Self-cascade MoS2 nanozymes for efficient intracellular antioxidation and hepatic fibrosis therapy

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.

Atomic Engineering of Single-Atom Nanozymes for Biomedical Applications

Single-atom nanozymes (SAzymes) showcase not only uniformly dispersed active sites but also meticulously engineered coordination structures. These intricate architectures bestow upon them an exceptional catalytic prowess, thereby captivating numerous minds and heralding a new era of possibilities in the biomedical landscape. Tuning the microstructure of SAzymes on the atomic scale is a key factor in designing targeted SAzymes with desirable functions. This review first discusses and summarizes three strategies for designing SAzymes and their impact on reactivity in biocatalysis. The effects of choices of carrier, different synthesis methods, coordination modulation of first/second shell, and the type and number of metal active centers on the enzyme-like catalytic activity are unraveled. Next, a first attempt is made to summarize the biological applications of SAzymes in tumor therapy, biosensing, antimicrobial, anti-inflammatory, and other biological applications from different mechanisms. Finally, how SAzymes are designed and regulated for further realization of diverse biological applications is reviewed and prospected. It is envisaged that the comprehensive review presented within this exegesis will furnish novel perspectives and profound revelations regarding the biomedical applications of SAzymes.

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.

Two-dimensional molybdenum disulfide nanosheets evoke nitric oxide-dependent antibacterial effects

Nanomaterials are currently being explored as novel antimicrobial agents. In this study, we first investigated the ability of two-dimensional (2D) molybdenum disulfide (MoS2) nanosheets to trigger neutrophil extracellular traps (NETs) using neutrophil-differentiated HL-60 cells as well as primary human peripheral blood neutrophils. We then addressed whether the MoS2 nanosheets themselves function as antibacterial agents. We found that MoS2 and Na2MoO4 both triggered NETs, as evidenced by the quantification of neutrophil elastase (NE) activity and immunofluorescence staining of extracellular NE, as well as scanning electron microscopy. The release of NETs was found to be nitric oxide (NO)-dependent. We also found that the MoS2 nanosheets but not the soluble salt prompted acellular NO production in the presence of NaNO2. The acellular generation of NO, suggestive of nanozyme properties of the MoS2 nanosheets, was demonstrated by electron paramagnetic resonance analysis. Electrochemical analysis using cyclic voltammetry confirmed the redox transition of the MoS2 nanosheets. Finally, MoS2 nanosheets inhibited the growth of Escherichia coli in the presence of sodium nitrate. Taken together, MoS2 nanosheets triggered cellular effects as well as acellular antibacterial effects, and we provided evidence for nitrite reductase-like properties of MoS2.

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.

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.

G-/C-rich ssDNA-based Fe and Cu/Fe nanoclusters with peroxidase-like activity for intracellular ROS production and cytotoxicity applications

Five G-/C-rich single-stranded DNA (ssDNA) with different sequences and lengths were templated to prepare the DNA-Cu, DNA-Fe, and bimetallic DNA-Cu/M nanoclusters (NCs). The peroxidase-like activities of these nanomaterials were studied using H₂O₂ and 3,3',5,5''-tetramethylbenzidine (TMB) as the reaction substrates in HAc-NaAc buffer. It was found that T30-G2-Fe NCs and T30-G2-Cu/Fe NCs, with a size of about 2 nm, exhibit similar and the strongest enzyme-like activity under optimal conditions. Both NCs possess a similarly high affinity to substrates, and the Michaelis-Menten constant (K_m) values to TMB and H₂O₂ are about 11 and 2-3 times lower than those of natural horseradish peroxidase (HRP), respectively. The activity of both nanozymes decreases to about 70% after being kept for one week in pH 4.0 buffer at 4 °C, which is comparable with HRP. Hydroxyl radicals (•OH) are the main reactive oxygen species (ROS) produced in the catalytic reaction. Moreover, both NCs can facilitate in situ generation of ROS in HeLa cells using endogenous H₂O₂. MTT assays indicate that the T30-G2-Cu/Fe NCs exhibit the strong selective cytotoxicity to HeLa cells over HL-7702 cells. The cellular viability is about 70% and 50% after incubating with 0.6 M NCs for 24 h without or with 2 mM H₂O₂, respectively. The current study shows that the T30-G2-Cu/Fe NCs have the potential for chemical dynamic treatment (CDT).

From liver fibrosis to hepatocarcinogenesis: Role of excessive liver H2O2 and targeting nanotherapeutics

Liver fibrosis and hepatocellular carcinoma (HCC) have been worldwide threats nowadays. Liver fibrosis is reversible in early stages but will develop precancerosis of HCC in cirrhotic stage. In pathological liver, excessive H₂O₂ is generated and accumulated, which impacts the functionality of hepatocytes, Kupffer cells (KCs) and hepatic stellate cells (HSCs), leading to genesis of fibrosis and HCC. H₂O₂ accumulation is associated with overproduction of superoxide anion (O₂^•−) and abolished antioxidant enzyme systems. Plenty of therapeutics focused on H₂O₂ have shown satisfactory effects against liver fibrosis or HCC in different ways. This review summarized the reasons of liver H₂O₂ accumulation, and the role of H₂O₂ in genesis of liver fibrosis and HCC. Additionally, nanotherapeutics targeting H₂O₂ were summarized for further consideration of antifibrotic or antitumor therapy.

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Liver fibrosis and HCC are closely related because ROS induced liver damage and inflammation, especially over-cumulated H₂O₂.

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Excess H₂O₂ diffusion in pathological liver was due to increased metabolic rate and diminished cellular antioxidant systems.

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Freely diffused H₂O₂ damaged liver-specific cells, thereby leading to fibrogenesis and hepatocarcinogenesis.

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Nanotherapeutics targeting H₂O₂ are summarized for treatment of liver fibrosis and HCC, and also challenges are proposed.

Partially oxidized MoS2 nanosheets with high water-solubility to enhance the peroxidase-mimic activity for sensitive detection of glutathione

Surface oxidation engineering is an effective strategy to construct nanomaterials with enhanced biocatalytic activity. In this study, a facile one-pot oxidation strategy was proposed to synthesize partially oxidized molybdenum disulfide nanosheets (ox-MoS₂ NSs), which exhibit good water solubility and can be used as an excellent peroxidase substitute. Under the oxidation process, Mo-S bonds are partially broke and S atoms are replaced by excess oxygen atoms, and the released abundant heat and gases efficiently expended the interlayer distance and weaken the van der Waals forces between adjacent layers. Porous ox-MoS₂ NSs can be easily exfoliated by further sonication, and the nanosheets exhibits excellent water dispersibility and no obvious sediment appear even after store for months. Benefiting from the desirable affinity property with enzyme substrates, optimized electronic structure and prominent electron transfer efficiency, the ox-MoS₂ NSs exhibit enhanced peroxidase-mimic activity. Furthermore, the ox-MoS₂ NSs catalyzed 3,3',5,5'-tetramethylbenzidine (TMB) oxidation reaction could be inhibited by the redox reaction that take place between glutathione (GSH) as well as the direct interaction between GSH and ox-MoS₂ NSs. Thus, a colorimetric sensing platform was constructed for GSH detection with good sensitivity and stability. This work provides a facile strategy for engineering structure of nanomaterials and improving enzyme-mimic performance.

Nanozyme can substitute a natural Ogataea polymorpha catalase enzyme in vivo

Nanomaterials possessing artificial, enzyme-like catalytic activity (nanozymes, NZs) have a great potential for application in research, immunological assays, biosensors, in vivo imaging, and as therapeutic agents. Despite the obvious advances in construction and understanding of functional properties of NZs, there is still no clear evidence of whether they can complement the loss of corresponding enzymatic activity in vivo. Herein, we report the first, to the best to our knowledge, example of successful substitution of natural enzyme activity by catalase-like platinum (nPt) and platinum-gold (nPtAu) nanoparticles transferred to the cells of methylotrophic yeast Ogataea polymorpha. The nPt NZs were synthesized by the chemical reduction method and used as a seed to produce the nPt(core)Au(shell) particles. The produced nPt NZs were 68.1 and 91.3 nm in size, while the hydrids were of 531.2 and 615.1 nm. Both nPt and nPtAu demonstrated catalase activity in vitro. The catalase-deficient strain Ogataea polymorpha C-105 was shown to be able to grow on methanol and a mixture of glucose and methanol in the presence although not in the absence of NZs, this correlating with the decrease in intracellular hydrogen peroxide production. The results provide the first example of complementation of the natural enzyme function by synthetic NZs, the phenomenon which can further be used in a screening for new catalase-like nanozymes and as a fruitful tool to modify living cells by nanoparticles possessing catalytic activity and to use such modified cells as sensitive elements in cell-based biosensors.

Nanodrug rescues liver fibrosis via synergistic therapy with H2O2 depletion and Saikosaponin b1 sustained release

Hypoxia and hydrogen peroxide (H₂O₂) accumulation form the profibrogenic liver environment, which involves fibrogenesis and chronic stimulation of hepatic stellate cells (HSCs). Catalase (CAT) is the major antioxidant enzyme that catalyzes H₂O₂ into oxygen and water, which loses its activity in different liver diseases, especially in liver fibrosis. Clinical specimens of cirrhosis patients and liver fibrotic mice are collected in this work, and results show that CAT decrease is closely correlated with hypoxia-induced transforminmg growth factor β1 (TGF-β1). A multifunctional nanosystem combining CAT-like MnO₂ and anti-fibrosis Saikosaponin b1 (Ssb1) is subsequently constructed for antifibrotic therapy. MnO₂ catalyzes the accumulated H₂O₂ into oxygen, thereby ameliorating the hypoxic and oxidative stress to prevent activation of HSCs, and assists to enhance the antifibrotic pharmaceutical effect of Ssb1. This work suggests that TGF-β1 is responsible for the diminished CAT in liver fibrosis, and our designed MnO₂@PLGA/Ssb1 nanosystem displays enhanced antifibrotic efficiency through removing excess H₂O₂ and hypoxic stress, which may be a promising therapeutic approach for liver fibrosis treatment.

Glutathione peroxidase-like nanozymes: mechanism, classification, and bioapplication

The field of nanozymes is developing rapidly. In particular, glutathione peroxidase (GPx)-like nanozymes, which catalytically reduce H₂O₂/organic hydroperoxides to H₂O/alcohols, have attracted considerable attention. GPx-like nanozymes are powerful antioxidant enzymes known to combat oxidative stress. They have broad applications, including cytoprotection, anti-inflammation, neuroprotection, tumor therapy, and anti-aging. Although much progress has been made, GPx-like nanozymes have not been well discussed or fully reviewed as other nanozymes. This review aims to summarize recent advances on GPx-like nanozymes from the vantage point of mechanism, classification, and bioapplication. Future prospects for advancing their design and application are also discussed.

Structure design mechanisms and inflammatory disease applications of nanozymes

Nanozymes are artificial enzymes with high catalytic activity, low cost, and good biocompatibility, and have received ever-increasing attention in recent years. Various inorganic and organic nanoparticles have been found to exhibit enzyme-like activities and are used as nanozymes for diverse biomedical applications ranging from tumor imaging and therapeutics to detection. However, their further clinical applications are hindered by the potential toxicity and long-term retention of nanomaterials in vivo. Clarifying the catalytic mechanism of nanozymes and identifying the key factors responsible for their behavior can guide the design of nanozyme structure, enlighten the ways to improve their enzyme-like activities, and minimize the dosage of nanozymes, leading to reduced toxicity to the human body for a real biomedical application prospect. In particular, inflammation occurring in numerous diseases is closely related to reactive oxygen species, and the active oxygen scavenging ability of nanozymes potentially exerts excellent therapeutic effects on inflammatory diseases. In this review, we systematically summarize the structure-activity relationship of nanozymes, including regulation strategies for size and morphology, surface structure, and composition. Based on the structure-activity mechanisms, a series of chemically designed nanozymes developed to target various inflammatory diseases are briefly summarized.

Precisely modulated 2D PdCu alloy nanodendrites as highly active peroxidase mimics for the elimination of biofilms

Pd-based nanomaterials are good candidates for antibacterial applications because of their high catalytic activity and good biocompatibility. Nonetheless, there is still much work to do to improve the catalytic activity of Pd nanomaterials as antibacterial agents, particularly for anti-biofilms. In this work, Cu was introduced into Pd to form a series of 2D PdCu alloy nanodendrites (PdCu NDs) as high-performance peroxidase mimics based on flexible control of compositions. Remarkably, catalytic kinetics show that the composition-dependent synergy in the PdCu NDs strongly enhances the peroxidase-like activity. The detailed theoretical study reveals that the tuning of the electrostatic adsorption and dissociative chemisorption of the H₂O₂ molecule on PdCu ND surfaces by the precise introduction of Cu plays a key role in obtaining superior peroxidase-like catalytic activity. Significantly, the distinct peroxidase-like properties of the fine-tuned PdCu NDs endow them with excellent biofilm elimination capability via the generation of hydroxyl radicals. This work offers a great opportunity to design noble metal nanozymes with enhanced performance, which might advance the development of nanozymes as a new class of highly efficient antibacterial agents.

Engineering Antioxidative Cascade Metal-Phenolic Nanozymes for Alleviating Oxidative Stress during Extracorporeal Blood Purification

Oxidative stress is a compelling risk factor in chronic kidney diseases and is further aggravated for individuals during extracorporeal blood purification, ultimately leading to multiple complications. Herein, antioxidative cascade metal-phenolic nanozymes (metal-tannic acid nanozymes, M-TA NMs) are synthesized via metal ions-mediated oxidative coupling of polyphenols; then M-TA NMs engineered hemoperfusion microspheres (Cu-TAn@PMS) are constructed for alleviating oxidative stress. M-TA NMs show adjustable broad-spectrum antioxidative activities toward multiple reactive nitrogen and oxygen species (RNOS) due to the adjustable catalytic active centers. Importantly, M-TA NMs could mimic the cascade processes of superoxide dismutase and catalase to maintain intracellular redox balance. Detailed structural and spectral analyses reveal that the existence of a transition metal could decrease the electronic energy band gaps of M-TA NMs to offer better electron transfers for RNOS scavenging. Notably, dynamic blood experiments demonstrate that Cu-TAn@PMS could serve as an antioxidant defense system for blood in hemoperfusion to scavenge intracellular reactive oxygen species (ROS) effectively even in the complex blood environment and further protect endogenous antioxidative enzymes and molecules. In general, this work developed antioxidative cascade nanozymes engineered microspheres with excellent therapeutic efficacy for the treatment of oxidative stress-related diseases, which exhibited potential for clinical blood purification and extended the biomedical applications of nanozymes.

Nanozymes in the Treatment of Diseases Caused by Excessive Reactive Oxygen Specie

Excessive reactive oxygen species (ROS) may generate deleterious effects on biomolecules, such as DNA damage, protein oxidation and lipid peroxidation, causing cell and tissue damage and eventually leading to the pathogenesis of diseases, such as neurodegenerative diseases, ischemia/reperfusion ((I/R)) injury, and inflammatory diseases. Therefore, the modulation of ROS can be an efficient means to relieve the aforementioned diseases. Several studies have verified that antioxidants such as Mitoquinone (a mitochondrial-targeted coenzyme Q10 derivative) can scavenge ROS and attenuate related diseases. Nanozymes, defined as nanomaterials with intrinsic enzyme-like properties that also possess antioxidant properties, are hence expected to be promising alternatives for the treatment of ROS-related diseases. This review introduces the types of nanozymes with inherent antioxidant activities, elaborates on various strategies (eg, controlling the size or shape of nanozymes, regulating the composition of nanozymes and environmental factors) for modulating their catalytic activities, and summarizes their performances in treating ROS-induced diseases.

Male zooid extracts of Antheraea pernyi ameliorates non-alcoholic fatty liver disease and intestinal dysbacteriosis in mice induced by a high-fat diet

The male zooid of Antheraea pernyi (A. pernyi) accumulates several nutrients and physiological activity-related substances for reproduction. Some components in the extracts of the male zooid of A. pernyi (EMZAP) have several functions, such as protecting the liver, enhancing immunity, antiatheroscloresis, anti-aging, and antitumor effects. In this study, we investigated the ameliorating effects on high-fat diet (HFD)-induced non-alcoholic fatty liver disease (NAFLD). The EMZAP treatment could ameliorate NAFLD and effectively decrease the serum total cholesterol, triglyceride and low-density lipoprotein levels and a significant increase in serum high-density lipoprotein levels was observed. Additionally, the EMZAP treatment reduced the levels of liver-function enzymes and pro-inflammatory cytokines (i.e., IL-6, IL-8, TNF-α, TGF-β₁) and also the oxidative stress indices and regulated the expression of genes associated with fatty acid metabolism (SREBP-1c, PPARα, ACOX-1, CPT-1) in the liver to prevent the development of NAFLD. Furthermore, EMZAP enhanced the diversity and richness of the beneficial intestinal microbes, suggesting its potential as a dietary supplement and functional food to combat NAFLD induced by HFD.

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.

Colorimetric and Fluorescence Dual-Mode Biosensors Based on Peroxidase-Like Activity of the Co3O4 Nanosheets

The mimic enzyme has become a research hotspot in recent years because of its advantages of high stability, convenient preparation, and low price. In this article, Co₃O₄ nanosheets synthesized by a simple hydrothermal method possess the characteristics of a peroxidase-like activity. The results demonstrated that 3,3′,5,5′-Tetramethylbenzidine (TMB) could be oxidized by H₂O₂ to produce a typical blue product (oxTMB) which has a strong absorption at 650 nm wavelength with the help of the Co₃O₄ nanosheets. Thus, a simple and sensitive colorimetric detection method for H₂O₂ was established with a good linear relationship (2–200 μM) and a low limit of detection (0.4 μM). Meanwhile, the colorimetric product can effectively quench the fluorescence emitted by Ru(bpy)₃²⁺. Therefore, a colorimetric and fluorescence dual detection mode photochemical sensor for H₂O₂ detection is constructed based on the principle of the inner filter effect (IFE) between the colorimetric product (oxTMB) and Ru(bpy)₃²⁺. It can effectively avoid the false positive problem of a single detection mode. In the presence of glucose oxidase, glucose can be catalyzed to produce gluconic acid and H₂O₂; therefore, the sensor can also be used for the determination of glucose with a good linear relationship (0.02–2 μM) and a low limit of detection (5 nM). Experimental results showed that the sensor has a high sensitivity and strong anti-interference ability which can be used for the detection of actual samples.