Enzyme mimic nanomaterials as nanozymes with catalytic attributes

Single-well colorimetric sensor array for discrimination and smartphone-assisted detection of catecholamines based on Fe-carbon dots nanozymes

BACKGROUND

Catecholamines (CAs), such as noradrenaline (NE), adrenaline (AD), and dopamine (DA), are essential signaling mediators that regulate various physiological functions. Monitoring their levels is crucial for studying and diagnosing diseases, as abnormal concentrations are associated with numerous health conditions. However, distinguishing between these CAs is challenging due to their highly similar molecular structures.

RESULTS

In this study, Fe-doped carbon dot-based nanozymes (Fe-CDs) with strong peroxidase-like activity were synthesized using a simple one-pot method. Fe-CDs-based sensing systems exhibit excellent stability, reproducibility, sensitivity (with detection limits of 26.6 nM for NE, 46.0 nM for AD, and 33.3 nM for DA), and anti-interference properties. A triple-channel single-well colorimetric sensor array was developed by collecting the absorbance at 20, 40, and 60 min as sensing units, enabling the effective differentiation and identification of various CAs.

SIGNIFICANCE

The Fe-CDs-based system has proven capable of detecting CAs in real human urine and fetal bovine serum. Additionally, the Fe-CDs-based smartphone-assisted platform provides efficient, highly sensitive, and on-site CAs detection, making it highly promising for biomedical and diagnostic applications.

Double crystallization-driven copper-2-methylimidazole nanoflowers: Stabilizing glucose oxidase and activating nanozyme functions for tandem catalysis

Based on the structural characteristics of metal-organic framework (MOF) synthesis, we designed a double-crystallized copper-2-methylimidazole nanoflower (DCu NF) platform in which glucose oxidase (GOx) was incorporated to form an enzyme-nanozyme hybrid for glucose sensing. The D-Cu@GOx NF system mimics a GOx-horseradish peroxidase-like multi-enzyme cascade, benefiting from synergistic oxidation capabilities. Double crystallization of Cu nanoflowers (Cu-NFs) was crucial for inducing nanozyme activity by creating a unique Fenton-like reaction site, enhancing both cascade activity and enzyme stability. The system was constructed using a self-assembly method, integrating Cu-NF synthesis with in situ GOx immobilization. The double crystallization of Cu-NFs expanded the surface area, forming D-Cu@GOx NFs, which significantly enhanced cascade activity and enzyme stability. The system demonstrated excellent glucose detection performance, maintaining 88 % of enzyme activity after 30 days at room temperature, with temperature resistance up to 60 °C and pH stability between 3 and 8. The enhanced oxidation from the Cu metal Fenton-like reaction site enabled sensitive glucose detection over a wide linear range (0-50 μM), with a limit of detection of 1.25 μM. The system also showed high reproducibility, with a relative standard deviation of <5 % across five replicate measurements. Furthermore, it successfully detected human blood glucose in real samples, with results comparable to standard clinical methods. This report presents Cu NF synthesis with an integrated GOx approach, demonstrating cost-effectiveness through enhanced stability and sensitivity that reduces enzyme usage and enables rapid, accurate glucose biosensing. The D-Cu@GOx NFs, a hybrid enzyme-nanozyme complex, offer improved sensitivity and stability for glucose detection in serum. By enhancing enzyme stability, the system eliminates the need for dual enzymes, reducing costs and improving efficiency, while maintaining cost-effectiveness for industrial and diagnostic applications.

Nanozymes or Spirulina Platensis: Enhancing Sheep Thermo-Tolerance Through Physio-Metabolic, Immune, and Antioxidant Pathways

This study evaluated the potential of supplementing sheep diets with cobalt (CoNPs), iron (FeNPs) nanoparticles, or Spirulina platensis (SP) to tackle the adverse impacts of heat stress by assessing growth performance, oxidative status, metabolic pathways, immune parameters, gene expression, and hormone levels in sheep exposed to hot environmental conditions. A total of 32 Rahmani male lambs were randomly divided into four equal groups (n = 8). The CON group was fed the control diet or supplemented with 2 mg/kg of CoNPs (CoNPs group), 50 mg/kg of FeNPs (FeNPs group), or 1 g of SP/kg (SP group) diet for 3 months. The average size of nanozymes CoNPs and FeNPs were 41 and 44 nm, respectively. The temperature humidity index (THI) was 81.99 overall the study period. All nanozyme or SP treatments significantly (P < 0.05) enhanced growth performance, including final and average body weight, and dry matter intake. Nanozyme treatments also achieved the best results regarding hematocrit (P < 0.01) and platelets (P < 0.01). All supplemented groups exhibited lower WBC and lymphocyte counts, and higher globulin levels in comparison to stressed sheep. Total protein levels were significantly (P < 0.001) elevated in the FeNPs and SP groups compared to the remaining groups. Rams fed CoNPs or SP had notably (P < 0.001) higher TC and TG levels, while the FeNPs group showed the lowest TC levels (P < 0.05), as well as the lowest VLDL and LDL levels (P < 0.05). The levels of blood immune markers, specifically lysozyme, IgG, and IgM, were significantly (P < 0.05) elevated in all supplemented groups in comparison to the untreated group. Furthermore, rams receiving FeNPs demonstrated higher (P < 0.05) values for TAC, CAT, SOD, and GPX, and lower MDA levels than the other groups. Additionally, the supplemented group exhibited greater (P < 0.05) leptin and testosterone levels than the stressed group. Further, serum concentrations of zinc, selenium, and iron were significantly (P < 0.05) greater in the nano-feed additives and SP groups compared to the HS group. Dietary supplementation with nanozymes or SP notably (P < 0.05) upregulated GPX1 and HSP70 expression and downregulated TNF-alpha mRNA levels (P < 0.05). In summary, dietary supplementation with nanozymes or microalgae robustly bolstered sheep's immune-antioxidant capacity, improved growth performance, and promoted health under heat stress conditions relevant to global warming.

Comprehensive wound healing using ETN@Fe7S8 complex by positively regulating multiple programmed phases

Wound healing requires coordinated progression through multiple programmed phases including hemostasis, infection control, inflammatory resolution, proliferation, and tissue remodeling. Many nanomaterials have shown great potential to promote wound healing, however, most of them only address partial aspects of these processes, making a recovery hard with adequate effects. In this study, we prepared a complex of nano-iron sulfide integrated with erythrocyte-templated nanozyme (ETN) (ETN@Fe7S8) for comprehensive treatment of wounds. Firstly, ETN served as a mediator to confine iron sulfide to form Fe7S8 nanocomposite in a solvothermal reaction. Secondly, the ETN@Fe7S8 demonstrated bactericidal effects against methicillin-resistant Staphylococcus aureus (MRSA) by releasing ferrous iron and polysulfide to induce ferroptosis-like cell death. Thirdly, ferrous iron along with polysulfide exerted anti-inflammatory effects by inhibiting the activation of the NF-κB signaling pathway, while the polysulfide also contributed to angiogenesis by promoting the activation of vascular endothelial growth factor A (VEGFA), initiated phosphorylation-mediated activation of the PI3K/AKT signaling pathway, a master regulatory cascade governing endothelial cell survival, migration, and angiogenesis. When employed for wound, ETN@Fe7S8 showed the ability to prevent infection, reduce inflammation, promote angiogenesis, enhance cell proliferation, and remodel keratinocytes. Along with the hemostatic effect, ETN@Fe7S8 thus performed comprehensive effects for wound healing in the whole recovery stages. Therefore, our findings provide a multifunctional candidate of ETN and nano-iron sulfide complex which is capable of regulating and promoting wound healing.

Immobilization of cholesterol oxidases on functionalized Silica Nanoparticles for biotransformation of cholesterol and 7-ketocholesterol

Cholesterol oxidation leads to the development of several oxysterols such as 7-ketocholesterol (7KC), which are linked to various age-related conditions. An approach to reduce their toxicity is proposed using enzymes from microbial sources to degrade them. Our earlier studies identified Pseudomonas aeruginosa PseA and Rhodococcus erythropolis MTCC 3951 as potential strains capable of using 7KC as their sole carbon source. These strains produced cholesterol oxidase as the primary enzyme in the degradation pathway. To enhance applicability, cholesterol oxidase (ChOx) enzymes from P. aeruginosa PseA (ChOxP), R. erythropolis MTCC 3951 (ChOxR), and a commercial variant from Streptomyces sp. (ChOxS) were immobilized on silane functionalized silica nanoparticles (SNP) using covalent-coupling methods. The immobilization efficiency was 68 %, 86 %, and 83 % for ChOxP, ChOxR, and ChOxS respectively. The catalytic efficiency of the immobilized enzyme was nearly twice that of the free enzyme, with increased stability across a wide range of temperatures (10-70°C) and pH levels (4.0-9.0), although the optimum pH (7.5) and temperature (30°C) remained unchanged. The nano-immobilized cholesterol oxidases were reusable up to 10 cycles. Further, enzyme immobilization on nanoparticles was confirmed by FTIR, SEM, and TEM. Biotransformation of cholesterol and 7KC using the nanobioconjugates produced pharmaceutically important molecules 4-cholesten-3-one and 4-cholesten-3,7-dione respectively.

Colorimetric detection of methotrexate leveraging the halogen peroxidase-mimicking activity of Bi2WO6 nanoflowers

This study explores Bi2WO6 nanoflowers as novel haloperoxidase (HPO) mimetics and their application in analytical science, aiming to develop an efficient colorimetric method for methotrexate (MTX) detection. Bi2WO6 nanoflowers were synthesized via a modified hydrothermal method and exhibited bromoperoxidase- and iodoperoxidase-like activities, catalyzing the bromination of phenol red (PR) and iodination of thymol blue (TB). After optimizing the reaction conditions, the kinetic parameters, including the Michaelis-Menten constant (Km) and maximum reaction velocity (Vmax), exceeded those of most of the reported HPO nanozymes. Investigation of the catalytic mechanism identified singlet oxygen (1O2) as a reactive intermediate. Leveraging the inhibitory effect of MTX on Bi2WO6-based nanozymes, a colorimetric assay for MTX was developed, demonstrating excellent detection performance in terms of a wide linear range and a low detection limit. Furthermore, the developed assay exhibited reliable performance in detecting actual samples. This study validates Bi2WO6 nanoflowers as efficient HPO nanozymes and provides a reliable approach for the rapid and simple detection of MTX.

Catalytic Production of Aromatic Amines from Nitroaromatics-Addressing a Critical Challenge in Environmental Remediation

The present work reviews the continuous-flow hydrogenation of nitroaromatic compounds (NACs) to aromatic amines, highlighting its significance in sustainable chemical manufacturing. These processes offer enhanced efficiency, scalability, and safety compared to traditional batch methods, addressing the environmental concerns associated with NACs contamination. In this context, the flow-mode processes of NACs hydrogenation may be considered as tools for catalytically driven extraction of fine chemical products. Within this review, key aspects, including an overview of flow reactor designs-such as packed-bed and microreactors-optimizing heat and mass transfer are discussed. Additionally, various catalytic materials, including bimetallic nanoparticles and metal-organic frameworks, are explored for their improved stability and selectivity in NACs reduction. The kinetics of these reactions aids in understanding the factors affecting reaction, and mass transfer rates. Despite the advantages, challenges remain, including catalyst deactivation and reactor design complexities, particularly during scale-up for industrial applications. Future trends indicate a shift toward hybrid systems integrating photocatalysis and biocatalysis, enhancing the versatility of continuous-flow processes. Ultimately, the adoption of these technologies is anticipated to play a crucial role in the circular economy by converting hazardous waste into valuable products, thereby fostering innovation and environmental preservation in the chemical industry.

Dual-mode colorimetric-fluorescence biosensor for endotoxin detection based on CS@Fe,Cu/CDs-MnO2 nanomaterials

Endotoxins are found in the outer membrane of all gram-negative bacteria and are a primary cause of endotoxemia, organ failure, and significant harm to human health. Limulus reagent as traditional detection method has certain limitations for the rapid and accurate detection of endotoxin due to the high costs associated with the horseshoe crab used in the sensing process. Herein, a fluorometric and colorimetric dual-mode biosensor was prepared for the rapid and sensitive detection of endotoxin. The chitosan-grafted Fe,Cu-doped carbon dots (CDs) was used to reduce KMnO4 to produce CS@Fe,Cu/CDs-MnO2, which demonstrated distinctive characteristics including high catalytic activity as an artificial nanozyme and a fluorescence quantum yield of 76 %. On the one hand, CS@Fe,Cu/CDs-MnO2 with the peroxidase-like activity and positively charged property can oxidize 3,3-diaminobenzidine tertrahydrochloride (DAB) and H2O2 to yield a brown product (oxDAB). Additionally, it can interact with negatively charged endotoxin through electrostatic forces, which leads to a reduction in its nanozyme catalytic activity. On the other hand, oxDAB can quench the CS@Fe,Cu/CDs-MnO2 fluorescence via inner-filter effect and static quenching. Therefore, a dual-mode biosensor that utilizes both fluorescence and colorimetric methods is developed with the aid of a smartphone. It was found that the gray value of absorbance increased linearly with endotoxin concentration in the range of 0.125-175 EU/L with a minimum limit of detection (LOD) of 0.058 EU/L, while the gray value of fluorescence intensity also demonstrated a linear increase upon the addition of endotoxin within the range of 0.05-90 EU/L with a LOD of 0.036 EU/L. The sensor is effectively utilized for detecting endotoxin in real injection samples, achieving acceptable recovery rates between 89.0 % and 101.3 %, with a relative standard deviation (RSD) of no more than 4.51 %. This indicates the reliability of the fabricated biosensor.

Nanozyme-based visual diagnosis and therapeutics for myocardial infarction: The application and strategy

BACKGROUND

Myocardial infarction (MI) is a heart injury caused by ischemia and low oxygen conditions. The occurrence of MI lead to the activation of a large number of neutrophils and macrophages, inducing severe inflammatory injury. Meanwhile, the inflammatory response produces much more free radicals, further exacerbating the inflammatory response and tissue damage. Efforts are being dedicated to developing antioxidants and enzymes, as well as small molecule drugs, for treating myocardial ischemia. However, poor pharmacokinetics and potential side effects limit the clinical application of these drugs. Recent advances in nanotechnology have paved new pathways in biomedical and healthcare environments. Nanozymes exhibit the advantages of biological enzymes and nanomaterials, including with higher catalytic activity and stability than natural enzymes. Thus, nanozymes provide new possibilities for the diagnosis and treatment of oxidative stress and inflammation-related diseases.

AIM OF REVIEW

We describe the application of nanozymes in the diagnosis and therapy of MI, aiming to bridge the gap between the diagnostic and therapeutic needs of MI.

KEY SCIENTIFIC CONCEPTS OF REVIEW

We describe the application of nanozymes in the diagnosis and therapy of MI, and discuss the new strategies for improving the diagnosis and treatment of MI. We review in detail the applications of nanozymes to achieve highly sensitive detection of biomarkers of MI. Due to their unique enzyme catalytic capabilities, nanozymes have the ability to sensitively detect biomolecules through colorimetric, fluorescent, and electrochemical assays. In addition, nanozymes exhibit excellent antioxidase-mimicking activity to treat MI by modulating reduction/oxidation (REDOX) homeostasis. Nanozymes can also passively or actively target MI tissue sites, thereby protecting ischemic myocardial tissue and reducing the infarct area. These innovative applications of nanozymes in the field of biomedicine have shown promising results in the diagnosis and treatment of MI, offering a novel therapeutic strategy.

Carbon dot superoxide dismutase nanozyme enhances reactive oxygen species scavenging in diabetic skin wound repair

INTRODUCTION

The accumulation of reactive oxygen species (ROS) in diabetic wounds leads to inflammation and impaired neovascularization. Recent studies have indicated that carbon dot nanozymes (C-dots) exhibiting superoxide dismutase (SOD)-like activity can neutralize excessive ROS and mitigate diseases associated with oxidative stress.

OBJECTIVES

Our study was designed to evaluate the therapeutic impact of C-dots on the healing of diabetic wounds and to unravel the complex molecular mechanisms through which these nanozymes modulate oxidative stress and inflammatory responses within the wound microenvironment.

METHODS AND RESULTS

We synthesized C-dots from carbon fiber and confirmed their structure using transmission electron microscopy. The presence of carbon-carbon double bonds on the C-dots was verified with X-ray photoelectron spectroscopy. We assessed the scavenging capacity of C-dots for superoxide anion, hydroxyl radical, and nitric oxide radical using electron spin resonance spectroscopy. Their SOD-like activity and total antioxidant capacity were evaluated with commercial assay kits. In vitro experiments showed that C-dots effectively scavenged excessive ROS, protecting human keratinocytes, vascular endothelial cells, and fibroblasts from oxidative stress-induced damage. Concurrently, C-dots increased the migratory capacity of fibroblasts. In a streptozocin-induced diabetic mice model, C-dots application enhanced skin wound healing, evidenced by accelerated re-epithelialization and orderly collagen matrix assembly. Mechanistic investigations indicated that C-dots markedly suppressed ROS generation and diminished the levels of inflammatory cytokines in the wound environment. Additionally, C-dots induced an M2 polarization phenotype in macrophages and promoted neovascularization, indicating a transition from the inflammatory to the proliferative phase. Quantitative proteomic analysis was conducted to further clarify the underlying mechanisms of C-dots in ameliorating diabetic wounds.

CONCLUSION

C-dots represent a robust nanomaterial-based strategy for treating diabetic wounds, with the ability to accelerate healing by alleviating oxidative stress, mitigating harmful inflammatory responses, and fostering angiogenesis. This highlights their significant therapeutic potential in the field of biomedicine.

Multifunctional cerium nanolabels in electrochemical immunosensing with improved robustness and performance: determination of TIM-1 in colorectal cancer scenarios as a case study

A multifunctional cerium oxide nanoparticles (CeO2NPs)-based nanolabel is exploited to implement an electrochemical sandwich-type immunoplatform for the determination of T-cell immunoglobulin and mucin domain 1 (TIM-1) biomarker, a mucin-like class I membrane glycoprotein associated with cancer angiogenesis. The immunoplatform is constructed using screen-printed electrodes where capture antibody is immobilized through the chemistry of diazonium salts. CeO2NPs exhibit robust pseudo-peroxidase activity even at high substrate concentrations. They are covalently functionalized in a simple manner after carboxylation with a detector antibody (dAb), acting dually as a nanozyme and nanocarrier for sensing bioreceptors. This allows the development of immunoplatforms with improved robustness and performance (in terms of a moderate enhancement in sensitivity, a significant expansion in the linear range, and a reduction in the background current) compared with the immunoplatforms prepared using nanolabels also decorated with the natural enzyme (horseradish peroxidase, HRP) or the conventional enzymatic labeling involving the dAb and an HRP-secondary antibody. Under the optimized experimental conditions, the developed electrochemical immunoplatform allows the highly sensitive detection of the TIM-1 glycoprotein, with a detection limit of 9.9 pg mL-1 and a linear working range of 33-600 pg mL-1. This performance permits biomarker quantification within clinically relevant ranges. This innovative configuration enables the precise diagnosis and stratification of colorectal cancer patients by analyzing plasma samples without pretreatment beyond a sample dilution and allows establishment of the first cut-off values reported for this purpose.

Fabrication of the multifunctional Pd modified NiCuFe Prussian blue analogue nanoplatform and its sensitive colorimetric detection of L-cysteine

It is essential to establish a simple, effective and sensitive platform for L-Cysteine (L-Cys) detection because the level of L-Cys is related to many diseases in the human body. Herein, we successfully fabricated polyaniline bridging NiCuFe Prussian blue analogue@palladium (NiCuFe@Pd) nanocomposite with integration of photothermal conversion performance and catalytic performance. And, various spectroscopic and microscopic techniques were adopted to prove the formation of the nanocomposite. 4-nitrothiophenol and 3,3',5,5'-tetramethylbenzidine (TMB) were employed to prove the catalytic activity of the nanocomposite. Due to the catalytic activity, the nanocomposite was used as a nanoplatform for colorimetric detection of L-Cys, which showed high sensitivity with a detection limit as low as 0.027 μM. In addition, the excellent photothermal conversion performance makes it a potential candidate for photothermal therapy for various diseases. This study may be beneficial to promote the construction of novel nanostructures and their medical application.

Self-Assembled DNA/SG-I Nanoflower: Versatile Photocatalytic Biosensors for Disease-Related Markers

DNA nanostructures have recently attracted more attention with functionalities, programmability, and biocompatibility. Herein, a novel self-assembled photocatalytic DNA/SYBR Green I (SG-I) nanoflower (DSNF) was successfully synthesized by rolling circle amplification. DSNF was self-assembled through liquid crystallization of a high concentration of DNA in the RCA products, without relying on the Watson-Crick base-pairing principle. Interestingly, DSNF not only possessed a larger specific surface area and good stability but also exhibited excellent photocatalytic activity that generates singlet oxygen and superoxide anion to oxidate 3,3',5,5'-tetramethylbenzidine. Meanwhile, the photocatalytic DSNF combined with an enzyme-linked immunosorbent assay to develop a new colorimetric sensor for highly specific, sensitive, and visual detection of carcinoembryonic antigens (CEAs). The colorimetric sensor achieved sensitive and low-cost quantitative detection of CEA in the linear range of 0.5-80.0 ng/mL, and the LOD was 0.5 ng/mL. In addition, three negative and seven positive clinical serum samples of CEA were obtained with 100% accuracy using the proposed colorimetric sensor, showing great potential in the clinical application of cancer diagnosis. We envision that this photocatalytic DSNF is expected to provide important perspectives in fluorescence imaging, photosensitizing cancer therapy, and clinical diagnosis fields.

Recent Development of Nanozymes for Combating Bacterial Drug Resistance: A Review

The World Health Organization has warned that without effective action, deaths from drug-resistant bacteria can exceed 10 million annually, making it the leading cause of death. Conventional antibiotics are becoming less effective due to rapid bacterial drug resistance and slowed new antibiotic development, necessitating new strategies. Recently, materials with catalytic/enzymatic properties, known as nanozymes, have been developed, inspired by natural enzymes essential for bacterial eradication. Unlike recent literature reviews that broadly cover nanozyme design and biomedical applications, this review focuses on the latest advancements in nanozymes for combating bacterial drug resistance, emphasizing their design, structural characteristics, applications in combination therapy, and future prospects. This approach aims to promote nanozyme development for combating bacterial drug resistance, especially towards clinical translation.

Bibliometric Analysis and Network Visualization of Nanozymes for Microbial Theranostics in the Last Decade

Nanozymes are a class of nanomaterials that are capable of mimicking the activities of natural enzymes. They are currently receiving considerable attention due to their advantageous properties. The objective of this study is to provide a comprehensive analysis of the advancements and trends in nanozymes for microbial theranostics research over the past decade through a detailed bibliometric approach. For this purpose, an effective search query was formulated, and relevant publications from 2013 to 2023 were collected from the Web of Science Core Collection database. Subsequently, the following softwares were employed for analysis: VOSviewer, the Bibliometrix R package, and GraphPad Prism 8.0.2. The findings revealed a statistically significant positive correlation (r = 0.993; p < 0.0001) between publications and citations, in addition to an important growth rate of scientific output of approximately 28.90%. China, India, and the USA were the most productive countries, whereas progress in low- and middle-income countries remained constrained. The Chinese Academy of Sciences was the most productive institution, and remarkably almost the top 10 productive authors were from China. Regarding keywords analysis, current research hotspots are primarily concentrated on the application of nanozymes in anti-biofilm-related research, antibacterial activity and therapy, the development of biosensors for microbial detection and control, and the advancement of wound disinfection and therapy.

Design Strategy of PepNzymes-SH for an Emerging Catalyst with Serine Hydrolase-Like Functionality

Serine hydrolases, as a class of green catalysts with hydrolytic and dehydrating activities, hold significant application value in the fields of biosynthesis and organic synthesis. However, practical applications face numerous challenges, including maintaining enzyme stability and managing usage costs. PepNzymes-SH, an emerging green catalytic material with enzyme-like activity, overcomes the operational limitations of natural enzymes and holds great promise as a substitute for hydrolases. Unfortunately, a systematic review of the design strategies for PepNzymes-SH is currently lacking. The core significance of this report lies in providing researchers with a comprehensive understanding and theoretical guidance through the summarization and performance evaluation of different design strategies of PepNzymes-SH. This review summarizes strategies for simulating and enhancing the stability of serine hydrolase active sites, oxyanion holes, and hydrophobic environmental structures. By comparing their catalytic activities, we assess the performance changes brought about by different strategies. Furthermore, the applications of PepNzymes-SH in the chemical, biomedicine, and environmental fields are also discussed.

Enzymatic properties of iron oxide nanoclusters and their application as a colorimetric glucose detection probe

Nanozymes have attracted attention owing to their distinct catalytic capabilities and potential applications, being advantageous compared to natural enzymes in terms of storage and cost efficiency. In this study, we investigated the enzymatic properties of iron oxide nanoclusters (IOCs) formed through the clustering of small nanoparticles. Our findings reveal that the enzymatic activity of IOCs is enhanced as their size increases. Additionally, we demonstrated that the size of the unit particles within IOCs is highly dependent on the nucleation environment, which is a crucial factor in determining the overall size of the IOCs. Importantly, the surface area of IOCs is more closely related to the size of the individual unit particles rather than the entire cluster. Smaller unit particle sizes within IOCs resulted in an increase in nanocluster size, thereby augmenting the specific surface area. The optimal IOC exhibited superior stability under various conditions and a broader range of reactivity compared to natural enzymes, making it a promising probe material for point-of-care tests across diverse environments. Furthermore, its effectiveness as a glucose detection probe was demonstrated, highlighting its potential for practical applications. The remarkable enzyme-like efficacy of IOCs not only enhances their utility in on-site detection technologies but also establishes them as a versatile detection probe.

Multifunctional Artificial Peroxisome Basing on Lactate Oxidase as a Self-Cascade Enhancing Active Oxygen Amplifier for Tumor Therapy

The intricacy, diversity, and heterogeneity of cancers make research focus on developing multimodal synergistic therapy strategies. Herein, an oxygen (O2) self-feeding peroxisomal lactate oxidase (LOX)-based LOX-Ce6-Mn (LCM) was synthesized using a biomineralization approach, which was used for cascade chemodynamic therapy (CDT)/photodynamic therapy (PDT) combination therapies through dual depletion of lactate (Lac) and reactive oxygen species (ROS) generation. After endocytosis into tumor cells, the endogenous hydrogen peroxide (H2O2) can be converted to O2 by the catalase-like (CAT) activity of LCM, which can facilitate the catalytic reaction of LOX to consume more Lac and alleviate tumor hypoxia to enhance the generation of singlet oxygen (1O2) upon light irradiation. In addition, the H2O2 produced by LOX catalysis and oxidase-like (OXD) activity of LCM can be catalyzed into highly toxic hydroxyl radicals (•OH) via the Fenton-like reaction, enhancing oxidative damage to tumor cells. Both in vitro and in vivo experiments confirmed that LCM significantly promoted ROS accumulation and effectively inhibited tumor growth by inducing tumor cell autophagy under the combined effect of Lac depletion and CDT with PDT. Therefore, integrally designed LCM for reprogramming metabolism and the tumor microenvironment offers a promising multimodal strategy for tumor treatments.

Engineering thermostability of industrial enzymes for enhanced application performance

Thermostability is a key factor for the industrial application of enzymes. This review categorizes enzymes by their applications and discusses the importance of engineering thermostability for practical use. It summarizes fundamental theories and recent advancements in enzyme thermostability modification, including directed evolution, semi-rational design, and rational design. Directed evolution uses high-throughput screening to generate random mutations, while semi-rational design combines hotspot identification with screening. Rational design focuses on key residues to enhance stability by improving rigidity, foldability, and reducing aggregation. The review also covers rational strategies like engineering folding energy, surface charge, machine learning methods, and consensus design, along with tools that support these approaches. Practical examples are critically assessed to highlight the benefits and limitations of these strategies. Finally, the challenges and potential contributions of artificial intelligence in enzyme thermostability engineering are discussed.

Nanoenzyme-based sensors for the detection of anti-tumor drugs

Natural enzymes are a class of biological catalysts that can catalyze a specific substrate. Although natural enzymes have catalytic activity, they are susceptible to the influence of external environment such as temperature, and storage requirements are more stringent. Since the first discovery of magnetic Fe3O4 nanoparticles with peroxidase-like activity in 2007, the research on nanoenzymes has entered a rapid development stage. Nanoenzymes synthesized by chemical methods not only have the catalytic activity of natural enzymes but also are more stable, easy to store, and convenient to prepare. Anthracyclines, as a commonly used anti-tumor chemotherapy drug, will produce many side effects such as myelosuppression and liver function damage after long-term use, which will affect its therapeutic effects. This paper reviews the characteristics, classification, and mechanisms of nanoenzymes. The detection of anti-tumor drugs, especially anthracycline drugs, using a nanoenzyme-based sensor was emphatically introduced. On this basis, the application of nanoenzyme-based sensors in the detection of anti-tumor drugs is  prospected.

Advances and Future Trends in Nanozyme-Based SERS Sensors for Food Safety, Environmental and Biomedical Applications

Nanozymes, a kind of nanoparticles with enzyme-mimicking activities, have attracted considerable attention due to their robust catalytic properties, ease of preparation, and resistance to harsh conditions. By combining nanozymes with surface-enhanced Raman spectroscopy (SERS) technology, highly sensitive and selective sensors have been developed. These sensors are capable of detecting a wide range of analytes, such as foodborne toxins, environmental pollutants, and biomedical markers. This review provides an overview of recent advancements in the synthesis and surface modification of nanozymes, highlighting their ability to mimic multiple enzymes and enhance catalytic performance. In addition, we explore the development and applications of nanozyme-based SERS sensors in food contaminants, environmental pollutants, and biomedical markers. The review concludes with perspectives and challenges facing the field, involving the need for deeper understanding of nanozyme principles and mechanisms, development of standardized systems for characterization, and the engineering of nanozymes with tailored properties for specific applications. Finally, we discuss the potential for integrating various techniques with nanozymes to create multi-modal detection platforms, paving the way for the next generation of analytical tools in the fields of food safety, environmental monitoring, and biomedical diagnostics.

Flavonoid-rich sesame leaf extract-mediated synthesis of nanozymes: Extraction optimization, chemical composition identification and bioactivity evaluation

Sesame leaves contain rich phenolic acids and flavonoids. However, their potential in nanozyme synthesis has not been investigated yet. Herein, we report the preparation of flavonoid-rich sesame leaf extract (SLE), composition identification, and its use in the construction of iron (Fe)-based nanozymes (Fe-SLE CPNs). SLE was obtained with an extraction yield of ∼14.5% with a total flavonoid content (TFC) of ∼850.85 mg RE/g. There were 83 flavonoid compounds in SLE, primarily including scutellarin, apigenin-7-glucuronid, narcissin, and hyperoside. Fe-SLE CPNs exhibited nanodot morphology with a hydrodynamic size of 79.34 nm and good stability in various physiological solutions, pH levels, and temperatures. The Fe-SLE CPNs were more efficient in the scavenging ability of reactive oxygen species (ROS) than SLE alone. Furthermore, a stronger anti-inflammatory effect of the Fe-SLE CPNs was shown by modulating the MyD88-NF-κB-MAPK signaling pathways. These findings imply that SLE-based nanozymes hold great potential for diverse applications.

Colorimetric-SERS dual-mode aptasensor for Staphylococcus aureus based on MnO2@AuNPs oxidase-like activity

The nanozyme-linked aptamer-sorbent assay (NLASA) is a rapid way to screen and characterize aptamer binding to targets. In this paper, a MnO2@AuNPs@aptamer (Apt) based NLASA coupled with colorimetric-SERS dual-mode for Staphylococcus aureus (S. aureus) detection is presented. Cu,Fe-CDs were used as the reducing agent to synthesize MnO2 and gold nanoparticles (AuNPs). Then, they were fabricated to obtain MnO2@AuNPs with oxidase (OXD)-like and SERS activities. The S. aureus aptamer was conjugated to MnO2@AuNPs and enhanced the OXD-like activity, which realized the specific capture of S. aureus in food matrices. In addition, S. aureus improves the oxidation of 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid (ABTS) but inhibits 3,3',5,5'-tetramethylbenzidine (TMB) to generate Raman-active oxTMB with MnO2@AuNPs@Apt. This sensor was used for detections of S. aureus in a concentration ranged from 101 to 107 CFU/mL with a detection limit of 0.926 CFU/mL (colorimetric) and 1.561 CFU/mL (SERS), and the recovery is 85%-105% in real samples.

Recent Advances in Nanozyme-Based Sensing Technology for Antioxidant Detection

Antioxidants are substances that have the ability to resist or delay oxidative damage. Antioxidants can be used not only for the diagnosis and prevention of vascular diseases, but also for food preservation and industrial production. However, due to the excessive use of antioxidants, it can cause environmental pollution and endanger human health. It can be seen that the development of antioxidant detection technology is important for environment/health maintenance. It is found that traditional detection methods, including high performance liquid chromatography, gas chromatography, etc., have shortcomings such as cumbersome operation and high cost. In contrast, the nanozyme-based detection method features advantages of low cost, simple operation, and rapidity, which has been widely used in the detection of various substances such as glucose and antioxidants. This article focuses on the latest research progress of nanozymes for antioxidant detection. Nanozymes for antioxidant detection are classified according to enzyme-like types. Different types of nanozyme-based sensing strategies and detection devices are summarized. Based on the summary and analysis, one can find that the development of commercial nanozyme-based devices for the practical detection of antioxidants is still challenging. Some emerging technologies (such as artificial intelligence) should be fully utilized to improve the detection sensitivity and accuracy. This article aims to emphasize the application prospects of nanozymes in antioxidant detection and to provide new ideas and inspiration for the development of detection methods.

Facile Preparation of Tannic Acid-Gold Nanoparticles for Catalytic and Selective Detection of Mercury(II) and Iron(II) Ions in the Environmental Water Samples and Commercial Iron Supplement

Tannic acid (TA), a plant-derived polyphenol rich in hydroxyl groups, serves as both a reducing agent and stabilizer for synthesizing gold nanoparticles (TA-AuNPs). This study presents a groundbreaking method that utilizes TA to fabricate TA-AuNPs and develop two distinct colorimetric detection systems for mercury (Hg2+) and iron (Fe2+) ions. The first detection system leverages the interaction between TA-AuNPs and Hg2+ to enhance the peroxidase-like activity of TA-AuNPs, facilitating the production of hydroxyl radicals upon reaction with hydrogen peroxide, which subsequently oxidizes 3,3',5,5'-tetramethylbenzidine (TMB) into a blue-colored product (ox-TMB). The second system capitalizes on TA-AuNPs to catalyze the Fenton reaction between Fe2+ and hydrogen peroxide in the presence of 2, 6-pyridinedicarboxylic acid, boosting the generation of hydroxyl radicals that oxidize TMB into a blue-colored ox-TMB. Absorbance measurements at 650 nm display a linear relationship with Hg2+ concentrations ranging from 0.40 to 0.60 μM (R2 = 0.99) and Fe2+ concentrations from 0.25 to 2.0 μM (R2 = 0.98). The established detection limits for Hg2+ and Fe2+ are 18 nM and 96 nM, respectively. Applications to real-world samples achieved an excellent spiked recovery, spanning 101.6% to 108.0% for Hg2+ and 90.0% to 112.5% for Fe2+, demonstrating the method's superior simplicity, speed, and cost-effectiveness for environmental monitoring of these ions compared to existing techniques.

Development of a nanocomposite hydrogel catalyzed H2O2/TMB system for determination of chlordiazepoxide in exhaled breath condensate

In this study, an enzyme mimic catalyzed H2O2-tetramethylbenzidine system based on UiO-66/Au NPs-PVA nanocomposite hydrogel was employed as an optical probe for chlordiazepoxide sensing. An excellent detection limit of 0.0032 μg mL-1 with a linear range of 0.005-2.0 μg mL-1 was obtained for chlordiazepoxide in exhaled breath condensate samples under optimal conditions. The validated system showed good repeatability, simplicity, and stability toward chlordiazepoxide sensing in the exhaled breath condensate of patients receiving this drug.

Immobilization of HRP enzyme on polymeric microspheres and its use in decolourisation of organic dyes

In this study, horseradish peroxidase (HRP) enzyme was immobilized on Pd(II) containing polymeric microspheres by adsorption method and used for the decolourisation of Methyl Orange (MO) and Rhodamine B (RB) dyes. The synthesized microspheres were characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy-Energy Dispersive X-ray (SEM/EDX), Thermal Gravimetric Analysis (TGA). The effects of pH, dye concentration, temperature, and H2O2 concentration on the decolourisation of MO and RB were determined. According to the results of various parameters studied, when 2-AEPS-napht-HRP support was used, MO and RB were biodegraded to 69.72% and 80.65%, respectively, within 60 min. When 2-AEPS-napht-Pd-HRP support was used, MO and RB were biodegraded to 58.35% and 90.81%, respectively, under optimum conditions. When the reproducibility results of the immobilized supports were examined, it was observed that they remained efficient during the first five reusability cycles and even reached 65% decolourisation efficiency after the 9th reuse. The immobilized enzyme (2AEPS-npht-HRP and 2AEPS-npht-Pd-HRP) showed remarkable resistance to higher temperatures compared to the free enzyme.

Development of Nanozymatic Characteristics in Metal-Doped Oxide Nanomaterials

Nanozymes are nanoscale materials that exhibit enzymatic-like activity, combining the benefits of nanomaterials with biocatalytic effects. The addition of metals to nanomaterials can enhance their nanozyme activity by mimicking the active sites of enzymes, providing structural support and promoting redox activity. In this study, nanostructured oxide and silicate-phosphate nanomaterials with varying manganese and copper additions were characterized. The objective was to assess the influence of metal modifications (Mn and Cu) on the acquisition of the nanozymatic activity by selected nanomaterials. An increase in manganese content in each material enhanced proteolytic activity (from 20 to 40 mUnit/mg for BG-Mn), while higher copper addition in glassy materials increased activity by 40%. Glassy materials exhibited approximately twice the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid radical activity (around 40 μmol/mL) compared to that of oxide materials. The proteolytic and antioxidant activities discussed in the study can be considered indicators for evaluating the enzymatic properties of the nanomaterials. Observations conducted on nanomaterials may aid in the development of materials with enhanced catalytic efficiency and a wide range of applications.

A metal-phenolic coordination framework nanozyme exhibits dual enzyme mimicking activity and its application is effective for colorimetric detection of biomolecules

Biomolecules play vital roles in many biological processes and diseases, making their identification crucial. Herein, we present a colorimetric sensing method for detecting biomolecules like cysteine (Cys), homocysteine (Hcy), and glutathione (GSH). This approach is based on a reaction system whereby colorless 3,3',5,5'-tetramethylbenzidine (TMB) undergoes catalytic oxidation to form blue-colored oxidized TMB (ox-TMB) in the presence of hydrogen peroxide (H2O2), utilizing the peroxidase and catalase-mimicking activities of metal-phenolic coordination frameworks (MPNs) of Cu-TA, Co-TA, and Fe-TA nanospheres. The Fe-TA nanospheres demonstrated superior activity, more active sites and enhanced electron transport. Under optimal conditions, the Fe-TA nanospheres were used for the detection of biomolecules. When present, biomolecules inhibit the reaction between TMB and H2O2, causing various colorimetric responses at low detection limits of 0.382, 0.776 and 0.750 μM for Cys, Hcy and GSH. Furthermore, it was successfully applied to real water samples with good recovery results. The developed sensor not only offers a rapid, portable, and user-friendly technique for multi-target analysis of biomolecules at low concentrations but also expands the potential uses of MPNs for other targets in the environmental field.

Construction and Application of Nanozyme Sensor Arrays

Compared with traditional "lock-key mode" biosensors, a sensor array consists of a series of sensing elements based on intermolecular interactions (typically hydrogen bonds, van der Waals forces, and electrostatic interactions). At the same time, sensor arrays also have the advantages of fast response, high sensitivity, low energy consumption, low cost, rich output signals, and imageability, which have attracted widespread attention from researchers. Nanozymes are nanomaterials which own enzyme-like properties. Because of the adjustable activity, high stability, and cost effectiveness of nanozymes, they are potential candidates for construction of sensor arrays to output different signals from analytes through the chemoresponse of colorants, which solves the shortcomings of traditional sensors that they cannot support multiple detection and lack universality. Recently, a sensor array based on nanozymes as nonspecific recognition receptors has attracted much more attention from researchers and has been applied to precise recognition of proteins, bacteria, and heavy metals. In this perspective, attention is given to nanozymes and the regulation of their enzyme-like activity. Particularly, the building principles and methods for sensor arrays based on nanozymes are analyzed, and the applications are summarized. Finally, the approaches to overcome the challenges and perspectives are also presented and analyzed for facilitating further research and development of nanozyme sensor arrays. This perspective should be helpful for gaining insight into research ideas within the field of nanozyme sensor arrays.

Artificial nonenzymatic antioxidant Prussian blue/KGM-BSA nanocomposite hydrogel dressing as ROS scavenging for diabetic wound healing

The process of diabetic wound healing was influenced by the excessive proliferation of reactive oxygen species (ROS). Therefore, in the process of healing diabetic wounds, it was crucial to removing ROS. This study designed composited nanoparticles: KBP, consisted by Konjac glucomannan, bovine serum albumin, and Prussian blue. Then they were embedded in Konjac glucomannan and hydroxypropyl trimethylammonium chloride chitosan composite hydrogel (KH), The KBP@KH hydrogel finally achieved excellent efficacy in diabetic wound healing. The in vitro and in vivo experiments demonstrated that KPB nanoparticles exhibited favorable ROS scavenging capability and biosafety. The KBP@KH hydrogel not only effectively eliminated ROS from diabetic wounds, but also exhibited excellent wound adaptability. The KBP@KH hydrogel facilitated angiogenesis and suppressed the production of inflammatory factors. Overall, the KBP@KH hydrogel dressing was characterized by its user-friendly nature, safety, and high efficiency.

Neuromodulation by nanozymes and ultrasound during Alzheimer's disease management

Alzheimer's disease (AD) is a neurodegenerative disorder with complex pathogenesis and effective clinical treatment strategies for this disease remain elusive. Interestingly, nanomedicines are under extensive investigation for AD management. Currently, existing redox molecules show highly bioactive property but suffer from instability and high production costs, limiting clinical application for neurological diseases. Compared with natural enzymes, artificial enzymes show high stability, long-lasting catalytic activity, and versatile enzyme-like properties. Further, the selectivity and performance of artificial enzymes can be modulated for neuroinflammation treatments through external stimuli. In this review, we focus on the latest developments of metal, metal oxide, carbon-based and polymer based nanozymes and their catalytic mechanisms. Recent developments in nanozymes for diagnosing and treating AD are emphasized, especially focusing on their potential to regulate pathogenic factors and target sites. Various applications of nanozymes with different stimuli-responsive features were discussed, particularly focusing on nanozymes for treating oxidative stress-related neurological diseases. Noninvasiveness and focused application to deep body regions makes ultrasound (US) an attractive trigger mechanism for nanomedicine. Since a complete cure for AD remains distant, this review outlines the potential of US responsive nanozymes to develop future therapeutic approaches for this chronic neurodegenerative disease and its emergence in AD management.

Perspectives for the Role of Single-Atom Nanozymes in Assisting Food Safety Inspection and Food Nutrition Evaluation

Single-atom nanozymes (SAzymes) have been greatly developed for rapid detection, owing to their rich active sites and excellent catalytic activity. Although several excellent reviews concentrating on SAzymes have been reported, they mainly focused on advanced synthesis, sensing mechanisms, and biomedical applications. To date, few reviews elaborate on the promising applications of SAzymes in food safety inspection and food nutrition evaluation. In this paper, we systematically reviewed the enzyme-like activity of SAzymes and the catalytic mechanism, in addition to recent research advances of SAzymes in the domain of food safety inspection and food nutrition evaluation in the past few years. Furthermore, current challenges hampering practical applications of SAzymes in food assay are summarized and analyzed, and possible research areas focusing on SAzyme-based sensors in rapid food testing are also proposed.

Nanozymes: A comprehensive review on emerging applications in cancer diagnosis and therapeutics

Nanozymes, a new class of nanomaterials-based artificial enzymes, have gained huge attraction due to their high operational stability, working efficiency in extreme conditions, and resistance towards protease digestion. Nowadays, they are effectively substituted for natural enzymes for catalysis by closely resembling the active sites found in natural enzymes. Nanozymes can compensate for natural enzymes' drawbacks, such as high cost, poor stability, low yield, and storage challenges. Due to their transforming nature, nanozymes are of utmost importance in the detection and treatment of cancer. They enable precise cancer detection, tailored drug delivery, and catalytic therapy. Through enhanced diagnosis, personalized therapies, and reduced side effects, their adaptability and biocompatibility can transform the management of cancer. The review focuses on metal and metal oxide-based nanozymes, highlighting their catalytic processes, and their applications in the prevention and treatment of cancer. It emphasizes their potential to alter diagnosis and therapy, particularly when it comes to controlling reactive oxygen species (ROS). The article reveals the game-changing importance of nanozymes in the future of cancer care and describes future research objectives, making it a useful resource for researchers, and scientists. Lastly, outlooks for future perspective areas in this rapidly emerging field have been provided in detail.

Green Synthesis of Au Magnetic Nanocomposites Using Waste Chestnut Skins and Their Application as a Peroxidase Mimic Nanozyme Electrochemical Sensing Platform for Sodium Nitrite

An electrochemical sensor with high sensitivity for the detection of sodium nitrite was constructed based on the peroxidase-like activity of Au magnetic nanocomposites (Au@Fe3O4). The Au@Fe3O4 composite nanoparticles were green-synthesized via the reduction of gold nanoparticles (AuNPs) from waste chestnut skins combined with the sonochemical method. The nanoparticles have both the recoverability of Fe3O4 and the advantage of being able to amplify electrical signals. Furthermore, the synergistic effect of green reduction and sonochemical synthesis provides a functional approach for the preparation of Au@Fe3O4 with significant peroxidase-like activities. The physicochemical properties were characterized using transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), the Brunauer-Emmett-Teller (BET) method, and Fourier transform infrared spectroscopy (FT-IR). The electrochemical properties of sodium nitrite were determined with cyclic voltammetry (CV) and chronoamperometry (i-t). The results revealed that Au@Fe3O4 acted as a peroxidase mimic to decompose hydrogen peroxide to produce free radicals, while ·OH was the primary free radical that promoted the oxidation of sodium nitrite. With the optimal detection system, the constructed electrochemical sensor had a high sensitivity for sodium nitrite detection. In addition, the current response had a good linear relationship with the sodium nitrite concentration in the range of 0.01-100 mmol/L. The regression equation of the working curve was y = 1.0752x + 4.4728 (R2 = 0.9949), and the LOD was 0.867 μmol/L (S/N = 3). Meanwhile, the constructed detection system was outstanding in terms of recovery and anti-interference and had a good detection stability of more than 96.59%. The sensor has been successfully applied to a variety of real samples. In view of this, the proposed novel electrochemical analysis method has great prospects for application in the fields of food quality and environmental testing.

Recent Advancements in the Formulation of Nanomaterials-Based Nanozymes, Their Catalytic Activity, and Biomedical Applications

Nanozymes are nanoparticles with intrinsic enzyme-mimicking properties that have become more prevalent because of their ability to outperform conventional enzymes by overcoming their drawbacks related to stability, cost, and storage. Nanozymes have the potential to manipulate active sites of natural enzymes, which is why they are considered promising candidates to function as enzyme mimetics. Several microscopy- and spectroscopy-based techniques have been used for the characterization of nanozymes. To date, a wide range of nanozymes, including catalase, oxidase, peroxidase, and superoxide dismutase, have been designed to effectively mimic natural enzymes. The activity of nanozymes can be controlled by regulating the structural and morphological aspects of the nanozymes. Nanozymes have multifaceted benefits, which is why they are exploited on a large scale for their application in the biomedical sector. The versatility of nanozymes aids in monitoring and treating cancer, other neurodegenerative diseases, and metabolic disorders. Due to the compelling advantages of nanozymes, significant research advancements have been made in this area. Although a wide range of nanozymes act as potent mimetics of natural enzymes, their activity and specificities are suboptimal, and there is still room for their diversification for analytical purposes. Designing diverse nanozyme systems that are sensitive to one or more substrates through specialized techniques has been the subject of an in-depth study. Hence, we believe that stimuli-responsive nanozymes may open avenues for diagnosis and treatment by fusing the catalytic activity and intrinsic nanomaterial properties of nanozyme systems.

Bio-barcode assay: A useful technology for ultrasensitive and logic-controlled specific detection in food safety: A review

Food safety is one of the greatest public health challenges. Developing ultrasensitive detection methods for analytes at ultra-trace levels is, therefore, essential. In recent years, the bio-barcode assay (BCA) has emerged as an effective ultrasensitive detection strategy that is based on the indirect amplification of various DNA probes. This review systematically summarizes the progress of fluorescence, PCR, and colorimetry-based BCA methods for the detection of various contaminants, including pathogenic bacteria, toxins, pesticides, antibiotics, and other chemical substances in food in over 120 research papers. Current challenges, including long experimental times and strict storage conditions, and the prospects for the application of BCA in biomedicine and environmental analyses, have also been discussed herein.

Novel insights into versatile nanomaterials integrated bioreceptors toward zearalenone ultrasensitive discrimination

Detrimental contamination of zearalenone (ZEN) in crops and foodstuffs has drawn intensive public attention since it poses an ongoing threat to global food security and human health. Highly sensitive and rapid response ZEN trace analysis suitable for complex matrices at different processing stages is an indispensable part of food production. Conventional detection methods for ZEN encounter many deficiencies and demerits such as sophisticated equipment and heavy labor intensity. Alternatively, the nanomaterial-based biosensors featured with high sensitivity, portability, and miniaturization are springing up and emerging as superb substitutes to monitor ZEN in recent years. Herein, we predominantly devoted to overview the progress in the fabrication strategies and applications of various nanomaterial-based biosensors, highlighting rationales on sensing mechanisms, response types, and practical analytical performance. Synchronously, the versatile nanomaterials integrating with diverse recognition elements for augmenting sensing capabilities are emphasized. Finally, critical challenges and perspectives to expedite ZEN detection are outlooked.

Sensing materials for fresh food quality deterioration measurement: a review of research progress and application in supply chain

Fresh food are consumed in large quantities worldwide. During the supply chain, microbial growth in fresh food can lead to the production of a number of metabolites, which make food highly susceptible to spoilage and contamination. The quality of fresh food changes in terms of smell, tenderness, color and texture, which causes a decrease in freshness and consumers acceptance. Therefore, the quality monitoring of fresh food has become an essential part in the supply chain. As traditional analysis methods are highly specialized, expensive and have a small scope of application, which cannot be applied to the supply chain to realize real-time monitoring. Recently, sensing materials have received a lot of attention from researchers due to the low price, high sensitivity and high speed. However, the progress of research on sensing materials has not been critically evaluated. The study examines the progress of research in the application of sensing materials for fresh food quality monitoring. Meanwhile, indicator compounds for spoilage of fresh food are analyzed. Moreover, some suggestions for future research directions are given.

Immobilized nanoparticles-mediated enzyme therapy; promising way into clinical development

Enzyme (Enz)-mediated therapy indicated a remarkable effect in the treatment of many human cancers and diseases with an insight into clinical phases. Because of insufficient immobilization (Imb) approach and ineffective carrier, Enz therapeutic exhibits low biological efficacy and bio-physicochemical stability. Although efforts have been made to remove the limitations mentioned in clinical trials, efficient Imb-destabilization and modification of nanoparticles (NPs) remain challenging. NP internalization through insufficient membrane permeability, precise endosomal escape, and endonuclease protection following release are the primary development approaches. In recent years, innovative manipulation of the material for Enz immobilization (EI) fabrication and NP preparation has enabled nanomaterial platforms to improve Enz therapeutic outcomes and provide low-diverse clinical applications. In this review article, we examine recent advances in EI approaches and emerging views and explore the impact of Enz-mediated NPs on clinical therapeutic outcomes with at least diverse effects.

Enhancing catalytic efficiency of carbon dots by modulating their Mn doping and chemical structure with metal salts

Nanozymes are emerging materials in various fields owing to their advantages over natural enzymes, such as controllable and facile synthesis, tunability in catalytic activities, cost-effectiveness, and high stability under stringent conditions. In this study, the effect of metal salts on the formation and catalytic activity of carbon dots (CDs), a promising nanozyme, is demonstrated. By introducing Mn sources that possess different counter anions, the chemical structure and composition of the CDs produced are affected, thereby influencing their enzymatic activities. The synergistic catalytic effect of the Mn and N-doped CDs (Mn&N-CDs) is induced by effective metal doping in the carbogenic domain and a high proportion of graphitic and pyridinic N. This highly enhanced catalytic effect of Mn&N-CDs allows them to respond sensitively to the interference factors of enzymatic reactions. Consequently, ascorbic acid, which is an essential nutrient for maintaining our health and is a reactive oxygen scavenger, can be successfully monitored using color change by forming oxidized 3,3',5,5'-tetramethylbenzidine with H₂O₂ and Mn&N-CDs. This study provides a basic understanding of the formation of CDs and how their catalytic properties can be controlled by the addition of different metal sources, thereby providing guidelines for the development of CDs for industrial applications.