaminants (EOCs) is a key concern for human beings. Advanced oxidation processes (AOPs) have become one of the core techniques of EOCs removal because of the high oxidation efficiency, complete mineralization, and controllable process. Sulfate radicals-based AOPs overcome the shortcomings of conventional Fenton processes. The development of efficient catalysts is major limitation of sulfate radicals-based AOPs for EOCs removal from wastewater. Metal organic framework (MOFs) receives growing global attention due to excellent properties of large surface area, flexible synthesis methods, and modifiable structure. Numerous researches have been conducted to fabricate MOFs-based catalysts. Herein, studies on MOFs-based materials as catalysts for catalytic removal of EOCs were summarized. The synthesis methods of MOFs were briefly described. Researches on MOFs materials as persulfate activators were reviewed from the perspective of Fenton-like and photo-Fenton system. Additionally, the effects of process factors including catalyst dosage, persulfate concentration, solution pH, coexisting inorganic anions, natural organic matter, and temperature on the catalytic efficiency were systematically summarized. Finally, the stability and toxicity of MOFs-based catalysts that affect the practical application was discussed. This work provides better understanding of sulfate radicals-based AOPs using MOFs-based catalysts for EOCs removal.

Epidermal growth factor is an excellent drug for promoting wound healing; however, its conventional administration strategies are associated with pharmacodynamic challenges, such as low transdermal permeability, reduction, and receptor desensitization. Here, we develop a microneedle-based self-powered transcutaneous electrical stimulation system (mn-STESS) by integrating a sliding free-standing triboelectric nanogenerator with a microneedle patch to achieve improved epidermal growth factor pharmacodynamics. We show that the mn-STESS facilitates drug penetration and utilization by using microneedles to pierce the stratum corneum. More importantly, we find that it converts the mechanical energy of finger sliding into electricity and mediates transcutaneous electrical stimulation through microneedles. We demonstrate that the electrical stimulation applied by mn-STESS acts as an "adjuvant" that suppresses the reduction of epidermal growth factor by glutathione and upregulates its receptor expression in keratinocyte cells, successfully compensating for receptor desensitization. Collectively, this work highlights the promise of self-powered electrical adjuvants in improving drug pharmacodynamics, creating combinatorial therapeutic strategies for traditional drugs.

Human-machine interfaces have penetrated various academia and industry fields such as smartphones, robotic, virtual reality, and wearable electronics, due to their abundant functional sensors and information interaction methods. Nevertheless, most sensors' complex structural design, monotonous parameter detection capability, and single information coding communication hinder their rapid development. As the frontier of self-powered sensors, the triboelectric nanogenerator (TENG) has multiple working modes and high structural adaptability, which is a potential solution for multi-parameter sensing and miniaturizing of traditional interactive electronic devices. Herein, a self-powered hybrid coder (SHC) based on TENG is reported to encode two action parameters of touch and press, which can be used as a smart interface for human-machine interaction. The top-down hollow structure of the SHC, not only constructs a compositing mode to generate stable touch and press signals but also builds a hybrid coding platform for generating action codes in synergy mode. When a finger touches or presses the SHC, Morse code and Gray code can be transmitted for text information or remote control of electric devices. This self-powered coder is of reference value for designing an alternative human-machine interface and having the potential to contribute to the next generation of highly integrated portable smart electronics.

Ultrasound as a clean, efficient, and cheap technique gains special attention in wastewater treatment. Ultrasound alone or coupled with hybrid processes have been widely studied for the treatment of pollutants in wastewater. Thus, it is essential to conduct a review about the research development and trends on this emerging technique. This work presents a bibliometric analysis of the topic associated with multiple tools such as Bibliometrix package, CiteSpace, and VOSviewer. The literature sources from 2000 to 2021 were collected from Web of Science database, and the data of 1781 documents were selected for bibliometric analysis in respect to publication trends, subject categories, journals, authors, institutions, as well as countries. Detailed analysis of keywords in respect to co-occurrence network, keyword clusters, and citation bursts was conducted to reveal the research hotspot and future directions. The development of the topic can be divided into three stages, and the rapid development begins from 2014. The leading subject category is Chemistry Multidisciplinary, followed by Environmental Sciences, Engineering Chemical, Engineering Environmental, Chemistry Physical, and Acoustics, and there exists difference in the publications of different categories. Ultrasonics Sonochemistry is the most productive journal (14.75 %). China is the leading country (30.26 %), followed by Iran (15.67 %) and India (12.35 %). The top 3 authors are Parag Gogate, Oualid Hamdaoui, and Masoud Salavati-Niasari. There exists close cooperation between countries and researchers. Analysis of highly cited papers and keywords gives a better understanding of the topic. Ultrasound can be employed to assist various processes such as Fenton-like process, electrochemical process, and photocatalysis for degradation of emerging organic pollutants for wastewater treatment. Research topics in this field evolve from typical studies on ultrasonic assisted degradation to latest studies on hybrid processes including photocatalysis for pollutants degradation. Additionally, ultrasound-assisted synthesis of nanocomposite photocatalysts receives increasing attention. The potential research directions include sonochemistry in pollutant removal, hydrodynamic cavitation, ultrasound-assisted Fenton or persulfate processes, electrochemical oxidation, and photocatalytic process.

Wireless wearable sweat analysis devices can monitor biomarkers at the molecular level continuously and in situ, which is highly desired for personalized health care. The miniaturization, integration, and wireless operation of sweat sensors improve the comfort and convenience while also bringing forward new challenges for power supply technology. Herein, a wireless self-powered wearable sweat analysis system (SWSAS) is designed that effectively converts the mechanical energy of human motion into electricity through hybrid nanogenerator modules (HNGMs). The HNGM shows stable output characteristics at low frequency with a current of 15 mA and a voltage of 60 V. Through real-time on-body sweat analysis powered by HNGM, the SWSAS is demonstrated to selectively monitor biomarkers (Na+ and K+ ) in sweat and wirelessly transmit the sensing data to the user interface via Bluetooth.

The endogenous electric field (EF) generated by transepithelial potential difference plays a decisive role in wound reepithelialization. For patients with large or chronic wounds, negative-pressure wound therapy (NPWT) is the most effective clinical method in inflammation control by continuously removing the necrotic tissues or infected substances, thus creating a proproliferative microenvironment beneficial for wound reepithelialization. However, continuous negative-pressure drainage causes electrolyte loss and weakens the endogenous EF, which in turn hinders wound reepithelialization. Here, an electrogenerative dressing (EGD) is developed by integrating triboelectric nanogenerators with NPWT. By converting the negative-pressure-induced mechanical deformation into electricity, EGD produces a stable and high-safety EF that can trigger a robust epithelial electrotactic response and drive the macrophages toward a reparative M2 phenotype in vitro. Translational medicine studies confirm that EGD completely reshapes the wound EF weakened by NPWT, and promotes wound closure by facilitating an earlier transition of inflammation/proliferation and guiding epithelial migration and proliferation to accelerate reepithelialization. Long-term EGD therapy remarkably advances tissue remodeling with mature epithelium, orderly extracellular matrix, and less scar formation. Compared with the golden standard of NPWT, EGD orchestrates all the essential wound stages in a noninvasive manner, presenting an excellent prospect in clinical wound therapy.

Flexible sweat sensors have found widespread potential applications for long-term wear and tracking and real-time monitoring of human health. However, the main substrate currently used in common flexible sweat sensors is thin film, which has disadvantages such as poor air permeability and the need for additional wearables. In this Review, the recent progress of sweat sensors has been systematically summarized by the types of monitoring methods of sweat sensors. In addition, this Review introduces and compares the performance of sweat sensors based on thin film and textile substrates such as fiber/yarn. Finally, opportunities and suggestions for the development of flexible sweat sensors are presented by summarizing the integration methods of sensors and human body monitoring sites.

The COVID-19 epidemic seriously threats the human society and provokes the panic of the public. Personal Protective Equipment (PPE) are widely utilized for frontline health workers to face the ongoing epidemic, especially disposable face masks (DFMs) to prevent airborne transmission of coronavirus. The overproduction and massive utilization of DFMs seriously challenge the management of plastic wastes. A huge amount of DFMs are discharged into environment, potentially induced the generation of microplastics (MPs) owing to physicochemical destruction. The MPs release will pose severe contamination burden on environment and human. In this review, environmental threats of DFMs regarding to DFMs fate in environment and DFMs threats to aquatic and terrestrial species were surveyed. A full summary of recent studies on MPs release from DFMs was provided. The knowledge of extraction and characterizations of MPs, the release behavior, and potential threats of MPs derived from DFMs was discussed. To confront the problem, feasible strategies for control DFMs pollution were analyzed from the perspective of source control and waste management. This review provides a better understanding the threats, fate, and management of DFMs linked to COVID-19 pandemic.

Abstract Advances in implantable bioelectronics for the nervous system are reinventing the stimulation, inhibition, and sensing of neuronal activity. These efforts promise not just breakthrough treatments of several neurological and psychiatric conditions but also signal the beginning of a new era of computer‐controlled human therapeutics. Batteries remain the major power source for all implanted electrical neuromodulation devices, which impairs miniaturization and necessitates replacement surgery when the battery is drained. Triboelectric nanogenerators (TENGs) have recently emerged as an innovative power solution for self‐powered, closed loop electrical neurostimulation devices. TENGs can leverage the biomechanical activities of different body organs to sustainably generate electricity for electrical neurostimulation. This review features advances in TENGs as they pave the way for self‐sustainable closed loop neurostimulation. A comprehensive review of TENG research for the neurostimulation of brain, autonomic, and somatic nervous systems is provided. The direction of growth of this field, publication trends, and modes of TENG in implantable bioelectronics are also discussed. Finally, an insightful outlook into challenges facing self‐sustainable neuromodulators to reach clinical practice is provided, and solutions for neurological maladies are proposed.

Water-soluble nonconjugated polymer nanoparticles (PNPs) with strong fluorescence emission were prepared from hyperbranched poly(ethylenimine) (PEI) and d-glucose via Schiff base reaction and self-assembly in aqueous phase. Preparation of the PEI–d-glucose (PEI-G) PNPs was facile (one-pot reaction) and environmentally friendly under mild conditions. Also, PEI-G PNPs showed a high fluorescence quantum yield in aqueous solution, and the fluorescence properties (such as concentration- and solvent-dependent fluorescence) and origin of intrinsic fluorescence were investigated and discussed. PEI-G PNPs were then used to develop a fluorescent probe for fast, selective, and sensitive detection of nitro-explosive picric acid (PA) in aqueous medium, because the fluorescence can be easily quenched by PA whereas other nitro-explosives and structurally similar compounds only caused negligible quenching. A wide linear range (0.05–70 μM) and a low detection limit (26 nM) were obtained. The fluorescence quenching mechanism was carefully explored, and it was due to a combined effect of electron transfer, resonance energy transfer, and inner filter effect between PA and PEI-G PNPs, which resulted in good selectivity and sensitivity for PA. Finally, the developed sensor was successfully applied to detection of PA in environmental water samples.

A hierarchical, intrafibrillarly mineralized collagen (HIMC) is achieved through a selective mineralization progress in the collagenous gap regions mediated by poly(acrylic acid) with appropriate molecular weight. The associated topographical features directly correlate with nanomechanical heterogeneities of the HIMC to accommodate a broad range of external loads. Moreover, this hierarchically staggered nanostructure provides an optimized microenvironment to improve bone regeneration by instructing host cells.

Studies on the self‐assembly of nanoparticles have been a hot topic in nanotechnology for decades and still remain relevant for the present and future due to their tunable collective properties as well as their remarkable applications to a wide range of fields. The novel properties of nanoparticle assemblies arise from their internal interactions and assemblies with the desired architecture key to constructing novel nanodevices. Therefore, a comprehensive understanding of the interparticle forces of nanoparticle self‐assemblies is a pre‐requisite to the design and control of the assembly processes, so as to fabricate the ideal nanomaterial and nanoproducts. Here, different categories of interparticle forces are classified and discussed according to their origins, behaviors and functions during the assembly processes, and the induced collective properties of the corresponding nanoparticle assemblies. Common interparticle forces, such as van der Waals forces, electrostatic interactions, electromagnetic dipole‐dipole interactions, hydrogen bonds, solvophonic interactions, and depletion interactions are discussed in detail. In addition, new categories of assembly principles are summarized and introduced. These are termed template‐mediated interactions and shape‐complementary interactions. A deep understanding of the interactions inside self‐assembled nanoparticles, and a broader perspective for the future synthesis and fabrication of these promising nanomaterials is provided.

Surface-enhanced Raman scattering (SERS) is expected as a technique that even theoretically detected chemicals at the single molecule level by surface plasmon phenomena of noble metal nanostructures. Insensitivity of detecting Raman weak-intensity molecules and low adsorptivity of gaseous molecules on solid substrates are two main factors hindering the application of SERS in gas detectors. In this manuscript, we demonstrated an operational SERS strategy to detect gaseous Raman weak-intensity aldehydes that have been considered as a biomarker of lung cancer for abnormal content was measured in volatile organic compounds (VOCs) of lung cancer patients. To enhance the adsorption of gaseous molecules, dendritic Ag nanocrystals mimicking the structural feature (dendritic) of moth’s antennae were formed, wherein the existence of numerous cavity traps in Ag dendritic nanocrystals prolonged reaction time of the gaseous molecules on the surface of solid surface through the “cavity-vortex” effect. By the nucleophilic addition reaction with the Raman-active probe molecule p-aminothiophenol (4-ATP) pregrafted on dendritic Ag nanocrystals, the gaseous aldehyde molecules were sensitively captured to detect at the ppb (parts per billion) level. Additionally, the sensitivity of this operational SERS strategy to detection of lung cancer biomarkers was not affected by the humidity, which represented a great potential in fast, easy, cost-effective, and noninvasive recognition of lung malignancies.

Three-dimensional Bi2O3/TiO2 hierarchical composites have been successfully prepared by a two-step hydrothermal method and subsequent calcination. The samples were characterized using XRD, SEM, TEM, EDS, BET and DRS. The measurement results signified that heterojunctions of various morphologies β-Bi2O3 growing on the three-dimensional hierarchical anatase TiO2 nanorods arrays on FTO glass were apparently formed. The morphology of Bi2O3 changed from three-dimension flower-like microstructures to the sphere-like nanoparticles as the Li(OH) dosage increased. The photocatalytic results showed that all samples exhibited much higher photocatalytic activities than that of pure Bi2O3 and TiO2 (P25) in photocatalytic degradation of methyl blue (MB) under visible-light irradiation. Whereas BTL4 sample exhibited the highest photoactivity with increasing the dosage of Li(OH) to 2 mmol. Furthermore, the absorption edge of the Bi2O3/TiO2 series composites displayed a broad-spectrum photoabsorption from UV to visible-light compared with the individual component. The as-synthesized Bi2O3/TiO2 composites possessed excellent photocatalytic activity and outstanding recyclability. The enhanced photocatalytic efficiency was mainly attributed to the Bi2O3/TiO2 p-n heterojunctions and hierarchical nanostructure. The recombination of photogenerated electron–hole pairs was efficiently suppressed by the Bi2O3/TiO2 p-n heterojunctions.

Oxygen evolution reaction (OER) is a pivotal step for many sustainable energy technologies, and exploring inexpensive and highly efficient electrocatalysts is one of the most crucial but challenging issues to overcome the sluggish kinetics and high overpotentials during OER. Among the numerous electrocatalysts, metal-organic frameworks (MOFs) have emerged as promising due to their high specific surface area, tunable porosity, and diversity of metal centers and functional groups. It is believed that combining MOFs with conductive nanostructures could significantly improve their catalytic activities. In this study, an MXene supported CoNi-ZIF-67 hybrid (CoNi-ZIF-67@Ti3C2Tx) was synthesized through the in-situ growth of bimetallic CoNi-ZIF-67 rhombic dodecahedrons on the Ti3C2Tx matrix via a coprecipitation reaction. It is revealed that the inclusion of the MXene matrix not only produces smaller CoNi-ZIF-67 particles, but also increases the average oxidation of Co/Ni elements, endowing the CoNi-ZIF-67@Ti3C2Tx as an excellent OER electrocatalyst. The effective synergy of the electrochemically active CoNi-ZIF-67 phase and highly conductive MXene support prompts the hybrid to process a superior OER catalytic activity with a low onset potential (275 mV vs. a reversible hydrogen electrode, RHE) and Tafel slope (65.1 mV∙dec−1), much better than the IrO2 catalysts and the pure CoNi-ZIF-67. This work may pave a new way for developing efficient non-precious metal catalyst materials.

Abstract Tendon injuries disrupt the balance between stability and mobility, causing compromised functions and disabilities. The regeneration of mature, functional tendons remains a clinical challenge. Here, we perform transcriptional profiling of tendon developmental processes to show that the extracellular matrix-associated protein periostin (Postn) contributes to the maintenance of tendon stem/progenitor cell (TSPC) functions and promotes tendon regeneration. We show that recombinant periostin (rPOSTN) promotes the proliferation and stemness of TSPCs, and maintains the tenogenic potentials of TSPCs in vitro. We also find that rPOSTN protects TSPCs against functional impairment during long-term passage in vitro. For in vivo tendon formation, we construct a biomimetic parallel-aligned collagen scaffold to facilitate TSPC tenogenesis. Using a rat full-cut Achilles tendon defect model, we demonstrate that scaffolds loaded with rPOSTN promote endogenous TSPC recruitment, tendon regeneration and repair with native-like hierarchically organized collagen fibers. Moreover, newly regenerated tendons show recovery of mechanical properties and locomotion functions.

Microelectronics, as indispensable tools in clinics, can monitor physiological signals, treat diseases, and promote human health. An efficient and uninterrupted energy supply is key to the application of implanted and wearable devices. Traditional energy supply systems typically rely on batteries and connections to external power sources; however, the inconvenience of charging, limited working life of the battery, and the risk of reoperation limit their applications, and meanwhile prompt investigation of self-driven, long-term power supplies. The nanogenerator, as an ideal power supply, collects biomechanical energy from physiological activities such as muscle movement, heartbeat, respiration, gastric peristalsis, and performs electrical signal conversion for detection of physiological/pathological indicators, cardiac pacing, nerve stimulation, tissue repair, and weight control. Here, we review the design of nanogenerators and their biomedical applications, which may inspire future development of self-powered medical devices.

Respiratory sensing provides a simple, non-invasive, and efficient way for medical diagnosis and health monitoring, but it relies on sensors that are conformal, accurate, durable, and sustainable working. Here, a stretchable, multichannel respiratory sensor inspired by the structure of shark gill cleft is reported. The bionic shark gill structure can convert transverse elastic deformation into longitudinal elastic deformation during stretching. Combining the optimized bionic shark gill structure with the piezoelectric and the triboelectric effect, the bionic shark gill respiratory sensor (BSG-RS) can produce a graded electrical response to different tensile strains. Based on this feature, BSG-RS can simultaneously monitor the breathing rate and breathing depth of the human body accurately, and realize the effective recognition of the different human body's breathing state under the supporting software. With good stretchability, wearability, accuracy, and long-term stability (50,000 cycles), BSG-RS is expected to be applied as self-powered smart wearables for mobile medical diagnostic analysis in the future.

Advanced oxidation processes (AOPs) are promising techniques for treatment of wastewater containing organic pollutants. MXenes as a new class of two-dimensional transition metal carbides exhibit unique characteristics and attract considerable attention as heterogeneous Fenton-like catalysts. This work provides a review on the Fenton-like degradation of organic pollutants using MXene-based materials. The synthesis methods of MXenes is described, as well as the representative properties of MXenes. The research advances on Fenton-like degradation of organic pollutants are summarized from the perspective of peroxide-based system, persulfate-based system, photo-Fenton system, and sono-Fenton system. The catalyst design, catalytic performance, and reaction mechanism of various catalysts are depicted in details. Additionally, the effects of process factors on catalytic performance are discussed. Challenges and perspectives of MXene-based catalysts for removal of organic pollutants are also discussed. Current researches prove the promising application of MXenes as potential Fenton-like catalysts. This work shed lights on the application of MXene materials in Fenton-like processes for future researches. • MXenes as Fenton-like catalysts for removal of organic pollutants gains growing attention. • The progress on synthesis methods and properties of MXenes is summarized. • The catalyst Cu/FeNPs@PC is magnetic and has good stability and reusability. • The catalytic performance and reaction mechanism of MXene catalysts are discussed in details. • Challenges and perspectives of MXene-based catalysts for removal of organic pollutants are depicted.

Engineering a complete, physiologically functional, periodontal complex structure remains a great clinical challenge due to the highly hierarchical architecture of the periodontium and coordinated regulation of multiple growth factors required to induce stem cell multilineage differentiation. Using biomimetic self-assembly and microstamping techniques, we construct a hierarchical bilayer architecture consisting of intrafibrillarly mineralized collagen resembling bone and cementum, and unmineralized parallel-aligned fibrils mimicking periodontal ligament. The prepared biphasic scaffold possesses unique micro/nano structure, differential mechanical properties, and growth factor-rich microenvironment between the two phases, realizing a perfect simulation of natural periodontal hard/soft tissue interface. The interconnected porous hard compartment with a Young's modulus of 1409.00 ± 160.83 MPa could induce cross-arrangement and osteogenic differentiation of stem cells in vitro, whereas the micropatterned soft compartment with a Young's modulus of 42.62 ± 4.58 MPa containing abundant endogenous growth factors, could guide parallel arrangement and fibrogenic differentiation of stem cells in vitro. After implantation in critical-sized complete periodontal tissue defect, the biomimetic bilayer architecture potently reconstructs native periodontium with the insertion of periodontal ligament fibers into newly formed cementum and alveolar bone by recruiting host mesenchymal stem cells and activating the transforming growth factor beta 1/Smad3 signaling pathway. Taken together, integration of self-assembly and microstamping strategies could successfully fabricate a hierarchical bilayer architecture, which exhibits great potential for recruiting and regulating host stem cells to promote synergistic regeneration of hard/soft tissues.

Converting CO2 into high-value-added chemicals by artificial photosynthesis technology effectively solves environmental problems and energy shortages. Nevertheless, it remains challenging to improve CO2 conversion rates due to low photo-utilization and rapid electron-hole recombination. In this study, we successfully synthesized direct Z-scheme ZnIn2S4/BaTiO3 heterojunction structure by a hydrothermal method. Specifically, compared with previous studies of various heterojunction catalysts, ZnIn2S4/BaTiO3 heterojunction structure achieved a remarkably high yield of 105.89 μmol g-1 h-1, increasing 2.55 and 3.62-fold over the individual performance of ZnIn2S4 and BaTiO3, respectively. Our investigation of photocatalytic mechanism suggest that the improved photocatalytic CO2 reduction performance can be attributed to the synergistic effects of the piezoelectric effect and Z-scheme electron transfer mechanism. These effects can synergistically enhance space charge separation and retain photogenerated electrons, thereby facilitating a more efficient CO2 reduction process. Consequently, this innovative piezoelectric effect-assisted Z-scheme heterojunction demonstrates immense potential to offer a novel strategy for addressing CO2 reduction challenges and advancing sustainable energy development.

Abstract Nanoscale replication of the hierarchical organization of minerals in biogenic mineralized tissues is believed to contribute to the better mechanical properties of biomimetic collagen scaffolds. Here, an intrafibrillar nanocarbonated apatite assembly is reported, which has a bone‐like hierarchy, and which improves the mechanical and biological properties of the collagen matrix derived from fibril‐apatite aggregates. A modified biomimetic approach is used, which based on the combination of poly(acrylic acid) as sequestration and sodium tripolyphosphate as templating matrix‐protein analogs. With this modified dual‐analog‐based biomimetic approach, the hierarchical association between collagen and the mineral phase is discerned at the molecular and nanoscale levels during the process of intrafibrillar collagen mineralization. It is demonstrated by nanomechanical testing, that intrafibrillarly mineralized collagen features a significantly increased Young's modulus of 13.7 ± 2.6 GPa, compared with pure collagen (2.2 ± 1.7 GPa) and extrafibrillarly‐mineralized collagen (7.1 ± 1.9 GPa). Furthermore, the hierarchy of the nanocarbonated apatite assembly within the collagen fibril is critical to the collagen matrix's ability to confer key biological properties, specifically cell proliferation, differentiation, focal adhesion, and cytoskeletal arrangement. The availability of the mineralized collagen matrix with improved nanomechanics and cytocompatibility may eventually result in novel biomaterials for bone grafting and tissue‐engineering applications.

To enhance the stability in humidity is very crucial to hybrid organic-inorganic lead halide perovskites in a broad range of applications. This report describes a coating stratergy of perovskite nanocrystals via polymethylmethacrylate-introduced ligand-assisted reprecipitation, using the interactions between the Pb cations on the surface of perovskite nanocrystals and the functional ester carbonyl groups in polymethylmethacrylate framework. The hydrophobic framework shields the open metal sites of hybrid organic-inorganic lead halide perovskites from being attacked by water, effectively retarding the diffusion of water into the perovskite nanocrystals. The as-prepared films demonstrate high resistance to heat and moisture. Additionally, the introduction of polymethylmethacrylate into ligand-assisted reprecipitation can effectively control the bulk precipitation and promote the stability of the perovskite solution.

The ozonation of acid red 18 (AR18) wastewater was investigated in an integrated process consisting of O3/Ca(OH)2 system and a newly-developed micro bubble gas-liquid reactor. The effects of operating parameters such as Ca(OH)2 dosage, reactor pressure, liquid phase temperature, initial dye concentration and inlet ozone concentration on decolorization and mineralization (TOC removal) were studied in order to know the ozonation performance of this new integrated process. The decolorization and TOC removal efficiency increased with increasing inlet ozone concentration and increasing Ca(OH)2 dosage before 2 g/L, as well as decreasing initial dye concentration. The optimum Ca(OH)2 dosage should exceed Ca(OH)2 solubility in liquid phase. The reactor pressure and liquid phase temperature have little effects on the decolorization and TOC removal efficiency. When Ca(OH)2 dosage exceeded 3 g/L, the decolorization and TOC removal of AR 18 almost reached 100% at 6 and 25 min, respectively. The intensification mechanism of Ca(OH)2 assisted ozonation was explored through the determination of CO32− and SO42− ions formed in the liquid phase and analysis of the precipitated substances. The mechanism for Ca(OH)2 intensified mineralization of dye solution is the simultaneous removal of CO32− ions, as hydroxyl radical scavengers, due to the presence of Ca2+ ions. Results indicated that the proposed new integrated process is a high efficient ozonation process for persistent organic wastewater treatment.

In this work, series of TiO2/WO3 hierarchical hollow sphere were fabricated by a simple one-pot method. XRD, SEM, TEM, XPS, and UV–vis DRS were carried out to systematically investigated the structure and properties of the samples with varying loadings of TiO2. And their photocatalytic activity was evaluated by photodegradation of malachite green under visible light irradiation. The results demonstrated that all the as-prepared TiO2/WO3 microspheres showed enhanced photodegradation efficiency compared to pure WO3 and TiO2 under visible light irradiation. The increasement of photocatalytic performance could be attributed to the efficient charge separation across the TiO2/WO3 heterostructure interface and highly effective utilization of visible light. Finally, a plausible mechanism of enhanced photodegradation activity upon the TiO2/WO3 heterojunctions has been proposed based on experimental results.

Extensive bone defect repair remains a clinical challenge, since ideal implantable scaffolds require the integration of excellent biocompatibility, sufficient mechanical strength and high biological activity to support bone regeneration. The inorganic nanomaterial-based therapy is of great significance due to their excellent mechanical properties, adjustable biological interface and diversified functions. Calcium–phosphorus compounds, silica and metal-based materials are the most common categories of inorganic nanomaterials for bone defect repairing. Nano hydroxyapatites, similar to natural bone apatite minerals in terms of physiochemical and biological activities, are the most widely studied in the field of biomineralization. Nano silica could realize the bone-like hierarchical structure through biosilica mineralization process, and biomimetic silicifications could stimulate osteoblast activity for bone formation and also inhibit osteoclast differentiation. Novel metallic nanomaterials, including Ti, Mg, Zn and alloys, possess remarkable strength and stress absorption capacity, which could overcome the drawbacks of low mechanical properties of polymer-based materials and the brittleness of bioceramics. Moreover, the biodegradability, antibacterial activity and stem cell inducibility of metal nanomaterials can promote bone regeneration. In this review, the advantages of the novel inorganic nanomaterial-based therapy are summarized, laying the foundation for the development of novel bone regeneration strategies in future.

Converting the mechanical energy of human motion into electricity is considered an ideal energy supply solution for portable electronics. However, low-frequency human movement limits conversion efficiency of conventional energy harvesting devices, which is difficult to provide sustainable power for portable electronic devices. Herein, a fitness gyroscope nanogenerator (fg-NG) based on a triboelectric nanogenerator (TENG) and electromagnetic generator (EMG) is developed that can convert low-frequency wrist motion into high-frequency rotation by using the frequency up-conversion effect of the gyroscope. Remarkably, the fg-NG can reach a rotational speed of over 8000 rpm by hand, increasing the frequency by more than 280 times. The fg-NG can continuously and stably output a current of 17 mA and a voltage of 70 V at frequency of 220-230 Hz. The fg-NG is demonstrated to consistently power a hygrothermograph, smart bracelet, and mobile phone. Also, it can be applicated to a self-powered intelligent training system, showing its immense application potential in portable electronics and wireless Internet of Things devices.

Exploitation of heterogeneous catalysts with high activity, stability and reusability gains increasing worldwide attention due to the tremendous demand for purification of dye wastewater. Copper/iron bimetallic catalysts have been proven to be powerful for persulfate activation to generate reactive radical species. Copper/iron nanoparticles loaded onto porous carbon (Cu/[email protected]) was innovatively designed and used as catalyst for peroxymonosulfate (PMS) activation. Cu/[email protected] manifests high catalytic activity for dye degradation over a wide pH range (4.0–10.0). Under conditions of 0.2 g/L catalyst, PMS 0.15 g/L and pH 4.8, nearly complete degradation (98.4%) of Rhodamine B occurs after 18 min. The rate constant is between 0.0946 and 0.1911 min−1 depending on initial solution pH. Mixed dyes can be efficiently degraded verified by UV–vis spectra and color variation of dye solution. Cu/[email protected] has good stability, magnetism, and reusability for recycling. A synergistic effect of promoting Cu2+/Cu+ and Fe3+/Fe2+ cycle is probability ascribed to the enhanced catalytic activity. The mechanism of catalytic degradation of dyes involves radical species (SO4-• and •OH) and non-radical pathways including 1O2 and mediated electron transfer. This work provides insights into rational design of binary metal catalysts that apply to treatment of dye wastewater.

Abstract Artificial intelligence‐enhanced skin‐like sensors based on flexible nanogenerators have been widely used in physiological signal acquisition, artificial organ, sensory simulation, human movement status recognition, and other biomedical related fields due to their excellent biocompatibility, comfortable wearing experience, high sensing accuracy, and low power consumption. In this paper, the working principle, evolution process, and several established general strategies of artificial intelligence‐enhanced skin‐like sensors are summarized in detail. More importantly, this paper further reviews several recent important advances on artificial intelligence enhanced skin‐like sensor, and systematically analyzes and compares these works according to their principles and application directions. In the discussion section, we also list the current concerns of stress adaptation, stretchability–conductivity, algorithm optimization, function integration, and propose potential solutions to these problems. We hope that the deep integration of artificial intelligence and flexible nanogenerators can bring more enlightenment to the progress of biomedical engineering in the future.

Abstract Electrical stimulation (ES), as one of the physical therapy modalities for tumors, has attracted extensive attention of researchers due to its promising efficacy. With the continuous development of material science, nanotechnology, and micro/nano processing techniques, novel electroactive nanomaterials and delicately designed devices have emerged to realize innovative ES therapies, which provide more possibilities and approaches for tumor treatment. Meanwhile, exploring the molecular biological mechanisms underlying different ES modalities affecting tumor cells and their immune microenvironment is also an unresolved hotspot emerging from the current biomedical engineering research. Focusing on the above research interests, in this review, we systematically summarized the effects of different ES parameters on the subcellular structure of tumor cells and the tumor immune microenvironment (TIME) in conjunction with the involved signaling pathways. In addition, we also reviewed the latest progress in novel self‐powered devices and electroactive nanomaterials for tumor therapy. Finally, the prospects for the development of electrostimulation tumor therapy are also discussed, bringing inspiration for the development of new physical therapy strategies in the future.

Macrophages are involved mainly in the balance between inflammation and tenogenesis during the healing process of tendinopathy. However, etiological therapeutic strategies to efficiently treat tendinopathy by modulating macrophage state are still lacking. In this study, we find that a small molecule compound Parishin-A (PA) isolated from Gastrodia elata could promote anti-inflammatory M2 macrophage polarization by inhibiting gene transcription and protein phosphorylation of signal transducers and activators of transcription 1. Local injection or sustained delivery of PA by mesoporous silica nanoparticles (MSNs) could almost recover the native tendon's dense parallel-aligned collagen matrix in collagenase-induced tendinopathy by modulating macrophage-mediated immune microenvironment and preventing heterotopic ossification. Especially, MSNs decrease doses of PA, frequency of injection and yield preferable therapeutic effects. Mechanistically, intervention with PA could indirectly inhibit activation of mammalian target of rapamycin to repress chondrogenic and osteogenic differentiation of tendon stem/progenitor cells by influencing macrophage inflammatory cytokine secretion. Together, pharmacological intervention with a natural small-molecule compound to modulate macrophage status appears to be a promising strategy for tendinopathy treatment.

Catalytic therapy based on piezoelectric nanoparticles has become one of the effective strategies to eliminate tumors. However, it is still a challenge to improve the tumor delivery efficiency of piezoelectric nanoparticles, so that they can penetrate normal tissues while specifically aggregating at tumor sites and subsequently generating large amounts of reactive oxygen species (ROS) to achieve precise and efficient tumor clearance. In the present study, we successfully fabricated tumor microenvironment-responsive assembled barium titanate nanoparticles (tma-BTO NPs): in the neutral pH environment of normal tissues, tma-BTO NPs were monodisperse and possessed the ability to cross the intercellular space; whereas, the acidic environment of the tumor triggered the self-assembly of tma-BTO NPs to form submicron-scale aggregates, and deposited in the tumor microenvironment. The self-assembled tma-BTO NPs not only caused mechanical damage to tumor cells; more interestingly, they also exhibited enhanced piezoelectric catalytic efficiency and produced more ROS than monodisperse nanoparticles under ultrasonic excitation, attributed to the mutual extrusion of neighboring particles within the confined space of the assembly. tma-BTO NPs exhibited differential cytotoxicity against tumor cells and normal cells, and the stronger piezoelectric catalysis and mechanical damage induced by the assemblies resulted in significant apoptosis of mouse breast cancer cells (4T1); while there was little damage to mouse embryo osteoblast precursor cells (MC3T3-E1) under the same treatment conditions. Animal experiments confirmed that peritumoral injection of tma-BTO NPs combined with ultrasound therapy can effectively inhibit tumor progression non-invasively. The tumor microenvironment-responsive self-assembly strategy opens up new perspectives for future precise piezoelectric-catalyzed tumor therapy.

Abstract The conversion of CO 2 into chemical fuels, which can be stored and utilized through photocatalysis, represents an effective, environmentally friendly, and sustainable means to address both environmental concerns and energy shortages. CO 2 , as a stable oxidation product, poses challenges for reduction through light energy alone, necessitating the use of catalysts. Thus, a crucial aspect of CO 2 photocatalytic reduction technology lies in the development of effective photocatalysts. Based on the basic principle of PCRR (photocatalytic CO 2 reduction reaction), the review provides a detailed introduction to the core issues in PCRR process, including the relationship between band gap and catalyst reduction performance, effective utilization of photogenerated carriers, product selectivity, and methods for product analysis. Then, the recent research progresses of various photocatalysts are reviewed in the form of research examples combined with the above basic principles. Finally, this review summarizes and provides insights into the effective techniques for enhancing the photocatalytic activity of CO 2 , while also offering future prospects in this field.

Abstract Ionically conductive fibers have promising applications; however, complex processing techniques and poor stability limit their practicality. To overcome these challenges, we proposed a stress-induced adaptive phase transition strategy to conveniently fabricate self-encapsulated hydrogel-based ionically conductive fibers (se-HICFs). se-HICFs can be produced simply by directly stretching ionic hydrogels with ultra-stretchable networks (us-IHs) or by dip-drawing from molten us-IHs. During this process, stress facilitated the directional migration and evaporation of water molecules in us-IHs, causing a phase transition in the surface layer of ionic fibers to achieve self-encapsulation. The resulting sheath-core structure of se-HICFs enhanced mechanical strength and stability while endowing se-HICFs with powerful non-contact electrostatic induction capabilities. Mimicking nature, se-HICFs were woven into spider web structures and camouflaged in wild environments to achieve high spatiotemporal resolution 3D depth-of-field sensing for different moving media. This work opens up a convenient route to fabricate stable functionalized ionic fibers.

A series La-doped WO3/SrTiO3 heterojunctions photocatalyst were successfully prepared using solvothermal method. The as-fabricated heterostructures composite included La-doped WO3 fluff spheres tightly grew on the surface of SrTiO3 cubic particles. The crystallanity, structural, morphological and optical features of the catalysts were characterized using several techniques including XRD, XPS, SEM, TEM UV−vis and HRTEM. The photocatalytic activity of the heterojunction was evaluated by the photocatalytic degradation of methyl orange (MO) under visible-light irradiation. The influence of La doping and SrTiO3 molar ratio on heterojunctions photocatalysts was investigated. Among the as-prepared photocatalysts, the LWS50 sample exhibited the highest photocatalytic activity, almost 100% MO were completely decomposed within 75 min under visible light irradiation (λ > 420 nm). Compared with the pure WO3 and SrTiO3, the enhancement of photocatalytic activity was mainly attributed to the three-dimensional hierarchical structure and the effectively transfer and separation of photogenerated electron–hole pairs in La doped WO3 and SrTiO3 heterojunctions

Class XIX myosin (Myo19) is a vertebrate-specific unconventional myosin, responsible for the transport of mitochondria. To characterize biochemical properties of Myo19, we prepared recombinant mouse Myo19-truncated constructs containing the motor domain and the IQ motifs using the baculovirus/Sf9 expression system. We identified regulatory light chain (RLC) of smooth muscle/non-muscle myosin-2 as the light chain of Myo19. The actin-activated ATPase activity and the actin-gliding velocity of Myo19-truncated constructs were about one-third and one-sixth as those of myosin-5a, respectively. The apparent affinity of Myo19 to actin was about the same as that of myosin-5a. The RLCs bound to Myo19 could be phosphorylated by myosin light chain kinase, but this phosphorylation had little effect on the actin-activated ATPase activity and the actin-gliding activity of Myo19-truncated constructs. Using dual fluorescence-labeled actin filaments, we determined that Myo19 is a plus-end-directed molecular motor. We found that, similar to that of the high-duty ratio myosin, such as myosin-5a, ADP release rate was comparable with the maximal actin-activated ATPase activity of Myo19, indicating that ADP release is a rate-limiting step for the ATPase cycle of acto-Myo19. ADP strongly inhibited the actin-activated ATPase activity and actin-gliding activity of Myo19-truncated constructs. Based on the above results, we concluded that Myo19 is a high-duty ratio molecular motor moving to the plus-end of the actin filament.

In this work, multiple heterojunction Ag/Bi/BiOCl0.8Br0.2 photocatalysts with novel porous micro-flower structure were fabricated via a facile one-step solvothermal route and characterized systematically. The TEM and HRTEM images clearly showed the heterogeneous nanostructures at the interface between Ag/Bi and BiOCl0.8Br0.2. The as-prepared Ag/Bi/BiOCl0.8Br0.2 composites displayed a strong optical absorption in the region of 250–1500 nm, especially in the unexploited near infrared region which accounts for most of the sunlight. The multiple heterojunction photocatalyst exhibited an outstanding photocatalytic activity for the degradation of Rhodamine B under the UV, visible and NIR light irradiation, respectively. The highly enhanced photocatalytic activity was attributed to the synergistic effects, including the reduced band gap, the surface plasmon resonance effect, efficient charge separation of photo-generated electron-holes. On the basis of the radical species trapping experiments, the holes and superoxide radicals were confirmed to be the mainly active species involved in the degradation of Rhodamine B under the NIR light irradiation. This study provides a novel strategy for designing highly performance plasmonic photocatalysts under the whole solar light irradiation.

To improve the utilization efficiency of solar energy and separation of photogenerated carries, a novel three-dimensional (3D) WO3-x/Bi/BiOCl hierarchical heterostructures with broad spectrum responsive photocatalytic activity have been fabricated through a facile solvothermal technique. The influences of varying loading of WO3-x on the physical performances of the as-obtained composites were systematically characterized by X-ray diffraction, scanning electron microscope, transmission electron microscopy, X-ray photoelectron spectroscopy, optical absorbance, photoluminescence and specific surface areas. The WO3-x/Bi/BiOCl displayed a strong optical absorption from 250 to 2500 nm, and showed the superior photocatalytic performance in degradation of rhodamine B (RhB) than that of individual components. Among the as-prepared samples, the sample S24 with the appropriate content of WO3-x displayed the best photocatalytic performance, which can photodegrade RhB with the efficiency of 100%, 100% and 96% under the UV light within 8 min, visible light within 3 min and near-infrared light within 120 min exposure, respectively. Furthermore, a plausible mechanism of the RhB degradation on WO3-x/Bi/BiOCl photocatalysts under the near-infrared light irradiation was proposed according to the photocatalytic activity and radical species trapping experiments.

To design functional nanomaterials for biomedical applications, the challenge for scientists is to gain further understanding of their unique toxicological properties. Nonspecific adhesion of proteins and endocytosis are considered to be the major biotoxic sources of imaging nanoprobes. Here, we fabricated ultrathin gadolinium oxide (Gd2O3) nanocoils with a low Young's modulus, which provides transformable properties in solution. The spatial configurational freedom of ultrathin nanocoils induces the steric repulsion to the nonspecific adsorption of proteins that, in turn, suppresses cellular uptake and thus improves their biocompatibility. The larger number of exposed surface gadolinium atoms of the ultrathin nanocoils provided enhanced T1 magnetic resonance (MR) imaging contrast with high signal activation. Such nanocontrast agents were applied to in vivo MR bioimaging to achieve prolonged circulation lifetime. The improved biocompatibility by transformable Gd2O3 nanocoils could open up a new perspective toward the design and construction of various nano-biomedicines in the future.

Abstract Osteoinductive synthetic biomaterials for replacing autografts can be developed by mimicking bone hierarchy and surface topography for host cell recruitment and differentiation. Until now, it has been challenging to reproduce a bone‐like staggered hierarchical structure since the energy change underlying synthetic pathways in vitro is essentially different from that of the natural process in vivo. Herein, a bone‐like hierarchically staggered architecture is reproduced under thermodynamic control involving two steps: fabrication of a high‐energy polyacrylic acid‐calcium intermediate and selective mineralization in collagenous gap regions driven by an energetically downhill process. The intermediate energy interval could easily be adjusted to determine different mineralization modes, with distinct morphologies and biofunctions. Similar to bone autografts, the staggered architecture offers a bone‐specific microenvironment for stem cell recruitment and multidifferentiation in vitro, and induces neo‐bone formation with bone marrow blood vessels by host stem cell homing in vivo. This work provides a novel perspective for an in vitro simulating biological mineralization process and proof of concept for the clinical application of smart biomaterials.

Carbonate aquifers probably constitute the most important thermal water resources in non-volcanic areas, and are characteristic of great energy potential and easier production as the most ideal targets for development in the future. The thermal waters in the aquifers within Southeast Chongqing (SEC) of China occur in an extensive region with an area of 198,000 km2, which are mainly hosted in the Cambrian and Ordovician carbonate-evaporite rocks. The thermal waters are mainly in pristine conditions and their genesis has not yet been fully understood. The occurrence of thermal waters in SEC is closely related to the presence of deep-seated faults which constitute pathways for the hydrothermal circulation. In this study, an investigation of water major ions and environmental isotopes from 14 hot springs and three drilled wells was carried out to examine their hydrogeochemical evolution and to estimate reservoir temperature. The thermal waters have outflow temperatures from 19 to 54.2 °C. They are divided into two hydrochemical groups with the Yushan Fault as a boundary: Group A, located to the west of the fault, are characterized by facies of chloride sodium waters with higher TDS; Group B, to the east of the fault, are more complicated sulfate-bicarbonate-chloride alkaline-earth waters with lower TDS. The hydrochemical processes such as dissolution of carbonate, gypsum and/or anhydrite, and halite, the common ion effect, and dedolomitization are evident based on the major ions and δ34SSO4 and δ18OSO4. The δ18O and δD compositions of the thermal waters suggest a meteoric recharge in a relatively wetter and colder climatic condition. The silica geothermometers show that the average reservoir temperatures are 63 ± 18 °C for Group A, and 82 ± 15 °C for Group B. The corresponding average reservoir depths are estimated to be 2.5 ± 0.7 km for Group A, and 3.2 ± 0.7 km for Group B. The corrected 14C ages of the thermal waters average at 14.8 ka BP, corresponding to the late Pleistocene. A conceptual circulation model is proposed for the thermal waters. Driven by gravity of topographic gradients, the percolating groundwater circulates at a specific depth, reaching a higher temperature and interacting with the host carbonate with imbedded evaporitic minerals (gypsum and/or anhydrite, and additional halite for Group A) to be saline deep-seated thermal fluids. The fluids rise along faults and emerge at the surface as thermal springs. The slow renewability rate of the thermal aquifers highlights the importance of assessing the resource before groundwater exploitation and extraction.

For the catalytic reductive amination of carbonyl compounds, the kind of active metal used is the most important factor determining the catalytic selectivity in heterogeneous catalysis systems. However, a detailed understanding of the intrinsic mechanism is still lacking. In this work, by evaluating the reductive amination of butyraldehyde and the hydrogenation reaction of secondary imine on various metal catalysts, the competitive hydrogenation reactions of primary imine and secondary imine are proven to be the key factors determining primary amine selectivity. DFT calculations verify that Co, Ni, and Ru, rather than Fe, Rh, Pd, and Pt, tend to show high primary amine selectivity in terms of adsorption energy and activation energy. It should be noted that the different stable adsorption modes of secondary imine on metal surfaces (C&N adsorption mode on Fe, Co, Ni, Ru, and Rh, and N adsorption mode on Pd and Pt) are key factors affecting these reaction characteristics. Moreover, microkinetic simulation proves that the coadsorption of NH3 improves primary amine selectivity on Co, Ni, and Ru surfaces. Combining the theoretical and experimental results, it is clearly verified that the active metal determines the catalytic selectivity of the primary amine by affecting the competitive hydrogenation reactions of the primary imine and secondary imine.

Sodium-chemistry based batteries with high theoretical capacity, high energy density, and low cost have caught tremendous attention for replacing traditional lithium-ion batteries. Unfortunately, sodium-chemistry based batteries suffer numerous pressing issues, including high chemical activity, sluggish reaction kinetics, dissolution/shuttling of intermediates, and severe sodium metal dendrite growth, which severely restricts their development and further commercialization. MXene are considered as promising candidates for resolving these above problems due to their superior intrinsic properties including two-dimensional (2D) morphology, mechanical flexibility, excellent electrical conductivity, tunable surface characteristics, and large surface area. This review summarizes the recent progress on sodium-chemistry based batteries using MXene architectures, discussing the synthesis approaches of MXene materials and working principles of various sodium-chemistry based batteries. Then, several typical cases of sodium-chemistry based batteries are analyzed based on representative works from the viewpoints of design concepts, fabrication approaches, engineering strategies, structural and composition tuning, specific functions of diverse MXenes, and electrochemical performance. Lastly, the remaining challenges/issues and future prospects of sodium-chemistry based batteries are presented and discussed. It is believed that this review may provide new insights for the development of MXene architectures and their practical utilization in sodium-chemistry based energy storage devices.

Infected bone defects are a major challenge in orthopedic treatment. Native bone tissue possesses an endogenous electroactive interface that induces stem cell differentiation and inhibits bacterial adhesion and activity. However, traditional bone substitutes have difficulty in reconstructing the electrical environment of bone. In this study, we develop a self-promoted electroactive mineralized scaffold (sp-EMS) that generates weak currents via spontaneous electrochemical reactions to activate voltage-gated Ca2+ channels, enhance adenosine triphosphate-induced actin remodeling, and ultimately achieve osteogenic differentiation of mesenchymal stem cells by activating the BMP2/Smad5 pathway. Furthermore, we show that the electroactive interface provided by the sp-EMS inhibits bacterial adhesion and activity via electrochemical products and concomitantly generated reactive oxygen species. We find that the osteogenic and antibacterial dual functions of the sp-EMS depend on its self-promoting electrical stimulation. We demonstrate that in vivo, the sp-EMS achieves complete or nearly complete in situ infected bone healing, from a rat calvarial defect model with single bacterial infection, to a rabbit open alveolar bone defect model and a beagle dog vertical bone defect model with the complex oral bacterial microenvironment. This translational study demonstrates that the electroactive bone graft presents a promising therapeutic platform for complex defect repair.

The modified coffee-ring effect is used to self-assemble highly uniform, long-range-ordered Ag nanowire arrays. As the oriented Ag nanowire arrays provide excellent membranes for surface-enhanced Raman scattering, the molecular mechanism of cell adhesion and growth is systematically studied and well understood. This work has important significance for life science research.

Abstract As the development in self‐assembly of nanoparticles, a main question is directed to whether the supercrystalline structure can facilitate generation of collective properties, such as coupling between adjacent nanocrystals or delocalization of exciton to achieve band‐like electronic transport in a 3D assembly. The nanocrystal surfaces are generally passivated by insulating organic ligands, which block electronic communication of neighboring building blocks in nanoparticle assemblies. Ligand removal or exchange is an operable strategy for promoting electron transfer, but usually changes the surface states, resulting in performance alteration or uncontrollable aggregation. Here, 3D, supercompact superparticles with well‐defined superlattice domains through a thermally controlled emulsion‐based self‐assembly method is fabricated. The interparticle spacing in the superparticles shrinks to ≈0.3 nm because organic ligands lie prone on the nanoparticle surface, which are sufficient to overcome the electron transfer barrier. The ordered and compressed superstructures promote coupling and electronic energy transfer between CdSSe quantum dots (QDs). Therefore, the acquired QD superparticles exhibit different optical properties and enhanced photoelectric activity compared to individual QDs.

A ruthenium-doped, collagen-based carbon scaffold (Ru-CCS), as a highly efficient electrocatalyst for the HER, is achieved<italic>via</italic>a biomimetic approach.

Bi2WO6/TiO2 heterojunction photocatalysts with two different microstructures were controllably fabricated via a facile two-step synthetic route. XRD, XPS, SEM, TEM, BET-surface, DRS, PL spectra, photoelectrochemical measurement (Mott-Schottky), and zeta-potential analyzer were employed to clarify structural and morphological characteristics of the obtained products. The results showed that Bi2WO6 nanoparticles/nanosheets grew on the primary TiO2 nanorods. The TiO2 nanorods used as a synthetic template inhibit the growth of Bi2WO6 crystals along the c-axis, resulting in Bi2WO6/TiO2 heterostructure with one-dimensional (1D) morphology. The photocatalytic properties of Bi2WO6/TiO2 heterojunction photocatalysts were strongly dependent on their shapes and structures. Compared with bare Bi2WO6 and TiO2, Bi2WO6/TiO2 composite have stronger adsorption ability and better visible light photocatalytic activities towards organic dyes. The Bi2WO6/TiO2 composite prepared in EG solvent with optimal Bi:Ti ratio of 2:12 (S-TB2) showed the highest photocatalytic activity, which could totally decompose Rhodamine B within 10 min upon irradiation with visible light (λ > 422 nm), and retained the high photocatalytic performance after five recycles, confirming its stability and practical usability. The results of PL indicated that Bi2WO6 and TiO2 could combine well to form a heterojunction structure which facilitated electron–hole separation, and lead to the increasing photocatalytic activity.

At present, the surface modification of perovskites by solvent treatment has become the most effective way to improve the performance of planar perovskite solar cells. Here, phthalocyanine nickel as an additive was introduced into the anti-solvent chlorobenzene to form a mixed anti-solvent. Prior to completion of the perovskite crystals, a mixed anti-solvent was infiltrated into the perovskite surface to improve the interfacial contact of the perovskite with the hole-transporting layer. This method improved the crystal quality of the perovskite film, thus enhanced the charge transfer efficiency, and suppressed the recombination of carriers effectively. The perovskite solar cell constructed with this perovskite films treated by the optimal concentration of nickel phthalocyanine in the anti-solvent solution yielded a power conversion efficiency of 19.18% and the filling factor of 74.38% under 100 mW cm−2 illuminations.

The oxygen–containing functional groups of graphene oxide (GO) play an important role in hydrogen storage. In addition to the contribution of the specific surface area and micro–porous porosity, the interactions of the functional groups with H2 molecules are also an important factor in the aspect of GO hydrogen storage. This paper explores the oxygen–containing functional groups affecting the hydrogen physisorption capacity of the GO and reduced graphene oxide (RGO) by experimental H2 adsorption measurement and theoretical calculation. Experimental results related to synthesis of GO and RGO via the modified Hummer's method and characterized using SEM, TEM, SAED, XRD, FTIR, TGA and Raman spectroscopy, are presented. Compared with RGO, the surface and edge of GO contain a large amount of oxygen–containing functional groups and its specific surface area is slightly increased through BET measurement. GO is found to exhibit better H2 uptake capacity (0.74 wt%) as compared to RGO (0.47 wt%) at 77 K and pressure up to 10 bars. The density functional theory is applied to optimize the adsorption configurations of H2 on the surface of samples. Calculation results show that the adsorption on the GO can be promoted by surface functional groups epoxy, hydroxyl, carboxyl and carbonyl; the enhancement of hydroxyl is greater than other species on the surface and the maximal adsorption energy reaches to −0.112 eV which is about twice that of graphene. As indicated above, these functional groups could be formed easily on the graphene surface, which not only enhance specific surface area and interlayer spacing, but also significantly change the location of carbons, redistributing the electron structure of graphene and enhancing the adsorption energy.

Piezoelectric nanomaterials are functional materials that hold a great promise for the nanoscale conversion of mechanical energy and electrical signals. Owing to their excellent electromechanical dependence, catalytic activity, and response sensitivity, piezoelectric nanomaterials are widely used in energy harvesting, sensors, actuators, resonators, and medical detectors. Nano‐piezoelectric materials exhibit unique electrical and chemical activities in the field of biomedical engineering, such as disease diagnosis and treatment. The working principles, device‐design mechanics, and classification of piezoelectric nanomaterials are systematically reviewed. Then, the recent advances in piezoelectric nanomaterials and their applications in tissue regeneration, antitumor/antibacterial therapy, cell force detection, controlled drug release, and pathological/physiological parameter monitoring are highlighted. Finally, the perspectives on the development of future smart piezoelectric nanomaterials, and how they can serve as a building block to inspire and impact the development of novel diagnosis and treatment applications, are presented.

Cardiomyocyte-based therapeutic strategy is a promising approach to treat myocardial injury; however, the prognostic power of this approach is currently limited by the immaturity of cardiomyocytes. Here, a flexible self-powered implantable electrical stimulator based on the triboelectric nanogenerator (TENG) was proposed to induce the maturation of cardiomyocytes by generating an electric field on the interdigitated electrode. The results showed that the TENG-based self-powered stimulator significantly promoted the maturation of neonatal rat cardiomyocytes (NRCMs) in vitro by increasing the expression of connexin 43, α-actinin, and c-troponin T. In addition, electrical stimulation also improved sarcomere organization and fracture formation, and significantly increased the intracellular Ca2+ levels, Ca2+ transient rate, and Ca2+ peak amplitudes of cardiomyocytes. TENG was also shown to be driven by the breath of rats and the heartbeat of rabbits, suggesting it could be used as an implantable medical electronic device for electrically promoting the maturation of neonatal cardiomyocytes. This work develops a TENG-based self-powered implantable medical device, which provides important technical support for clinical treatment of myocardial defects and restoration of the physiological function of cardiac tissue.

With the development of the Internet of Things era, smart wearable devices have gradually entered people’s daily life, and these devices have provided great convenience to human beings in terms of real-time detection of human health and information transmission. Smart wearable electronic devices have also been gradually developed from smart bracelets, smart watches, and smart glasses into fibers or textiles. Organic thin-film transistor (OTFT) as a key component of flexible electronic devices has an important role in signal amplification, signal filtering, signal transmission, signal reception, and storage. In this article, we introduce the recent progress of OTFT based on 2-D film and 1-D fiber from the substrate of OTFT and focus on the preparation method and performance of OTFT based on 1-D fiber from the conductive fiber. In addition, some practical applications of OTFT sensors in human health detection are introduced. Index Electronic textiles, organic thin-film transistor (OTFT), smart wearables.

Food-derived carbon quantum dots (CQDs) can relatively easily be synthesized and chemically manipulated for a broad spectrum of biomedical applications. However, their toxicity may hinder their actual use. Here, Spinacia oleracea-derived CQDs i.e., CQD-1 and CQD-2, were synthesized by means of different shredding methods and followed by a microwave-assisted hydrothermal approach. Subsequently, these CQDs were analyzed in vitro and in an in vivo mice model to test their biocompatibility and potential use as bioimaging agents and for activation of osteogenic differentiation.When comparing CQD-1 and CQD-2, it was found that CQD-1 exhibited 7.6 times higher photoluminescent (PL) emission intensity around 411 nm compared to CQD-2. Besides, it was found that the size distribution of CQD-1 was 2.05 ± 0.08 nm, compared with 2.14 ± 0.04 nm for CQD-2. Upon exposure to human bone marrow-derived mesenchymal stem cells (hBMSCs) in vitro, CQD-1 was endocytosed into the cytoplasm and significantly increased the differentiation of hBMSCs up to 10 μg mL−1 after 7 and 14 days. Apparently, the presence of relatively low doses of CQD-1 showed virtually no toxic or histological effects in the major organs in vivo. In contrast, high doses of CQD-1 (1 mg mL-1) caused cell death in vitro ranging from 35% on day 1 to 80% on day 3 post-exposure, and activated the apoptotic machinery and increased lymphocyte aggregates in the liver tissue. In conclusion, S. oleracea-derived CQDs have the potential for biomedical applications in bioimaging and activation of stem cells osteogenic differentiation. Therefore, it is postulated that CQD-1 from S. oleracea remains potential prospective material at appropriate doses and specifications.

Conventional perovskites solar cells have been afflicted with serious hysteresis effect, resulting in difficult to accurate the real power conversion efficiency of devices. Here, an additive of KSCN was applied to enhance the crystallization of perovskite crystals, increased the perovskite grain size, reduced the density of defects, led to a high-quality thin film. Correspondingly, devices with a power conversion efficiency of 19.23% and fill factor of 75.08% under AM 1.5G 100 mW cm−2 irradiation were achieved. In comparison with typical devices, these solar cells showed improved photovoltaic performance, stability, reproducibility, carrier mobility and lower hysteresis effect, which was attributed to the high-quality thin film. Our work demonstrated a facile and effective approach for fabricating solar cells with no-hysteresis and high-performance towards commercialization.

Full-spectrum-responsive Ag/Bi/BiOCl hierarchical micro-flower heterojunction via a facile in-situ solvothermal route. The samples were characterized by XRD, SEM, TEM, XPS, BET and UV–Vis–NIR. The in-situ incorporation of Bi into the semiconductor BiOCl nanosheets with oxygen vacancies could be regulated efficiently by the Ag+ additive content. The samples presented a strong optical absorption in the whole region of 200–2400 nm and displayed excellent photocatalytic performance over the full solar spectrum. The presence of metallic Ag, Bi and oxygen vacancies strengthened the light absorption and promoted the charge-carrier separation of BiOCl, resulted in higher photocatalytic activity than that of pure BiOCl and P25 under UV and visible light irradiation. Furthermore, the photocatalytic responsiveness of Ag/Bi/BiOCl was successfully extended to the NIR region. On the basis of the radical species trapping experiments, h+, •O2−, and •OH were confirmed to be the mainly active species involved in the degradation of organic pollutants in the NIR region.

Tissue engineering has enabled development of nanostructured collagen scaffolds to meet current challenges in regeneration of lost bone. In this study, extrafibrillarly-mineralized and intrafibrillarly-mineralized collagen scaffolds were fabricated separately by a conventional crystallization method and a biomimetic, bottom-up crystallization method. Atomic force microscopy (AFM) was employed to examine the nanotopography and nanomechanics of the mineralized collagen scaffolds. The in vitro cell responses to the surface of the mineralized collagen scaffolds were analyzed by laser scanning microscope and field emission scanning electron microscopy. AFM imaging showed that these two mineralized collagen scaffolds exhibited different nanostructure, including the size, morphology and location of the apatites in collagen fibrils. The nanomechanical testing demonstrated that the intrafibrillarly-mineralized collagen scaffold, with bone-like hierarchy, featured a significantly increased Young's modulus compared with the extrafibrillarly-mineralized collagen scaffold in both dry and wet conditions. However, these two mineralized collagen scaffolds had a similar thermal behavior. From the cell culture experiments, the intrafibrillarly-mineralized collagen scaffold showed higher cell proliferation and alkaline phosphatase activity than the extrafibrillarly-mineralized collagen scaffold. The utmost significance of this study is that the nanostructure of the mineralized collagen scaffolds can affect the initial cell adhesion, morphology and further osteogenic potential. The present study will help us to fabricate novel biomaterials for bone grafting and tissue engineering applications.

Iron precursors are used to tune the structure and FTS performance of graphene oxide supported iron catalysts.

Hydrogen storage properties of Li-decorated graphene oxides containing epoxy and hydroxyl groups are studied by using density functional theory. The Li atoms form Li4O/Li3OH clusters and are anchored strongly on the graphene surface with binding energies of −3.20 and −2.84 eV. The clusters transfer electrons to the graphene substrate, and the Li atoms exist as Li+ cations with strong adsorption ability for H2 molecules. Each Li atom can adsorb at least 2H2 molecules with adsorption energies greater than −0.20 eV/H2. The hydrogen storage properties of Li-decorated graphene at different oxidation degrees are studied. The computations show that the adsorption energy of H2 is −0.22 eV/H2 and the hydrogen storage capacity is 6.04 wt% at the oxidation ratio O/C = 1/16. When the O/C ratio is 1:8, the storage capacity reaches 10.26 wt% and the adsorption energy is −0.15 eV/H2. These results suggest that reversible hydrogen storage with high recycling capacities at ambient temperature can be realized through light-metal decoration on reduced graphene oxides.

The carbon deposition and permeation on nickel surfaces were investigated from thermodynamic and kinetic aspects by using density functional theory (DFT), ab initio atomic thermodynamics, and classical molecular dynamics (MD) simulations. The resulting evolution of particle morphology, crystalline composition, and barriers of typical surface reactions were explored. The exposed facets of Ni show distinct thermodynamic and kinetic sensitivity to carbon deposition and permeation. Thermodynamically, with increasing carbon chemical potential, the carbon coverage and the surface energies of facets change, which leads to the evolving of the equilibrium morphology of Ni particles, favoring higher exposure of the (111) surface. MD simulations show that carbon deposition triggers surface reconstruction at high temperature, and the rate of carbon permeation increases with temperature. Kinetically, the permeation on most Ni surfaces is facile at relatively low temperature except for (111), which shows a threshold temperature of 800 K. Evaluation of a representative probe reaction (methane activation) shows that the reaction barrier and reaction energy increase with the degree of carbide formation, while no general trend is observed for the reverse reaction (CH3 + H). Our study provides an atomic level insight into the carbon deposition process on Ni surfaces and indicates that it is crucial to consider carbon deposition and permeation to understand the particle morphology, crystalline composition, and catalytic performances of Ni.

The structure-activity relationship is a universal principle in nature that relates the structure of a material to its physiochemical properties and behaviors. A classic example of this relationship involves elemental carbon, which exhibits unique properties derived from different atomic arrangements (e.g., diamond, graphite, fullerene, carbon nanotube, and graphene). Nanoparticles also demonstrate this principle because they can effectively serve as artificial atoms that self-assemble into superstructures. These superstructures naturally obey the structure-activity relationship and can be adjusted by regulation of various structural parameters. Additionally, the self-assembled superstructures have collective properties that significantly differ from the properties of original monodisperse particles and bulk materials. Thus, customized functional materials can be designed according to the structure-activity collective properties of these superstructures to create nanodevices with the desired physical and chemical properties. In this review, we discuss the influences of structural parameters, such as particle spacing, size distribution, lattice structure, and order degree, on the properties of superstructures. The application statuses of self-assembly materials are then presented from the perspectives of various scientific and engineering fields (e.g., optics, electrics, catalysis, and biomedicine), along with future development prospects.

Bone injuries are common in clinical practice. Given the clear disadvantages of autologous bone grafting, more efficient and safer bone grafts need to be developed. Bone is a multidirectional and anisotropic piezoelectric material that exhibits an electrical microenvironment; therefore, electrical signals play a very important role in the process of bone repair, which can effectively promote osteoblast differentiation, migration, and bone regeneration. Piezoelectric materials can generate electricity under mechanical stress without requiring an external power supply; therefore, using it as a bone implant capable of harnessing the body's kinetic energy to generate the electrical signals needed for bone growth is very promising for bone regeneration. At the same time, devices composed of piezoelectric material using electromechanical conversion technology can effectively monitor the structural health of bone, which facilitates the adjustment of the treatment plan at any time. In this paper, the mechanism and classification of piezoelectric materials and their applications in the cell, tissue, sensing, and repair indicator monitoring aspects in the process of bone regeneration are systematically reviewed.

The low elastic modulus and time-consuming formation process represent the major challenges that impede the penetration of nanoparticle superstructures into daily life applications. As observed in the molecular or atomic crystals, more effective interactions between adjacent nanoparticles would introduce beneficial features to assemblies enabling optimized mechanical properties. Here, a straightforward synthetic strategy is showed that allows fast and scalable fabrication of 2D Ag-mercaptoalkyl acid superclusters of either hexagonal or lamellar topology. Remarkably, these ordered superstructures exhibit a structure-dependent elastic modulus which is subject to the tether length of straight-chain mercaptoalkyl acids or the ratio between silver and tether molecules. These superclusters are plastic and moldable against arbitrarily shaped masters of macroscopic dimensions, thereby opening a wealth of possibilities to develop more nanocrystals with practically useful nanoscopic properties.

The liquid phase of foam systems plays a major role in improving the fluidity of oil, by reducing oil viscosity and stripping oil from rock surfaces during foam-flooding processes. Improving the oil displacement capacity of the foam’s liquid phase could lead to significant improvement in foam-flooding effects. Oil-liquid interfacial tension (IFT) is an important indicator of the oil displacement capacity of a liquid. In this study, several surfactants were used as foaming agents, and polymers were used as foam stabilizers. Foaming was induced using a Waring blender stirring method. Foam with an oil-liquid IFT of less than 10–3 mN/m was prepared after a series of adjustments to the liquid composition. This study verified the possibility of a foam system with both an ultra-low oil-liquid IFT and high foaming properties. Our results provide insight into a means of optimizing foam fluids for enhanced oil recovery.

In this study, layered perovskite HSr2Nb3O10 ultrathin nanosheets (HSNO-ns) was successfully exfoliated within 2 h by a facile microwave-assisted method. Then, HSNO-ns/CdS heterojunction was fabricated through a facile hydrothermal route for deposition of CdS nanoparticles on HSNO-ns. The photocatalytic performances of composites were systematically investigated and discussed by varying the CdS content. The results illustrated that the photocatalytic hydrogen production rate of HSNO-ns were significantly increased by coupled CdS nanoparticles on the HSNO-ns. The optimized HSNO-ns/CdS3 composites without noble metal showed highest photocatalytic activity, which was about 8.38 times and 330 times higher than that of pristine CdS and HSNO-ns, respectively, under the visible light irradiation (≥420 nm) using triethanolamine as sacrificial agent. The enhanced photocatalytic H2 production activity was predominantly attributed to the strong optical absorption capacity, high specific surface area and improved charge carrier separation efficiency. Our present work provides a new pathway into the design of two-dimension nanosheets-based photocatalysts and promotes their practical application in various environmental and energy issues.

Hydrodeoxygenation (HDO) is a promising way to produce the second generation bio-diesel from aliphatic acid based biomass. Compared with the monometallic Ni/SiO2, appropriate introduction of Fe results in the complete conversion of lauric acid and nearly 100% yield of alkane as well as satisfactory stability on conversion. Further study on mechanism shows that the NiFe intermetallic compounds (IMC) catalyst promotes the ratedetermining step, i.e., C11H23COOH → C11H23CHO, which is attributed to the synergistic effect of Ni-Fe bimetallic sites according to the characterization and calculation. For one thing, strong spin polarization enhances the interaction between Fe sites and aliphatic acid, and the subsequent dissociation of C-OH bond indicated by the DOS and transition state analysis. For another, dissociation of H2 on Ni site is promoted because of the higher charge density around Ni in the IMC according to the in-suit FTIR and Bader analysis. However, with the repeated use of the catalyst, the selectivity to alkane decreased gradually, which is ascribed to the oxidation of metal Ni-Fe bimetallic sites. This demonstrates that the reduced Ni-Fe bimetallic sites rather than the oxidized ones are the active phases in the HDO of aliphatic acid to produce alkanes with the NiFe IMC.

In Fischer-Tropsch synthesis (FTS), the cobalt catalyst of hcp phase has higher C5+ and lower CH4 selectivity than fcc phase. However, a detailed explanation of the intrinsic mechanism is still...

Orderly hierarchical structure with balanced mechanical, chemical, and electrical properties is the basis of the natural bone microenvironment. Inspired by nature, we developed a piezocatalytically-induced controlled mineralization strategy using piezoelectric polymer poly-L-lactic acid (PLLA) fibers with ordered micro-nano structures to prepare biomimetic tissue engineering scaffolds with a bone-like microenvironment (pcm-PLLA), in which PLLA-mediated piezoelectric catalysis promoted the in-situ polymerization of dopamine and subsequently regulated the controllable growth of hydroxyapatite crystals on the fiber surface. PLLA fibers, as analogs of mineralized collagen fibers, were arranged in an oriented manner, and ultimately formed a bone-like interconnected pore structure; in addition, they also provided bone-like piezoelectric properties. The uniformly sized HA nanocrystals formed by controlled mineralization provided a bone-like mechanical strength and chemical environment. The pcm-PLLA scaffold could rapidly recruit endogenous stem cells, and promote their osteogenic differentiation by activating cell membrane calcium channels and PI3K signaling pathways through ultrasound-responsive piezoelectric signals. In addition, the scaffold also provided a suitable microenvironment to promote macrophage M2 polarization and angiogenesis, thereby enhancing bone regeneration in skull defects of rats. The proposed piezocatalytically-induced controllable mineralization strategy provides a new idea for the development of tissue engineering scaffolds that can be implemented for multimodal physical stimulation therapy.

Abstract Designing high‐performance and low‐cost electrocatalysts for oxygen evolution reaction (OER) is critical for the conversion and storage of sustainable energy technologies. Inspired by the biomineralization process, we utilized the phosphorylation sites of collagen molecules to combine with cobalt‐based mononuclear precursors at the molecular level and built a three‐dimensional (3D) porous hierarchical material through a bottom‐up biomimetic self‐assembly strategy to obtain single‐atom catalysts confined on carbonized biomimetic self‐assembled carriers (Co SACs/cBSC) after subsequent high‐temperature annealing. In this strategy, the biomolecule improved the anchoring efficiency of the metal precursor through precise functional groups; meanwhile, the binding‐then‐assembling strategy also effectively suppressed the nonspecific adsorption of metal ions, ultimately preventing atomic agglomeration and achieving strong electronic metal‐support interactions (EMSIs). Experimental characterizations confirm that binding forms between cobalt metal and carbonized self‐assembled substrate (Co–O 4 –P). Theoretical calculations disclose that the local environment changes significantly tailored the Co d‐band center, and optimized the binding energy of oxygenated intermediates and the energy barrier of oxygen release. As a result, the obtained Co SACs/cBSC catalyst can achieve remarkable OER activity and 24 h durability in 1 M KOH ( η 10 at 288 mV; Tafel slope of 44 mV dec −1 ), better than other transition metal‐based catalysts and commercial IrO 2 . Overall, we presented a self‐assembly strategy to prepare transition metal SACs with strong EMSIs, providing a new avenue for the preparation of efficient catalysts with fine atomic structures.

Abstract Single layer blue phosphorus (SLBP) is a promising two–dimensional material for nanoelectronic devices, but the electronic structure and hydrogen storage property of modified SLBP received little attention. Li atoms can be strongly bonded on SLBP in a 1:1 Li/P ratio with a binding energy larger than the cohesive energy of bulk Li. The geometric structure of SLBP suggests the 3s3p orbitals of the P atom hybridize in sp3 manner. But our analyses show that the 3s and 3p orbitals form bonding and antibonding orbitals respectively. The 3s orbitals are fully occupied as they have much lower energies, and the bonding orbitals formed by P 3p are occupied in pure SLBP. The decorated Li atoms transfer their 2s electrons to the antibonding orbital formed by P 3p. The Li atoms exist as +1 cations and they are ionically bonded on SLBP. H2 molecules adsorbed on the Li+ cations are strongly polarized and form strong adsorption. When two H2 are adsorbed on each Li atom decorated at the 1:1 Li/P ratio, the hydrogen storage capacity reaches 9.52 wt% but the H2 molecules are arranged in two layers with the adsorption energy −0.168 eV/H2. When the Li atoms are decorated alternatively on the two sides of the P6 rings with a Li/P ratio of 1:2, each Li atom can absorb two H2 molecules in a single–layer; the hydrogen storage capacity is 5.48 wt% and the adsorption energy reaches −0.227 eV/H2. These results mean the Li–decorated SLBP can work at ambient temperature with high reversible hydrogen storage capacity.

The fluorescent carbon dots (CDs) have found their extensive applications in sensing, bioimaging, and photoelectronic devices. In general terms, the synthesis of CDs is straight-forward, though their subsequent purification can be laborious. Therefore, there is a need for easier ways to generate solid CDs with a high conversion yield. Herein, we used collagen waste as a carbon source in producing solid CDs through a calcination procedure without additional chemical decomposition treatment of the raw material. Considering a mass of acid has destroyed the original protein macromolecules into the assembled structure with amino acids and peptide chains in the commercial extraction procedure of collagen product. The residual tissues were assembled with weak intermolecular interactions, which would easily undergo dehydration, polymerization, and carbonization during the heat treatment to produce solid CDs directly. The calcination parameters were surveyed to give the highest conversion yield at 78%, which occurred at 300°C for 2 h. N and S atomic doping CDs (N-CDs and S-CDs) were synthesized at a similar process except for immersion of the collagen waste in sulfuric acid or nitric acid in advance. Further experiments suggested the prepared CDs can serve as an excellent sensor platform for Fe 3+ in an acid medium with high anti-interference. The cytotoxicity assays confirmed the biosafety and biocompatibility of the CDs, suggesting potential applications in bioimaging. This work provides a new avenue for preparing solid CDs with high conversion yield.

Abstract Messenger RNA (mRNA) vaccines are third‐generation nucleic acid vaccines developed after first‐generation inactivated and live‐attenuated vaccines and second‐generation subunit and viral vector vaccines, characterized by a rapid response to pathogen mutation, simple production process, and high production capacity. The basic mechanism through which mRNA vaccines provide immune protection is the introduction into the body of mRNA expressing a target antigen through a specific delivery system and expression of the corresponding protein in vivo, which stimulates a specific immunological response. Multiple mRNA vaccine platforms against infectious diseases and cancers have shown encouraging results in both animal models and human subjects; in particular, mRNA vaccines against COVID‐19 have been widely adopted around the world. However, the development of mRNA vaccines has not been straightforward. The rapid progress of mRNA vaccines would not have been possible without major recent advances in innate immune sensing and in vivo delivery strategies. Creative research in mRNA design, lipid/polymer/novel nanocarrier development, and coupling to wearable/implantable electrostimulation medical devices may drive the evolution of mRNA vaccines.

In addition to the main reaction, understanding the structure-activity relationship in the side reactions is another important goal for catalysis science. In this work, the catalytic activities and selectivities of various active metals were studied in the reductive amination of furfural (FAL). Compared with Co- and Ni-based catalysts, the excessive hydrogen of furfurylamine (FAM) was found over Ru-based catalysts at much higher reaction temperature (130 vs. 50 °C). Moreover, the evaluation of FAM hydrogenation undoubtedly substantiated the intimate relationship between H2 reaction pressure and catalytic activity. Combining the theoretical and experimental results, it is clearly verified that the active metal determines the excessive hydrogen of FAM by affecting the competitive adsorption of FAM and H on the active sites.

The motivation for making heterometallic compounds stemmed from their emergent synergistic properties and enhanced capabilities for applications. However, the atomically precisely controlled synthesis of heterometallic compounds remains a daunting challenge of the complications that arise when applying several metals and linkers. Herein, a stepwise and controlled method is reported for the accurate addition of second and third metals to homometallic aluminum macrocycles based on the synergistic coordination and hard-soft acid-base theory. These heterometallic compounds showed a good Lewis acid catalytic effect, and the addition of hetero-metals significantly improved the catalytic effect and rate, among that the conversion rate of compound AlOC-133 reached 99.9% within half an hour. This method combines both the independent controllability of stepwise assembly with the universality of one-step methods. Based on the large family of clusters, the establishment of this method paves the way for the controllable and customized molecular-level synthesis of heterometallic materials and creates materials customized for preferential application.

Bone infection poses a major clinical challenge that can hinder patient recovery and exacerbate postoperative complications. This study has developed a bioactive composite scaffold through the co-assembly and intrafibrillar mineralization of collagen fibrils and zinc oxide (ZnO) nanowires (IMC/ZnO). The IMC/ZnO exhibits bone-like hierarchical structures and enhances capabilities for osteogenesis, antibacterial activity, and bacteria-infected bone healing. During co-cultivation with human bone marrow mesenchymal stem cells (BMMSCs), the IMC/ZnO improves BMMSC adhesion, proliferation, and osteogenic differentiation even under inflammatory conditions. Moreover, it suppresses the activity of Gram-negative Porphyromonas gingivalis and Gram-positive Streptococcus mutans by releasing zinc ions within the acidic infectious microenvironment. In vivo, the IMC/ZnO enables near-complete healing of infected bone defects within the intricate oral bacterial milieu, which is attributed to IMC/ZnO orchestrating M2 macrophage polarization, and fostering an osteogenic and anti-inflammatory microenvironment. Overall, these findings demonstrate the promise of the bioactive scaffold IMC/ZnO for treating bacteria-infected bone defects.

Micro-supercapacitors (MSCs) have drawn tremendous attention as promising candidates to power miniaturized portable/wearable electronics, but they still suffer from unsatisfactory electrochemical performance (e.g., insufficient energy density, mediocre rate capability), thus impeding their widespread applications. Here, a synergistic surface and structure engineering strategy achieved by downsizing to quantum dot scale, doping of heteroatoms, and introducing defects and functional groups is proposed to regulate the physicochemical properties of Ti3C2Tx MXene. Encouragingly, the resulting MSCs based on defect-rich nitrogen-doped Ti3C2Tx quantum dots (QDs) possess excellent electrochemical performance as demonstrated by large operating voltage (3.0 V in ionic liquid and 1.0 V in aqueous electrolyte), perfect rectangular CV shape even at 1000 V·s-1, high volumetric capacitance of 33.1 F·cm-3, and superior cycling stability after 10000 cycles. By employing experimental characterizations and density functional theory calculations, the remarkable performance of the MSCs is mainly due to the special chemical states as well as the unique surface and structural features of Ti3C2Tx QDs, which offer abundant active sites, shorten ion diffusion pathways, promote ion/electron transports, and provide enhanced capacitance. This work provides a new strategy for the design of high-performance MSCs and a reference for the applications of MXene QDs in other energy-related fields.

<h2>Summary</h2> A carbon capture and utilization strategy, especially the electrocatalytic CO₂ reduction reaction (eCO₂RR), is a promising option for achieving carbon neutrality and mitigating climate change. However, currently, the electricity employed for the eCO₂RR is mainly derived from gray electricity, and it is often difficult to offset the carbon emissions from power generation of the eCO₂RR, which cannot truly achieve carbon neutrality. To circumvent these issues, a self-powered carbon-neutral system integrating the triboelectric nanogenerator-electromagnetic generator (TENG-EMG) with the eCO₂RR for industrial exhaust gases is constructed. In this system, the TENG-EMG-based composite generator can convert the kinetic energy of industrial flue gases into green electricity. Subsequently, single-atom copper catalysts can efficiently utilize the electricity generated by generators to realize a remarkably high Faraday efficiency for ethanol. In sharp contrast to traditional eCO₂RRs, a self-driven carbon-neutral system can dramatically reduce the costs of generating and transmitting electricity and can truly achieve zero or even negative carbon emissions.

Abstract Wearable electronics with multi‐functionalities are widely utilized in various domains, including everyday living, healthcare, military training, and sports. Advances in flexible electronic technology, new materials, artificial intelligence technology, and sensor technology have accelerated the rapid development of smart wearable devices toward multifunctional and highly integrated trends. The energy supply technology based on the human‐body energy harvesting method endows wearable, multifunctional electronic devices with sustainable, renewable, and self‐powered characteristics, which proposes a solution strategy for the function expansion and energy supply of wearable devices. Herein, this paper discusses recent research on various methods of harvesting human body energy and wearing parts respectively, focusing on the new materials, structures, and processes involved in the representative studies, as well as the impact on energy harvesting and output, and functional applications. Furthermore, the challenges and obstacles faced in the creation of wearable multifunctional devices based on human self‐sufficiency and propose solution strategies to propel them in order to advance the creation of the next wave of intelligent wearable technology are also discussed.

Single-layer blue phosphorus (SLBP) has displayed charming photoelectric performances, but its property in hydrogen storage is not outstanding due to the weak interactions. To expand the application of SLBP in hydrogen storage, we attempt to screen SLBP-based materials with stable structures and strong polarity using density functional theory by doping lightweight elements and grafting alkali metal atoms. The simulation results indicate that the lightweight elements (B, C, N, O and F) doped SLBP systems have more stable structures due to the strong orbital interaction than pure SLBP, and exhibit electron deficient characteristics. Compared to the pure SLBP, the H2 adsorption energies of the doped systems improve and range from 0.05 to 0.09 eV, but it still cannot meet the requirements of ideal hydrogen storage. Therefore, the lightweight element doped SLBP systems are further grafted by Li atom. Under the synergistic effect of doping lightweight elements and grafting Li atoms, H2 molecules are strongly polarized, and the corresponding adsorption energies of H2 reach to 0.16, 0.26, 0.28, 0.30, and 0.10 eV, respectively. It is worth emphasizing in the C-doped SLBP system that the hydrogen storage capacity of reaches 5.53 wt.% for each Li atom adsorbs one hydrogen molecule and the corresponding adsorption energy is 0.23 eV/H2 when the ratio of C to P atoms increases to 6:26. For each Li atom adsorbs two hydrogen molecules in the same hydrogen storage system, the hydrogen storage capacity reaches 10.48 wt.% with 0.18 eV/H2 adsorption energy. We hope these results can provide theoretical basis and scientific guidance for searching for SLBP-based materials with excellent hydrogen storage performances at ambient temperature.

The polarization of dielectric materials in electric field lags behind the external field and the relaxation losses energy. In this paper, the relaxation characteristics of the fractional models established by using a fractional differential operator (cap-resistor) are analyzed. It is found that the cap-resistor just corresponds to the complex impedance used by Cole brothers to represent the dissipation in the dielectrics, and Cole–Cole equation is a special case of the generalized fractional Maxwell model. The fractional models are used to simulate the dielectric relaxation of liquid crystal cells embedded with Pd nanoparticles. The Cole–Cole plot of the relaxation data shows outspread wings in the low frequency range, and the fractional models can represent the relaxation behavior very well.

Due to the high–efficiency and stable solar–to–hydrogen conversion efficiency, dye–sensitized photocatalytic hydrogen evolution is considered to be one of the ideal ways to solve today's energy and environmental problems. The coupling interaction between sensitization matrix and light–absorbing dye play an important role for the activity of the dye–sensitized photocatalytic hydrogen evolution. In this work, amide–functionalized carbon nanospheres as a new–style sensitization matrix is prepared by a low–cost and uncomplicated two–step liquid phase reactions. Because amide groups on the surface of carbon nanospheres add additional adsorption sites by introducing H–bonding and enhancing coupling interaction between the sensitization matrix and dye molecules, the adsorption capacity of amide–functionalized carbon nanospheres increase 6.7 times compared with bare carbon nanospheres. Based on the material excellent adsorption performance, the Eosin Y dye–sensitized amide–functionalized carbon nanospheres with Pt co–catalyst exhibits high–efficiency activity for H2 generation (607.4 μmol for testing 2 h), which is 14.3 and 6.4 times higher photocatalytic hydrogen evolution activity than Pt and carbon nanospheres with Pt assist. Moreover, the highest apparent quantum efficiency of photocatalyst can reach to 32.9% at 430 nm. The significantly improved photocatalytic hydrogen evolution performance of catalyst could be mainly ascribed to enhance amino groups adsorption active sites, which can fix the light–absorbing dyes on the surface of sensitization matrix and shorten the transmission distance of photogenerated charges.

Abstract A high‐performance electron transport layer (ETL)‐free planar fluorine‐doped tin oxide (FTO)/perovskite/hole‐transport material/Au solar cell was prepared. We revealed that a plasma‐cleaning pretreatment for FTO substrates could significantly improve the quality of perovskite films, leading to the promotion of charge separation, an increase in the electron‐transport rate, and a decrease in the recombination reaction at the FTO/perovskite interface. Finally, the efficiency of the cells was greatly improved. A power conversion efficiency of over 15 % and a fill factor of 0.68 were achieved under AM 1.5G 100 mW cm −2 irradiation without the use of a compact n‐type metal‐oxide blocking layer.

Abstract A broad range of carbon sources have been used to fabricate varieties of carbon quantum dots (CQDs). However, the majority of these studies concern the influence of primary structures and chemical compositions of precursors on the CQDs; it is still unclear whether or not the superstructures of carbon sources have effects on the physiochemical properties of the synthetic CQDs. In this work, the concept of molecular assembly is first introduced into the design of a new carbon source. Compared with the tropocollagen molecules, the hierarchically assembled collagen scaffolds, as a new carbon source, immobilize functional groups of the precursors through hydrogen bonds, electrostatic attraction, and hydrophobic forces. Moreover, the accumulation of functional groups in collagen self‐assembly further promotes the covalent bond formation in the obtained CQDs through a hydrothermal process. Both of these two chemical superiorities give rise to high quality CQDs with enhanced emission. The assembled collagen scaffold‐based CQDs with heteroatom doping exhibit superior stability, and could be further applied as effective fluorescent probes for Fe 3+ detection and cellular cytosol imaging. These findings open a wealth of possibilities to explore more nanocarbons from precursors with assembled superstructures.

<bold>SYW</bold> showed a gelation-induced emission of light, and its gel showed a reversible response of its emission to trifluoroacetic acid vapour, with a detection limit of 3.2 ppb.

Photocatalytic hydrogen evolution (PHE) is a promising way to generate hydrogen driven by solar light. Noble metallic Pt is usually used as a co–catalyst to catalyze this reaction. However, Pt can also act as an active center for H2 and O2 recombination reverse reaction, which results in the low photocatalytic efficiency for H2 generation. Herein, the H2 and O2 recombination can remarkably be inhibited by incorporating amide–functionalized groups onto graphene surface and edge, which act as the oxygen adsorbent site and reduce migration of O2 molecules in the dye–sensitized PHE system. Theoretical studies verify that the adsorption energy of oxygen change remarkable due to orbital hybridization by N 2p in amide group with O 2p in O2 molecule, leading to redistribution the electron structure of graphene, and change of electrical properties of sensitized matrix. By amide–functionalized graphene (AF–RGO), we achieved high H2 evolution activity over AF–RGO/Pt nanohybrid catalyst under visible light irradiation. The quantum efficiency of AF–RGO/Pt (AF–RGO prepared at 140 °C) achieved 36.4% at 430 nm. This superior photocatalytic performance can be attributed to the repression of H2 and O2 recombination and the synergy of electrical properties. This work is helpful to design high active catalyst for solar hydrogen generation.

Pyrolysis oil is a promising material for renewable energy through a hydrogenation process. However, the polymerization, initiated especially by pyrolysis oil water-soluble fraction (PS), is a big hurdle to hydrogenation. The types and structures of the polymerization chemicals, their polymerization mechanisms are very important for upgrading pyrolysis oil. This study firstly compared the polymerization rates of water-soluble fraction (PS) and water-insoluble fraction (PL) by accelerating aging fresh PS and PL at different temperatures (80 °C, 90 °C, 100 °C and 110 °C) for 24 h and at 110 °C for different durations (12 h, 24 h, 36 h, 48 h and 60 h), respectively. The thermogravimetric and differential thermogravimetry analysis results showed that PS polymerized much more rapidly than PL. Then, PS polymerization was further investigated by evaluating the changes in its physical properties (water content, viscosity and element content) and chemical compositions (gas chromatography and liquid chromatogram) before and after aging. The results showed that hydroxy aldehydes and ketones (especially glycoaldehyde, hydroxyacetone and levoglucosan), dicarbonyl compounds (especially succindialdehyde) and α, β-unsaturated carbonyl compounds (especially 3-methyl-2-cyclopenten-1-one and dehydrate resultants of some aldol condensation products) were mainly responsible for PS polymerization.

The production of valuable chemicals and fuels from pyrolysis oil or its fractions is an appealing strategy. Glycolic acid and formic acid have widespread applications in the food processing and chemical industries. Here we investigated the feasibility of generating glycolic acid and formic acid from pyrolysis oil water-soluble fraction (WS) using H3PMo12O40·nH2O catalyst. Firstly, in order to clarify the possible reaction pathways in WS oxidation process, levoglucosan and glycolaldehyde, two principal substances present in WS, were respectively used as the substrate for oxidation to the two acids. Secondly, in order to find the optimum reaction conditions, the conversion of a mixture of levoglucosan and glycolaldehyde, as a surrogate of WS, was investigated under various process conditions. Thirdly, the actual WS was tested under the optimum reaction conditions, and the result gave a glycolic acid yield of 15.7% and a formic acid yield of 27.4%. Owing to the negative effects of phenols, cyclopentanones and furans in it, the result was different from that obtained with model mixture as substrate, in terms of the total yield of the two acids and the selectivity of glycolic acid over formic acid. Among various purifying methods of WS, activated carbon adsorption was effective, which resulted in a glycolic acid yield of 31.7% and a formic acid yield of 23.6%, making the conversion result of processed WS close to the conversion result of model mixture.