Real-time monitoring of dynamic microvesicles (MVs), vesicles associated with living cells, is of great significance in deeply understanding their origin, transport, and function. However, specific labeling MVs poses a challenge due to the lack of unique biomarkers that differentiate them from other cellular compartments. Here, we present a strategy to selectively label MVs by evaluating a series of lipid layer-sensitive cationic indolium-coumarin fluorescent probes (designated as IC-Cn, with n ranging from 1 to 18) that feature varying aliphatic side chains (C n H2n+1). Through in situ cell imaging and analysis, we found that IC-Cn location is highly related to their lipophilicities and the phospholipid layer hydrophobic microenvironments in cellular compartments. In detail, IC-C1 and IC-C2 specifically localize MVs both inside and outside cells. In contrast, IC-C3, IC-C4, and IC-C5 label cellular MVs and mitochondria but with distinct fluorescence lifetimes. Using these probes strategically, we have discovered that, in addition to the biogenesis of MVs from plasma membranes and damaged mitochondria, newly formed MVs can undergo fusion and fission processes. Moreover, mitochondria-derived MVs, beyond being released from parent cells, can fuse with lysosomes to facilitate the removal of dysfunctional mitochondria. The work not only provides new insights into MV physiology but also inspires the design strategies for probes used in specific labeling in cell studies.

The shuttle of lithium polysulfides (LiPSs) and sluggish redox kinetics have posed significant barriers to advancing lithium–sulfur batteries. The design of lithiophilic‐sulfiphilic cathode show great promise, however, the integration of these multifunction through precise atomic‐level synergy remains a critical challenge. Herein, defective CoSe 2 quantum dots (QDs) confined within carbon microspheres (CoSe 2 @C) are prepared as sulfur cathode host material. The exposure of the highly active (111) facets provides more active sites and accelerates the catalytic conversion kinetics of LiPSs. Additionally, the abundant selenium vacancies exhibit dual‐bonding capability with Li and S atoms, thereby improving the adsorption of LiPSs and lowering the reaction energy barrier. Moreover, the carbon microspheres matrix effectively alleviates the aggregation of CoSe 2 QDs and increases the specific surface area. Benefiting from the above merits, the titled cathode exhibits enhanced conductivity and charge transfer, which effectively enhances the dynamics and alleviates shuttle effects. Consequently, the Li–S batteries assembled with CoSe 2 @C cathodes show extraordinary performance with an initial specific capacity of 1397 mAh g −1 at 0.2 C, a decay rate of 0.029% per cycle after 1000 cycles at 2 C. This work offers viewpoint for designing highly efficient catalysts for Li–S batteries.

Developing highly efficient and robust catalysts based on earth-abundant materials for electrochemical water splitting remains a great challenge. Herein, we report the synthesis of a well-defined hydrogen spillover electrocatalyst, i.e., sulfur vacancy-enriched Co9S8-Ni3S4 hollow heterostructure, via a self-sacrificial template strategy. The introduction of sulfur vacancies greatly decreases the work function of Ni3S4, thereby narrowing the work function difference (Delta phi) with Co9S8. The reduced electron density at their interface facilities the hydrogen species (H*) transfer to trigger hydrogen spillover. Density functional theory (DFT) calculations reveal that H2O molecules preferentially adsorb and dissociate at Co sites of Co9S8 to generate active H* intermediates, which subsequently migrate to Ni sites of Ni3S4 domains for H-2 formation. The hydrogen spillover mechanism is strongly supported by experimental characterizations, including pH-dependent kinetics, in-situ Raman and electrochemical impedance analysis. Benefiting from these synergistic effects, the titled catalyst exhibited excellent electrocatalytic activity for alkaline hydrogen evolution reaction, requiring only 83 mV to achieve 10 mA cm(2), along with remarkable durability, showing no detectable degradation even at 1 A cm(2) for 100 h. This work deepens the fundamental understanding of hydrogen spillover mechanism and offers a practical strategy for developing highly active and durable catalysts for water splitting.

Autophagy, a lysosomal degradation pathway critical for cell survival, differentiation, development, and maintaining homeostasis, plays a crucial role in cellular health. Maintaining an adequate level of adenosine triphosphate (ATP), the central molecule in energy metabolism, is equally essential for these processes. However, the interplay between autophagy and energy metabolism remains incompletely understood due to technical challenges, including the need for high-precision, dynamic detection within organelles, and sensitivity to the acidic lysosomal environment. To address these limitations, we developed HR-MP, a ratiometric fluorogenic nanoprobe specifically designed for visualizing ATP levels in acidic lysosomes during autophagy. HR-MP exhibits selective, rapid, and quantitative ATP detection in vitro, allowing it to quantitatively monitor lysosomal ATP fluctuations in complex biological environments with excellent biocompatibility, membrane permeability, and lysosome-targeting ability. Importantly, HR-MP enables real-time tracking of ATP fluctuations during starvation- or drug-induced autophagy in living cells, providing a powerful tool for elucidating the links between autophagy and energy metabolism.

Developing highly efficient and robust catalysts based on earth-abundant materials for electrochemical water splitting remains a great challenge. Herein, we report the synthesis of a well-defined hydrogen spillover electrocatalyst, i.e., sulfur vacancy-enriched Co9S8-Ni3S4 hollow heterostructure, via a self-sacrificial template strategy. The introduction of sulfur vacancies greatly decreases the work function of Ni3S4, thereby narrowing the work function difference (Δϕ) with Co9S8. The reduced electron density at their interface facilities the hydrogen species (H*) transfer to trigger hydrogen spillover. Density functional theory (DFT) calculations reveal that H2O molecules preferentially adsorb and dissociate at Co sites of Co9S8 to generate active H* intermediates, which subsequently migrate to Ni sites of Ni3S4 domains for H2 formation. The hydrogen spillover mechanism is strongly supported by experimental characterizations, including pH-dependent kinetics, in-situ Raman and electrochemical impedance analysis. Benefiting from these synergistic effects, the titled catalyst exhibited excellent electrocatalytic activity for alkaline hydrogen evolution reaction, requiring only 83 mV to achieve 10 mA cm2, along with remarkable durability, showing no detectable degradation even at 1 A cm2 for 100 h. This work deepens the fundamental understanding of hydrogen spillover mechanism and offers a practical strategy for developing highly active and durable catalysts for water splitting.

The transition to green and sustainable catalysts necessitates efficient and safe preparation techniques using abundant and renewable resources. Many metal nanoparticles (NPs) are excellent catalysts but suffer from poor colloidal stability. NP immobilization or fabrication of metal nanostructures on solid supports can avoid issues with NP aggregation and facilitate the reuse of catalysts, but it may result in a decrease in the catalytic performance of the NPs. Here, we show that well-defined colloidal silver, gold, and platinum NPs can be self-assembled in bacterial nanocellulose (BC) membranes, yielding BC-NP nanocomposites that are highly catalytically active using the reduction of 4-nitrophenol (4-NP) as a model reaction. The large effective surface area of BC enables the assembly of large quantities of NPs, resulting in materials with excellent catalytic performance. To address the mass transport limitations of reactants through the 3D nanofibrillar BC network, the membranes were dissociated using sonication to produce dispersed nanocellulose fibrils. This process dramatically reduced the time required for the adsorption of the NPs from days to minutes. Moreover, the catalytic performance of the nanofibril-supported NPs was drastically improved. A turnover frequency above 21,000 h(-1) was demonstrated, which is more than one order of magnitude higher than that for previously reported soft substrate-supported AuNP-based catalytic materials. The ease of fabrication, abundance, and low environmental footprint of the support material, along with reusability, stability, and unprecedented catalytic performance, make BC-NP nanocomposites a compelling option for green and sustainable catalysis.

Photo-/electrocatalysis serves as a cornerstone in addressing global energy shortages and environmental pollution, where the development of efficient and stable catalysts is essential yet challenging. Despite extensive efforts, it's still a formidable task to develop catalysts with excellent catalytic behaviours, stability, and low cost. Because of its high precision, favorable controllability and repeatability, radiation technology has emerged as a potent and versatile strategy for the synthesis and modification of nanomaterials. Through meticulous control of irradiation parameters, including energy, fluence and ion species, various inorganic photo-/electrocatalysts can be effectively synthesized with tailored properties. It also enables the efficient adjustment of physicochemical characteristics, such as heteroatom-doping, defect generation, heterostructure construction, micro/nanostructure control, and so on, all of which are beneficial for lowering reaction energy barriers and enhancing energy conversion efficiency. This review comprehensively outlines the principles governing radiation effects on inorganic catalysts, followed by an in-depth discussion of recent advancements in irradiation-enhanced catalysts for various photo-/electrocatalytic applications, such as hydrogen and oxygen evolution reactions, oxygen reduction reactions, and photocatalytic applications. Furthermore, the challenges associated with ionizing and non-ionizing radiation are discussed and potential avenues for future development are outlined. By summarizing and articulating these innovative strategies, we aim to inspire further development of sustainable energy and environmental solutions to drive a greener future.

The aviation industry relies on lightweight carbon fiber-reinforced polymers (CFRP) for fuel efficiency, which necessitates lightning strike protection (LSP) and electromagnetic shielding due to their electrical insulating characteristics. Traditional metallic meshes used for LSP are heavy and corrosion-prone, prompting the exploration of alternatives. This research showcases CFRP nanocomposites with enhanced LSP properties through the incorporation of graphene nanoplatelets (GNPs) and carbon nanotubes (CNTs). While the enhanced conductivity in the nanofilled epoxy matrix did not impact the overall conductivity of CFRP panels, a significant damage reduction was observed after simulated lightning strike tests. Similar approaches in the literature have also noted this discrepancy, but no attempts to reconcile it have been made. This work provides a framework to explain the damage reduction mechanism while accounting for the modest conductivity improvements in the nanoreinforced CFRPs. Additionally, a simple, nondestructive method to assess surface resin degradation after a lightning strike test is proposed, based on the fluorescence of diphenyl ketones. The discussion is supported by electrical conductivity measurements, damage pattern evaluation using the proposed UV-illumination method, ATR-FTIR, and scanning electron microscopy analysis pre- and postlightning strike simulation.

Temperature homeostasis is critical for cells to perform their physiological functions. Among the diverse methods for temperature detection, fluorescent temperature probes stand out as a proven and effective tool, especially for monitoring temperature in cells and suborganelles, with a specific emphasis on mitochondria. The utilization of these probes provides a new opportunity to enhance our understanding of the mechanisms and interconnections underlying various physiological activities related to temperature homeostasis. However, the complexity and variability of cells and suborganelles necessitate fluorescent temperature probes with high resolution and sensitivity. To meet the demanding requirements for intracellular/subcellular temperature detection, several strategies have been developed, offering a range of options to address this challenge. This review examines four fundamental temperature-response strategies employed by small molecule and polymer probes, including intramolecular rotation, polarity sensitivity, Förster resonance energy transfer, and structural changes. The primary emphasis was placed on elucidating molecular design and biological applications specific to each type of probe. Furthermore, this review provides an insightful discussion on factors that may affect fluorescent thermometry, providing valuable perspectives for future development in the field. Finally, the review concludes by presenting cutting-edge response strategies and research insights for mitigating biases in temperature sensing.

Background Thrombin is a multifunctional regulatory enzyme of the haemostasis and has both pro- and anticoagulant roles. It has, therefore, been a main target for drug discovery over many decades. Thrombin is a serine protease and possesses two positively charged regions called exosites, through which it is known to bind to many substrates. Dabigatran is a thrombin inhibitor and is widely used as an oral anticoagulant for the antithrombotic treatment of atrial fibrillation and venous thromboembolism. The mechanism by which dabigatran inhibits thrombin is the blockage of the active site, however, its effect on thrombin binding to its substrates has not been studied thoroughly and is thus poorly understood. Material and Methods The effect of dabigatran on thrombin binding to platelets was evaluated by flow cytometry using fluorescently labelled thrombin and washed platelets. Further, to confirm the results we utilized modern techniques for biomolecular binding studies, microscale thermophoresis (MST) and surface plasmon resonance (SPR), which validated the results. Results Dabigatran inhibited thrombin binding to platelets as analysed by flow cytometry. The inhibition was dose dependent with IC50 of 118 nM which was slightly lower than for inhibition of platelet activation and is close to the clinically relevant plasma concentration of dabigatran. MST and SPR also confirmed inhibitory effect of dabigatran on thrombin binding to platelets. Conclusion Apart from blocking the active site, dabigatran also inhibits thrombin binding to platelets. Since thrombin has numerous functions beyond the cardiovascular system, this finding may have important implications.

Integrating imaging and therapeutic capabilities into a single entity can offer enhanced diagnostic accuracy and treatment efficacy in clinically effective formulations. Due to the diversity of chemical structures and/or limited solubility of inhibitors or fluorophores, it is essential to employ a robust delivery carrier that can facilitate drug absorption and distribution during its circulation in the blood. This study explores the potential of hollow gadolinium oxide (Gd2O3) nanocarriers in imaging and drug delivery applications. The citric acid (CA)-capped hollow gadolinium oxide nanocarriers were synthesized via urea-assisted precipitation and hydrothermal methods using carbon spheres as sacrificial templates. The resulting nanosized hollow spheres displayed a spherical morphology and demonstrated relaxation rates in the longitudinal and transverse directions, as indicated by their r 1 and r(2) values of 1.8 and 5.3 s(-1) mM(-1), respectively. To mimic the physiological conditions, the hollow gadolinium oxide spheres were loaded separately with antibiotic sparfloxacin and the azo dye Congo red at neutral pH (7.4) and body temperature (37 degrees C). The CR-loaded nanospheres exhibited a time-dependent internalization behavior with HeLa cells, suggesting their imaging potential for intracellular drug delivery. Furthermore, the SP-loaded nanospheres demonstrated antimicrobial activity against both Gram-positive and Gram-negative bacteria, demonstrating their therapeutic potential against bacterial infections. To mitigate the risk of leaching of Gd3+ ions and their inherent toxicity, a CA coating was applied to hollow gadolinium oxide surface which resulted in outstanding cell viability of the surface functionalized nanocarriers. In addition, the CA coating offered additional support for the increased encapsulation and continuous release of drug molecules until 1 week (168 h). The characterization data provide evidence for the potential of CA-capped hollow gadolinium oxide spheres as positive MR contrast agents and their applicability as safe and controlled drug carriers.

AbstractAs one of the major causes of antimicrobial resistance, β‐lactamase develops rapidly among bacteria. Detection of β‐lactamase in an efficient and low‐cost point‐of‐care testing (POCT) way is urgently needed. However, due to the volatile environmental factors, the quantitative measurement of current POCT is often inaccurate. Herein, we demonstrate an artificial intelligence (AI)‐assisted mobile health system that consists of a paper‐based β‐lactamase fluorogenic probe analytical device and a smartphone‐based AI cloud. An ultrafast broad‐spectrum fluorogenic probe (B1) that could respond to β‐lactamase within 20 s was first synthesized, and the detection limit was determined to be 0.13 nmol/L. Meanwhile, a three‐dimensional microfluidic paper‐based analytical device was fabricated for integration of B1. Also, a smartphone‐based AI cloud was developed to correct errors automatically and output results intelligently. This smart system could calibrate the temperature and pH in the β‐lactamase level detection in complex samples and mice infected with various bacteria, which shows the problem‐solving ability in interdisciplinary research, and demonstrates potential clinical benefits.

The nitrogen reduction reaction (NRR) offers a sustainable pathway for ammonia production. However, its effectiveness is hindered by the selective adsorption of nitrogen and the subsequent occurrence of the hydrogen evolution reaction. In this work, a novel and efficient NRR catalyst, Au@CuS heterostructured nanoparticles supported on carbon-coated Ni-doped CoS2 hollow nanocages (Au@CuS/Ni-CoS2/C), was designed and synthesized to enhance the conversion of N-2 to NH3 under ambient conditions. The defective Ni-CoS2@C nanocages not only provide a larger surface area for the loading of Au@CuS nanoparticles but also improve conductivity and promote synergistic effects among different components within catalyst. Both experimental investigations and density functional theory (DFT) calculations reveal that the integration of Au and CuS leads to unique inorganic donor-acceptor couplings with electron enriched in Au nanoparticles due to the higher work function of Au compared to CuS. This electron enrichment expedites the adsorption and dissociation of N-2 molecules over the electron-rich Au active sites, thereby significantly optimizing the adsorption of intermediates and catalyzing subsequent hydrogenation reduction processes. Benefiting from these synergistic advantages, the resulting Au@CuS/Ni-CoS2/C catalyst exhibited high NRR electrocatalytic activity with a maximum NH3 yield of 25.61 mu g h(-1) mg(-1) cat. and a Faraday efficiency of 14.99 % at -0.3 V (vs. reversible hydrogen electrode, RHE), surpassing those of Au@CuS, Ni-CoS2/C, and Au/Ni-CoS2/C. This work presents a new strategy for precisely adjusting the valence state of Au species, thereby facilitating the production of valuable ammonia through NRR.

Melem is the basic structural unit of g-C3N4. When directly utilized as a photocatalyst, the separation efficiency of photogenerated electron-hole pairs is low. In this study, we constructed a Melem-based all-organic heterojunction (PICN) by reacting the -NH2 at the terminal of the Melem unit with the anhydride of PDA. The photocatalytic efficiency for H2O2 production of the heterojunction is 4.2 times that of CN. Introducing -Cl at the bay position of PDI further enhances the photocatalytic H2O2 production efficiency by 1.6 times. This enhancement is attributed to the introduction of -Cl, which not only broadens the UV-visible light absorption range of the sample but also improves the interface electron transfer efficiency between Melem and PDICl. Moreover, the introduction of -Cl can also reduce the overpotential of the O2 reduction reaction on the surface of the sample. These novel findings may provide insights for the design of organic heterojunction photocatalysts.

A D–π–A typed fluorescence lifetime probe for sensitively detecting viscosity has been designed and synthesized. BSOH has been successfully applied to real-time monitoring mitochondrial viscosity in live cells by fluorescence lifetime imaging.

Developments in alternative methods of surface treatment for aluminum alloys are urgent because conventional chrome (Cr)-based protocols have toxic side effects and carcinogenic hexavalent chrome (Cr(VI)) issues. We have recently studied that in-situ cerium (Ce) sealing has huge potential to achieve improved anti-corrosion resistance. As a continuation, herein, we present a new aerosol-based wet coating method for Cr-free cerium (Ce) sealing on anodized alloy 2024-T3. The new method is based on a Beneq nFOG system, where the reactive Ce(III) and hydroperoxide (H2O2) are parallelly fed into the system to collide and produce Ce(IV)-rich mist needed for the in-situ generation of cerium oxide particles in the sealing process. The characterizations on surface morphology, composition, and cross-section reveal that nFOG method can generate highly distributed particles and clusters in the surface anodic microstructures. The performance investigations confirm that the resulting surfaces present very competitive anti-corrosion properties to those from the other methods. This work provides a new strategy to minimize the usage of chemicals in the process of wet coating surface treatment.

The aviation industry is increasingly using lightweight carbon fiber reinforced polymer composites to reduce aircraft weight and fuel consumption. These materials have a high strength-to-weight ratio and are ideal for aeronautical use, but have limited electrical conductivity and require additional lightning strike protection to prevent damage. Conventional lightning strike protection (LSP) systems made of metallic meshes add weight and corrosion issues, which justifies the development of novel, lightweight alternatives. The present paper reports a clear improvement in lightning strike damage tolerance by incorporating graphene nanoplatelets and carbon nanotubes into a one-layer carbon fiber reinforced epoxy composite. The addition of 3 wt.% graphene nanoplatelets or a combination of 2.5 wt.% graphene nanoplatelets and 0.5 wt.% carbon nanotubes significantly reduces damage after a simulated lightning strike at 60,000 A. These fillers enhance the epoxy's conductivity, but when carbon fiber is present, no substantial conductivity improvement is observed. The damage reduction is then attributed to the composite's increased ability to carry higher current densities, especially with the hybrid filling formulation, enhancing overall lightning strike tolerance. Scanning electron microscopy is used to analyze the material before and after a simulated lightning strike, while ATR-FTIR is employed to investigate the epoxy resin's thermal oxidation into diphenyl ketone. The presence of diphenyl ketone allows for damage evaluation using UV-illumination, as it exhibits bright fluorescence in the visible region. This study demonstrates the potential of reinforced nanocomposite materials as lightweight, one-layer lightning strike protection for aviation.

The electrocatalysts are critical to the electrocatalytic nitrogen reduction reaction (e-NRR) technique and its development. Herein, through morphological structure modulation, three-dimensional (3D) fibrous silica nanospheres (KCC-1) are firstly fabricated as the supporting scaffold, followed by the coating of nitrogen-doped carbon and interspersing of copper nanoparticles. The resulting carbon spheres (KNC) has very uniform interspersion of copper nanoparticles (Cu-NPs) in the 3D fibrous structure ensuring high accessible active sites for nitrogen molecules; the thin surface carbon layer offering a rich channel for electron transport; and nitrogen dopant allowing efficient electron transfer of copper atoms throng metal-nitrogen covalent bonds. When used as electrocatalysts to e-NRR, KNC exhibits good electrochemical activity, selectivity, and good stability, and can obtain an ammonia yield of approximately 6.67 µg h−1 mgcat−1 and an excellent Faraday efficiency (FE) of 8.1% in 0.1 M sodium sulfate solution at −0.4 V (vs. RHE).

Mitophagy has a critical role in maintaining cellular homeostasis through acidic lysosomes engulfing excess or impaired mitochondria, thereby pH fluctuation is one of the most significant indicators for tracking mitophagy. Then such precise pH tracking demands the fluorogenic probe that has tailored contemporaneous features, including mitochondrial-specificity, excellent biocompatibility, wide pH-sensitive range of 8.0–4.0, and especially quantitative ability. However, available molecular probes cannot simultaneously meet all the requirements since it is extremely difficult to integrate multiple functionalities into a single molecule. To fully address this issue, we herein integrate two fluorogenic pH sensitive units, a mitochondria-specific block, cell-penetrating facilitator, and biocompatible segments into an elegant silica nano scaffold, which greatly ensures the applicability for real-time tracking of pH fluctuations in mitophagy. Most significantly, at a single wavelength excitation, the integrated pH-sensitive units have spectra-distinguishable fluorescence towards alkaline and acidic pH in a broad range that covers mitochondrial and lysosomal pH, thus enabling a ratiometric analysis of pH variations during the whole mitophagy. This work also provides constructive insights into the fabrication of advanced fluorescent nanoprobes for diverse biomedical applications.

Gadolinium chelates are employed worldwide today as clinical contrast agents for magnetic resonance imaging. Until now, the commonly used linear contrast agents based on the rare-earth element gadolinium have been considered safe and well-tolerated. Recently, concerns regarding this type of contrast agent have been reported, which is why there is an urgent need to develop the next generation of stable contrast agents with enhanced spin-lattice relaxation, as measured by improved T-1 relaxivity at lower doses. Here, we show that by the integration of gadolinium ions in cerium oxide nanoparticles, a stable crystalline 5 nm sized nanoparticulate system with a homogeneous gadolinium ion distribution is obtained. These cerium oxide nanoparticles with entrapped gadolinium deliver strong T-1 relaxivity per gadolinium ion (T-1 relaxivity, r(1) = 12.0 mM(-1) s(-1)) with the potential to act as scavengers of reactive oxygen species (ROS). The presence of Ce3+ sites and oxygen vacancies at the surface plays a critical role in providing the antioxidant properties. The characterization of radial distribution of Ce3+ and Ce4+ oxidation states indicated a higher concentration of Ce3+ at the nanoparticle surfaces. Additionally, we investigated the ROS-scavenging capabilities of pure gadolinium-containing cerium oxide nanoparticles by bioluminescent imaging in vivo, where inhibitory effects on ROS activity are shown.