Biomimetic Nanozyme Research Articles

Biomimetic nanozyme-based electrochemical sensor integrated with microfluidic cell for on-site uric acid detection

Uric acid (UA) is the key indicator highly associated with gout, and on-site UA detection is of great significance for personalized health management. Herein, we propose an integrated microfluidic electrochemical sensing platform for real-time UA detection. The platform mainly consists of a biomimetic nanozyme-based electrochemical sensor and a microfluidic cell. The biomimetic nanozyme with desirable catalytic activity can effectively promote UA oxidation, and the corresponding working mechanism is clarified through density functional theory calculation. Besides, the well-designed microfluidic cell is capable of impurity removal and sample storage. Based on these designs, the whole process of sample pretreatment and target detection can all be achieved on one integrated platform, allowing for user-friendly test. This developed platform shows satisfactory sensing performance for UA with a detection limit of 4.2 μM. In addition, it is successfully applied to UA determination in artificial saliva and serum samples, showing desirable application prospects in clinical diagnosis.

Self‐Oxygenated Biomimetic Nanozyme for Tumor Catalytic Immunotherapy

AbstractThe treatment of solid tumors remains a significant challenge due to the complex, immunosuppressive tumor microenvironment (TME). This manuscript introduces the self‐oxygenated biomimetic nanozyme system, SS‐MSN@Au‐BOM, which innovatively combines catalytic therapy with immunotherapy to modulate the TME for enhanced therapeutic efficacy. Employing mesoporous silicon nanoparticles doped with disulfide bonds, the system integrates gold nanozymes that exhibit glucose oxidase (GOx)‐like and peroxidase (POD)‐like activities, along with a catalase (CAT) function derived from bacterial outer membrane (BOM) coatings. SS‐MSN@Au‐BOM significantly disrupted tumor growth by catalyzing endogenous hydrogen peroxide to generate cytotoxic ROS and essential oxygen, enhancing intratumoral ROS levels while alleviating hypoxia. This catalytic action facilitates immunogenic cell death, enhances dendritic cell maturation, and T‐cell activation. Notably, the system shows excellent biocompatibility, effective tumor targeting, and prolonged systemic circulation. SS‐MSN@Au‐BOM offers a dual‐functional approach that effectively disrupts the TME and promotes robust antitumor immunity. This study paves the way for further clinical investigation and the development of enzyme‐based therapeutics, potentially transforming the landscape of cancer treatment.

Biomimetic Nanozyme-Decorated Smart Hydrogel for Promoting Chronic Refractory Wound Healing.

Chronic refractory wounds have become a serious threat to human health and are characterized by prolonged inflammation, recurrent bacterial infections, and elevated ROS levels. However, current therapeutic strategies usually target a unilateral healing function and are unable to tackle the complexity and sensitivity of chronic refractory wound healing. This study fabricated a biomimetic nanozyme based on rhein (Cu-rhein NSs), which effectively mimics the activity of superoxide dismutase (SOD) for scavenging various free radicals. Additionally, zinc oxide microspheres (ZnO MSs) were prepared to enhance the antibacterial activity and mechanical properties of the modified hydrogel. Cu-rhein NSs and ZnO MSs were comodified onto an extracellular matrix-mimetic dual-network smart hydrogel constructed from oxidized sodium alginate, gelatin, and borax via dynamic borate and Schiff base bonds. The smart hydrogel presented the good biocompatibility and targeted the unique acidic microenvironment with high oxidative stress of chronic refractory wounds, intelligently releasing bionic nanozymes to effectively eliminate bacteria, reduce inflammatory responses, and scavenge multiple free radicals for reducing ROS. In vivo experiments on the rat model based on diabetic infection showed that the smart hydrogel could effectively eliminate bacteria, promote vascular regeneration and collagen deposition, reduce inflammatory response, and accelerate the healing of diabetic-infected wounds (almost complete healing within 14 days). The advantages of an intelligent, biomimetic tissue regeneration cascade management strategy against diabetic infected wound healing are highlighted.

Neutrophil membrane-based biomimetic metal-polyphenol self-assembled nanozyme for the targeting treatment of early brain injury following subarachnoid hemorrhage

Early brain injury (EBI) refers to the immediate injury and neuroinflammation in the brain after subarachnoid hemorrhage (SAH). The current drugs used to treat SAH are inadequate due to their disappointing ability to penetrate the blood–brain barrier (BBB) and their limited anti-inflammatory effects, leading to unsatisfactory therapeutic outcomes for EBI. Herein, we developed a biomimetic nanozyme (Fe-DMY) using a metal-polyphenol self-assembly method, involving the coordination of ferric ion (Fe3+) and dihydromyricetin (DMY), then encapsulated Fe-DMY in neutrophil membranes (NM) to form NM@Fe-DMY, which targets to neuroinflammatory regions. NM@Fe-DMY exhibits strong catalase- and superoxide dismutase-like catalytic activities, suggesting its potential to reduce oxidative stress in SAH. This leads to reduced lipid peroxidation, increased expression of glutathione peroxidase 4 and prevented ferroptosis. Furthermore, The NM@Fe-DMY has demonstrated effective penetration of the BBB in vivo, accumulating in SAH injury region and exhibiting significant therapeutic efficacy including neural function recovery and improvement of spatial memory. Importantly, NM@Fe-DMY also induces the polarization of microglia from M1-like to M2-like subtypes, interrupting the detrimental cycle of neuroinflammation in EBI. This study introduces a new NM-wrapped biomimetic nanozyme strategy for effectively targeting neuroinflammatory regions and enhancing the treatment of EBI following SAH.

Hollow Cu/CoS2 Nanozyme with Defect-Induced Enzymatic Catalytic Sites and Binding Pockets for Highly Sensitive Fluorescence Detection of Alkaline Phosphatase.

Along with an ever-deepening understanding of the catalytic principle of natural enzymes, the rational design of high-activity biomimetic nanozymes has become a hot topic in current research. Inspired by the active centers of natural enzymes consisting of catalytic sites and binding pockets, a Cu-doped CoS2 hollow nanocube (Cu/CoS2 HNCs) nanozyme integrating substitution defects and vacancies is developed through a defect engineering strategy. It is shown that the vacancies and substitution defects in the developed Cu/CoS2 HNC nanozymes serve as binding pockets and catalytic sites, respectively. The construction of this key active center and the accelerated electron transfer from the Co/Cu redox cycle significantly improve the substrate affinity and catalytic efficiency of the Cu/CoS2 HNCs nanozymes, which results in the excellent catalytic performance of the Cu/CoS2 HNC nanozymes. Using the superior enzymatic activity of Cu/CoS2 HNCs, a fluorescence detection platform for alkaline phosphatase (ALP) is established, which is a wider detection range and lower limit of detection (LOD) than previous work. This work broadens the family of nanozymes and provide a new idea for the development of novel nanozymes with high enzyme activity, as well as a guideline for the construction of highly sensitive fluorescent sensors.

3D Cryo‐Printed Hierarchical Porous Scaffolds Harmonized with Hybrid Nanozymes for Combinatorial Mitochondrial Therapy: Enhanced Diabetic Bone Regeneration via Micromilieu Remodeling

AbstractRegeneration of bone defects in diabetic patients has always been a significant challenge in clinical treatment. The pathologic diabetic micromilieu, characterized by mitochondrial dysfunction, excessive reactive oxygen species (ROS) accumulation, cellular senescence, and chronic inflammation, compromises innate bone healing capacity. 3D cryo‐printing technology is utilized in bone tissue engineering to fabricate hierarchical porous scaffolds that promote a conducive microenvironment for cellular adhesion, migration, proliferation, and nutrient exchange. Nanozymes are used as synthetic mimics of natural enzymes to scavenge ROS, addressing the limitations of natural antioxidative enzymes. To remodel the diabetic bone regeneration micromilieu, a 3D cryo‐printed polyaryletherketone with carboxyl groups (PAEK‐COOH) and 45S5 bioactive glass (BG) hierarchical porous scaffold (PBG scaffold), harmonized with hybrid nanozymes comprising SS31‐enhanced manganese dioxide (MnO2)‐ferritin biomimetic nanozyme (MF@S nanozyme), is developed for combinatorial mitochondrial therapy. The MF@S nanozyme specifically targets mitochondria to enhance mitochondrial function, scavenge ROS accumulated in mitochondria, and suppress mitochondrial ROS (mtROS) production, and thus rejuvenate aging cells, regulate macrophage polarization, and modulate differentiation of osteoblasts and osteoclasts. This 3D cryo‐printed PBG‐MF@S hierarchical porous scaffold combines with a combinatorial mitochondrial therapy system to remodel the diabetic micromilieu and presents a promising therapeutic approach for the regeneration of bone defects in diabetes.

Hydroxylase-like Biomimetic Nanozyme Synthesized via a Urea-Mediated MOF Pyrolytic Reconstruction Strategy for Non-"o-Phenol hydroxyl"-Dependent Dopamine Electrochemical Sensing.

Dopamine (DA), an essential neurotransmitter, is closely associated with various neurological disorders, whose real-time dynamic monitoring is significant for evaluating the physiological activities of neurons. Electrochemical sensing methods are commonly used to determine DA, but they mostly rely on the redox reaction of its o-phenolic hydroxyl group, which makes it difficult to distinguish it from substances with this group. Here, we design a biomimetic nanozyme inspired by the coordination structure of the copper-based active site of dopamine β-hydroxylase, which was successfully synthesized via a urea-mediated MOF pyrolysis reconstruction strategy. Experimental studies and theoretical calculations revealed that the nanozyme with Cu-N3 coordination could hydroxylate the carbon atom of the DA β-site at a suitable potential and that the active sites of this Cu-N3 structure have the lowest binding energy for the DA β-site. With this property, the new oxidation peak achieves the specific detection of DA rather than the traditional electrochemical signal of o-phenol hydroxyl redox, which would effectively differentiate it from neurotransmitters, such as norepinephrine and epinephrine. The sensor exhibited good monitoring capability in DA concentrations from 0.05 to 16.7 μM, and its limit of detection was 0.03 μM. Finally, the sensor enables the monitoring of DA released from living cells and can be used to quantitatively analyze the effect of polystyrene microplastics on the amount of DA released. The research provides a method for highly specific monitoring of DA and technical support for initial screening for neurocytotoxicity of pollutants.

Nutrients deprivation of biomimetic nanozymes for cascade catalysis triggered and oxidative damage induced tumor eradication

Nutrients deprivation of biomimetic nanozymes for cascade catalysis triggered and oxidative damage induced tumor eradication

Neutrophil Hitchhiking Biomimetic Nanozymes Prime Neuroprotective Effects of Ischemic Stroke in a Tailored “Burning the Bridges” Manner

AbstractReperfusion injury of ischemic stroke, characterized by the uncontrolled production of reactive oxygen species (ROS) and inflammatory reactions, continues to present a major problem in clinical treatment. Neutrophils are forerunners to infiltrate cerebral ischemic regions and contribute to reperfusion injury. Herein, this study reports a tailored “burning the bridges” strategy by designing biomimetic nanozymes (D@HPB@SPM NPs) to diminish reperfusion injury of ischemic stroke. D@HPB@SPM NPs are composed of a sialic acid (SA)‐modified platelet membrane shell and a hollow Prussian blue nanoparticle core loaded with Deoxyribonuclease I (DNase I). Due to the unique binding affinity of SA to L‐selectin, which is abundantly expressed in circulating neutrophils, D@HPB@SPM NPs can effectively hitchhike on neutrophils across the blood‐brain barrier into the injured brain parenchyma after intravenous injection. Following this, neutrophils are activated and unleash D@HPB@SPM NPs through producing neutrophil extracellular traps (NETs). D@HPB@SPM NPs not only relieve oxidative stress injury by efficiently scavenging ROS, but also mitigate neutrophil‐induced reperfusion injury by degrading NETs in a manner similar to “burning the bridges”. The encouraging accumulation of D@HPB@SPM NPs to cerebral ischemic regions and their efficient therapeutic efficacy are systematically validated in ischemic stroke rats. This work offers a fresh insight for ischemic stroke treatment.

Mn-Based Artificial Mitochondrial Complex "VI" Acts as an Electron and Free Radical Conversion Factory to Suppress Macrophage Inflammatory Response.

Disturbance in the mitochondrial electron transport chain (ETC) is a key factor in the emerging discovery of immune cell activation in inflammatory diseases, yet specific regulation of ETC homeostasis is extremely challenging. In this paper, a mitochondrial complex biomimetic nanozyme (MCBN), which plays the role of an artificial "VI" complex and acts as an electron and free radical conversion factory to regulate ETC homeostasis is creatively developed. MCBN is composed of bovine serum albumin (BSA), polyethylene glycol (PEG), and triphenylphosphine (TPP) hierarchically encapsulating MnO2 polycrystalline particles. It has nanoscale size and biological properties like natural complexes. In vivo and in vitro experiments confirm that MCBN can target the mitochondrial complexes of inflammatory macrophages, absorb excess electrons in ETC, and convert the electrons to decompose H2O2. By reducing the ROS and ATP bursts and converting existing free radicals, inhibiting NLRP3 inflammatory vesicle activation and NF-κB signaling pathway, MCBN effectively suppresses macrophage M1 activation and inflammatory factor secretion. It also demonstrates good inflammation control and significantly alleviates alveolar bone loss in a mouse model of ligation-induced periodontitis. This is the first nanozyme that mimics the mitochondrial complex and regulates ETC, demonstrating the potential application of MCBN in immune diseases.

Discerning biomimetic nanozyme electrodes based on g-C3N4 nanosheets and molecularly imprinted polythiophene nanofibers for detecting creatinine in microliter droplets of human saliva

The growing risk of death associated with kidney dysfunction underlines the requirement for a cost-effective and precise point-of-care (POC) diagnostic tool to identify chronic kidney disease (CKD) at an early stage. This work reports the development of a non-invasive POC diagnostic based on cost-efficient, disposable electrodes and in situ-designed biomimetic nanozymes. The nanozymes are composed of graphitic carbon nitride nanosheets (gCN) and creatinine-imprinted polythiophene nanofibers (miPTh). Microscopic analyses reveal porous nanofibrous surface morphology of biomimetic miPTh/gCN nanozymes. Bulk imprinting and the inclusion of conductive gCN nanosheets drastically reduced the charge transfer resistance and improved the electron exchange kinetics at the nanozyme-electrolyte interface. The electrochemical oxidation of creatinine is studied via cyclic voltammetry (CV), and differential pulse voltammetry (DPV), which exhibit excellent creatinine recognition ability of biomimetic miPTh/gCN nanozyme sensors compared to pristine polymeric or non-imprinted nanozymes. The sensor reveals linear response toward 200–1000 nmol L−1 creatinine, high sensitivity (4.27 μA cm−2 nmol−1 L), sub-nanomolar detection limit (340 pmol L−1), and excellent selectivity over common salivary analytes. To corroborate its real-world utility, the miPTh/gCN nanozyme sensor shows an impressive 94.8% recovery of spiked creatinine concentrations in microliter droplets of human saliva samples. This disposable sensor reveals great potential in the realm of reliable and efficient non-invasive POC diagnostics for healthcare delivery.

Biomimetic nanozymes target the heart to suppress ferroptosis for ameliorating doxorubicin-induced cardiotoxicity via synergetic effect of antioxidant stress and Nrf2/Hmox1 inhibition

Abstract Background Doxorubicin (DOX) is the first-line standard treatment of numerous cancer. However, DOX may lead to irreversible degenerative cardiomyopathy, congestive heart failure, and various arrhythmias, known as doxorubicin-induced cardiotoxicity (DIC), which limits the clinical applications. Studies reported that ferroptosis plays an important role on the development of DIC. Targeted intervention of ferroptosis with the specific inhibitors, such as ferrostatin-1 (Fer-1), could effectively prevent DIC. In recent years, catalytic nanozymes, such as cerium oxide (CeO2), have received much attention due to their strong antioxidant properties. Purpose Our previous research found that the transferrin receptor (TfR) protein expression was significantly upregulated in DIC mice (Figure 1) . In this study, we synthesized a biomimetic CeO2-based nanozyme by biomineralization with transferrin (Tf) proteins as the template, and then we assessed its targeted therapy for DIC via Tf-TfR mediated endocytosis. Method Cellular uptake, cytotoxicity test, intracellularmitochondrial membrane potential (MMP), reactive oxygen species (ROS), mitochondrial ferrous ions and lipid peroxidation toxicity were verified with rat cardiomyocytes line H9c2 cells. Afterward, the male C57BL/6N mice were randomly divided into control, DOX, DOX+Fer-1, and DM+NPs groups. Heart structure and function were measured by echocardiographic, electrocardiography and epicardial electrical labeling. Western blot determine mitochondrial homeostasis regulation-related proteins and Nrf2/Hmox1 signalling pathway. Finally, the biodistribution and biocompatibility of CeO2@Tf was assessed. Results Transmission electron microscopy images revealed the encapsulated CeO2@Tf was≈ 5 nm in diameter. The nanozyme significantly reversed cardiac structural and electrical remodeling and reduced myocardial necrosis. Meanwhile, RNA sequencing of ventricular tissue revealed increased cardiac Hmox1 mRNA levels in DIC mice (Figure 2). Further, it demonstrated that nanozyme intervention not only significantly suppressed the oxidative stress, mitochondrial lipid peroxidation and mitochondrial membrane potential damage, but also inhibited activation of Nrf2/Hmox1 signalling pathway to restore mitochondria-dependent ferroptosis. Furthermore, the nanozyme could be cleared by the hepatobiliary systems, and showed a good biocompatibility. Conclusions The current study showed that biomimetic mineralization of hybrid CeO2-based nanozyme against DIC were mediated by effect of antioxidant stress and the inhibition of Nrf2/Hmox1 signalling pathway, thereby maintaining mitochondrial homeostasis and function, and re-storing mitochondria-dependent ferroptosis. Furthermore, the nanozyme could be a promising prevention and treatment candidate for clinical translation as a novel cardiomyocyte ferroptosis protector to mitigate DIC and improve the prognosis and quality of life of cancer patients.

Near-Infrared Triggered Self-Accelerating Nanozyme Camouflaged with a Cancer Cell Membrane for Precise Targeted Imaging and Enhanced Cancer Immunotherapy.

Although cancer immunotherapy has made encouraging progress, clinical therapeutic efficiency is often modest due to inadequate immunogenicity and immune resistance. Developing promising nanoagents for simultaneously activating tumor-specific immunity and suppressing immune resistance to achieve efficient immunotherapy is still challenging. Herein, we developed a biomimetic nanozyme consisting of a gold nanorod@mesoporous ceria core-shell scaffold with gold nanoparticle deposition and cancer cell membrane camouflage. The nanozyme exhibited near-infrared (NIR)-enhanced GOx-mimicking activity at high temperatures and performed well under hypoxic environments due to an increased in situ oxygen supply. In cancer cells, the nanozyme induced and amplified hyperthermia by triggering self-accelerating cascade reactions to deplete glucose and inhibiting the expression of heat shock protein under NIR irradiation, which can cause mitochondrial dysfunction and redox balance disruption to activate pyroptosis and elicit a robust immune response. Additionally, the immune checkpoint blockade caused by encapsulated JQ1-mediated PD-L1 downregulation synergistically contributed to excellent immune therapeutic effects. Besides, we demonstrated that cancer cell membrane coating endows the nanozyme targeting ability to tumor. The proposed nanozyme will broaden the application of GOx and have the potential as the nanoplatform for imaging-guided and O2-consuming combined treatments.

An enzyme free self-cascade catalytic system with Au deposited bimetallic organic framework as a dual active nanozyme for glucose detection with a smartphone readout platform

A new kind of dual active biomimetic nanozyme was constructed for the establishment of an enzyme free self-cascade catalytic system. Herein, Au/FeNi-MOF nanozyme was designed and constructed by depositing Au quantum dots on a three-dimensional bimetallic organic framework via electrostatic self-assembly. By regulating the immobilization of Au quantum dots on the surface of FeNi-MOF, Au quantum dots not only exhibited stable glucose oxidase-like activity (GOx-like), but enhanced the peroxidase-like activity (POD-like) of FeNi-MOF. The obtained Au/FeNi-MOF nanozyme with both GOx-like and enhanced POD-like activities was used to mimick the cascade catalytic reaction of natural enzymes, thereby construct an enzyme free self-cascade catalytic colorimetric detection system for glucose. The detection method has a linear range of 0.02–10 mM and a detection limit as low as 15 μM with good accuracy and reproducibility. Based on the above performance, a smartphone readout platform for glucose detection was further developed. In this scheme the smartphone was used to extract and recognize the RGB values of the reaction system which were consequently converted into gray values. We recognized that evaluating glucose levels through a smartphone readout platform has the advantage of simple, convenient, and reliable, while revealing its potential application in medical monitoring.

A Bioinspired Atomically Thin Nanodot Supported Single-Atom Nanozyme for Antibacterial Textile Coating.

Surface antibacterial coatings with outstanding antibacterial efficiency have attracted increasing attention in medical protective clothing and cotton surgical clothing. Although nanozymes, as a new generation of antibiotics, are used to combat bacteria, their catalytic performance remains far from satisfactory as alternatives to natural enzymes. Single-atom nanodots provide a solution to the low catalytic activity bottleneck of nanozymes. Here, atomically thin C3 N4 nanodots supported single Cu atom nanozymes (Cu-CNNDs) are developed by a self-tailoring approach, which exhibits catalytic efficiency of 8.09 × 105 M-1 s-1 , similar to that of natural enzyme. Experimental and theoretical calculations show that excellent peroxidase-like activity stems from the size effect of carrier optimizing the coordination structure, leading to full exposure of Cu-N3 active site, which improves the ability of H2 O2 to generate hydroxyl radicals (•OH). Notably, Cu-CNNDs exhibit over 99% superior antibacterial efficacy and are successfully grafted onto cotton fabrics. Thus, Cu-CNNDs blaze an avenue for exquisite biomimetic nanozyme design and have great potential applications in antibacterial textiles.

An Immunomodulatory Biomimetic Single-Atomic Nanozyme for Biofilm Wound Healing Management.

Nanozyme-driven catalytic antibacterial therapy has become a promising modality for bacterial biofilm infections. However, current catalytic therapy of biofilm wounds is severely limited by insufficient catalytic efficiency, excessive inflammation, and deep tissue infection. Drawing from the homing mechanism of natural macrophages, herein, a hollow mesoporous biomimetic single-atomic nanozyme (SAN) is fabricated to actively target inflamed parts, suppress inflammatory factors, and eliminate deeply organized bacteria for enhance biofilm eradication. In the formulation, this biomimetic nanozyme (Co@SAHSs@IL-4@RCM) consists of IL-4-loaded cobalt SANs-embedded hollow sphere encapsulate by RAW 264.7 cell membrane (RCM). Upon accumulation at the infected sites through the specific receptors of RCM, Co@SAHS catalyze the conversion of hydrogen peroxide into hydroxyl radicals and are further amplify by NIR-II photothermal effect and glutathione depletion to permeate and destroy biofilm structure. This behavior subsequently causes the dissociation of RCM shell and the ensuing release of IL-4 that can reprogram macrophages, enabling suppression of oxidative injury and tissue inflammation. The work paves the way to engineer alternative "all-in-one" SANs with an immunomodulatory ability and offers novel insights into the design of bioinspired materials.

Coordinating Etching Inspired Synthesis of Fe(OH)3 Nanocages as Mimetic Peroxidase for Fluorescent and Colorimetric Self-Tuning Detection of Ochratoxin A.

The development of multifunctional biomimetic nanozymes with high catalytic activity and sensitive response is rapidly advancing. The hollow nanostructures, including metal hydroxides, metal-organic frameworks, and metallic oxides, possess excellent loading capacity and a high surface area-to-mass ratio. This characteristic allows for the exposure of more active sites and reaction channels, resulting in enhanced catalytic activity of nanozymes. In this work, based on the coordinating etching principle, a facile template-assisted strategy for synthesizing Fe(OH)3 nanocages by using Cu2O nanocubes as the precursors was proposed. The unique three-dimensional structure of Fe(OH)3 nanocages endows it with excellent catalytic activity. Herein, in the light of Fe(OH)3-induced biomimetic nanozyme catalyzed reactions, a self-tuning dual-mode fluorescence and colorimetric immunoassay was successfully constructed for ochratoxin A (OTA) detection. For the colorimetric signal, 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) can be oxidized by Fe(OH)3 nanocages to form a color response that can be preliminarily identified by the human eye. For the fluorescence signal, the fluorescence intensity of 4-chloro-1-naphthol (4-CN) can be quantitatively quenched by the valence transition of Ferric ion in Fe(OH)3 nanocages. Due to the significant self-calibration, the performance of the self-tuning strategy for OTA detection was substantially enhanced. Under the optimized conditions, the developed dual-mode platform accomplishes a wide range of 1 ng/L to 5 μg/L with a detection limit of 0.68 ng/L (S/N = 3). This work not only develops a facile strategy for the synthesis of highly active peroxidase-like nanozyme but also achieves promising sensing platform for OTA detection in actual samples.

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.

Stem cell-derived hepatocyte therapy using versatile biomimetic nanozyme incorporated nanofiber-reinforced decellularized extracellular matrix hydrogels for the treatment of acute liver failure

Reactive oxygen species (ROS)-associated oxidative stress, inflammation storm, and massive hepatocyte necrosis are the typical manifestations of acute liver failure (ALF), therefore specific therapeutic interventions are essential for the devastating disease. Here, we developed a platform consisting of versatile biomimetic copper oxide nanozymes (Cu NZs)-loaded PLGA nanofibers (Cu NZs@PLGA nanofibers) and decellularized extracellular matrix (dECM) hydrogels for delivery of human adipose-derived mesenchymal stem/stromal cells-derived hepatocyte-like cells (hADMSCs-derived HLCs) (HLCs/Cu NZs@fiber/dECM). Cu NZs@PLGA nanofibers could conspicuously scavenge excessive ROS at the early stage of ALF, and reduce the massive accumulation of pro-inflammatory cytokines, herein efficiently preventing the deterioration of hepatocytes necrosis. Moreover, Cu NZs@PLGA nanofibers also exhibited a cytoprotection effect on the transplanted HLCs. Meanwhile, HLCs with hepatic-specific biofunctions and anti-inflammatory activity acted as a promising alternative cell source for ALF therapy. The dECM hydrogels further provided the desirable 3D environment and favorably improved the hepatic functions of HLCs. In addition, the pro-angiogenesis activity of Cu NZs@PLGA nanofibers also facilitated the integration of the whole implant with the host liver. Hence, HLCs/Cu NZs@fiber/dECM performed excellent synergistic therapeutic efficacy on ALF mice. This strategy using Cu NZs@PLGA nanofiber-reinforced dECM hydrogels for HLCs in situ delivery is a promising approach for ALF therapy and shows great potential for clinical translation.

Engineered Biomimetic Copper Sulfide Nanozyme Mediates "Don't Eat Me" Signaling for Photothermal and Chemodynamic Precision Therapies of Breast Cancer.

The rapid development of nanomedicine has brought hope and confidence to the precise treatment of tumors. However, the efficacy of nanoparticle-mediated therapy is severely limited due to phagocytosis and clearance by macrophages. CD47 is a well-documented ″don't eat me″ signaling molecule that binds to the SIRPα receptor on the macrophage surface, inhibiting the phagocytic behavior of the macrophages. In this study, CD47-overexpressing cancer cell membranes were used to coat hollow copper sulfide nanoparticles. The nanoparticles were shown to have an extended circulatory half-life and to actively target breast cancer, leading to increased accumulation in the tumor tissue. An excellent photothermal therapeutic effect was produced by near-infrared laser irradiation. At the same time, β-lapachone within the nanoparticles generated large amounts of hydrogen peroxide in the tumor environment, which was then catalyzed by the copper sulfide nanozyme to cytotoxic hydroxyl radicals, exerting a chemodynamic therapeutic effect. This engineered biomimetic nanozyme, through the mediation of the ″don't eat me″ signal, achieved both photothermal and chemodynamic precision treatments of breast cancer, creating a new mode of safe and effective tumor treatment.