Sensitive visual detection of norfloxacin in water by smartphone assisted colorimetric method based on peroxidase-like active cobalt-doped Fe3O4 nanozyme.

Norfloxacin is widely used owing to its strong bactericidal effect on Gram-negative bacteria. However, the residual norfloxacin in the environment can be biomagnified via food chain and may damage the human liver and delay the bone development of minors. Present work described a reliable and sensitive smartphone colorimetric sensing system based on cobalt-doped Fe3O4 magnetic nanoparticles (Co-Fe3O4 MNPs) for the visual detection of norfloxacin. Compared with Fe3O4, Co-Fe3O4 MNPs earned more remarkably peroxidase-like activity and TMB (colorless) was rapidly oxidized to oxTMB (blue) with the presence of H2O2. Interestingly, the addition of low concentration of norfloxacin can accelerate the color reaction process of TMB, and blue deepening of the solution can be observed with the naked eye. However, after adding high concentration of norfloxacin, the activity of nanozyme was inhibited, resulting in the gradual fading of the solution. Based on this principle, a colorimetric sensor integrated with smartphone RGB mode was established. The visual sensor exhibited good linearity for norfloxacin monitoring in the range of 0.13-2.51 µmol/L and 17.5-100 µmol/L. The limit of visual detection was 0.08 µmol/L. In the actual water sample analysis, the spiked recoveries of norfloxacin were over the range of 95.7%-104.7 %. These results demonstrated that the visual sensor was a convenient and fast method for the efficient and accurate detection of norfloxacin in water, which may have broad application prospect.

Integrated triple signal amplification strategy for ultrasensitive electrochemical detection of gastric cancer-related microRNA utilizing MoS2-based nanozyme, hybridization chain reaction, and horseradish peroxidase.

Early diagnosis and treatment of gastric cancer (GC) play a vital role in improving efficacy, reducing mortality and prolonging patients' lives. Given the importance of early detection of gastric cancer, an electrochemical biosensor was developed for the ultrasensitive detection of miR-19b-3p by integrating MoS2-based nanozymes, hybridization chain reaction (HCR) with enzyme catalyzed reaction. The as-prepared MoS2-based nanocomposites were used as substrate materials to construct nanoprobes, which can simultaneously load probe DNA and HCR initiator for signal amplification. Moreover, the MoS2-based nanocomposites are also employed as nanozymes to amplify electrochemical response. The presence of miR-19b-3p induced the assembly of MoS2-based nanoprobes on the electrode surface, which can activate in-situ HCR reaction to load a large number of horseradish peroxidase (HRP) for signal amplification. Coupling with the co-catalytic ability of HRP and MoS2-based nanozymes, the designed electrochemical biosensor can detect as low as 0.7 aM miR-19b-3p. More importantly, this biosensor can efficiently analyze miR-19b-3p in clinical samples from healthy people and gastric cancer patients due to its excellent sensitivity and selectivity, suggesting that this biosensor has a potential application in early diagnosis of disease.

Preparation of Fe,Co,P-Codoping Peroxidase-like Green-Emitting Carbon Dots and Its Application in Monitoring the Freshness of Aquatic Products.

Carbon dot (CD) nanozymes with excellent fluorescence properties and mimetic enzyme activity have exhibited great potential in monitoring the freshness of meat products. This paper reports the synthesis of Fe, Co, and P codoped CD nanozymes (quantum yields = 48.76%) through a one-step hydrothermal route. The product showed green fluorescence and peroxidase (POD) activity. Because the fluorescence intensity and emission wavelength of prepared CDs change with pH, a pH sensor has been developed to monitor the pH change caused by volatile biogenic amines during the spoilage process of aquatic products. Moreover, this CD biosensor has been used to realize the sensitive and visual detection of hypoxanthine (Hx, the marker of the spoilage of aquatic products) based on the inhibitory effect of Hx upon the POD activity of CDs. This study provides a new strategy for preparing high-quality CD nanozymes and its application in low-cost and visual monitoring of the freshness of aquatic products.

Facile construction of Mo-based nanozyme system via ZIF-8 templating with enhanced catalytic efficiency and antibacterial performance.

Although Zeolitic Imidazolate Framework-8 (ZIF-8) shows significant promise in chemodynamic therapy of bacterial infections due to its large specific surface area and enzyme-like activity, it still faces a considerable gap compared to natural enzymes. The dependency on low pH and high concentrations of hydrogen peroxide ((H2O2) is a major factor limiting the clinical progress of nanozymes. Single-atom nanozymes (SA-zyme), which exhibit superior catalytic performance, are expected to overcome this limitation. In this study, we used ZIF-8 as a template to prepare structurally regular molybdenum-based single-atom nanozymes (Mo-zyme) by coordinating molybdenum atoms with nitrogen atoms within the zeolitic imidazolate framework and evaporating the zinc element at high temperatures. The cascade catalytic performance of the nanodrugs was enhanced by loading glucose oxidase (GOx) and encapsulating it with a hyaluronic acid (HA) layer to form a composite (Mo/GOx@HA). Upon contact with hyaluronidase from bacteria in infected tissues, the cascade reaction is triggered, resulting in the degradation of the HA shell, and releasing the encapsulated GOx. Once exposed, GOx catalyzes the oxidation of glucose into gluconic acid, resulting in a localized decrease in pH and continuous production of H2O2. The combination of lowered pH and increased H2O2 concentration significantly amplifies the catalytic activity of the Mo-zyme. This enhanced activity facilitates the in situ generation of hydroxyl radicals (•OH) on the bacterial surface, leading to effective and efficient bacterial eradication. Wound infection treatment has demonstrated that the as-prepared Mo/GOx@HA exhibits excellent antibacterial and anti-inflammatory activity. This work provided a promising enzymatic cascade reaction nanoplatform for the treatment of bacteria infected wounds.

Photothermal amplified multizyme activity for synergistic photothermal-catalytic tumor therapy.

Nano-enzymatic catalytic therapy has been widely explored as a promising tumor therapeutic method with specific responsiveness to the tumor microenvironment (TME). However, the inherent lower and simplex catalytic efficiency impairs their anti-tumor efficacy. Therefore, developing novel nanozymes with relatively high and multiple catalytic characteristics, simultaneously enhancing the enzyme-like activity of nanozymes using the proper method, photothermal promoted catalytic property, is a reliable way. In this paper, we report a manganese oxide/nitrogen-doped carbon composite nanoparticles (MnO-N/C NPs) with multi-enzyme mimetic activity and photothermal conversional effect. The peroxidase (POD)-like/oxidase (OXD)-like/catalase (CAT)-like activity of MnO-N/C nanozymes was accelerated upon exposure to an 808 nm NIR laser. In vitro and in vivo results proved that the MnO-N/C NPs shown excellent magnetic resonance imaging (MRI) guided synergistic photothermal-enhanced catalytic treatment and photothermal therapy of liver cancer. The photothermal enhanced multi-enzyme activity maximizes the efficacy of catalytic and photothermal therapy while reducing harm to healthy cells, thereby offering valuable insights for the development of next-generation photothermal nanozymes to enhance tumor therapy.

Progress in antibacterial applications of nanozymes.

Bacterial infections are a growing problem, and antibiotic drugs can be widely used to fight bacterial infections. However, the overuse of antibiotics and the evolution of bacteria have led to the emergence of drug-resistant bacteria, severely reducing the effectiveness of treatment. Therefore, it is very important to develop new effective antibacterial strategies to fight multi-drug resistant bacteria. Nanozyme is a kind of enzyme-like catalytic nanomaterials with unique physical and chemical properties, high stability, structural diversity, adjustable catalytic activity, low cost, easy storage and so on. In addition, nanozymes also have excellent broad-spectrum antibacterial properties and good biocompatibility, showing broad application prospects in the field of antibacterial. In this paper, we reviewed the research progress of antibacterial application of nanozymes. At first, the antibacterial mechanism of nanozymes was summarized, and then the application of nanozymes in antibacterial was introduced. Finally, the challenges of the application of antibacterial nanozymes were discussed, and the development prospect of antibacterial nanozymes was clarified.

Mimicomes: Mimicking Multienzyme System by Artificial Design.

Enzymes are widely distributed in organelles of cells, which are capable of carrying out specific catalytic reactions. In general, several enzymes collaborate to facilitate complex reactions and engage in vital biochemical processes within cells, which are also called cascade systems. The cascade systems are highly efficient, and their dysfunction is associated with a multitude of endogenous diseases. The advent of nanotechnology makes it possible to mimic these cascade systems in nature and realize partial functions of natural biological processes both in vitro and in vivo. To emphasize the significance of artificial cascade systems, mimicomes is first proposed, a new concept that refers to the artificial cascade catalytic systems. Typically, mimicomes are able to mimic specific natural biochemical catalytic processes or facilitate the overall catalytic efficiency of cascade systems. Subsequently, the evolution and development of different types of mimicomes in recent decades are elucidated exhaustedly, from the natural enzyme-based mimicomes (immobilized enzyme and vesicle mimicomes) to the nanozyme-based mimicomes and enzyme-nanozyme hybrid mimicomes. In conclusion, the remaining challenges in the design of multifunctional mimicomes and their potential applications are summarized, offering insights into their future prospects.

Ultra-Small Copper-Based Multienzyme-Like Nanoparticles Protect Against Hepatic Ischemia-Reperfusion Injury Through Scavenging Reactive Oxygen Species in Mice.

Hepatic ischemia-reperfusion injury (IRI) is a severe complication that occurs in the process of liver transplantation, hepatectomy, and other end-stage liver disease surgery, often resulting in the failure of surgery operation and even patient death. Currently, there is no effective way to prevent hepatic IRI clinically. Here, it is reported that the ultra-small copper-based multienzyme-like nanoparticles with catalase-like (CAT-like) and superoxide dismutase-like (SOD-like) catalytic activities significantly scavenge the surge-generated endogenous reactive oxygen species (ROS) and effectively protects hepatic IRI. Density functional theory calculations confirm that the nanoparticles efficiently scavenge ROS through their synergistic effects of the ultra-small copper SOD-like activity and manganese dioxides CAT-like activity. Furthermore, the results show that the biocompatible CMP NPs significantly protected hepatocytes from IRI in vitro and in vivo. Importantly, their therapeutic effect is much stronger than that of N-acetylcysteamine acid (NAC), an FDA-approved antioxidative drug. Finally, it is demonstrated that the protective effects of CMP NPs on hepatic IRI are related to suppressing inflammation and hepatocytic apoptosis and maintaining endothelial functions through scavenging ROS in liver tissues. The study can provide insight into the development of next-generation nanomedicines for scavenging ROS.

Zinc-based Polyoxometalate Nanozyme Functionalized Hydrogels for optimizing the Hyperglycemic-Immune Microenvironment to Promote Diabetic Wound Regeneration.

BACKGROUND: In diabetic wounds, hyperglycemia-induced cytotoxicity and impaired immune microenvironment plasticity directly hinder the wound healing process. Regulation of the hyperglycemic microenvironment and remodeling of the immune microenvironment are crucial. RESULTS: Here, we developed a nanozymatic functionalized regenerative microenvironmental regulator (AHAMA/CS-GOx@Zn-POM) for the effective repair of diabetic wounds. This novel construct integrated an aldehyde and methacrylic anhydride-modified hyaluronic acid hydrogel (AHAMA) and chitosan nanoparticles (CS NPs) encapsulating zinc-based polymetallic oxonate nanozyme (Zn-POM) and glucose oxidase (GOx), facilitating a sustained release of release of both enzymes. The GOx catalyzed glucose to gluconic acid and (H2O2), thereby alleviating the effects of the hyperglycemic microenvironment on wound healing. Zn-POM exhibited catalase and superoxide dismutase activities to scavenge reactive oxygen species and H2O2, a by-product of glucose degradation. Additionally, Zn-POM induced M1 macrophage reprogramming to the M2 phenotype by inhibiting the MAPK/IL-17 signaling diminishing pro-inflammatory cytokines, and upregulating the expression of anti-inflammatory mediators, thus remodeling the immune microenvironment and enhancing angiogenesis and collagen regeneration within wounds. In a rat diabetic wound model, the application of AHAMA/CS-GOx@Zn-POM enhanced neovascularization and collagen deposition, accelerating the wound healing process. CONCLUSIONS: Therefore, the regenerative microenvironment regulator AHAMA/CS-GOx@Zn-POM can achieve the effective conversion of a pathological microenvironment to regenerative microenvironment through integrated control of the hyperglycemic-immune microenvironment, offering a novel strategy for the treatment of diabetic wounds.

Applications of nanomaterials with enzyme-like activity for the detection of phytochemicals and hazardous substances in plant samples.

Plants such as herbs, vegetables, fruits, and cereals are closely related to human life. Developing effective testing methods to ensure their safety and quantify their active components are of significant importance. Recently, nanomaterials with enzyme-like activity (known as nanozymes) have been widely developed in various assays, including colorimetric, fluorescence, chemiluminescence, and electrochemical analysis. This review presents the latest advances in analyzing phytochemicals and hazardous substances in plant samples based on nanozymes, including some active ingredients, organophosphorus pesticides, heavy metal ions, and mycotoxins. Additionally, the current shortcomings and challenges of the actual sample analysis were discussed.

Achieving ultrasensitive detection of glyphosate in fruits and vegetables using a triple-mode strategy based on carbon dots nanozymes derived from expired drugs.

Rapid and sensitive detection of glyphosate (GLP) holds significant importance in the monitoring of environmental pollution and potential risks to human health. In this study, carbon dots nanozymes (CDszymes) with peroxidase-like activity were synthesized rapidly using a microwave-assisted method, employing expired drugs as raw materials. In the presence of H2O2, CDszymes catalyze the oxidation of TMB to generate blue oxTMB, which exhibits a photothermal effect under near-infrared light irradiation; an inner filter effect (IFE) may occur between oxTMB and CDszymes. By coupling the cascade catalysis of AChE and ChOx to generate H2O2, GLP effectively inhibits the activity of AChE, constructing a colorimetric/fluorescent/photothermal response platform for GLP. In colorimetry, the detection limit of GLP was 0.33 ng/mL. The detection limits of GLP by fluorescence method and photothermal method were 0.02 ng/mL and 0.41 ng/mL, respectively. The efficacy of this methodology has been successfully demonstrated in fruit and vegetable, it also provides a strategy for the high-value conversion of expired drugs.

Mn-Ce Symbiosis: Nanozymes with Multiple Active Sites Facilitate Scavenging of Reactive Oxygen Species (ROS) Based on Electron Transfer and Confinement Anchoring.

Regulating appropriate valence states of metal active centers, such as Ce3+/Ce4+ and Mn3+/Mn2+, as well as surface vacancy defects, is crucial for enhancing the catalytic activity of cerium-based and manganese-based nanozymes. Drawing inspiration from the efficient substance exchange in rhizobia-colonized root cells of legumes, we developed a symbiosis nanozyme system with rhizobia-like nano CeOx clusters robustly anchored onto root-like Mn3O4 nanosupports (CeOx/Mn3O4). The process of "substance exchange" between Ce and Mn atoms-reminiscent of electron transfer-not only fine-tunes the metal active sites to achieve optimal Ce3+/Ce4+ and Mn3+/Mn2+ ratios but also enhances the vacancy ratio through interface defect engineering. Additionally, the confinement anchoring of CeOx on Mn3O4 ensures efficient electron transfer in catalytic reactions. The final CeOx/Mn3O4 nanozyme demonstrates potent catalase-like (CAT- like) and superoxide dismutase-like (SOD-like) activities, excelling in both chemical settings and cellular environments with high reactive oxygen species (ROS) levels. This research not only unveils a novel material adept at effectively eliminating ROS but also presents an innovative approach for amplifying nanozyme efficacy.

Bioinspired Homonuclear Diatomic Iron Active Site Regulation for Efficient Antifouling Osmotic Energy Conversion.

Membrane-based reverse electrodialysis is globally recognized as a promising technology for harnessing osmotic energy. However, its practical application is greatly restricted by the poor anti-fouling ability of existing membrane materials. Inspired by the structural and functional models of natural cytochrome c oxidases (CcO), the first use of atomically precise homonuclear diatomic iron composites as high-performance osmotic energy conversion membranes with excellent anti-fouling ability is demonstrated. Through rational tuning of the atomic configuration of the diatomic iron sites, the oxidase-like activity can be precisely tailored, leading to the augmentation of ion throughput and anti-fouling capacity. Composite membranes featuring direct Fe-Fe motif configurations embedded within cellulose nanofibers (CNF/Fe-DACs-P) surpass state-of-the-art CNF-based membranes with power densities of ca. 6.7 W m-2 and a 44.5-fold enhancement in antimicrobial performance. Combined, experimental characterization and density functional theory simulations reveal that homonuclear diatomic iron sites with metal-metal interactions can achieve ideally balanced adsorption and desorption of intermediates, thus realizing superior oxidase-like activity, enhanced ionic flux, and excellent antibacterial activity.

Intra-articular injection of platinum nanozyme-loaded silk fibroin/pullulan hydrogels relieves osteoarthritis through ROS scavenging and ferroptosis suppression.

Reactive oxygen species (ROS)-mediated ferroptosis plays a critical role in the development of osteoarthritis (OA). Consequently, it is speculated that anti-ferroptosis agents could represent a novel therapeutic strategy for managing OA. In this study, a hydrogel incorporating platinum (Pt) nanozyme was synthesized by dispersing Pt nanoparticles (NPs) within a matrix of silk fibroin (SF) and oxidized pullulan (oxPL). This hydrogel allows for a substantial and sustained release of up to 30 days. The gelation time (from 140.3 ± 42.3 s to 460.0 ± 40.0 s), swelling capacity (from 57.7 ± 3.8 % to 24.0 ± 7.0 %), and degradation rate (from 60.3 ± 4.7 % to 32.0 ± 4.6 %) of the hydrogels can be modulated by adjusting the Pt NP content. The Pt@SF/oxPL hydrogel effectively eliminates ROS due to its catalase-like and superoxide dismutase-like enzymatic properties. In vitro studies demonstrated that Pt@SF/oxPL efficiently mitigated the process of ferroptotic cell death in chondrocytes. More critically, intra-articular administration of Pt@SF/oxPL showcased therapeutic advantages by both protecting and stimulating the regeneration of cartilage throughout the progression of OA. Collectively, this study suggests that Pt@SF/oxPL hydrogels could potentially serve as an effective treatment for OA, presenting a novel nanozyme-based therapeutic approach for this condition.

Freeze-Driven Adsorption of Oligonucleotides with polyA-Anchors on Au@Pt Nanozyme.

A promising and sought-after class of nanozymes for various applications is Pt-containing nanozymes, primarily Au@Pt, due to their easy preparation and remarkable catalytic properties. This study aimed to explore the freeze-thaw method for functionalizing Pt-containing nanozymes with oligonucleotides featuring a polyadenine anchor. Spherical gold nanoparticles ([Au]NPs) were synthesized and subsequently used as seeds to produce urchin-like Au@Pt nanoparticles ([Au@Pt]NPs) with an average diameter of 29.8 nm. The nanoparticles were conjugated with a series of non-thiolated DNA oligonucleotides, each consisting of three parts: a 5'-polyadenine anchor (An, with n = 3, 5, 7, 10; triple-branched A3, or triple-branched A5), a random sequence of 23 nucleotides, and a linear polyT block consisting of seven deoxythymine residues. The resulting conjugates were characterized using transmission electron microscopy, spectroscopy, dynamic light scattering, and emission detection of the fluorescent label at the 3'-end of each oligonucleotide. The stability of the conjugates was found to depend on the type of oligonucleotide, with decreased stability in the row of [Au@Pt]NP conjugates with A7 > A5 > 3A3 > 3A5 > A10 > A3 anchors. These [Au@Pt]NP-oligonucleotide conjugates were further evaluated using lateral flow test strips to assess fluorescein-specific binding and peroxidase-like catalytic activity. Conjugates with A3, A5, A7, and 3A3 anchors showed the highest levels of signals of bound labels on test strips, exceeding conjugates in sensitivity by up to nine times. These findings hold significant potential for broad application in bioanalytical systems.

Nanozymes in Biomedical Applications: Innovations Originated From Metal-Organic Frameworks.

Nanozymes exhibit significant potential in medical theranostics, environmental protection, energy development, and biopharmaceuticals due to their exceptional catalytic performance. Compared with natural enzymes, nanozymes have the advantages of simple preparation and purification, convenient production and low cost. Therefore, it is very important to prepare nanozymes quickly and efficiently, which not only helps to expand their application scope, but also can further exert their great potential in various fields. Metal-organic frameworks (MOF) materials serve as versatile substrates for constructing nanozymes, offering unique advantages like adjustable structure, high specific surface area, and porous channels. MOF coordination nodes constructed from metal ions or metal clusters have unique properties that can be leveraged to tailor nanozyme characteristics for different applications. This review describes and analyzes recent methods for constructing nanozymes using MOF materials, and explores their application prospects in biomedicine. By expounding the preparation techniques and biomedical applications of nanozymes, this review aims to inspire researchers to develop innovative nanozyme materials and explore new application directions.

A dual-mode composite nanozyme-based cascade colorimetric-fluorescence aptasensor for Salmonella Typhimurium detection.

BACKGROUND: Salmonella Typhimurium poses a serious threat to human health worldwide, necessitating the development of a rapid, sensitive, and convenient method for S. Typhimurium detection. Nanozymes are considered ideal signal report elements, which are extensively used for developing colorimetric methods. However, single-component nanozymes display low catalytic activity, and colorimetric methods are susceptible to environmental interference, reducing the sensitivity and accuracy of detection results. To address these drawbacks, this study constructed a dual-mode composite nanozyme-based cascade colorimetric-fluorescence aptasensor for S. Typhimurium detection in food. RESULTS: In this study, the composite Fe3O4@MIL-100(Fe) nanozymes were successful synthesized and demonstrated substantial peroxide-like activity, with 4.76-fold higher specificity activity (SA) than that of Fe3O4 nanozymes. Then, a glucose oxidase (GOx)-Fe3O4@MIL-100(Fe) cascade reaction was developed for colorimetric detection via an aptamer to facilitate the formation of Fe3O4@MIL-100(Fe)/S. Typhimurium/carboxylated g-C3N4 (CCN)-GOx sandwich complexes. Meanwhile, the fluorescence mode was achieved by measuring the fluorescence intensity of the sandwich complexes. In optimum conditions, the dual-mode detection limits (LOD) were 1.8 CFU/mL (colorimetric mode) and 1.2 CFU/mL (fluorescence mode), respectively, with the S. Typhimurium concentration ranging from 10 CFU/mL to 107 CFU/mL. Finally, the feasibility of the dual-mode colorimetric-fluorescence method was validated via three actual samples, yielding recovery rates of 77.32 % to91.17 % and 82.17 % to 103.7 %, respectively. SIGNIFICANCE AND NOVELTY: This study successfully develops a composite nanozyme-based cascade colorimetric and fluorescence dual-mode aptasensor for S. Typhimurium detection. It presents several distinct benefits, such as a broader linear range (10-107 CFU/mL), a lower LOD value (1.2 CFU/mL), and more accurate results. More importantly, the proposed dual-mode method displays a low LOD in colorimetric mode, demonstrating considerable potential for S. Typhimurium on-site detection in food.

The biomedical applications of nanozymes in orthopaedics based on regulating reactive oxygen species.

Nanozymes, a category of nanomaterials with enzyme-like activity, have garnered growing interest in various biomedical contexts. Notably, nanozymes that are capable of regulating reactive oxygen species levels by emulating antioxidant or prooxidant enzymes within cells hold significant therapeutic potential for a range of disorders. Herein, we overview the catalytic mechanisms of four exemplary nanozymes within the orthopedic domain. Subsequently, we emphasize recent groundbreaking advancements in nanozyme applications in orthopaedics, encompassing osteoarthritis, osteoporosis, intervertebral disc degeneration, bone defects, spinal cord injury, gout, rheumatoid arthritis, osteosarcoma and bone infection. Furthermore, we discuss the emerging area's future prospects and several noteworthy challenges in biomedical application. This review not only fosters the ongoing development of nanozyme research but also fosters the emergence of more potent nanozymes for the treatment of orthopaedical diseases in the future.

Sensitive colorimetric detection of heparin using reverse modulation of peroxidase- and oxidase-mimetic activities in Fe3O4@PDA@MnO2 nanocomposites.

Heparin, a widely studied glycosaminoglycan, plays crucial roles in the regulation of various physiological and pathological processes. Therefore, it's important to develop highly selective and sensitive methods for convenient monitoring of heparin levels in biological systems. We report the design and synthesis of Fe3O4@PDA@MnO2 nanoparticles (FPM-NPs), which exhibit dual enzymatic activities, enabling quantitative detection of heparin. The FPM-NPs feature a unique tri-layer spherical shell structure, possessing both peroxidase-like and oxidase-like activities, and catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) in the presence or absence of H2O2. Remarkably, upon co-incubated with heparin, the oxidase activity of FPM-NPs decreases, while the peroxidase activity increases. By leveraging these dual enzymatic properties of FPM-NPs, a highly sensitive and specific colorimetric detection of heparin is achieved, with a detection limit reaching 6.51 nM and a good linear response to quantify heparin ranging 10-800 nM. Additionally, the developed FPM-NPs are successfully applied to measure heparin in fetal bovine serum samples. We also extend this detection method to a paper-based chip, enabling portable detection of heparin through grayscale analysis of mobile phone photographs. The multi-nanozyme-based heparin detection approach provides a new perspective for future research on expanding the application of nanocomposite materials in biomedical detection and analysis.

Single-Atom Ce-Doped Metal Hydrides with High Phosphatase-like Activity Amplify Oxidative Stress-Induced Tumor Apoptosis.

Phosphates within tumors function as key biomolecules, playing a significant role in sustaining the viability of tumors. To disturb the homeostasis of cancer cells, regulating phosphate within the organism proves to be an effective strategy. Herein, we report single-atom Ce-doped Pt hydrides (Ce/Pt-H) with high phosphatase-like activity for phosphate hydrolysis. The resultant Ce/Pt-H exhibits a 26.90- and 6.25-fold increase in phosphatase-like activity in comparison to Ce/Pt and Pt-H, respectively. Mechanism investigations elucidate that the Ce Lewis acid site facilitates the coordination with phosphate groups, while the surface hydrides enhance the electron density of Pt for promoting catalytic ability in H2O cleavage and subsequent nucleophilic attack of hydroxyl groups. Finally, by leveraging its phosphatase-like activity, Ce/Pt-H can effectively regulate intracellular phosphates to disrupt redox homeostasis and amplify oxidative stress within cancer cells, ultimately leading to tumor apoptosis. This work provides fresh insights into noble-metal-based phosphatase mimics for inducing tumor apoptosis.