Nanozymatic Antioxidant System Based on MoS2 Nanosheets

Advances in Nano-Immunomodulatory Systems for the Treatment of Acute Kidney Injury

Acute kidney injury (AKI) occurs when there is an imbalance in the immune microenvironment, leading to ongoing and excessive inflammation. Numerous immunomodulatory therapies have been suggested for the treatment of AKI, the current immunomodulatory treatment delivery systems are suboptimal and lack efficiency. Given the lack of effective treatment, AKI can result in multi-organ dysfunction and even death, imposing a significant healthcare burden on both the family and society. This underscores the necessity for innovative treatment delivery systems, such as nanomaterials, to better control pathological inflammation, and ultimately enhance AKI treatment outcomes. Despite the modification of numerous immunomodulatory nanomaterials to target the AKI immune microenvironment with promising therapeutic results, the literature concerning their intersection is scarce. In this article, the pathophysiological processes of AKI are outlined, focusing on the immune microenvironment, discuss significant advances in the comprehension of AKI recovery, and describe the multifunctionality and suitability of nanomaterial-based immunomodulatory treatments in managing AKI. The main obstacles and potential opportunities in the swiftly advancing research field are also clarified.

Transition metal phosphide/ molybdenum disulfide heterostructures towards advanced electrochemical energy storage: recent progress and challenges

Transition metal phosphide @ molybdenum disulfide (TMP@MoS2) heterostructures, consisting of TMP as the core main catalytic body and MoS2 as the outer shell, can solve the three major problems in the field of renewable energy storage and catalysis, such as lack of resources, cost factors, and low cycling stability. The heterostructures synergistically combine the excellent conductivity and electrochemical performance of transition metal phosphides with the structural robustness and catalytic activity of molybdenum disulfide, which holds great promise for clean energy. This review addresses the advantages of TMP@MoS2 materials and their synthesis methods-e.g., hydrothermal routes and chemical vapor deposition regarding scalability and cost. Their electrochemical energy storage and catalytic functions e.g., hydrogen and oxygen evolution reactions (HER and OER) are also extensively explored. Their potential within battery and supercapacitor technologies is also assessed against leading performance metrics. Challenges toward industry-scale scalability, longevity, and environmental sustainability are also addressed, as are optimization and large-scale deployment strategies.

pH-responsive molybdenum disulphide composite nanomaterials for skin wound healing using "ROS leveraging" synergistic immunomodulation

With the increasing prevalence of drug-resistant bacterial infections, wound bacterial infections have evolved into an escalating medical problem that poses a threat to the individual health as well as global public health. Traditional drug therapy not only suffers from a single treatment method, low drug utilisation and limited therapeutic effect, but long-term antibiotic abuse has significantly increased bacterial resistance. It is imperative to develop an antibiotic-free biomaterial with antibacterial and anti-inflammatory properties. The current use of photothermal therapy (PTT) and photodynamic therapy (PDT) relies on the generation of massive reactive oxygen species (ROS), which inevitably aggravates the inflammatory response. Herein, we developed AuAg bimetallic nanoparticles based on PDA modification and prepared a novel MoS2-based composite nanomaterials (AuAg@PDA-MoS2 NPs) with multiple mechanisms of antibacterial and anti-inflammatory potentials through the adhesion of PDA. In the early phase, PDT and PTT generated a large amount of ROS for rapid sterilisation. While in the later stage, MoS2 mimicked the peroxidase activity to leverage the ROS, balancing the generation of ROS in the infected environment to achieve the long-term anti-inflammatory. In vitro experiments showed that the killing efficiency of AuAg@PDA-MoS2 NPs was nearly 99 % under the irradiation of 808 nm near-infrared light for 10 min, which demonstrated excellent antibacterial activity. In vivo experiments showed that 808 nm NIR-assisted AuAg@PDA-MoS2 NPs to effectively inhibit infection, alleviated the inflammation, and accelerated the wound healing process. Therefore, AuAg@PDA-MoS2 NPs as a novel biomaterial could achieve programmed antimicrobial and anti-inflammatory effects, which has a promising potential for future application in the treatment of infected wounds.

Engineered molybdenum disulfide nanosheets as scavengers against oxidative stress inhibit ferroptosis to alleviate acute kidney injury

Acute kidney injury (AKI) is a common clinical kidney dysfunction associated with high morbidity, elevated mortality, and poor prognosis. It results from redox imbalance caused by abnormal excess production of endogenous reactive oxygen species (ROS) at the renal tubules, which in turn initiates a series of pathological processes, such as cellular apoptosis, necrosis, and ferroptosis, eventually leading to structural and functional impairment of the kidney. Thereinto, ferroptosis induced by the lethal accumulation of lipid peroxidation is extensively involved in renal damage. Nanotechnology-mediated therapeutic strategies to scavenge excessive ROS and thereby inhibit ferroptosis represents a promising strategy for AKI management. Herein, we report two engineered ultrathin molybdenum disulfide (MoS2) nanosheets (NSs) modified with polyvinylpyrrolidone (PVP) and bovine serum albumin (BSA), respectively, with excellent biocompatibility and antioxidative defense capability for AKI treatment. The engineered NSs, with a readily variable valence state of molybdenum ions, rescued cell viability by consuming various forms of cellular ROS and significantly facilitated glutathione peroxidase 4 (GPX4) expression to mitigate ferroptosis in renal tubular epithelial cells. In a glycerol-induced AKI mouse model, the PVP-MoS2 NSs were largely accumulated in the injured kidneys, where they provided robust antioxidative protection against ROS attack and suppressed the oxidative stress-induced inflammatory response, thereby maintaining normal kidney function. Of the two engineered NSs, PVP-MoS2 displayed superior biological stability and therapeutic effects and could thus serve as a powerful antioxidant platform for use in the treatment of AKI and other ROS-associated diseases. This study underscores the potential of two-dimensional nanomaterials in precisely treating AKI and other ferroptosis-related diseases.

Design and advances in antioxidant hydrogels for ROS-induced oxidative disease

Reactive oxygen species (ROS) play a crucial role in human physiological processes, but oxidative stress caused by excessive ROS may lead to a variety of acute and chronic diseases. Despite the development of various strategies and biomaterials, an efficiently and broadly applied method for treatment of ROS-induced oxidative disease remains a bottleneck. Aiming to improve the local oxidative stress environment, numerous bioactive hydrogels with antioxidant properties have emerged and are proven to quickly and continuously eliminate excessive ROS. To deeply understand the design principles and applications of antioxidant hydrogels is highly beneficial for designing antioxidant hydrogels for treatment of oxidative disease. This review provides a detailed summary of recent advances in design and applications of antioxidant hydrogels for various ROS-induced oxidative diseases. In this review, the kinds of antioxidant components in antioxidant hydrogels are outlined in detail. Additionally, the crosslinking methods and the biomedical applications of antioxidant hydrogels are widely summarized and discussed, especially focusing on their usage in different types of diseases and the attention given to the treatment of diseases such as skin wounds, myocardial infarction, and osteoarthritis. Finally, the future development direction of antioxidant hydrogel is further proposed. STATEMENT OF SIGNIFICANCE: Oxidative stress is a pivotal biochemical process that plays a critical role in cellular homeostasis. Excessive cellular oxidative stress triggers an inflammatory response, which is implicated in a spectrum of associated diseases. Given the critical need for managing oxidative stress, antioxidant therapies have become a vital focus in medical research. Hydrogels have garnered substantial interest among biomaterial scientists due to their hydrophilic nature and biocompatibility. The review delves into the realm of antioxidant hydrogels, encompassing the classification of antioxidant components, the synthesis and fabrication of hydrogels, and a comprehensive overview of the biological applications and challenges of these antioxidant hydrogels. Aiming to provide new perspectives for researchers in developing cutting-edge therapeutic approaches that leverage antioxidant hydrogels.

Bifunctional mesoporous HMUiO-66-NH2 nanoparticles for bone remodeling and ROS scavenging in periodontitis therapy

Periodontal bone defects represent an irreversible consequence of periodontitis associated with reactive oxygen species (ROS). However, indiscriminate removal of ROS proves to be counterproductive for tissue repair and insufficient for addressing existing bone defects. In the treatment of periodontitis, it is crucial to rationally alleviate local ROS while simultaneously promoting bone regeneration. In this study, Zr-based large-pore hierarchical mesoporous metal-organic framework (MOF) nanoparticles (NPs) HMUiO-66-NH2 were successfully proposed as bifunctional nanomaterials for bone regeneration and ROS scavenging in periodontitis therapy. HMUiO-66-NH2 NPs demonstrated outstanding biocompatibility both in vitro and in vivo. Significantly, these NPs enhanced the osteogenic differentiation of bone mesenchymal stem cells (BMSCs) under normal and high ROS conditions, upregulating osteogenic gene expression and mitigating oxidative stress. Furthermore, in vivo imaging revealed a gradual degradation of HMUiO-66-NH2 NPs in periodontal tissues. Local injection of HMUiO-66-NH2 effectively reduced bone defects and ROS levels in periodontitis-induced C57BL/6 mice. RNA sequencing highlighted that differentially expressed genes (DEGs) are predominantly involved in bone tissue development, with notable upregulation in Wnt and TGF-β signaling pathways. In conclusion, HMUiO-66-NH2 exhibits dual functionality in alleviating oxidative stress and promoting bone repair, positioning it as an effective strategy against bone resorption in oxidative stress-related periodontitis.

Multienzyme-Activity Sulfur Quantum Dot Nanozyme-Mediated Cascade Reactions in Whole-Stage Symptomatic Therapy of Infected Bone Defects

Integrating the therapeutic efficacy of early bacterial clearance, midstage inflammatory remission, and late-stage effective tissue healing is considered a pivotal challenge in symptomatic treatment of infected bone defects (IBDs). Herein, a microenvironment-adaptive nanoplatform based on a sulfur quantum dot (SQD) nanozyme was proposed for whole-stage symptomatic therapy of IBDs by mediating the sequence of enzyme cascade reactions. The SQD nanozyme prepared by a size-engineering modification strategy exhibits enhanced multienzyme activity compared to conventional micrometer- and nanometer-sized sulfur particles. In the early stages of bacterial infection, the SQD nanozyme self-activates superoxide dismutase-peroxidase activity, resulting in the production of reactive oxygen species (ROS) that effectively eliminate bacteria. After disinfection, the SQD nanozyme self-switched to superoxide dismutase-catalase mimetic behavior and eliminated excess ROS, efficiently promoting macrophage polarization to an anti-inflammatory phenotype in the midinflammatory microenvironment. Importantly, SQD nanozyme-mediated M2 macrophage polarization significantly improved the damaged bone immune microenvironment, accelerating bone repair at late-stage tissue healing. Therefore, this strategy offers a promising and viable approach for the treatment of infectious tissue healing by developing multienzyme-activity nanozymes that respond intelligently to the microenvironment at different stages, effectively fighting bacteria, reducing inflammation, and promoting tissue regeneration for whole-stage symptomatic therapy.

Nanocomposite membrane for simultaneous removal of dye and heavy metal ions from wastewater

A catalytic 2D nanocomposite membrane (CNC) was fabricated and used for the simultaneous removal of methylene blue (MB) and heavy metal ions in aqueous solution. Both molybdenum disulfide (MoS2) and graphene oxide (GO) were incorporated in a chitosan polymer matrix, and the fabricated CNC membrane exhibited performance as a nanofiltration membrane. Here MoS2 activated H2O2 to generate very reactive oxygen species (ROS), such as hydroxyl radicals, allowing the catalytic breakdown of the organic dye contaminants and reducing heavy metal ions. Greater than 99% efficiencies were achieved for the simultaneous removal of methylene blue (MB) and the heavy metal Co2+. Moreover, significant removal efficiencies in the 89-96% range were demonstrated for other heavy metal ions of Cu2+, Pb2+, and Ni2+. The generated ROS were trapped by terephthalic acid (TA) and confirmed by fluorescence emission spectroscopy. The used membrane was regenerated and reused with a flux recovery rate of more than 91% after 4 experimental cycles. These promising results indicated that the novel catalytic 2D nanocomposite membrane showed a high potential for the simultaneous removal of organic contraminants and heavy metal ions from textile industry wastewater.

2D MXene Biomaterials for Catalytic Medical Applications

In recent years, two-dimensional transition metal carbides, nitrides, and carbonitrides, termed as MXenes, have been widely applied in energy storage, photocatalysis and biomedicine owing to their unique physicochemical properties of large specific surface area, high electrical conductivity, excellent optical performance, good stability, etc. Moreover, due to their strong light absorption capacity in the first and second near-infrared bio-window, and their ability of being simply functionalized with multiple organic/inorganic materials, MXene biomaterials have shown great potential in the field of catalytic therapy. This review will summarize the common catalytic mechanism of MXene biomaterials and their latest applications in catalytic medicine such as tumor therapy, antibacterial and anti-inflammatory, and present the current challenges and opportunities in clinical translation for future development to promote the advancement of MXene biomaterials in the field of catalytic medicine.

Stimulus-responsive biomacromolecule wound dressings for enhanced drug delivery in chronic wound healing: A review

Addressing the challenge of poor wound healing in chronic wounds remains complex, as the underlying physiological mechanisms are still not fully understood. Traditional wound dressings often fail to meet the specific needs of the chronic wound healing process. Recently, considerable interest has shifted toward employing biomacromolecule-based smart wound dressings to facilitate wound healing. These stimuli-responsive dressings have undergone substantial development to manage local drug delivery, demonstrating promising therapeutic effects in treating chronic wound defects. They have displayed improved drug release profiles both in vitro and in vivo. Recently, there have been advancements in the development of innovative dual and multi-stimuli responsive dressings that react to combinations of signals including pH-temperature, pH-enzyme, pH-ROS, pH-glucose, pH-NIR, and multiple stimuli. This paper offers an in-depth review of recent progress in responsive wound dressings based on biomacromolecules, with a specific focus on their design, drug release capabilities, and therapeutic advantages.

Computer-aided nanodrug discovery: recent progress and future prospects

Nanodrugs, which utilise nanomaterials in disease prevention and therapy, have attracted considerable interest since their initial conceptualisation in the 1990s. Substantial efforts have been made to develop nanodrugs for overcoming the limitations of conventional drugs, such as low targeting efficacy, high dosage and toxicity, and potential drug resistance. Despite the significant progress that has been made in nanodrug discovery, the precise design or screening of nanomaterials with desired biomedical functions prior to experimentation remains a significant challenge. This is particularly the case with regard to personalised precision nanodrugs, which require the simultaneous optimisation of the structures, compositions, and surface functionalities of nanodrugs. The development of powerful computer clusters and algorithms has made it possible to overcome this challenge through in silico methods, which provide a comprehensive understanding of the medical functions of nanodrugs in relation to their physicochemical properties. In addition, machine learning techniques have been widely employed in nanodrug research, significantly accelerating the understanding of bio-nano interactions and the development of nanodrugs. This review will present a summary of the computational advances in nanodrug discovery, focusing on the understanding of how the key interfacial interactions, namely, surface adsorption, supramolecular recognition, surface catalysis, and chemical conversion, affect the therapeutic efficacy of nanodrugs. Furthermore, this review will discuss the challenges and opportunities in computer-aided nanodrug discovery, with particular emphasis on the integrated "computation + machine learning + experimentation" strategy that can potentially accelerate the discovery of precision nanodrugs.

A two-in-one molybdenum disulfide-chitosan nanoparticles system for activating plant defense mechanisms and reactive oxygen species to treat Citrus Huanglongbing

Citrus Huanglongbing (HLB) poses an enormous challenge to Citrus cultivation worldwide, necessitating groundbreaking interventions beyond conventional pharmaceutical methods. In this study, we propose molybdenum disulfide-chitosan nanoparticles (MoS2-CS NPs) through electrostatic adsorption, preserving the plant-beneficial properties of molybdenum disulfide (MoS2), while enhancing its antibacterial effectiveness through chitosan modification. MoS2-CS NPs exhibited significant antibacterial efficacy against RM1021, and the closest relatives to Candidatus Liberibacter asiaticus (CLas), Erwinia carotovora, and Xanthomonas citri achieved survival rates of 7.40 % ± 1.74 %, 8.94 % ± 1.40 %, and 6.41 % ± 0.56 %, respectively. In vivo results showed, CLas survival rate of 10.42 % ± 3.51 %. Furthermore, treatment with MoS2-CS NPs resulted in an increase in chlorophyll and carotenoid content. Concomitantly, a significant reduction in malondialdehyde (MDA), soluble sugar, hydrogen peroxide (H2O2), and starch contents was also observed. Mechanistically, MoS2-CS NPs enhanced the activity of antioxidant-related enzymes by upregulating the expression of antioxidant genes, thereby galvanizing the antioxidant system to alleviate oxidative stress. Collectively, this dual functionality-combining direct antibacterial action with the activation of plant defense mechanisms-marks a promising strategy for managing Citrus Huanglongbing and suggests potential agricultural applications for MoS2-based antibacterial treatments.

Tunable Structured 2D Nanobiocatalysts: Synthesis, Catalytic Properties and New Horizons in Biomedical Applications

2D materials have offered essential contributions to boosting biocatalytic efficiency in diverse biomedical applications due to the intrinsic enzyme-mimetic activity and massive specific surface area for loading metal catalytic centers. Since the difficulty of high-quality synthesis, the varied structure, and the tough choice of efficient surface loading sites with catalytic properties, the artificial building of 2D nanobiocatalysts still faces great challenges. Here, in this review, a timely and comprehensive summarization of the latest progress and future trends in the design and biotherapeutic applications of 2D nanobiocatalysts is provided, which is essential for their development. First, an overview of the synthesis-structure-fundamentals and structure-property relationships of 2D nanobiocatalysts, both metal-free and metal-based is provided. After that, the effective design of the active sites of nanobiocatalysts is discussed. Then, the progress of their applied research in recent years, including biomedical analysis, biomedical therapeutics, pharmacokinetics, and toxicology is systematically highlighted. Finally, future research directions of 2D nanobiocatalysts are prospected. Overall, this review to provide cutting-edge and multidisciplinary guidance for accelerating future developments and biomedical applications of 2D nanobiocatalysts is expected.

Composite hydrogels with antioxidant and robust adhesive properties for the prevention of radiation-induced dermatitis

Radiotherapy is a pivotal means of cancer treatment, but it often leads to radiation dermatitis, a skin injury caused by radiation-induced excess reactive oxygen species (ROS). Scavenging free radicals in the course of radiation therapy will be an effective means to prevent radiation dermatitis. This study demonstrates a novel double network hydrogel doped with MoS2 nanosheets for the prevention of radiation-induced dermatitis. The resultant SPM hydrogel constructed from polyacrylamide (PAM) and sodium alginate (SA) nanofiber presented favorable mechanical and adhesion properties. It could conform well to the human body's irregular contours without secondary dressing fixation, making it suitable for skin protection applications. The in vitro and in vivo experiments showed that the antioxidant properties conferred by MoS2 nanosheets enable SPM to effectively mitigate excessive ROS and reduce oxidative stress, thereby preventing radiation dermatitis caused by oxidative damage. Biosafety assessments indicated good biocompatibility of the composite hydrogel, suggesting SPM's practicality and potential as an external dressing for skin radiation protection.

Advances in metal-organic framework-based nanozymes in ROS scavenging medicine

Reactive oxygen species (ROS) play important roles in regulating various physiological functions in the human body, however, excessive ROS can cause serious damage to the human body, considering the various limitations of natural enzymes as scavengers of ROS in the body, the development of better materials for the scavenging of ROS is of great significance to the biomedical field, and nanozymes, as a kind of nanomaterials which can show the activity of natural enzymes. Have a good potential for the development in the area of ROS scavenging. Metal-organic frameworks (MOFs), which are porous crystalline materials with a periodic network structure composed of metal nodes and organic ligands, have been developed with a variety of active nanozymes including catalase-like, superoxide dismutase-like, and glutathione peroxidase-like enzymes due to the adjustability of active sites, structural diversity, excellent biocompatibility, and they have shown a wide range of applications and prospects. In the present review, we first introduce three representative natural enzymes for ROS scavenging in the human body, methods for the detection of relevant enzyme-like activities and mechanisms of enzyme-like clearance are discussed, meanwhile, we systematically summarize the progress of the research on MOF-based nanozymes, including the design strategy, mechanism of action, and medical application, etc. Finally, the current challenges of MOF-based nanozymes are summarized, and the future development direction is anticipated. We hope that this review can contribute to the research of MOF-based nanozymes in the medical field related to the scavenging of ROS.

Transition-Metal-Oxide-Based Nanozymes for Antitumor Applications

Transition metal oxide (TMO)-based nanozymes have appeared as hopeful tools for antitumor applications due to their unique catalytic properties and ability to modulate the tumor microenvironment (TME). The purpose of this review is to provide an overview of the latest progress made in the field of TMO-based nanozymes, focusing on their enzymatic activities and participating metal ions. These nanozymes exhibit catalase (CAT)-, peroxidase (POD)-, superoxide dismutase (SOD)-, oxidase (OXD)-, and glutathione oxidase (GSH-OXD)-like activities, enabling them to regulate reactive oxygen species (ROS) levels and glutathione (GSH) concentrations within the TME. Widely studied transition metals in TMO-based nanozymes include Fe, Mn, Cu, Ce, and the hybrid multimetallic oxides, which are also summarized. The review highlights several innovative nanozyme designs and their multifunctional capabilities. Despite the significant progress in TMO-based nanozymes, challenges such as long-term biosafety, targeting precision, catalytic mechanisms, and theoretical supports remain to be addressed, and these are also discussed. This review contributes to the summary and understanding of the rapid development of TMO-based nanozymes, which holds great promise for advancing nanomedicine and improving cancer treatment.

Sequential Regulation of Local Reactive Oxygen Species by Ir@Cu/Zn-MOF Nanoparticles for Promoting Infected Wound Healing

Most antimicrobials treat wound infections by an oxidation effect, which is induced by the generation of reactive oxygen species (ROS). However, the potential harm of the prolonged high level of ROS should not be ignored. In this study, we presented a novel cascade-reaction nanoparticle, Ir@Cu/Zn-MOF, to effectively regulate the ROS level throughout the healing progress of the infected wound. The nanoparticles consisted of a copper/zinc-modified metal-organic framework (Cu/Zn-MOF) serving as the external structure and an inner core composed of Ir-PVP NPs, which were achieved through a process known as "bionic mineralization". The released Cu2+ and Zn2+ from the shell structure contributed to the production of ROS, which acted as antimicrobial agents during the initial stage. With the disintegration of the shell, the Ir-PVP NP core was gradually released, exhibiting the property of multiple antioxidant enzyme activities, thereby playing an important role in clearing excessive ROS and alleviating oxidative stress. In a full-layer infected rat wound model, Ir@Cu/Zn-MOF nanoparticles presented exciting performance in promoting wound healing by clearing the bacteria and accelerating neovascularization as well as collagen deposition. This study provided a promising alternative for the repair of infected wounds.

Unveiling the role of inorganic nanoparticles in Earth's biochemical evolution through electron transfer dynamics

This article explores the intricate interplay between inorganic nanoparticles and Earth's biochemical history, with a focus on their electron transfer properties. It reveals how iron oxide and sulfide nanoparticles, as examples of inorganic nanoparticles, exhibit oxidoreductase activity similar to proteins. Termed "life fossil oxidoreductases," these inorganic enzymes influence redox reactions, detoxification processes, and nutrient cycling in early Earth environments. By emphasizing the structural configuration of nanoparticles and their electron conformation, including oxygen defects and metal vacancies, especially electron hopping, the article provides a foundation for understanding inorganic enzyme mechanisms. This approach, rooted in physics, underscores that life's origin and evolution are governed by electron transfer principles within the framework of chemical equilibrium. Today, these nanoparticles serve as vital biocatalysts in natural ecosystems, participating in critical reactions for ecosystem health. The research highlights their enduring impact on Earth's history, shaping ecosystems and interacting with protein metal centers through shared electron transfer dynamics, offering insights into early life processes and adaptations.

Peroxidase like Zn doped Prussian blue facilitates salinity tolerance in winter wheat through seed dressing

Salt stress severely limits the growth and yield of wheat in saline-alkali soil. While nanozymes have shown promise in mitigating abiotic stress by scavenging reactive oxygen species (ROS) in plants, their application in alleviating salt stress for wheat is still limited. This study synthesized a highly active nanozyme catalyst known as ZnPB (Zn-modified Prussian blue) to improve the yield and quality of wheat in saline soil. According to the Michaelis-Menten equation, ZnPB demonstrates exceptional peroxidase-like enzymatic activity, thereby mitigating oxidative damage caused by salt stress. Additionally, studies have shown that the ZnPB nanozyme is capable of regulating intracellular Na+ efflux and K+ retention in wheat, resulting in a decrease in proline and soluble protein levels while maintaining the integrity of macromolecules within the cell. Consequently, field experiments demonstrated that the ZnPB nanozyme increased winter wheat yield by 12.15 %, while also significantly enhancing its nutritional quality. This research offers a promising approach to improving the salinity tolerance of wheat, while also providing insights into its practical application.

Acetylcholine triggered enzymatic cascade reaction based on Fe7S8 nanoflakes catalysis for organophosphorus pesticides visual detection

BACKGROUND

Organophosphorus pesticides (OPs) play important roles in the natural environment, agricultural fields, and biological prevention. The development of OPs detection has gradually become an effective strategy to avoid the dangers of pesticides abuse and solve the severe environmental and health problems in humans. Although conventional assays for OPs analysis such as the bulky instrument required analytical methods have been well-developed, it still remains the limitation of inconvenient, inefficient and lab-dependence analysis in real samples. Hence, there is an urgent demand to develop efficient detection methods for OPs analysis in real scenarios.

RESULTS

Here, by virtue of the highly efficient catalytic performance in Fe7S8 nanoflakes (Fe7S8 NFs), we propose an OPs detection method that rationally integrated Fe7S8 NFs into the acetylcholine (ACh) triggered enzymatic cascade reaction (ATECR) for proceeding better detection performances. In this method, OPs serve as the enzyme inhibitors for inhibiting ATECR among ACh, acetylcholinesterase (AChE), and choline oxidase (CHO), then reduce the generation of H2O2 to suppress the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) that catalyzed by Fe7S8 NFs. Benefiting from the integration of Fe7S8 NFs and ATECR, it enables a sensitive detection for OPs (e.g. dimethoate). The proposed method has presented good linear ranges of OPs detection ranging from 0.1 to 10 μg mL-1. Compared to the other methods, the comparable limits of detection (LOD) of OPs are as low as 0.05 μg mL-1.

SIGNIFICANCE

Furthermore, the proposed method has also achieved a favorable visual detection performance of revealing OPs analysis in real samples. The visual signals of OPs can be transformed into RGB values and gathered by using smartphones, indicating the great potential in simple, sensitive, instrument-free and on-site analysis of pesticide residues in environmental monitoring and biosecurity research.

Bacteria-responsive programmed self-activating antibacterial hydrogel to remodel regeneration microenvironment for infected wound healing

There is still an urgent need to develop hydrogels with intelligent antibacterial ability to achieve on-demand treatment of infected wounds and accelerate wound healing by improving the regeneration microenvironment. We proposed a strategy of hydrogel wound dressing with bacteria-responsive self-activating antibacterial property and multiple nanozyme activities to remodel the regeneration microenvironment in order to significantly promote infected wound healing. Specifically, pH-responsive H2O2 self-supplying composite nanozyme (MSCO) and pH/enzyme-sensitive bacteria-responsive triblock micelles encapsulated with lactate oxidase (PPEL) were prepared and encapsulated in hydrogels composed of L-arginine-modified chitosan (CA) and phenylboronic acid-modified oxidized dextran (ODP) to form a cascade bacteria-responsive self-activating antibacterial composite hydrogel platform. The hydrogels respond to multifactorial changes of the bacterial metabolic microenvironment to achieve on-demand antibacterial and biofilm eradication through transformation of bacterial metabolites, and chemodynamic therapy enhanced by nanozyme activity in conjunction with self-driven nitric oxide (NO) release. The composite hydrogel showed 'self-diagnostic' treatment for changes in the wound microenvironment. Through self-activating antibacterial therapy in the infection stage to self-adaptive oxidative stress relief and angiogenesis in the post-infection stage, it promotes wound closure, accelerates wound collagen deposition and angiogenesis, and completely improves the microenvironment of infected wound regeneration, which provides a new method for the design of intelligent wound dressings.

Antioxidant Hydrogels: Antioxidant Mechanisms, Design Strategies, and Applications in the Treatment of Oxidative Stress-Related Diseases

Oxidative stress is a biochemical process that disrupts the redox balance due to an excess of oxidized substances within the cell. Oxidative stress is closely associated with a multitude of diseases and health issues, including cancer, diabetes, cardiovascular diseases, neurodegenerative disorders, inflammatory conditions, and aging. Therefore, the developing of antioxidant treatment strategies has emerged as a pivotal area of medical research. Hydrogels have garnered considerable attention due to their exceptional biocompatibility, adjustable physicochemical properties, and capabilities for drug delivery. Numerous antioxidant hydrogels have been developed and proven effective in alleviating oxidative stress. In the pursuit of more effective treatments for oxidative stress-related diseases, there is an urgent need for advanced strategies for the fabrication of multifunctional antioxidant hydrogels. Consequently, the authors' focus will be on hydrogels that possess exceptional reactive oxygen species and reactive nitrogen species scavenging capabilities, and their role in oxidative stress therapy will be evaluated. Herein, the antioxidant mechanisms and the design strategies of antioxidant hydrogels and their applications in oxidative stress-related diseases are discussed systematically in order to provide critical insights for further advancements in the field.

Antioxidant nanozymes as next-generation therapeutics to free radical-mediated inflammatory diseases: A comprehensive review

Recent developments in exploring the biological enzyme mimicking properties in nanozymes have opened a separate avenue, which provides a suitable alternative to the natural antioxidants and enzymes. Due to high and tunable catalytic activity, low cost of synthesis, easy surface modification, and good biocompatibility, nanozymes have garnered significant research interest globally. Several inorganic nanomaterials have been investigated to exhibit catalytic activities of some of the key natural enzymes, including superoxide dismutase (SOD), catalase, glutathione peroxidase, peroxidase, and oxidase, etc. These nanozymes are used for diverse biomedical applications including therapeutics, imaging, and biosensing in various cells/tissues and animal models. In particular, inflammation-related diseases are closely associated with reactive oxygen and reactive nitrogen species, and therefore effective antioxidants could be excellent therapeutics due to their free radical scavenging ability. Although biological enzymes and other artificial antioxidants could perform well in scavenging the reactive oxygen and nitrogen species, however, suffer from several drawbacks such as the requirement of strict physiological conditions for enzymatic activity, limited stability in the environment beyond their optimum pH and temperature, and high cost of synthesis, purification, and storage make then unattractive for broad-spectrum applications. Therefore, this review systematically and comprehensively presents the free radical-mediated evolution of various inflammatory diseases (inflammatory bowel disease, mammary gland fibrosis, and inflammation, acute injury of the liver and kidney, mammary fibrosis, and cerebral ischemic stroke reperfusion) and their mitigation by various antioxidant nanozymes in the biological system. The mechanism of free radical scavenging by antioxidant nanozymes under in vitro and in vivo experimental models and catalytic efficiency comparison with corresponding natural enzymes has also been presented.

Reaction Mechanisms and Kinetics of Nanozymes: Insights from Theory and Computation

"Nanozymes" usually refers to inorganic nanomaterials with enzyme-like catalytic activities. The research into nanozymes is one of the hot topics on the horizon of interdisciplinary science involving materials, chemistry, and biology. Although great progress has been made in the design, synthesis, characterization, and application of nanozymes, the study of the underlying microscopic mechanisms and kinetics is still not straightforward. Density functional theory (DFT) calculations compute the potential energy surfaces along the reaction coordinates for chemical reactions, which can give atomistic-level insights into the micro-mechanisms and kinetics for nanozymes. Therefore, DFT calculations have been playing an increasingly important role in exploring the mechanisms and kinetics for nanozymes in the past years. The calculations either predict the microscopic details for the catalytic processes to complement the experiments or further develop theoretical models to depict the physicochemical rules. In this review, the corresponding research progress is summarized. Particularly, the review focuses on the computational studies that closely interplay with the experiments. The relevant experimental results without DFT calculations will be also briefly discussed to offer a historic overview of how the computations promote the understanding of the microscopic mechanisms and kinetics of nanozymes.

Multienzyme-Like Nanozymes: Regulation, Rational Design, and Application

Nanomaterials with more than one enzyme-like activity are termed multienzymic nanozymes, and they have received increasing attention in recent years and hold huge potential to be applied in diverse fields, especially for biosensing and therapeutics. Compared to single enzyme-like nanozymes, multienzymic nanozymes offer various unique advantages, including synergistic effects, cascaded reactions, and environmentally responsive selectivity. Nevertheless, along with these merits, the catalytic mechanism and rational design of multienzymic nanozymes are more complicated and elusive as compared to single-enzymic nanozymes. In this review, the multienzymic nanozymes classification scheme based on the numbers/types of activities, the internal and external factors regulating the multienzymatic activities, the rational design based on chemical, biomimetic, and computer-aided strategies, and recent progress in applications attributed to the advantages of multicatalytic activities are systematically discussed. Finally, current challenges and future perspectives regarding the development and application of multienzymatic nanozymes are suggested. This review aims to deepen the understanding and inspire the research in multienzymic nanozymes to a greater extent.

Promoting collateral formation in type 2 diabetes mellitus using ultra-small nanodots with autophagy activation and ROS scavenging

BACKGROUND

Impaired collateral formation is a major factor contributing to poor prognosis in type 2 diabetes mellitus (T2DM) patients with atherosclerotic cardiovascular disease. However, the current pharmacological treatments for improving collateral formation remain unsatisfactory. The induction of endothelial autophagy and the elimination of reactive oxygen species (ROS) represent potential therapeutic targets for enhancing endothelial angiogenesis and facilitating collateral formation. This study investigates the potential of molybdenum disulfide nanodots (MoS2 NDs) for enhancing collateral formation and improving prognosis.

RESULTS

Our study shows that MoS2 NDs significantly enhance collateral formation in ischemic tissues of diabetic mice, improving effective blood resupply. Additionally, MoS2 NDs boost the proliferation, migration, and tube formation of endothelial cells under high glucose/hypoxia conditions in vitro. Mechanistically, the beneficial effects of MoS2 NDs on collateral formation not only depend on their known scavenging properties of ROS (H2O2, •O2-, and •OH) but also primarily involve a molecular pathway, cAMP/PKA-NR4A2, which promotes autophagy and contributes to mitigating damage in diabetic endothelial cells.

CONCLUSIONS

Overall, this study investigated the specific mechanism by which MoS2 NDs mediated autophagy activation and highlighted the synergy between autophagy activation and antioxidation, thus suggesting that an economic and biocompatible nano-agent with dual therapeutic functions is highly preferable for promoting collateral formation in a diabetic context, thus, highlighting their therapeutic potential.

Inorganic Fe-O and Fe-S oxidoreductases: paradigms for prebiotic chemistry and the evolution of enzymatic activity in biology

Oxidoreductases play crucial roles in electron transfer during biological redox reactions. These reactions are not exclusive to protein-based biocatalysts; nano-size (<100 nm), fine-grained inorganic colloids, such as iron oxides and sulfides, also participate. These nanocolloids exhibit intrinsic redox activity and possess direct electron transfer capacities comparable to their biological counterparts. The unique metal ion architecture of these nanocolloids, including electron configurations, coordination environment, electron conductivity, and the ability to promote spontaneous electron hopping, contributes to their transfer capabilities. Nano-size inorganic colloids are believed to be among the earliest 'oxidoreductases' to have 'evolved' on early Earth, playing critical roles in biological systems. Representing a distinct type of biocatalysts alongside metalloproteins, these nanoparticles offer an early alternative to protein-based oxidoreductase activity. While the roles of inorganic nano-sized catalysts in current Earth ecosystems are intuitively significant, they remain poorly understood and underestimated. Their contribution to chemical reactions and biogeochemical cycles likely helped shape and maintain the balance of our planet's ecosystems. However, their potential applications in biomedical, agricultural, and environmental protection sectors have not been fully explored or exploited. This review examines the structure, properties, and mechanisms of such catalysts from a material's evolutionary standpoint, aiming to raise awareness of their potential to provide innovative solutions to some of Earth's sustainability challenges.

Deeper insight into ferroptosis: association with Alzheimer's, Parkinson's disease, and brain tumors and their possible treatment by nanomaterials induced ferroptosis

Ferroptosis is an emerging and novel type of iron-dependent programmed cell death which is mainly caused by the excessive deposition of free intracellular iron in the brain cells. This deposited free iron exerts a ferroptosis pathway, resulting in lipid peroxidation (LiPr). There are mainly three ferroptosis pathways viz. iron metabolism-mediated cysteine/glutamate, and LiPr-mediated. Iron is required by the brain as a redox metal for several physiological activities. Due to the iron homeostasis balance disruption, the brain gets adversely affected which further causes neurodegenerative diseases (NDDs) like Parkinson's and Alzheimer's disease, strokes, and brain tumors like glioblastoma (GBS), and glioma. Nanotechnology has played an important role in the prevention and treatment of these NDDs. A synergistic effect of nanomaterials and ferroptosis could prove to be an effective and efficient approach in the field of nanomedicine. In the current review, the authors have highlighted all the latest research in the field of ferroptosis, specifically emphasizing on the role of major molecular key players and various mechanisms involved in the ferroptosis pathway. Moreover, here the authors have also addressed the correlation of ferroptosis with the pathophysiology of NDDs and theragnostic effect of ferroptosis and nanomaterials for the prevention and treatment of NDDs.

Mimicking Antioxidases and Hyaluronan Synthase: A Zwitterionic Nanozyme for Photothermal Therapy of Osteoarthritis

Restoring joint homeostasis is crucial for relieving osteoarthritis (OA). Current strategies are limited to unilateral efforts in joint lubrication, inhibition of inflammation, free radicals scavenging, and cartilage regeneration. Herein, by modifying molybdenum disulfide (MoS2 ) with Mg2+ -doped polydopamine and coating with polysulfobetaines, a dual-bionic photothermal nanozyme (MPMP) is constructed to mimic antioxidases/hyaluronan synthase for OA therapy. Photothermally enhanced lubrication lowers the coefficient of friction (0.028) in the early stage of OA treatment. The antioxidases-mimicking properties of MPMP nanozyme contribute to eliminating reactive oxygen and nitrogen species (ROS/RNS) (over 90% of scavenging ratio for H2 O2 /·OH/O· 2 - /DPPH/ABTS+ ) and supplying O2 . With NIR irradiation, the MPMP nanozyme triggers thermogenesis (upregulating HSP70 expression) and Mg2+ release, which promotes the chondrogenesis in inflammatory conditions by deactivating NF-κB/IL-17 signaling pathways and enhancing MAPK signaling pathway. Benefiting from HSP70 and Mg2+ , MPMP-NIR shows HAS-mimicking activity to increase the intracellular (twofold) and extracellular (3.12-fold) HA production. Therefore, MPMP-NIR demonstrates superior spatiotemporally therapeutic effect on OA in mice model, in terms of osteophytes (83.41% of reduction), OARSI scores (88.57% of reduction), and ACAN expression (2.70-fold of increment). Hence, insights into dual-bionic nanozymes can be a promising strategy for OA therapy or other inflammation-related diseases.

Design and Mechanism Insight of Monodispersed AuCuPt Alloy Nanozyme with Antitumor Activity

The abrogation of the self-adaptive redox evolution of tumors is promising for improving therapeutic outcomes. In this study, we designed a trimetallic alloy nanozyme AuCuPt-PpIX (ACPP), which mimics up to five naturally occurring enzymes: glucose oxidase (GOD), superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and glutathione peroxidase (GPx). Facilitated by these enzyme-mimicking traits, the constructed ACPP nanozymes can not only disrupt the established redox homeostasis in tumors through a series of enzymatic cascade reactions but also achieve cyclic regeneration of the relevant enzyme substrates. Density functional theory (DFT) calculations have theoretically explained the synergistic effect of multimetallic doping and the possible mechanism of enzymatic catalysis. The doped Cu and Pt sites are conducive to the adsorption, activation, and dissociation of reactant molecules, whereas the Au sites are conducive to desorption, which significantly improves catalytic efficiency via a synergistic effect. Additionally, ACPP nanozymes can improve the effect of protoporphyrin (PpIX)-enabled sonodynamic therapy (SDT) by alleviating hypoxia and initiating ferroptosis by inducing lipid peroxidation (LPO) and inhibiting GPX4 activity, thus achieving multimodal synergistic therapy. This study presents a typical paradigm to enable the use of multimetallic alloy nanozymes for the treatment of tumor cells with self-adaptive properties.

Reactive oxygen nanobiocatalysts: activity-mechanism disclosures, catalytic center evolutions, and changing states

Benefiting from low costs, structural diversities, tunable catalytic activities, feasible modifications, and high stability compared to the natural enzymes, reactive oxygen nanobiocatalysts (RONBCs) have become dominant materials in catalyzing and mediating reactive oxygen species (ROS) for diverse biomedical and biological applications. Decoding the catalytic mechanism and structure-reactivity relationship of RONBCs is critical to guide their future developments. Here, this timely review comprehensively summarizes the recent breakthroughs and future trends in creating and decoding RONBCs. First, the fundamental classification, activity, detection method, and reaction mechanism for biocatalytic ROS generation and elimination have been systematically disclosed. Then, the merits, modulation strategies, structure evolutions, and state-of-art characterisation techniques for designing RONBCs have been briefly outlined. Thereafter, we thoroughly discuss different RONBCs based on the reported major material species, including metal compounds, carbon nanostructures, and organic networks. In particular, we offer particular insights into the coordination microenvironments, bond interactions, reaction pathways, and performance comparisons to disclose the structure-reactivity relationships and mechanisms. In the end, the future challenge and perspectives for RONBCs are also carefully summarised. We envision that this review will provide a comprehensive understanding and guidance for designing ROS-catalytic materials and stimulate the wide utilisation of RONBCs in diverse biomedical and biological applications.

Revealing Redox Behavior of Molybdenum Disulfide and Its Application as Rechargeable Antioxidant Reservoir

Molybdenum disulfide (MoS2) is a representative two-dimensional transition metal dichalcogenide and has a unique electronic structure and associated physicochemical properties. The redox property of MoS2 has recently attracted significant attention from various fields, such as biomedical applications. Intriguingly, MoS2 functions as an antioxidant in certain applications and as a pro-oxidant in others. We use the mediated electrochemical probing method to understand the redox behavior of MoS2. This method reveals that MoS2 (i) has a reversible and fast redox activity at a mild potential (between -0.20 and +0.25 V vs Ag/AgCl), (ii) functions as an antioxidant for molecules that have different redox mechanisms (electron or hydrogen atom transfer), and (iii) is electrochemically or molecularly rechargeable. Finally, we show that MoS2 reduces oxidized molecules more efficiently than the potent natural antioxidant, curcumin. This study enhances our understanding of MoS2 and shows its potential as an advanced antioxidant reservoir.

Modified TPP-MoS2 QD Blend as a Bio-Functional Model for Normalizing Microglial Dysfunction in Alzheimer's Disease

Alzheimer's disease (AD) is the most prevalent neurodegenerative disease of old age. Accumulation of β-amyloid peptide (Aβ) and mitochondrial dysfunction results in chronic microglial activation, which enhances neuroinflammation and promotes neurodegeneration. Microglia are resident macrophages of the brain and spinal cord which play an important role in maintaining brain homeostasis through a variety of phenotypes, including the pro-inflammatory phenotype and anti-inflammatory phenotypes. However, persistently activated microglial cells generate reactive species and neurotoxic mediators. Therefore, inhibitors of microglial activation are seen to have promise in AD control. The modified TPP/MoS2 QD blend is a mitochondrion-targeted nanomaterial that exhibits cytoprotective activities and antioxidant properties through scavenging free radicals. In the present study, the cell viability and cytotoxicity of the DSPE-PEG-TPP/MoS2 QD blend on microglial cells stimulated by Aβ were investigated. The levels of reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) were also assessed. In addition, pro-inflammatory and anti-inflammatory cytokines, such as tumor necrosis factor α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β), transforming growth factor beta (TGF-β), inducible nitric oxide synthase (iNOS) and arginase-1 (Arg-I) were measured in the presence or absence of the DSPE-PEG-TPP/MoS2 QD blend on an immortalized microglia cells activated by accumulation of Aβ. We found that the DSPE-PEG-TPP/MoS2 QD blend was biocompatible and nontoxic at specific concentrations. Furthermore, the modified TPP/MoS2 QD blend significantly reduced the release of free radicals and improved the mitochondrial function through the upregulation of MMP in a dose-dependent manner on microglial cells treated with Aβ. In addition, pre-treatment of microglia with the DSPE-PEG-TPP/MoS2 QD blend at concentrations of 25 and 50 μg/mL prior to Aβ stimulation significantly inhibited the release and expression of pro-inflammatory cytokines, such as IL-1β, IL-6, TNF-α, and iNOS. Nevertheless, the anti-inflammatory cytokines TGF-β and Arg-I were activated. These findings suggest that the modified TPP/MoS2 QD blend reduced oxidative stress, inflammation and improved the mitochondrial function in the immortalized microglial cells (IMG) activated by Aβ. Overall, our research shows that the DSPE-PEG-TPP/MoS2 QD blend has therapeutic promise for managing AD and can impact microglia polarization.

Microenvironment Restruction of Emerging 2D Materials and their Roles in Therapeutic and Diagnostic Nano-Bio-Platforms

Engineering advanced therapeutic and diagnostic nano-bio-platforms (NBPFs) have emerged as rapidly-developed pathways against a wide range of challenges in antitumor, antipathogen, tissue regeneration, bioimaging, and biosensing applications. Emerged 2D materials have attracted extensive scientific interest as fundamental building blocks or nanostructures among material scientists, chemists, biologists, and doctors due to their advantageous physicochemical and biological properties. This timely review provides a comprehensive summary of creating advanced NBPFs via emerging 2D materials (2D-NBPFs) with unique insights into the corresponding molecularly restructured microenvironments and biofunctionalities. First, it is focused on an up-to-date overview of the synthetic strategies for designing 2D-NBPFs with a cross-comparison of their advantages and disadvantages. After that, the recent key achievements are summarized in tuning the biofunctionalities of 2D-NBPFs via molecularly programmed microenvironments, including physiological stability, biocompatibility, bio-adhesiveness, specific binding to pathogens, broad-spectrum pathogen inhibitors, stimuli-responsive systems, and enzyme-mimetics. Moreover, the representative therapeutic and diagnostic applications of 2D-NBPFs are also discussed with detailed disclosure of their critical design principles and parameters. Finally, current challenges and future research directions are also discussed. Overall, this review will provide cutting-edge and multidisciplinary guidance for accelerating future developments and therapeutic/diagnostic applications of 2D-NBPFs.

Protein-Assisted Molybdenum Disulfide as Biomimetic Nanozyme for Antibacterial Application

Molybdenum-based nanomaterials with variable oxidation states can be developed as nanozyme catalysts. In this work, we developed a one-pot method for the preparation of molybdenum disulfide assisted by protein. Protamine was used as a cationic template to link molybdate anions and form complexes. During hydrothermal synthesis, protamine can affect the nucleation process of molybdenum disulfide and inhibit their aggregation, which facilitates the fabrication of small-sized molybdenum disulfide nanoparticles. Moreover, the abundant amino/guanidyl groups of protamine could both physically adsorb and chemically bond to molybdenum disulfide and further modulate the crystal structures. The optimized size and crystalline structure enabled a higher exposure of active sites, which enhanced the peroxidase-like activity of molybdenum disulfide/protamine nanocomposites. Meanwhile, the antibacterial activity of protamine was retained in the molybdenum disulfide/protamine nanocomposites, which could synergize with the peroxidase-like activity of molybdenum disulfide to kill bacteria. Therefore, the molybdenum disulfide/protamine nanocomposites are good candidates for antibacterial agents with lower chances of antimicrobial resistance. This study establishes an easy way to design artificial nanozymes by compounding suitable components.

Antioxidant Nanozymes: Mechanisms, Activity Manipulation, and Applications

Antioxidant enzymes such as catalase, superoxide dismutase, and glutathione peroxidase play important roles in the inhibition of oxidative-damage-related pathological diseases. However, natural antioxidant enzymes face some limitations, including low stability, high cost, and less flexibility. Recently, antioxidant nanozymes have emerged as promising materials to replace natural antioxidant enzymes for their stability, cost savings, and flexible design. The present review firstly discusses the mechanisms of antioxidant nanozymes, focusing on catalase-, superoxide dismutase-, and glutathione peroxidase-like activities. Then, we summarize the main strategies for the manipulation of antioxidant nanozymes based on their size, morphology, composition, surface modification, and modification with a metal-organic framework. Furthermore, the applications of antioxidant nanozymes in medicine and healthcare are also discussed as potential biological applications. In brief, this review provides useful information for the further development of antioxidant nanozymes, offering opportunities to improve current limitations and expand the application of antioxidant nanozymes.

Photooxidative Behavior of Polystyrene Nanocomposites Filled with Two-Dimensional Molybdenum Disulfide

This study aimed to investigate how an ultralow content of a molybdenum disulfide (MoS₂) two-dimensional particle affects the photodegradation mechanism of polystyrene (PS). Here, an accelerated weathering study was presented on neat polystyrene and its nanocomposites produced with 0.001, 0.002, 0.003 and 0.005 wt% of molybdenum disulfide (MoS₂) exposed for various irradiation intervals (up to 8 weeks). The polymer photo-transformations were monitored using size exclusion chromatography (SEC), infrared spectroscopy (FTIR), and UV-Vis spectroscopy. The FTIR and UV/Vis results indicate that the PS degradation mechanism was not altered by the presence of MoS₂ particles; however, the degradation reactions were slowed down at higher MoS₂ contents (>0.003%). The SEC results proved the stabilizer effect due to MoS₂ particles, where M¯n, M¯w, and M¯w/M¯n values after 8 weeks were less modified when compared with the neat PS results. The MoS₂ acted as a UV stabilizer, and these two-dimensional particles acted by deactivating the free radicals generated by the PS matrix, even considering the low amount of the filler (<0.005 wt%).

Nanodrugs alleviate acute kidney injury: Manipulate RONS at kidney

Currently, there are no clinical drugs available to treat acute kidney injury (AKI). Given the high prevalence and high mortality rate of AKI, the development of drugs to effectively treat AKI is a huge unmet medical need and a research hotspot. Although existing evidence fully demonstrates that reactive oxygen and nitrogen species (RONS) burst at the AKI site is a major contributor to AKI progression, the heterogeneity, complexity, and unique physiological structure of the kidney make most antioxidant and anti-inflammatory small molecule drugs ineffective because of the lack of kidney targeting and side effects. Recently, nanodrugs with intrinsic kidney targeting through the control of size, shape, and surface properties have opened exciting prospects for the treatment of AKI. Many antioxidant nanodrugs have emerged to address the limitations of current AKI treatments. In this review, we systematically summarized for the first time about the emerging nanodrugs that exploit the pathological and physiological features of the kidney to overcome the limitations of traditional small-molecule drugs to achieve high AKI efficacy. First, we analyzed the pathological structural characteristics of AKI and the main pathological mechanism of AKI: hypoxia, harmful substance accumulation-induced RONS burst at the renal site despite the multifactorial initiation and heterogeneity of AKI. Subsequently, we introduced the strategies used to improve renal targeting and reviewed advances of nanodrugs for AKI: nano-RONS-sacrificial agents, antioxidant nanozymes, and nanocarriers for antioxidants and anti-inflammatory drugs. These nanodrugs have demonstrated excellent therapeutic effects, such as greatly reducing oxidative stress damage, restoring renal function, and low side effects. Finally, we discussed the challenges and future directions for translating nanodrugs into clinical AKI treatment.

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AKI is a common clinical acute syndrome with high morbidity and mortality but without effective clinical drug available.

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Hypoxia and accumulation of toxic substances are key pathological features of various heterogeneous AKI.

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Excessive RONS is the core of the pathological mechanism of AKI.

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The development of nanodrugs is expected to achieve successful treatment in AKI.

Alleviating the unwanted effects of oxidative stress on Aβ clearance: a review of related concepts and strategies for the development of computational modelling

Treatment for Alzheimer's disease (AD) can be more effective in the early stages. Although we do not completely understand the aetiology of the early stages of AD, potential pathological factors (amyloid beta [Aβ] and tau) and other co-factors have been identified as causes of AD, which may indicate some of the mechanism at work in the early stages of AD. Today, one of the primary techniques used to help delay or prevent AD in the early stages involves alleviating the unwanted effects of oxidative stress on Aβ clearance. 4-Hydroxynonenal (HNE), a product of lipid peroxidation caused by oxidative stress, plays a key role in the adduction of the degrading proteases. This HNE employs a mechanism which decreases catalytic activity. This process ultimately impairs Aβ clearance. The degradation of HNE-modified proteins helps to alleviate the unwanted effects of oxidative stress. Having a clear understanding of the mechanisms associated with the degradation of the HNE-modified proteins is essential for the development of strategies and for alleviating the unwanted effects of oxidative stress. The strategies which could be employed to decrease the effects of oxidative stress include enhancing antioxidant activity, as well as the use of nanozymes and/or specific inhibitors. One area which shows promise in reducing oxidative stress is protein design. However, more research is needed to improve the effectiveness and accuracy of this technique. This paper discusses the interplay of potential pathological factors and AD. In particular, it focuses on the effect of oxidative stress on the expression of the Aβ-degrading proteases through adduction of the degrading proteases caused by HNE. The paper also elucidates other strategies that can be used to alleviate the unwanted effects of oxidative stress on Aβ clearance. To improve the effectiveness and accuracy of protein design, we explain the application of quantum mechanical/molecular mechanical approach.

An anti-poisoning nanosensor for in situ monitoring of intracellular endogenous hydrogen sulfide

Intracellular H₂S plays an important regulatory role in cell metabolism. The limited sensing materials and severe sensor passivation hinder its quantification. We functionalized conductive nanowires with MoS₂ and quercetin in a large-scale manner, developed single nanowire sensors with excellent electrocatalytic and anti-poisoning performance, and achieved the accurate quantification of H₂S within single cells.

Multienzyme-Mimicking Au@Cu2O with Complete Antioxidant Capacity for Reactive Oxygen Species Scavenging

Most enzyme catalysts are unable to achieve effective oxidation resistance because of the monotonous mimicking function or production of secondary reactive oxygen species (ROS). Herein, the Au@Cu₂O heterostructure with multienzyme-like activities is deigned, which has significantly improved antioxidant capacity compared with pure Cu₂O for the scavenging of highly cell-damaging secondary ROS, i.e.,·OH. Experiments and theoretical calculations show that the heterostructure exhibits a built-in electric field and lattice mismatch at the metal-semiconductor interface, which facilitate to generate abundant oxygen vacancies, redox couples, and surface electron deficiency. On the one hand, the presence of rich oxygen vacancies and redox couple can enhance the adsorption and activation of oxygen-containing ROS (including O₂^·- and H₂O₂). On the other hand, the electron transfer between the electron-deficient Au@Cu₂O surface and electron donor would promote peroxide-like activity and avoid producing ·OH. Importantly, endogenous ·OH could be eliminated in both acidic and neutral conditions, which is no longer limited by the volatile physiological environment. Therefore, Au@Cu₂O can simulate superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and glutathione peroxidase (GPx) to form a complete antioxidant system. The deigned nanoenzyme is explored in the real sample world such as A549 cells and zebrafish. This work provides theoretical and practical strategies for the construction of a complete antioxidant enzyme system.

Natural Morin-Based Metal Organic Framework Nanoenzymes Modulate Articular Cavity Microenvironment to Alleviate Osteoarthritis

Osteoarthritis (OA) is always characterized as excessive reactive oxygen species (ROS) inside articular cavity. Mimicking natural metalloenzymes with metal ions as the active centers, stable metal organic framework (MOF) formed by natural polyphenols and metal ions shows great potential in alleviating inflammatory diseases. Herein, a series of novel copper-morin-based MOF (CuMHs) with different molar ratios of Cu²⁺ and MH were employed to serve as ROS scavengers for OA therapy. As a result, CuMHs exhibited enhanced dispersion in aqueous solution, improved biocompatibility, and efficient ROS-scavenging ability compared to MH. On the basis of H₂O₂-stimulated chondrocytes, intracellular ROS levels were efficiently declined and cell death was prevented after treated by Cu₆MH (Cu²⁺ and MH molar ratio of 6:1). Meanwhile, Cu₆MH also exhibited efficient antioxidant and anti-inflammation function by down-regulating the expression of IL6, MMP13, and MMP3, and up-regulating cartilage specific gene expression as well. Importantly, Cu₆MH could repair mitochondrial function by increasing mitochondrial membrane potential, reducing the accumulation of calcium ions, as well as promoting ATP content production. In OA joint model, intra-articular (IA) injected Cu₆MH suppressed the progression of OA. It endowed that Cu₆MH might be promising nanoenzymes for the prevention and treatment of various inflammatory diseases.

A molybdenum-based nanoplatform with multienzyme mimicking capacities for oxidative stress-induced acute liver injury treatment

PEGylated MoS2nanosheets were synthesized and modified with bovine serum albumin. These nanosheets exhibited a hepatoprotective effect, which reduces the number of apoptotic and necrotic tissues and inhibits the production of pro-inflammatory factors in disease models.

Biorefining waste into nanobiotechnologies can revolutionize sustainable agriculture

Modern agriculture has evolved technological innovations to sustain crop productivity. Recent advances in biorefinery technology use crop residue as feedstock, but this raises carbon sequestration concerns as biorefining utilizes carbon that would otherwise be returned to the soil, thus causing a decline in crop productivity. Furthermore, biorefining generates abundant lignin waste that significantly impedes the efficiency of biorefineries. Valorizing lignin into advanced nanobiotechnologies for agriculture provides a unique opportunity to balance bioeconomy and soil carbon sequestration. Integration of agricultural practices such as utilization of agrochemicals, fertilizers, soil modifiers, and mulching with lignin nanobiotechnologies promotes crop productivity and also enables advanced manufacturing of high-value bioproducts from lignin. Lignin nanobiotechnologies thus represent state-of-the-art innovations to transform both the bioeconomy and sustainable agriculture.

Manganese-Based Nanozymes: Preparation, Catalytic Mechanisms, and Biomedical Applications

Manganese (Mn) has attracted widespread attention due to its low-cost, nontoxicity, and valence-rich transition. Various Mn-based nanomaterials have sprung up and are employed in diverse fields, particularly Mn-based nanozymes, which combine the physicochemical properties of Mn-based nanomaterials with the catalytic activity of natural enzymes, and are attracting a surge of research, especially in the field of biomedical research. In this review, the typical preparation strategies, catalytic mechanisms, advances and perspectives of Mn-based nanozymes for biomedical applications are systematically summarized. The application of Mn-based nanozymes in tumor therapy and sensing detection, together with an overview of their mechanism of action is highlighted. Finally, the prospective directions of Mn-based nanozymes from five perspectives: innovation, activity enhancement, selectivity, biocompatibility, and application broadening are discussed.

Nanomaterials alleviating redox stress in neurological diseases: mechanisms and applications

Overproduced reactive oxygen and reactive nitrogen species (RONS) in the brain are involved in the pathogenesis of several neurological diseases, such as Alzheimer's disease, Parkinson's disease, traumatic brain injury, and stroke, as they attack neurons and glial cells, triggering cellular redox stress. Neutralizing RONS, and, thus, alleviating redox stress, can slow down or stop the progression of neurological diseases. Currently, an increasing number of studies are applying nanomaterials (NMs) with anti-redox activity and exploring the potential mechanisms involved in redox stress-related neurological diseases. In this review, we summarize the anti-redox mechanisms of NMs, including mimicking natural oxidoreductase activity and inhibiting RONS generation at the source. In addition, we propose several strategies to enhance the anti-redox ability of NMs and highlight the challenges that need to be resolved in their application. In-depth knowledge of the mechanisms and potential application of NMs in alleviating redox stress will help in the exploration of the therapeutic potential of anti-redox stress NMs in neurological diseases.

Biochar Nanozyme from Silkworm Excrement for Scavenging Vapor-Phase Free Radicals in Cigarette Smoke

Serious lung diseases and other health problems caused by tobacco consumption are becoming more and more prominent all over the world. Scavenging the excessive harmful free radicals in cigarette smoke is proven to be an effective method in reducing the above problems. Carbon-based nanozymes have been widely studied due to their ability of scavenging free radicals. Accordingly, the biochar derived from silkworm excrement was reported as a nanozyme with free radical scavenging ability. The biochar nanozyme calcination at 900 °C with better free radical scavenging abilities was loaded into commercial cigarette filters for the following free radical scavenging verification in tobacco smoke. Mouse model results reveal the lung tissue could be improved by the addition of biochar nanozyme. This work not only provides an effective approach to reduce the harm caused by tobacco but also provides potential applications to rationally realize low-cost, ease of production, and a wide variety of biochar sources.