Engineering the regulation strategy of active sites to explore the intrinsic mechanism over single‑atom catalysts in electrocatalysis

The development of efficient and sustainable energy sources is a crucial strategy for addressing energy and environmental crises, with a particular focus on high-performance catalysts. Single-atom catalysts (SACs) have attracted significant attention because of their exceptionally high atom utilization efficiency and outstanding selectivity, offering broad application prospects in energy development and chemical production. This review systematically summarizes the latest research progress on SACs in five key electrochemical reactions: hydrogen evolution reaction, oxygen reduction reaction, carbon dioxide reduction reaction, nitrogen reduction reaction, and oxygen evolution reaction. Initially, a brief overview of the current understanding of electrocatalytic active sites in SACs is provided. Subsequently, the electrocatalytic mechanisms of these reactions are discussed. Emphasis is placed on various modification strategies for SAC surface-active sites, including coordination environment regulation, electronic structure modulation, support structure regulation, the introduction of structural defects, and multifunctional site design, all aimed at enhancing electrocatalytic performance. This review comprehensively examines SAC deactivation and poisoning mechanisms, highlighting the importance of stability enhancement for practical applications. It also explores the integration of density functional theory calculations and machine learning to elucidate the fundamental principles of catalyst design and performance optimization. Furthermore, various synthesis strategies for industrial-scale production are summarized, providing insights into commercialization. Finally, perspectives on future research directions for SACs are highlighted, including synthesis strategies, deeper insights into active sites, the application of artificial intelligence tools, and standardized testing and performance requirements.

Supramolecular assembly of multi-purpose tissue engineering platforms from human extracellular matrix

Recapitulating the biophysical and biochemical complexity of the extracellular matrix (ECM) remains a major challenge in tissue engineering. Hydrogels derived from decellularized ECM provide a unique opportunity to replicate the architecture and bioactivity of native ECM, however, they exhibit limited long-term stability and mechanical integrity. In turn, materials assembled through supramolecular interactions have achieved considerable success in replicating the dynamic biophysical properties of the ECM. Here, we merge both methodologies by promoting the supramolecular assembly of decellularized human amniotic membrane (hAM), mediated by host-guest interactions between hAM proteins and acryloyl-β-cyclodextrin (AcβCD). Photopolymerization of the cyclodextrins results in the formation of soft hydrogels that exhibit tunable stress relaxation and strain-stiffening. Disaggregation of bulk hydrogels yields an injectable granular material that self-reconstitutes into shape-adaptable bulk hydrogels, supporting cell delivery and promoting neovascularization. Additionally, cells encapsulated within bulk hydrogels sense and respond to the biophysical properties of the surrounding matrix, as early cell spreading is favored in hydrogels that exhibit greater susceptibility to applied stress, evidencing proper cell-matrix interplay. Thus, this system is shown to be a promising substitute for native ECM in tissue repair and modelling.

Endogenous dual-responsive and self-adaptive silk fibroin-based scaffold with enhancement of immunomodulation for skull regeneration

Despite the current biomaterials (e.g. titanium mesh and polyether ether ketone) have been applied to clinical skull repair, the limitations on mechanical match, shape adaptability, bioactivity and osteointegration have greatly limited their clinical application. In this work, we constructed a water and inflammatory microenvironment dual-responsive self-adaptive silk fibroin-magnesium oxide-based scaffold with the matrix metalloproteinase-2-responsive gelatin-methacryloyl-interleukin-4 (IL-4) coating, which presented good mechanical compliance, quickly shape matching and intraoperative reprocessability. With the capability of responding to an acute inflammation microenvironment followed by a triggered on-demand release of the IL-4, the combination of immunoactive IL-4 and Mg2+ co-ordinately facilitated metabolic reprogramming by suppressing glycolysis, promoting mitochondrial oxidative phosphorylation and modulating adenosine 5'-monophosphate-activated protein kinase (AMPK) signalling pathways in macrophages, resulting in significantly facilitating M2 macrophage activation. During the stage of tissue remodelling, the sustained release of Mg2+ further promoted macrophage M2 polarization and the expression of anti-inflammatory cytokines, significantly reduced immune response and improved ectopic osteogenesis ability. Meanwhile, the cranial defect models of male rats demonstrated that this scaffold could significantly enhance biomineralized deposition and vascularisation, and achieve good bone regeneration of cranial defects. Overall, the bioactive scaffold provides a promising biomaterial and alternative repair strategy for critical-size skull defect repair.

Topological defects induced intra-tissue heterogeneity of mesenchymal stem cell via regulatory self-organization and differentiation

Currently, in vitro fabrication of intra-tissue heterogeneity remains a critical challenge in development of adult stem cell based tissue engineering. Interestingly, as a typical structure in symmetry-breaking phase transitions, topological defects are extensively presented in biological substances. These topological defects are commonly observed within cell monolayer in vitro and demonstrated to be effective in induction of intra-tissue heterogeneity by regulating cell migration. Nevertheless, their impacts on the behavior of mesenchymal stem cells (MSCs) remain elusive. In this study, micro-grooved substrates were utilized to explore the role of topological defects in regulation of MSCs' self-organization and osteogenic differentiation. The results indicated that topological defects could induce the central aggregates of MSCs at central region of +1 and +1/2 topological defects by modulating centripetal migration. On the contrast, negatively charged topological were able to induce centrifugal migration and further inducing heterogeneous distribution of MSCs. Subsequently, these heterogeneously distributed MSCs were capable of inducing intra-tissue heterogeneity in terms of proliferation, stemness maintenance and osteogenic differentiation via regulatory morphogenesis.

Nanoscale palladium-Mo6S8/carbon nanowires toward efficient electrochemical hydrogen evolution and hydrogen peroxide detection

Chevrel phase (CP) molybdenum sulfides (Mo6S8) have attracted extensive research attention in the field of energy conversion and storage due to their unique electronic structures and rich open channels. However, comprehensive understanding of intrinsic kinetic mechanisms governing the electrocatalytic bi-functional hydrogen evolution reaction (HER) and hydrogen peroxide (H2O2) sensing on CP-based composites is still lacking. Herein, nanosized palladium (Pd) and Mo6S8 particles were assembled in carbon nanowires (C NWs) via electrospinning followed by pyrolysis. The as-obtained novel Pd-Mo6S8/C NWs exhibited excellent performance in terms of a low overpotential of -194 mV at η10 for HER, and an ultrahigh sensitivity of 2231 μA mM-1 cm-2 with a limit of detection of 25 nM for H2O2 sensing. The experimental and theoretical findings demonstrated that Pd and Mo6S8 nanoparticles (NPs) exhibited exceptional catalytic activity and strong electronic interactions. The synergistic effects of these two components could effectively modulate the binding strength of reactants and intermediates on the catalyst surface, ultimately leading to improved electrochemical catalytic performance toward reduction of small molecules. Moreover, verification of the stable tolerance in various environments and good selectivity of the electrocatalyst promoted the further use of Pd-Mo6S8/C NWs-based electrochemical sensing system for sensing additional H2O2 in milk samples, proving the widespread potential of this material for practical applications. This study significantly advances the understanding of nanoscale and bi-functional CP-based composites.

Investigation of the protein corona and biodistribution profile of polymeric nanoparticles for intra-amniotic delivery

When exposed to the biological environment, nanoparticles (NPs) form a protein corona that influences delivery profile. We present a study of protein corona formation and NP biodistribution in amniotic fluid (AF) for poly(lactic-co-glycolic acid) (PLGA) and poly(lactic-acid) (PLA) NPs, with and without polyethylene glycol (PEG), as well as poly(amine-co-ester)-PEG (PACE-PEG) NPs. The presence of surface PEG and polyvinyl alcohol (PVA) were characterized to investigate surfactant role in determining protein corona formation. The surface density of PEG groups demonstrated an inverse correlation with the total amount of protein surface adsorption. All PEGylated NPs exhibited a dense brush conformation and demonstrated higher levels of stability in AF than non-PEGylated NPs. The protein corona composition varied by core polymer, while the amount of protein adsorption varied by PEGylation status. In A549 cells, in vitro cellular association of each NP type correlated with the amount of albumin that was found in the protein corona. In vivo, only PEGylated NPs were able successfully distribute to fetal organs, likely due to the enhanced stability imparted by PEG. PLGA-PEG and PACE-PEG NPs had both high levels of albumin in the protein corona and high biodistribution to the fetal lung, consistent with the association with lung cells in vitro. PLA-PEG NPs distributed exclusively to the fetal bowel, which we propose is associated with known gastrointestinal targeting keratin proteins. By furthering our understanding of polymeric NP behavior in AF, this novel study provides a basis for optimization of intra-amniotic NP delivery systems targeting congenital pulmonary and gastrointestinal diseases.

pH effects on graphene foam capacitance induced by adsorption of 1-pyrenemethylamine

The interfacial capacitance of graphene foam electrodes (Gii-Sens) in contact to aqueous media (determined by electrochemical impedance spectroscopy) is strongly affected by adsorption of 1-pyrenemethylamine (PMA). An order of magnitude increase in capacitance upon adsorption is ascribed predominantly to the quantum capacitance contribution (i.e. changes in the electronic density of states in graphene layers) in response to the cationic adsorbent. A change in capacitance (reversible) is observed as a function of pH. Although likely to be linked to the amine protonation, the change in measured capacitance occurs over a wide range of pH values (approx. linear from pH 2 to pH 12) and could provide a diagnostic capacitance-based tool for pH. Exploratory measurements in pure human serum (with pH adjustment) suggest that the capacitance effect is specific to protons and correlated to pH even in complex sensing media. However, the response of the graphene foam electrode surface is sensitive to the preparation and storage conditions and currently not fully understood.

Boosting ammonium-ion storage of V2O5·nH2O by encapsulating engineering of polyaniline

The design and development of new host materials for ammonium-ion supercapacitors (NH4+-SCs) has been one of the topics of ongoing concern in recent years. Vanadium oxide has always been one of the most eye-catching electrode materials in the field of aqueous NH4+ energy storage. However, in the process of repeated charge/discharge, due to the direct contact with the aqueous electrolyte, vanadium oxide dissolution and structural collapse inevitably appear, and there is also the problem of low intrinsic conductivity, so it is urgent to address these issues. In this work, the conductive polymer polyaniline (PANI) is coated on the surface of V2O5·nH2O (VOH) by a simple hydrothermal method to form V2O5·nH2O@polyaniline (VOH@PANI) nanobelts with core-shell structure to improve the structural endurance and NH4+ storage capacity. The experimental and theoretical calculation results show that the introduction of PANI shells on VOH nanobelts can enhance the structural stability, ion/charge transfer and transport dynamics, thereby improving the NH4+ storage capacity and making it an ideal host material for NH4+-SCs. VOH@PANI core-shell composite has a specific capacitance of 453 F·g-1 at 0.5 A·g-1, far exceeding VOH (271 F·g-1) and PANI (295 F·g-1). The VOH@PANI//active carbon (AC) hybrid supercapacitor (HSC) composed of VOH@PANI cathode and AC anode has good electrochemical performance and practical application value. The technique offers suggestions for strengthening electrical conductivity and preventing structural collapse of other fragile materials.

Enhancement of carbon monoxide catalytic oxidation performance by co-doping silver and cerium in three-dimensionally ordered macroporous Co-based catalyst

Carbon monoxide (CO) catalytic oxidation offers an effective solution for environmental pollutant; however, its progress is limited by sluggish kinetics, and efficient catalysts remain scarce. Herein, we prepared Ag-Ce co-doped three-dimensionally ordered macroporous (3DOM) Co-based catalysts through the synergistic approach of co-doping and morphology control, systematically investigating their CO catalytic oxidation mechanisms. The appropriate amount of Ag-Ce co-doping maintained the original 3DOM structure, promote the mass transfer and diffusion of CO, promoted the redox capacity by increasing the ratio of Co3+ to surface reactive oxygen species (O-/ O2-), achieving low temperature conversion of CO. Specifically, concentration of Co3+ is promoted via Co2+ + Ag+ → Ag0 + Co3+ and then combining the generated the active oxygen specie reduce the CO conversion temperature (Co3+ + O-/ O2- + CO → CO2 + Co2+). Among them 3D-5 %AgCo16Ce1 exhibited a lower activation energy (Ea) and T50, which were only 48.79 KJ mol-1 and 76.8 °C, respectively. Theoretical calculation indicated that the synergistic of co-doped system can lower down the O2 dissociation energy barrier by 0.242 eV compared with 3D-Co16Ce1, thus facilizing the generation of active oxygen species and improving the oxidation kinetic of CO. This work innovated the preparation method of 3DOM co-doped system and provided opportunities to design high-performance heterogeneous catalysts.

Metal effect boosts the photoelectric properties of two-dimentional Dion-Jacobson (3AMPY)(MA)3M4I13 perovskites

Two-Dimentional (2D) Dion-Jacobson (DJ) perovskites are emerging photovoltaic materials due to their excellent rigid structures and improved environmental stability compared to 2D Ruddlesden-Popper (RP) perovskites. Herein, we adopt 3-(aminomethyl)pyridine (3AMPY) as the divalent interlayer spacer to alleviate the toxicity of lead and explore more highly potential DJ alternatives, the optoelectronic and photovoltaic performance of lead-free DJ (3AMPY)(MA)3M4I13 perovskites are investigated by first-principles calculations, where the central metals are considered as Ba, Cd, Cu, Ge, Mg, Mn, Ni, Sn and Zn to replace Pb. Our findings reveal that introducing Mn, Cd, Ni, and Ge can effectively tune the bandgap within the optimal range of 0.90-1.60 eV for solar cell application. Notably, (3AMPY)(MA)3Ni4I13 exhibits the most favorable optical response capacity, with the light-harvesting efficiency maintaining 80 % in the UV-Vis range. (3AMPY)(MA)3Ge4I13 displays the most excellent carrier transport with electron mobility as high as 555.43 cm2 V-1 s-1, exhibiting a great advantage over 2D perovskites. The predicted photovoltaic performance shows that (3AMPY)(MA)3Mg4I13 possesses the largest open circuit voltage (VOC) (2.12 V), (3AMPY)(MA)3Ge4I13 has the highest short circuit current density (Jsc) (38.90 mA/cm2), and (3AMPY)(MA)3Mn4I13 is with the highest power conversion efficiency (PCE) of 22.55 %. The metal substitutions with Cd, Ni, and Ge show promoted photovoltaic potential over (3AMPY)(MA)3Pb4I13. These results form a basis for broadening the potential candidates of this 2D DJ series in photovoltaic perovskite solar cells (PSCs).

Delafossite-embedded Z-scheme heterojunction photocathode with abundant heterointerfaces for boosted photoelectrochemical performance

Layered delafossite, an inherently p-type semiconductor, has emerged as a highly promising photocathode material for photoelectrochemical (PEC) water splitting. However, its PEC performance and scalability are significantly limited by the shortcomings of conventional photoelectrode fabrication techniques, which often involve inferior physical adhesion or require harsh processing conditions. In this study, a CuxO layer is introduced via in-situ oxidation of a copper foam (CF) substrate to achieve embedded anchoring of delafossite CuFeO2 (CFO), thereby developing a robust embedded CF/(CFO@CuxO) photocathode. This configuration features extensive and strong 3D semiconductor/semiconductor heterointerfaces. The embedded structure significantly reduces the carrier diffusion length to the CF, thereby enhancing photocarrier collection efficiency. Additionally, this unique geometric design provides abundant heterointerfaces with all-round contact, promoting efficient carrier separation while strengthening interfacial binding. Theoretical calculations further reveal the formation of a strong built-in electric field and a Z-scheme heterostructure, which facilitate effective photocarrier separation and transfer while maintaining robust redox activity. Remarkably, the photocurrent density of the embedded CF/(CFO@CuxO) photocathode at zero bias is 2.73-fold higher than that of the traditional sandwich-stacked CF/CuxO/CFO photocathode and 21.55-fold higher than that of the original CF/CFO photocathode. Furthermore, the scalability of this approach is demonstrated through the fabrication of a 100 cm2 embedded photocathode. This work presents a scalable and cost-effective nanofabrication technique for robust photoactive films, enabling efficient and stable PEC water splitting.

Delamination of NiFe layered double hydroxides into perforated monolayers for efficient water splitting

The introduction of vacancies can significantly change the coordination and valence states of the catalytic active sites, thereby modulating the electronic structure to promote the oxygen evolution reaction (OER). However, atomic-level vacancy engineering on low-dimensional layered double hydroxides (LDHs) has not been achieved, which could be due to the significant structural damage and/or carbonate (CO32-) contamination occurring during the vacancy creating process. In this study, atomic-scale cation vacancies were generated in LDHs without apparent structure damage and carbonate contamination. Perforated monolayer nanosheets with an utmost exposure of active sites were successfully obtained through a subsequent exfoliation in formamide. Compared to bulk LDHs, the flocculated vacancy-containing nanosheets exhibit a small overpotential of 245 mV at a current density of 10 mA cm-2 and maintain excellent stability at a high current density of 500 mA cm-2. Density functional theory (DFT) calculations indicate that introducing cation vacancies on monolayer NiFe-LDH nanosheets and creating unsaturated Ni-Fe sites can effectively reduce the Gibbs free energy of the OER process. The two-electrode electrolyzer assembled with commercial Pt/C for overall water splitting can operate at a cell voltage as low as 1.50 V to yield a current density of 10 mA cm-2. It also demonstrates long-term stability of 50 h at a large current density of 500 mA cm-2. The current strategy of atomic cation vacancy engineering on monolayer LDHs provides important insights into the design of low-cost LDH-based catalysts toward efficient alkaline water electrolysis and other energy-related applications.

Direct upcycling of highly efficient sorbents for emerging organic contaminants into high energy content supercapacitors

The escalation of anthropogenic activities contributes to the accumulation of chemicals in life-supporting ecosystems and water reserves, while nearly 80% of the global population faces a high risk of water insecurity. Therefore, advanced nanomaterials for environmental remediation and ecosystem preservation are essential. However, their adoption has been slow, mainly due to the need for water treatment strategies that comply with sustainability criteria. This work showcases the efficient removal of emerging pharmaceutical pollutants from water using functionalized graphenes and the direct upcycling of the used sorbents into electrodes for energy storage, without the need for any intermediate treatment. Remarkably, the performance of the repurposed sorbents as supercapacitor electrodes exceeds that of the parent functionalized graphenes by up to 100% in a full cell device. This enhanced performance and cycling stability are attributed to improved charge transport and redox activity induced by the strong adsorption of the pollutants, as supported by theoretical calculations. The findings open avenues for reclaiming the value of spent sorbents, mitigating the environmental and economic burden of their disposal or regeneration, while fostering sustainable resource management, and energy storage.

Porous TiP2O7/nitrogen-doped carbon composite with tailored crystal orientation as diffusion-controlled high-rate anode for lithium-ion batteries

TiP2O7 is a lithium-ion batteries anode material with outstanding stability and high safety due to its strong polyanion three-dimensional frame structure. However, poor electrical conductivity severely represses the rate capability of TiP2O7 anode. Herein, a porous TiP2O7/nitrogen-doped carbon (CN) composite with tailored (630) and (600) preferential crystallographic orientation is achieved by the ball-milling and thermal treatment strategy. The TiP2O7/CN (630) anode retains specific capacities of 194.3 and 128.9 mA h/g at high current densities of 5 and 10 A/g, respectively, superior than that of the TiP2O7/CN (600). Remarkably, kinetic analysis reveals that the charge storage process in the TiP2O7/CN (630) anode is predominantly diffusion-controlled, with the diffusion-controlled capacity contributing up to 52 % even at a high scan rate of 2 mV/s. Density functional theory calculation confirms the lower lithium ions migration energy barrier of (630) crystallographic orientation of TiP2O7. In addition, due to the homogeneity of porous structure and composition, the TiP2O7/CN (630) anode maintains a capacity of 389mA h/g after 1000 cycles at 1 A/g. Thereby, the synthesis strategy for preferred orientation TiP2O7-based anode is instructive for the structural design of high-rate metal-based composite oxides for lithium-ion batteries.

Heterojunction nanofluidic memristors based on peptide chain valves for neuromorphic applications

Memristors exhibit significant potential for neuromorphic computing due to their unique properties. This study introduces a heterojunction nanofluidic memristor (HJNFM) and explores its applications in simulating synapses and constructing neural networks. The HJNFM consists of a SnS2 and MoS2 heterojunction nanochannel with a peptide chain valve. The opening and closing dynamics of peptide chain valve alter ionic conductance of the nanochannel and realize the memristor characteristics. The sequence of the peptide chain also affects the electrical properties of HJNFM. Additionally, by setting up multi SnS2 strips in the nanochannel, the multi-HJNFM can achieve permanent memory and emulate synaptic features including short-term and long-term memory. Notably, we construct a convolutional neural network from multi-HJNFMs, which achieves 94 % accuracy in a digit recognition task. This study presents a new approach to constructing nanofluidic memristors, which could be advantageous for developing new forms of neuromorphic computing in the future.

Adsorption suppression and viscosity transition in semidilute PEO/silica nanoparticle mixtures under the protein limit

Understanding the interplay between polymer adsorption and colloidal interactions is essential for designing advanced materials with tailored properties. This study investigates the adsorption-driven aggregation and rheological transitions in semidilute mixtures of silica nanoparticles and high-molecular-weight poly(ethylene oxide) (PEO) in the protein limit, where the polymer's size exceeds that of the particles. By systematically varying the ratio of the particle hydrodynamic size to the polymer's hydrodynamic screening length (Rh,silica/ξh,PEO), distinct regimes of adsorption suppression, aggregation onset, and saturation were identified. Below Rh,silica/ξh,PEO = 1, adsorption was suppressed due to the entropic penalty of polymer distortion, resulting in negligible viscosity changes and stable particle dispersions. Near Rh,silica/ξh,PEO = 1, the adsorption energy overcame the entropy loss, triggering rapid aggregation and a sharp increase in viscosity, accompanied by the emergence of a slow relaxation mode in dynamic light scattering. At higher ratios (Rh,silica/ξh,PEO > 2), adsorption saturated, forming dense PEO-silica aggregates, as confirmed by small-angle neutron scattering. These findings challenge conventional theories of polymer adsorption and emphasize the critical role of polymer conformational entropy and adsorption energy balance. This study provides a framework for understanding polymer-mediated colloidal interactions in semidilute regimes, with implications for the rational design of polymer-colloid composites in materials science, biophysics, and industrial formulations.

Modulating nanopore size and ion transport using (Anti)-Polyelectrolyte effects inspired by the nuclear pore complex

This study explores the modulation of nanopore size and ion transport through (anti)-polyelectrolyte effects, which is inspired by the nuclear pore complex. We aimed to control ionic selectivity and rectification by applying these effects to synthetic nanopores. Single bicylindrical nanopores were fabricated on the PET membranes and functionalized with PEI/HA or PLL/PAA polyelectrolyte layers. Varying the structural and charge characteristics under different pH levels and ionic strengths revealed that at low salt concentrations, charge density and surface charge polarity significantly impacted ion selectivity and transport. At higher concentrations, conformational changes in the polyelectrolytes influenced the conductance via volume expansion or compaction. Our findings highlight the distinct roles of charge inversion and molecular expansion in nanopore transport, which can be modulated by pH and ionic environment. This work provides insights for developing highly selective ion channels with potential applications in filtration, biosensing, and nanofluidics, where precise ion transport and selective rectification are essential.

Anionic regulation Fe/NiOOH electrocatalysts to boost electrooxidation performance of biomass derived 5-hydroxymethylfurfural

Nickel-based catalysts show great potential as promising candidates for the electrocatalytic oxidation of 5-hydroxymethylfurfural (HMF). However, the limited adsorption capacity of nickel-based catalysts for OH- and HMF limits their further development. In this study, amorphous Fe/NiOOH-SOx was generated from nanosheets (Fe/NiOOH-Ni3S2), which was pre-fabricated on nickel foam via pre-reconstruction and anionic regulation strategy. The optimized catalyst Fe/NiOOH-Ni3S2 demonstrated exceptional activity in the HMF oxidation reaction (HMFOR) with a current density of 10 mA cm-2 at 1.32 V vs RHE, accompanying with the 98.9 % HMF conversion, 97.8 % 2,5-Furandicarboxylic acid (FDCA) selectivity, 96.8 % Faraday efficiency, and stability for ten cycles. The incorporating amorphous FeOOH reduces the electron density around Ni, promoting the formation of high-valent Ni spices. Meanwhile, the SOx combined with amorphous hydroxy nickel oxide provides unsaturated sites, which enhances the adsorption capacity of HMF. Density functional theory (DFT) computations reveal that the designed amorphous Fe/NiOOH and surface-adsorbed SOx collectively modulate the electronic structure of the catalyst, causing an upwards shift of the NiOOH d-band center and enhancing adsorption capacities for both HMF and OH-. This study proposes the adsorption enhancement mechanism of regulating electronic structure and offers a rational strategy for HMFOR electrocatalysts.

Hierarchical assembly of Pt single atoms and WC nanocrystals on porous carbon Boosting hydrogen evolution reactions

Optimizing the accessibility and chemical microenvironment of Pt single atoms (SAs) is essential for enhancing the efficiency of hydrogen evolution reaction (HER). Herein, we present a hierarchical catalyst (Pt3/WC/HS) featuring highly accessible Pt SAs moderately coordinated with WC nanoparticles and uniformly anchored on monodisperse porous carbon nanospheres. With a Pt content of 2.8 wt%, Pt3/WC/HS achieves an ultralow overpotential of 8 mV at 10 mA cm-2, outperforming commercial 20 wt% Pt/C. Additionally, the catalyst exhibits outstanding HER activity in proton exchange membrane water electrolyzers (PEMWE), simulated seawater, and neutral media. Notably, in a coal-assisted hydrogen production system that decouples oxygen evolution reaction (OER) from HER, Pt3/WC/HS achieves 400 mA cm-2 at an applied potential of just 0.5 V. Spectroscopic characterizations and density functional theory (DFT) reveal that WC stabilizes the Pt SAs while retaining an active electronic configuration in the Pt 5 [Formula: see text] orbital, shifting *H adsorption from thermodynamically unfavorable to spontaneous. Moreover, the interconnected porous framework of Pt3/WC/HS ensures high Pt site accessibility at the three-phase interface. This work demonstrates a versatile and high-performance HER catalyst suitable for diverse hydrogen evolution systems and offers a rational design strategy for single-atom catalysts.

Defect-Driven hydrogen Evolution: Enhanced hydrogen spillover on Pt-MoS2 interface via sulfur vacancies

The hydrogen spillover is considered a powerful strategy for improving the kinetics of hydrogen evolution reaction (HER) due to the decoupling of hydrogen adsorption and desorption. However, the hydrogen spillover rate strongly depends on the metal-support interfaces, and the Fermi levels (Ef) difference between metal and support hinders the occurrence of hydrogen spillover. Here, we prepared platinum (Pt) doped on molybdenum disulfide (MoS2) with sulfur vacancies (Sv) catalyst (Pt/Sv-MoS2) and investigated the internal relationship between metal-support interfaces and hydrogen spillover mechanism. The experimental and theoretical results show that sulfur (S) vacancies reduce the work function (ΔΦ) at the metal-support interface, thus accelerating the migration rate of hydrogen from Pt to Sv-MoS2. Meanwhile, the introduction of S vacancies promotes the high dispersion of Pt nanoparticles (Pt NPs) and weakens the electron supply from Pt to MoS2, facilitating active hydrogen (*H) adsorption step and thus increasing the hydrogen coverage on the Pt sites. Consequently, the prepared Pt/Sv-MoS2 catalyst exhibited significantly enhanced HER activity, achieving an overpotential of 26 mV at 10 mA·cm-2 and a Tafel slope of only 28 mV·dec-1, which is superior to commercial 20 % Pt/C.

Machine learning accelerated analysis of microwave-assisted synthesis parameters on calcium carbonate particles

The synthesis of calcium carbonate (CaCO3) particles is crucial for tailoring their structural and chemical properties for specific advanced applications. However, precision synthesis is challenging due to bulk crystallization effects, which makes it difficult to predict the outcomes of chemical synthesis. Microwave-assisted synthesis offers significant advantages, including faster reaction times, energy efficiency, and potential for solventless reactions, making it valuable in various chemical fields. The advent of machine learning has shifted materials research from traditional trial-and-error methods to precise computational science. In this study, we use microwave technology to examine the effects of temperature, pressure, concentration, and time on CaCO3 particle synthesis, focusing on morphology, size, shape, and phase composition. Machine learning models, such as decision trees, random forests, and gradient boosting, enable us to predict particle phases based on initial parameters and identify key factors influencing particle formation. Results indicate that temperature is more critical than concentration, pressure, and time for CaCO3 polymorph formation. The dominant phase transitions from vaterite to aragonite at 100 °C. At temperatures above 100 °C, higher concentrations result in increased pressure, leading to the synthesis of smaller particles. This is due to enhanced crystal nucleation density and higher kinetic energy, which inhibit crystal growth. SHapley Additive ExPlanations (SHAP) analysis was used to enhance the interpretability of regression models and understand the contributions of each variable to CaCO3 phase composition predictions. This research pioneers the integration of microwave-assisted synthesis and machine learning to precisely control and understand the properties of micro- and nano-sized CaCO3 particles.

Non-enzymatic electrochemical sensors for point-of-care testing: Current status, challenges, and future prospects

Current electrochemical sensors in point-of-care (POC) testing devices rely mainly on enzyme-based sensors owing to superior sensitivity and selectivity. Nevertheless, the poor stability, high reagent cost, complex fabrication methods and requirement of specific operational conditions make their adaptability in real-world applications unfavorable. Non-enzymatic electrochemical sensors are thus developed as they are more robust and cost-effective strategies. The advancement in material science and nanotechnology enables the development of novel non-enzymatic electrodes with favorable analytical performance. However, the developments are yet far from being adopted as viable products. This review therefore aims to gain insight into the field and evaluate the current progress and challenges to eventually propose future research directions. Here, fabrication strategies based on traditional and emerging technology are discussed in the light of analytical performance and cost-effectiveness. Moreover, the discussion is given on the pros and cons of non-enzymatic sensors when they are employed with various kinds of sample matrices, i.e., clinical and non-clinical samples, which must be taken into consideration for sensor development. Furthermore, molecular imprinting technology in tackling the selectivity issue is introduced and current progress is provided. Finally, the promising strategies from literature for solving the remaining challenges are included which could facilitate further development of robust POC testing devices based non-enzymatic sensors. We believe that once researchers and technology developers have reached the point where most problems are solved, the non-enzymatic sensors are going to be the robust choice for POC testing in clinical diagnostic, ensuring food safety, monitoring contaminants in environment, and bioprocess control.

Terahertz waves promote Ca2+ transport in the Cav2.1 channel

CaV2.1 channels are the structural foundation for neurotransmitter transmission and other vital biological processes. If autoimmune-mediated reduction in presynaptic CaV2.1 leads to a decrease in calcium influx during a presynaptic action potential, which decreases chemical neurotransmission, leading to a debilitating neuromuscular weakness, also known as Lambert-Eaton myasthenia syndrome. The selectivity filter is a core structural component of CaV2.1 channels, with a pivotal role in regulating the selective permeation of Ca2+ ions. Due to the vibration and rotation frequencies of the selectivity filter of CaV2.1 being located in the terahertz band, terahertz waves at specific frequencies may resonate with it, thereby affecting Ca2+ current passing through CaV2.1. Therefore, it is highly worthwhile to study how the terahertz waves regulate the CaV2.1 channel. In this study, we investigate the structure of CaV2.1 channels using molecular dynamics simulations. The effect of external terahertz waves on the channel has been examined at different resonant frequencies of the selectivity filter. We found that when the frequency of terahertz waves applied is around the symmetrical vibration frequency of the carboxyl group in the selectivity filter, the PMF of CaV2.1 significantly decreases, promoting the transport of Ca2+ ions through CaV2.1. The reason behind this is that the terahertz waves resonate with the carboxyl groups of the selectivity filter, affecting the hydrogen network between the hydrated water of Ca2+ ions and the selectivity filter. These findings open up new treatment avenues for channel diseases such as Lambert-Eaton myasthenic syndrome treated with terahertz waves.

SERS-based approaches in the investigation of bacterial metabolism, antibiotic resistance, and species identification

Surface-enhanced Raman scattering (SERS) is an inelastic scattering phenomenon that occurs when photons interact with substances, providing detailed molecular structure information. It exhibits various advantages including high sensitivity, specificity, and multiple-detection capabilities, which make it particularly effective in bacterial detection and antibiotic resistance research. In this review, we review the recent development of SERS-based approaches in the investigation of bacterial metabolism, antibiotic resistance, and species identification. Although the promising applications have been realized in clinical microbiology and diagnostics, several challenges still limit the further development, including signal variability, the complexity of spectral data interpretation, and the lack of standardized protocols. To overcome these obstacles, more reproducible and standardized methodologies, particularly in nanomaterial design and experimental condition optimization. Furthermore, the integration of SERS with machine learning and artificial intelligence can automate spectral analysis, improving the efficiency and accuracy of bacterial species identification, resistance marker detection, and metabolic monitoring. Combining SERS with other analytical techniques, such as mass spectrometry, fluorescence microscopy, or genomic sequencing, could provide a more comprehensive understanding of bacterial physiology and resistance mechanisms. As SERS technology advances, its applications are expected to extend beyond traditional microbiology to areas like environmental monitoring, food safety, and personalized medicine. In particular, the potential for SERS to be integrated into point-of-care diagnostic devices offers significant promise for enhancing diagnostics in resource-limited settings, providing cost-effective, rapid, and accessible solutions for bacterial infection and resistance detection.

Ultrathin lithium chalcogenide-based nanohybrid SEI layer for suppressing lithium dendrite growth and polysulfide shuttle in Li-S batteries

To advance high-energy-density Li-S batteries, it is crucial to develop strategies that enhance the energy efficiency, power capability, and cycle stability of both lithium metal anodes (LMAs) and sulfur cathodes (SCs). This study introduces an ultra-thin (∼60 nm) lithium telluride (t-Li2Te) layer on a conventional polypropylene (PP) separator, designed to improve the Coulombic efficiency (CE) and cycling stability of LMAs and SCs. The t-Li2Te layer features a nanoporous structure of aggregated Li2Te nanoparticles, with nanopores filled by solid-electrolyte interface (SEI) materials during initial lithium deposition. This t-Li2Te-SEI nanohybrid layer significantly enhanced CE for LMA, reaching maximum capacity within four cycles with only 25 % total capacity loss, contrasting with a 210 % capacity loss over ten cycles in the bare PP-based anode without t-Li2Te. In high cut-off capacity tests (4 mA h cm-2), the t-Li2Te-based system achieved stable cycling over 350 cycles, extending cycle life tenfold compared to the bare PP-based anode. For SC applications, the t-Li2Te-SEI nanohybrid layer attained an initial CE of 98.3 %, notably higher than that (93.1 %) of the reference system. After 100 cycles, the t-Li2Te-based SC system retained 85 % capacity, showing a 20 % improvement over systems without the nanohybrid layer.

Trap-array slippery surfaces for high-throughput, precise, and flexible evaporation-induced supraparticle synthesis

Supraparticles, the small aggregation entities of functional micro/nanoparticles, are crucial in materials science, chemistry, and nanotechnology owing to their unique properties and wide range of applications. Evaporation-driven self-assembly of colloidal droplets on surfaces has proven effective for supraparticle synthesis. However, challenges such as low production rates, adhesion risks, cross-contamination, and limited flexibility continue to hinder the widespread adoption of this method. To address these challenges, this study proposes an innovative strategy that uses the novel lotus-seed head and Nepenthes-inspired trap-array slippery surfaces (TASS). These surfaces feature a macroscopic trap array and a lubricant layer for high-throughput supraparticle synthesis. The lubricant traps provide a self-locating and stable lubrication effect, enabling the retreatment of addressable droplet array contact lines during evaporation, leading to the successful fabrication and collection of the supraparticle array. Additionally, the method demonstrates high synthesis flexibility, allowing for the creation of various supraparticle structures, morphologies, and porosities. As a proof of concept, core-shell magnet-actuated photocatalytic supraparticles were synthesized using TASS and showed enhanced contaminant degradation efficiency. This novel surface-template strategy provides a promising approach for large-scale, evaporation-driven supraparticle synthesis, with potential applications in catalysis, energy storage, and carbon capture.

Self-activated oxophilic surface of porous molybdenum carbide nanosheets promotes hydrogen evolution activity in alkaline environment

Molybdenum carbides are promising alternatives to Pt-based catalysts for the hydrogen evolution reaction (HER) due to their similar d-band electronic configuration. Notably, MoxC exhibits superior HER kinetics in alkaline media compared to acidic conditions, contrasting with Pt-based catalysts. Herein, we present 3D porous β-Mo2C nanosheets, achieving an overpotential of 111 mV at 10 mA cm-2 in 1 M KOH, significantly lower than in acidic environments. Simulations on pristine Mo2C surface reveal that water dissociation poses a higher energy barrier in alkaline media, suggesting that crystal structure alone does not dictate kinetics. Operando attenuated total reflection surface-enhanced infrared absorption spectroscopy shows that Mo2C activates interfacial water, generating liquid-like and free water, and facilitates hydroxyl species adsorption, reducing activation energy to below 38.43 ± 0.19 kJ/mol. Our findings on the self-activation effect offer insights into the HER mechanism of Mo-based electrocatalysts and guide the design of highly active HER catalysts.

MIL-101(Fe)-derived nickel-iron quasi-metal organic framework as efficient catalyst for oxygen evolution reaction

Metal-organic frameworks (MOFs) have emerged as promising precursors for the development of efficient non-noble metal electrocatalysts for oxygen evolution reaction (OER). Quasi-metal-organic frameworks, characterized by partially fractured connections between metal nodes and organic ligands, have attracted significant attention due to their large exposed active interfaces. To stimulate the development of quasi-MOF-based materials as OER catalysts, herein a Ni-Fe quasi-MOF catalyst was prepared through the pyrolysis of MIL-101(Fe) and subsequent ion exchange with Ni2+. The optimum catalyst MIL-101(Fe)350-Ni exhibits the lowest overpotential (290 mV) to achieve a current density of 10 mA cm-2, the smallest Tafel slope (89 mV dec-1) and the largest double-layer capacitance (0.268 mF cm-2). Furthermore, the current density drops only by ∼5 % (from 10 to 9.45 mA cm-2) after 20 h durability test. Experimental analysis suggests that the enhanced OER performance arises from the strong coupling effect between Fe and Ni, which improves the electron transfer efficiency and facilitates the active species generation. This work provide a feasible direction for constructing bimetallic quasi metal-organic frameworks to enhance the electrocatalytic OER performance and stability.

An insight into in silico strategies used for exploration of medicinal utility and toxicology of nanomaterials

Nanomaterials (NMs) and the exploration of their comprehensive uses is an emerging research area of interest. They have improved physicochemical and biological properties and diverse functionality owing to their unique shape and size and therefore they are being explored for their enormous uses, particularly as medicinal and therapeutic agents. Nanoparticles (NPs) including metal and metal oxide-based NPs have received substantial consideration because of their biological applications. Computer-aided drug design (CADD) involving different strategies like homology modelling, molecular docking, virtual screening (VS), quantitative structure-activity relationship (QSAR) etc. and virtual screening hold significant importance in CADD used for lead identification and target identification. Despite holding importance, there are very few computational studies undertaken so far to explore their binding to the target proteins and macromolecules. Although the structural properties of nanomaterials are well documented, it is worthwhile to know how they interact with the target proteins making it a pragmatic issue for comprehension. This review discusses some important computational strategies like molecular docking and simulation, Nano-QSAR, quantum chemical calculations based on Density functional Theory (DFT) and computational nanotoxicology. Nano-QSAR modelling, based on semiempirical calculations and computational simulation can be useful for biomedical applications, whereas the DFT calculations make it possible to know about the behaviour of the material by calculations based on quantum mechanics, without the requirement of higher-order material properties. Other than the beneficial interactions, it is also important to know the hazardous consequences of engineered nanostructures and NPs can penetrate more deeply into the human body, and computational nanotoxicology has emerged as a potential strategy to predict the delirious effects of NMs. Although computational tools are helpful, yet more studies like in vitro assays are still required to get the complete picture, which is essential in the development of potent and safe drug entities.

Surface-engineered nanobeads for regioselective antibody binding: A robust immunoassay platform leveraging catalytic signal amplification

Regulating protein interactions and protein corona formation of nanomaterials is crucial for advancing nanomedicine, where surface engineering of nanomaterials plays a pivotal role in precise control over biological interactions. Here, we present a surface-engineered nanoparticle-based immunoassay platform using carboxyl-enriched polystyrene nanobeads (CEPS) with regioselectively controlled antibody-binding properties. Proteomic analysis and theoretical simulation revealed that CEPS has an enhanced Fc-specific binding affinity for immunoglobulins compared to conventional carboxylated polystyrene beads, with a higher surface carboxyl density critically mediating protein interactions. This regioselective antibody binding with unique Fc-specific affinity eliminates the need for complex surface modifications, streamlining the assay process and broadening the applicability across various immunoassay formats. Additionally, incorporating a palladium catalyst within CEPS enables solvent-triggered on-demand catalytic signal amplification using a leucodye substrate, providing a more stable alternative to enzyme-based methods while significantly enhancing detection sensitivity and stability. The platform demonstrated enhanced performance in detecting clinically relevant biomarkers, including C-reactive protein, interferon-gamma, and the receptor-binding domain of SARS-CoV2, achieving lower detection limits and faster response times compared to conventional enzyme-based ELISA systems. Notably, the CEPS-based assay retained catalytic activity for over 140 days at room temperature, underscoring its potential for reliable, long-term use in diverse diagnostic applications.

Coordination-driven room-temperature phosphorescent carbon dot nanozymes for dual-mode glutathione detection

Integrating long-lived room-temperature phosphorescence (RTP) into nanozymes to build multifunctional nanozymes can benefit biomedical analysis by expanding sensing modes and developing advanced sensing strategies but it is challenging. Herein, a general strategy for fabricating phosphorescent nanozymes by anchoring Co-Nx active centers on SiO2 nanospheres with carbon dots (CDs) encapsulated inside (CDs@SiO2@Co) is developed for dual-mode colorimetric-phosphorescent detection of glutathione (GSH). Specifically, surface Co-Nx active centers enhanced O2 adsorption and activation (O2 to 1O2), providing oxidase-like activity to induce the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB), generating a distinct colorimetric signal. The SiO2 layer inhibited non-radiative transitions of the CDs to promote RTP, and spatially separated Co ions from CDs to prevent RTP quenching caused by Co-CD interactions, resulting in CDs@SiO2@Co with long-lived RTP (lifetime: 1.14 s), providing a phosphorescent channel free from autofluorescence interference. Upon introduction of GSH, the color product-oxidized TMB (oxTMB) was reduced, and the quenched RTP caused by the oxTMB internal filter effect was restored. Based on this principle, a sensitive and reliable dual-mode colorimetric-phosphorescent method was developed for detecting GSH in plasma and cells. Furthermore, owing to the tunable optical properties of CDs and the flexibility of substituting metal active centers, this strategy can be extended to construct various phosphorescent nanozymes with adjustable RTP emission wavelengths and diverse enzyme-like activities, advancing the development of nanozymes and bioanalytical platforms.

A Nd-doped NiCo spinel dual functional catalyst for both oxygen reduction reactions and oxygen evolution reactions: Enhanced activity through surface reconstruction

The design of efficient, low-cost, highly active and thermally stable electrocatalysts is critical for both oxygen reduction reactions (ORR) and oxygen evolution reactions (OER). While some spinel metal oxides exhibit good activities for either ORR or OER, a bifunctional spinel metal oxide that can provide decent activities for both ORR and OER would be most desirable. To date, rare earth metal-modified spinel oxides have not been well-studied, but they are thought to be able to boost both ORR and OER simultaneously. Hence, a Nd-doped NiCo2O4 catalyst was synthesized in this work to evaluate its potential for improving both ORR and OER reactions. We hypothesized that this catalyst would be a viable option, as the highly oxidized Co4+ (hydroxycobalt oxide) generated from surface reconstruction could be an active site for OER while Ni2+ is intrinsically an active site for ORR. Amazingly, our study revealed that the addition of Nd in spinel metal oxides was able to inhibit the formation of Co4+ at low potentials while the Ni species promoted the formation of Co4+ from Co2+, thus achieving a balance between Co2+ and Co4+ which resulted in a multi-step oxidation process of Co2+ → Co3+ → Co4+. In addition, by tuning the amount of Nd doped, an optimum electrocatalyst Nd0.1Ni0.9Co2O4 with excellent activities for both ORR (i.e. the half-wave potential E1/2 = 0.735 V) and OER (i.e. the overpotential at 10 mA cm-2 E10 mA·cm-2 = 302 mV) in alkaline conditions was developed. In summary, this work may have opened a new pathway for applying spinel metal oxides as bifunctional catalysts in future commercial ORR and OER processes.

Bioresorbable, amorphous magnesium-fiber reinforced bone cement with enhanced mechanical and biological properties

In this study, we developed and characterized a fully biodegradable composite bone cement reinforced with short, randomly oriented amorphous magnesium fibers. Fibers of composition Mg60Zn35Ca5 (in at.%) with 50 μm diameter and 2 mm length were produced by wire spinning and then mixed with a magnesium calcium phosphate cement using fiber volume fractions between 10 and 20 %. The interface strength between the fibers and cement was improved by treating the fibers with diammonium hydrogen phosphate. Compared to the reference cement without fibers, flexural strength was increased by 18 % for the composites with 13 and 18 vol% fibers, and the work of fracture was increased by over 1000× in all cases (p < 0.05, n = 6). Immersion in simulated body fluid for two and four weeks showed that the cement's struvite phase degrades first, and overall, the composite degrades slower. The degradation rate can be tailored to the application by changing the fiber percentage or the cement/fiber composition. Murine pre-osteoblastic cells (MC3T3) cultured in extracts of reference and composite cements had significantly higher cell viability, and composites with 13 vol% fibers also had a significantly higher number of cells compared to the control, indicating that the fibers can enhance and promote pre-osteoblastic cell growth. The results demonstrate that amorphous magnesium fibers enhance both the mechanical and biological properties of ceramic bone cement, expanding their prospects for clinical application.

Microfluidic cell carriers for cultured meat

Cultured meat aims to produce meat mass from cell culture instead of conventional livestock slaughtering. Due to anchorage-dependent and 3D culturing manner of cells, cell carriers are critical in cultured meat. Various cell carriers have been used for expansion of seed cells and cultured meat tissue construction, such as commercial microcarriers, electrospray microspheres, and 3D-printed microfibers, but facing suboptimal effect of cell growth and specific differentiation. Compared to traditional methods, microfluidics can purposefully fabricate cell carriers with diverse structures and components, thereby achieving adequate simulation of natural muscle. Research has shown that microfluidic fibrous carriers possessed excellent effect in cultured meat tissue construction. This review overviews application and potential of microfluidic cell carriers in cultured meat. Starting with introduction of materials for carrier construction, we discuss limitations of traditional cell carriers and focus on microfluidic carrier in cultured meat. Finally, we present challenges and perspectives of microfluidics for cultured meat.

Sequential simulation of regeneration-specific microenvironments using scaffolds loaded with nanoplatelet vesicles enhances bone regeneration

Bone regeneration is a complex and coordinated physiological process, and the different stages of this process have corresponding microenvironments to support cell development and physiological activities. However, biological scaffolds that provide different three-dimensional environments during different stages of bone regeneration are lacking. In this study, we report a novel composite scaffold (NPE@DCBM) inspired by the stages of bone regeneration; this scaffold was composed of a fibrin hydrogel loaded with nanoplatelet vesicles (NPVs), designated as NPE, and decellularized cancellous bone matrix (DCBM) microparticles. Initially, the NPE rapidly established a temporary microenvironment conducive to cell migration and angiogenesis. Subsequently, the DCBM simulated the molecular structure of bone and promoted new bone formation. In vitro, the NPVs regulated lipid metabolism in bone marrow mesenchymal stem cells (BMSCs), reprogramed the fate of BMSCs by activating the PI3K/AKT and MAPK/ERK positive feedback pathways, and increased BMSC functions, including proliferation, migration and proangiogenic potential. In vivo, NPV@DCBM accelerated bone tissue regeneration and repair. Initially, the NPE rapidly induced angiogenesis between DCBM microparticles, and subsequently, BMSCs differentiated into osteoblasts with DCBM microparticles at their core. In summary, the design of this composite scaffold that sequentially mimics different bone regeneration microenvironments may provide a promising strategy for bone regeneration, with clinical translational potential.

Biophysical insights into the impact of lateral electric field stimulation to cellular microenvironment: Implications for bioelectronic medicine applications

In the last few decades, electrical stimulation devices have been clinically used for a wide spectrum of applications, ranging from deep brain stimulation to drug and gene delivery. Despite such clinical relevance, the impact of electrical stimulation on the cellular biophysical processes has not been explored significantly. We report here the analytical results to develop quantitative biophysical insights into the influence of lateral electric field stimulation on bioelectric stresses in the intercellular/extracellular region and the membrane tension. In developing quantitative insights, we solved Laplace equation with appropriate boundary conditions in an azimuthally asymmetric system with a single cell. The magnitude of the stresses increases with the electric field strength in a parabolic manner. In case of cell without surface charges, the intracellular stress field is predicted to have both compressive and tensile regions with a maximum of 2 μPa, while a maximum tensile stress of 20 μPa in extracellular region could be predicted, at field strength of 300 V/m. While considering surface charges, the magnitude of extracellular normal and shear stresses at the cell membrane is an order of magnitude higher when compared to without surface charges. Based on the variation of shear stress tensors at cell membrane, the critical field strength for membrane rupture was found to be 5.3 kV/mm and 20 kV/mm for a cell without and with surface charges respectively. The impact of the bioelectric stresses on the mechanotransduction induced cytoskeletal reorganization and stress driven cellular signalling modulation were substantiated using quantitative results from the study.

Engineering multifunctional surface topography to regulate multiple biological responses

Surface topography or curvature plays a crucial role in regulating cell behavior, influencing processes such as adhesion, proliferation, and gene expression. Recent advancements in nano- and micro-fabrication techniques have enabled the development of biomimetic systems that mimic native extracellular matrix (ECM) structures, providing new insights into cell-adhesion mechanisms, mechanotransduction, and cell-environment interactions. This review examines the diverse applications of engineered topographies across multiple domains, including antibacterial surfaces, immunomodulatory devices, tissue engineering scaffolds, and cancer therapies. It highlights how nanoscale features like nanopillars and nanospikes exhibit bactericidal properties, while many microscale patterns can direct stem cell differentiation and modulate immune cell responses. Furthermore, we discuss the interdisciplinary use of topography for combined applications, such as the simultaneous regulation of immune and tissue cells in 2D and 3D environments. Despite significant advances, key knowledge gaps remain, particularly regarding the effects of topographical cues on multicellular interactions and dynamic 3D contexts. This review summarizes current fabrication methods, explores specific and interdisciplinary applications, and proposes future research directions to enhance the design and utility of topographically patterned biomaterials in clinical and experimental settings.

N-doped graphene quantum dots combined with Ag nanoparticles for luminescence based analytical sensing of gentamycin after solid-phase extraction in a molecularly-imprinted polymer

A luminescence-based method was developed to detect gentamicin using silver nanoparticles (AgNPs) associated with nitrogen-doped graphene quantum dots (N-GQDs). When gentamicin sulfate interacts with the AgNPs/N-GQDs system, the characteristic blue fluorescence of N-GQDs, which had been previously turned off by AgNPs, is restored. Under specific conditions (such as the amount of synthesis dispersion and pH), this AgNPs/N-GQDs probe enabled quantification of gentamicin ranging from 3.0 × 10-7 to 6.0 × 10-6 mol L-1. To address interference from other substances during the analysis, a solid-phase extraction, with a kanamycin-imprinted polymer cartridge, enabled accurate results. Two veterinary pharmaceutical samples were used to test the method and results were in agreement with those achieved by obtained using high-performance liquid chromatography with analyte chemical derivatization. This new method is straightforward, sensitive, and selective, and it is also considered eco-friendly (0.63 score Analytical greenness calculator) since it avoids the use of toxic chemical derivatization reagents, use nanoquantities of carbon and silver based nanomaterials and aqueous systems.

Interface-driven energy filtering effect and enhanced thermoelectric performance of Ag2Se/SnS composites: An experimental and theoretical insights

This study examined the thermoelectric (TE) and mechanical properties of n-type Ag2Se/SnS nanocomposites synthesized via hydrothermal methods and hot-press densification. The incorporation of SnS nanosheets into the Ag2Se matrix enhanced the thermoelectric performance, achieving a maximum figure of merit (zT) value of 0.91 at 393 K for the sample with 2.5 wt% SnS, representing a 13 % improvement over that of Ag2Se. This enhancement is attributed to an increased power factor (∼2704 μWm-1 K-2 at 393 K) resulting from band convergence and a reduced thermal conductivity (κ ∼ 0.744 Wm-1 K-1 at 303 K) owing to interfacial phonon scattering. Furthermore, the nanocomposites exhibited enhanced mechanical properties, with Vickers hardness increasing by up to 28 % compared to that of Ag2Se. Density functional theory (DFT) calculations were employed to assess the structural and electronic properties of Ag2Se and Ag2Se/SnS nanocomposites. The computed bandgap confirmed improved electrical conductivity, whereas the binding energy and electron density difference analyses elucidated the interaction strength and charge transfer in the nanocomposite. These findings elucidate the potential of Ag2Se/SnS nanocomposites as promising thermoelectric materials for room-temperature applications and demonstrate the efficacy of nanostructuring in enhancing thermoelectric and mechanical properties.

Immunogenic cuproptosis in cancer immunotherapy via an in situ cuproptosis-inducing system

Cell death-based therapies combined with immunotherapy have great potential in cancer therapy. To further explore and apply the combined therapies, the immunogenicity of different cell death modes in colorectal cancer (CRC) was evaluated by a cause-and-effect framework encompassing 12 cell death modes. Results show robust correlations among cuproptosis, immunogenic cell death (ICD) and immunity in CRC, as observed in our in-house and other independent cohorts, which are substantiated by in vitro and in vivo experiments. Subsequent investigations demonstrate that cuproptosis induces endoplasmic reticulum stress, leading to the release of damage-associated molecular patterns from CRC cells and triggering the maturation of antigen-presenting cells. Moreover, for in vivo therapeutic approaches, an in situ cuproptosis-inducing system was devised, which can further strengthen the effects of immune cells. Through the combined analysis including single-cell RNA sequencing, cuproptosis is shown to mobilize cytotoxic T lymphocytes and M1 macrophages within the tumor microenvironment (TME). Additionally, co-treatment with Imiquimod, the TLR7 agonist, augments the anti-tumor immune responses induced by cuproptosis. Overall, we provide compelling evidence that cuproptosis induces ICD thus fostering an inflammatory TME, and the cuproptosis-based delivery system further promotes this inflammatory environment, demonstrating considerable potential for enhancing tumor therapy efficacy.

Cryopreservable, scalable and ready-to-use cell-laden patches for diabetic ulcer treatment

Stem cell-laden hydrogel patches are promising candidates to treat chronic ulcers due to cells' long-lasting and dynamic responses to wound microenvironment. However, their clinical translations are prohibited by the cryopreservation difficulty due to their weak mechanical strength and slow biotransport capability, and by the morphological mismatch between clinical ulcers and pre-fabricated patches. Here we report a stem cell-laden alginate-dopamine hydrogel patch that can be readily cryopreserved, processed, and scaled toward clinical usages. This cell-hydrogel patch not only maintains cell viability and structure integrity during cryopreservation, but also can be directly utilized without centrifugation or incubation post cryopreservation. In addition, this tissue-adhesive hydrogel patch enables close wound contact and fast cellular response, and its scalable and flexible structure enables assembly for large or irregularly shaped ulcers. Therefore, it accelerates ulcer healing and reduces scar formation via continuous, versatile, self-adjusting paracrine of imbedded, cryopreserved stem cells. These findings highlight its potential for scalable clinical applications in chronic wound management and pave the way for broader adoption of ready-to-use regenerative therapies.

Hybrid heterojunction containing rich oxygen vacancies for suppressing lattice oxygen release of Li-rich Mn-based layered oxides cathodes

Li-rich manganese-based layered oxides (LLOs) cathode materials possess the high theoretical capacity (>250 mAh g-1), which have garnered significant global attention as promising cathode materials for the next generation of high-energy density lithium-ion batteries. However, the irreversible release of lattice oxygen in LLOs severely limits its commercial application. Herein, a facile ultrasonic-assisted calcination method is employed to induce the formation of hybrid heterojunction containing rich oxygen vacancies (HROV) composed of C3N4@LLOs and Li3PO4@LLOs on the surface of LLOs, thereby obtaining modified LLOs (M-LLOs). M-LLOs exhibit enhanced initial Coulombic efficiency from 80.18 % to 85.1 %, elevated initial discharge specific capacity from 270.2mAh g-1 to 311.5 mAh g-1, and improved capacity retention rate after 300 cycles at 1C from 58.8 % to 84.2 %. Combining in-situ characterization techniques with density functional theory (DFT) calculations reveal the performance improvement mechanism of M-LLOs, which demonstrates that HROV effectively suppresses the irreversible release of lattice oxygen, enhances the binding strength of Mn-O bonds in M-LLOs, and consequently stabilize the structural phase transitions during charge/discharge processes. These results provide insights into understanding the functional role of hybrid heterojunctions in suppressing lattice oxygen release of LLOs, and provide essential theoretical foundations to accelerate the commercialization process of LLOs.

MXene-enabled organic synaptic fiber for ultralow-power and biochemical-mediated neuromorphic transistor

Fibrous bioelectronic provides an intrinsically accessible platform for artificial nerve and real-time physiological perception. However, advanced fiber-based artificial synapse remains a challenge due to the contradictory conductance demands for brain-like energy consumption and ultrasensitive biomarker perception. Herein, taking advantage of the highly accessible surface, rich functional groups and excellent electrical conductivity, a hierarchical nanostructured MXene (Ti3C2Tx)-enabled artificial neurofiber was proposed for neuromorphic organic electrochemical transistors (OECT) with biomolecule-mediated plasticity. The device can successfully emulate the typical short-term/long-term synaptic behaviors in both protonic gel electrolyte and aprotic ionic liquid gel electrolyte, with a minimum energy consumption of 1.21 fJ/spike and 0.10 fJ/spike. Uric acid (UA), a neurocognitive function and acute joint pain involved biomarker, and its specific enzyme were investigated to simulate the neurotransmitter-receptor induced postsynaptic synaptic weight modulation and pain sensitization process. The OECT showed excellent sensitivity and anti-interference performance. Moreover, selective and concentration-depended synaptic behaviors were successfully achieved in both phosphate-buffered saline (PBS) and artificial urine environments with significant memory effects. This study provided a potential to combine artificial neuromorphic devices with biological sensory neural networks.

Challenges and material innovations in drug delivery to central nervous system tumors

Central nervous system (CNS) tumors, encompassing a diverse array of neoplasms in the brain and spinal cord, pose significant therapeutic challenges due to their intricate anatomy and the protective presence of the blood-brain barrier (BBB). The primary treatment obstacle is the effective delivery of therapeutics to the tumor site, which is hindered by multiple physiological, biological, and technical barriers, including the BBB. This comprehensive review highlights recent advancements in material science and nanotechnology aimed at surmounting these delivery challenges, with a focus on the development and application of nanomaterials. Nanomaterials emerge as potent tools in designing innovative drug delivery systems that demonstrate the potential to overcome the limitations posed by CNS tumors. The review delves into various strategies, including the use of lipid nanoparticles, polymeric nanoparticles, and inorganic nanoparticles, all of which are engineered to enhance drug stability, BBB penetration, and targeted tumor delivery. Additionally, this review highlights the burgeoning role of theranostic nanoparticles, integrating therapeutic and diagnostic functionalities to optimize treatment efficacy. The exploration extends to biocompatible materials like biodegradable polymers, liposomes, and advanced material-integrated delivery systems such as implantable drug-eluting devices and microfabricated devices. Despite promising preclinical results, the translation of these material-based strategies into clinical practice necessitates further research and optimization.

ROS-triggered biomimetic hydrogel soft scaffold for ischemic stroke repair

Millions of individuals worldwide suffer from ischemic stroke (IS). The focal hypo-perfused brain brings about hostile pathological environment, which further restricts endogenous neurogenesis post-stroke. In this work, we report an ROS-triggered hyaluronic acid (HA) and platelet lysates (pls) composite biomimetic hydrogel soft scaffold (pls gel) encapsulating matrix metalloproteinase (MMPs)-responsive triglycerol monostearate nanoparticles loaded with docosahexaenoic acid (TGMS@DHA, TD). Pls gel was chosen to be the hydrogel matrix to mimic brain extracellular matrix (ECM) to provide physical support for cell infiltration and accelerate angiogenesis as a growth factors (GFs) box. The borate ester bonded hydrogel could respond to reactive oxygen species and relieve oxidative stress. The loaded TD nanoparticles could be enzymatically cleaved by overexpressed MMPs in cerebral infarcted site, which could improve the adverse effects triggered by overexpressed MMPs. DHA with rich unsaturated bonds was proven that not only inhibit neuroinflammatory and oxidative stress, but also take part in promote neurogenesis. In brief, the ROS-triggered hydrogel scaffold pls gel@TD created an optimized microenvironment to manipulate the survival and differentiation of neural stem cells and promote endogenous regenerative repair processes. The in vitro results exhibited the biomimetic soft scaffold eliminated oxygen-glucose deprivation-derived free radical, saved mitochondrial dysfunction, reduced neuronal apoptosis, and promoted neovascularization. In the mice focal IS model, the biomimetic hydrogel scaffold regulated pathological environment in the ischemic site and induced migration and differentiation of endogenous neural stem cells, consequently relieved neuron ischemia injury. During the long-term observation, the hydrogel improved mice neurobehavioral functions. In conclusion, the hydrogel soft scaffold pls gel@TD was demonstrated to have promising therapeutic effects on remodeling pathological environment by transforming the hostile state into a pro-regenerative one in the infarct site, consequently promoting endogenous regenerative repair processes.

Insight into the Facilitated surface reconstruction of NiFe layered double hydroxide by constructing heterostructures with Prussian blue analogues for enhanced oxygen evolution reaction

The dynamic surface electrochemical reconstruction of electrocatalysts in alkaline media for oxygen evolution reaction (OER) has been extensively documented, especially for layered double hydroxides (LDHs). However, there remines a limited understanding on how to effectively promote electrochemical reconstruction towards the desired highly active oxyhydroxide surface,which is crucial for enhancing the OER performance. The NiCo-PBA/NiFe LDH heterostructured catalyst was successfully synthesized by a one-step hydrothermal method. The incorporation of Prussian blue analogues (PBAs) was found to significantly promote the surface depth reconstruction of NiFe LDH, achieving a much higher degree of reconstruction compared to the natural electrochemical activation. In-situ Raman spectroscopy, various ex-situ characterizations, and density functional theory (DFT) calculations reveal that the introduction of PBAs intensifies the dissolution-reconstruction process and facilitates phase transition to form high-valent oxyhydroxide structures with optimized electron transfer pathways. The reconstructed NiCo-PBA/NiFe LDH-Re100 demonstrates exceptional electrocatalytic activity and long-term durability during the OER process. This study provides novel insights into the design of heterostructured catalysts and highlights their significant potential for applications in efficient electrocatalysis.

Multifunctional piezoelectric hydrogels under ultrasound stimulation boost chondrogenesis by recruiting autologous stem cells and activating the Ca2+/CaM/CaN signaling pathway

Articular cartilage, owing to the lack of undifferentiated stem cells after injury, faces significant challenges in reconstruction and repair, making it a major clinical challenge. Therefore, there is an urgent need to design a multifunctional hydrogels capable of recruiting autologous stem cells to achieve in situ cartilage regeneration. Here, our study investigated the potential of a piezoelectric hydrogel (Hyd6) for enhancing cartilage regeneration through ultrasound (US) stimulation. Hyd6 has multiple properties including injectability, self-healing capabilities, and piezoelectric characteristics. These properties synergistically promote stem cell chondrogenesis. The fabrication and characterization of Hyd6 revealed its excellent biocompatibility, biodegradability, and electromechanical conversion capabilities. In vitro and in vivo experiments revealed that Hyd6, when combined with US stimulation, significantly promotes the recruitment of autologous stem cells and enhances chondrogenesis by generating electrical signals that promote the influx of Ca2+, activating downstream CaM/CaN signaling pathways and accelerating cartilage formation. An in vivo study in a rabbit model of chondral defects revealed that Hyd6 combined with US treatment significantly improved cartilage regeneration, as evidenced by better integration of the regenerated tissue with the surrounding cartilage, greater collagen type II expression, and improved mechanical properties. The results highlight the potential of Hyd6 as a novel therapeutic approach for treating cartilage injuries, offering a self-powered, noninvasive, and effective strategy for tissue engineering and regenerative medicine.

Trojan horse strategy and TfR/ LDLR-Mediated transcytosis determine the dissemination of mycobacteria in tuberculous meningoencephalitis

Tuberculous meningoencephalitis (TBM), caused by the Mycobacterium tuberculosis complex, stands as one of the most lethal infections affecting the central nervous system (CNS). The understanding of the mechanisms underlying the neuroinvasion of Mycobacterium bovis (M. bovis) remains limited. Our findings reveal that M. bovis could exploit host transferrin receptor (TfR)- and low-density lipoprotein receptor (LDLR)-mediated transcytosis, while simultaneously utilizing infected macrophages as vectors to traverse the blood-brain barrier (BBB). Infected macrophages accelerate the M. bovis' neuroinvasion and promote its proliferation and dissemination to various organs. Persistent infection disrupts BBB integrity by degrading tight junction proteins and upregulating intercellular cell adhesion molecule-1 (iCAM-1), facilitating macrophage adhesion and migration, which contribute to the pathogen's entry into the brain. This study established a murine TBM model by administering M. bovis through carotid artery injection, accurately mimicking the interactions between the pathogen and the BBB. These findings offer insights into the mechanisms of TBM and serve as a foundation for developing targeted therapeutic strategies.

Nanotherapeutic strategies exploiting biological traits of cancer stem cells

Cancer stem cells (CSCs) represent a distinct subpopulation of cancer cells that orchestrate cancer initiation, progression, metastasis, and therapeutic resistance. Despite advances in conventional therapies, the persistence of CSCs remains a major obstacle to achieving cancer eradication. Nanomedicine-based approaches have emerged for precise CSC targeting and elimination, offering unique advantages in overcoming the limitations of traditional treatments. This review systematically analyzes recent developments in nanomedicine for CSC-targeted therapy, emphasizing innovative nanomaterial designs addressing CSC-specific challenges. We first provide a detailed examination of CSC biology, focusing on their surface markers, signaling networks, microenvironmental interactions, and metabolic signatures. On this basis, we critically evaluate cutting-edge nanomaterial engineering designed to exploit these CSC traits, including stimuli-responsive nanodrugs, nanocarriers for drug delivery, and multifunctional nanoplatforms capable of generating localized hyperthermia or reactive oxygen species. These sophisticated nanotherapeutic approaches enhance selectivity and efficacy in CSC elimination, potentially circumventing drug resistance and cancer recurrence. Finally, we present an in-depth analysis of current challenges in translating nanomedicine-based CSC-targeted therapies from bench to bedside, offering critical insights into future research directions and clinical implementation. This review aims to provide a comprehensive framework for understanding the intersection of nanomedicine and CSC biology, contributing to more effective cancer treatment modalities.

Harnessing the power of physicochemical material property screening to direct breast epithelial and breast cancer cells

Understanding cell-material interactions is crucial for advancing biomedical applications, influencing cellular behavior and medical device performance. Material properties can be manipulated to direct cell responses, benefiting applications from regenerative medicine to implantable devices such as silicone breast implants. Knowledge about the interaction differences between healthy and cancer cells with implants may guide implant design to more precisely influence cell adhesion and proliferation of healthy cells while inhibiting cancer cells, tailoring outcomes to specific cellular responses. To show-case this potential, breast epithelial cells and breast cancer cells were investigated regarding their interaction with a broad range of combined physicochemical properties. This study employed a silicone-based high-throughput screening method utilizing Double Orthogonal Gradients (DOGs) to investigate the influence of topography, stiffness, and wettability on breast epithelial cells (MCF10a) and breast cancer cells (MCF7). Results show distinct cellular responses, including decreased proliferation rates in both MCF10a and MCF7 cells with the introduction of surface topography and the dominant influence of wettability on cell adhesion, proliferation, and cluster formation. The screening identified specific regions of interest (ROIs) where MCF10a cell proliferation outperformed MCF7 cells and that topography inhibits cluster formation (tumorigenesis), offering potential prospects for the creation of novel implant surfaces.