Preparation of copper-based protein-inorganic hybrid nanoflowers with peroxidase-like activity for colorimetric detection of biothiols.

Platinum-zinc oxide as a super signal amplifier for ultrasensitive electrochemical immunodetection of CEA.

A dual-mode biosensing platform based on polydopamine-modified FeCoMOF/Co3O4 nanoenzyme for sensitive detection of Escherichia coli O157:H7.

Smartphone-assisted colorimetric detection of FEN1 and its inhibitors via RCA-magnetic beads-urease cascade amplification.

Donnan-like effect driven synthesis of brush-confined Prussian blue Nanozymes with low crystallinity for multifunctional applications.

Ratiometric colorimetric and smartphone-assisted detection of nitrite based on ZIF-67@MnO2 nanozyme: Water and food analysis.

Addressing the stability-activity imbalance of natural enzyme-nanozyme self-cascade catalysis for tumor-specific therapy while inhibiting tumor metastasis via multiple killing mechanisms remains a challenge. Herein, we constructed a tumor microenvironment (TME)-responsive mannose-modified MoS2-tannic acid (TA)-Fe-glucose oxidase (GOx) nanoreactor (MTFGM) via a spatial confinement strategy relying on metal-polyphenol coordination and electrostatic interactions for addressing this issue. GOx was confined on MoS2 via hydrogen bonds and π-π stacking. TA's polyphenol network and mannose's shielding effect enhanced GOx stability by preventing off-target catalysis, while TA-Fe on MoS2 boosted peroxidase (POD)-like catalytic activity by facilitating Fe3+/Fe2+ electron transfer for cocatalysis. In the TME, GOx depleted glucose to self-supply H2O2 and gluconic acid, which activated the POD-like activity of MTFGM to decompose H2O2 into toxic hydroxyl radicals (•OH) with a maximum reaction rate 4-fold higher and turnover number 170-fold higher than pristine MoS2. Simultaneously, MoS2-TA-Fe's glutathione peroxidase-like activity plus H2Sn production continuously consumed glutathione (GSH) to break tumor antioxidant defense. This cascade synergistically induced four tumor-killing mechanisms: GOx-mediated metabolic starvation, •OH-triggered apoptosis, GSH depletion-driven ferroptosis, and cystine accumulation/H2Sn-induced disulfidptosis collectively disrupt tumor redox homeostasis and inhibit metastasis. Our work clarifies the structure-activity relationship of confinement-based cascade nanoreactors and provides a TME-responsive multiple cell death paradigm for tumor-specific therapy.

Background/Objectives: Alkaline phosphatase (ALP) is a crucial enzyme in numerous pathological processes and a significant biomarker in clinical diagnostics. Conventional ALP detection methods are hampered by reliance on complex sample pretreatment, sophisticated instrumentation, time-consuming procedures, and high costs. This study aimed to develop a simple, rapid, and cost-effective colorimetric sensing method for ALP detection with enhanced resistance to matrix interference in biological samples. Methods: We designed a colorimetric assay based on bimetallic gold–platinum nanocatalysts (AuPt NPs) exhibiting peroxidase-like (POD-like) activity. The detection principle involves a dual-reaction cascade: (1) Alkaline phosphatase (ALP) catalyzes the conversion of trisodium L-ascorbic acid-2-phosphate (AA2P) into ascorbic acid (AA), and (2) the generated AA reduces oxidized 3,3′,5,5′-tetramethylbenzidine (oxTMB) produced by the catalytic activity of AuPt NPs. This method was evaluated for its detection performance in diluted human serum without complex sample pretreatment. Results: AuPt NPs exhibited resistance to biological matrix interference, enabling sensitive detection of ALP. The assay showed a linear ALP detection range of 0–90 mU·mL−1 (R2 = 0.994) and a limit of detection of 3.91 mU·mL−1. In spiked human serum, recoveries were 95.45–111.97%, with negligible interference from ions and biomolecules. Conclusions: We developed a simple, rapid, and reliable colorimetric sensor for ALP detection based on AuPt NPs. It overcomes limitations of conventional methods, holding great potential for clinical diagnostics and point-of-care applications.

Ferroelectric materials, due to their spontaneous polarization, can enable efficient electron-hole pair separation, which subsequently enhances reactive oxygen species (ROS) production. This has gradually become a significant direction for screening high-performance nanozymes. This work explores the selective peroxidase (POD)-like activity of a classical ferroelectric material, BiFeO3 nanoparticles (BiFeO3 NPs), enabling efficient catalytic generation of ROS. Capitalizing on this nanozyme property, a sensitive colorimetric assay for alkaline phosphatase (ALP) detection was developed. BiFeO3 NPs can catalyze the oxidation of the chromogenic substrate 3,3',5,5'-tetramethylbenzidine (TMB) by H2O2, whereas pyrophosphate (PPi) significantly inhibits this catalytic activity. Conversely, ALP restores the catalytic activity of BiFeO3 by catalyzing the hydrolysis of PPi. The colorimetric signal generated through this specific inhibition-recovery mechanism enables the sensitive detection of ALP. Under optimal reaction conditions, the developed method demonstrated a linear response range of 0.040 to 1.0 U/L, achieving a detection limit as low as 0.026 U/L with high selectivity and robust anti-interference capability. Additionally, this method was successfully implemented for ALP detection in artificial saliva samples, achieving recoveries of 95.6-102.9% with a relative standard deviation below 5.0%, showcasing its practical potential for detection in complex biological fluids. This research provides new insights into the application of ferroelectric materials in nanozyme applications and offers a reliable technical approach for the efficient detection of ALP.

DNAzyme walker-triggered HCR dual amplification mediated by MOF-derived bimetallic Fe-Ni-doped porous carbon nanozyme for homogeneous dual-mode aptasensor detection of profenofos.

Reliable enrichment monitoring and removal of CrO42- and S2- using multivalent W-doped Ag quantum-dot biomimetic nanozyme.

The development of biosensors for infectious diseases is crucial, especially in the post pandemic era. Point-of-care (POC) devices are highly needed in developing countries to provide quick and cost-effective results. Nanoparticles with enzymatic-like activity, also known as nanozymes, show great promise for diagnostic applications and have recently gained significant attention. In this study, bovine serum albumin (BSA)-protected copper nanoclusters (Cu NCs) with enzymatic-like characteristics were created and analysed for their intrinsic enzymatic-like activity, physicochemical properties, and colloidal stability. The Cu NCs were synthesized via the use of BSA as a capping and reducing agent to ensure their biocompatibility and colloidal stability. Various techniques, such as UV‒Vis spectroscopy, photoluminescence (PL), dynamic light scattering (DLS), elemental analysis, and transmission electron microscopy (TEM), have been used to characterize the prepared Cu NCs. The Cu NCs demonstrated oxidase- and peroxidase-like activity by catalyzing the oxidation of o-phenylenediamine (OPD) into 2,3-diaminophenazine (DAP), the oxOPD product. Showing higher oxidase-like activity by 1.6x compared to the peroxidase-like activity at the same substrate concentration. Their catalytic properties were utilized to detect two common bacteria, gram-negative Escherichia coli (E. coli) and gram-positive Staphylococcus aureus (S. aureus), demonstrating a differential label-free detection of different strains at concentrations higher than 105 CFU mL- 1. This study introduces a promising and affordable application for a label-free biosensor used in detecting infectious diseases.

The total antioxidant capacity (TAC) of food products is a key parameter for assessing food quality and safety. In this work, iron-doped carbon dots (Fe-CDs) were successfully prepared using waste coffee grounds as a precursor with a satisfactory fluorescence quantum yield of 9.6%. The Fe-CDs exhibited exceptional peroxidase-like activity, which can oxidize colorless 3,3',5,5'-tetramethylbenzidine (TMB) to form blue oxTMB. Concurrently, oxTMB induced an inner filter effect, quenching the fluorescence of Fe-CDs. After being added to antioxidants such as glutathione, ascorbic acid, and L-cysteine, the generated reactive oxygen species (ROS) are consumed, thereby preventing the oxidation of TMB. The color of the mixed solution changed from dark to light blue, accompanied by the fluorescence recovery of Fe-CDs. Nevertheless, these three antioxidants possessed remarkable differences in ROS elimination capability, which resulted in different signal responses in absorption and fluorescence, and were successfully used for constructing the colorimetric/fluorescent dual-channel sensor array. Furthermore, the sensor array signals were processed using principal component analysis to achieve simultaneous detection of glutathione, ascorbic acid, and L-cysteine, and were able to effectively discriminate between mixtures and individual antioxidants. The constructed sensor array was successfully applied for the TAC detection in various foods (including vegetables, fruit, and beverages) and for the precise differentiation of antioxidants in milk samples. Overall, the prepared sensor array exhibited outstanding potential in detecting food quality.

To enable rapid, on-site monitoring of amoxicillin and ensure controlled administration, we have developed a paper-based analytical device (PAD) incorporating a molecularly imprinted polymer (MIP) anchored on graphitic carbon nitride (g-C₃N₄) nanosheets. The MIP@g-C₃N₄ composite was synthesized via in situ polymerization of 3-aminopropyl triethoxysilane (APTES) and tetraethyl orthosilicate (TEOS) around amoxicillin templates on g-C₃N₄, yielding highly specific binding cavities upon template removal. The g-C₃N₄ nanozyme's intrinsic peroxidase-like activity catalyzes the oxidation of colorless 3,3',5,5'-tetramethylbenzidine (TMB) to its blue oxidized form (oxTMB) in the presence of hydrogen peroxide. In the absence of amoxicillin, a vivid blue signal develops, whereas competitive binding of amoxicillin at the MIP sites inhibits nanozyme activity, causing a proportional decrease in color intensity. Analytical characterization demonstrated a linear response over 0-100 µM amoxicillin, with a limit of detection (LOD) of 0.97 µM. The integration with the PAD format permits semi-quantitative visual readout and quantitative determination via a portable smartphone, all within minutes and without the need for complex instrumentation. When applied to spiked milk and tap water, the MIP@g-C₃N₄ sensor achieved recoveries of 92-105% with negligible interference from structurally related antibiotics. The marriage of MIP selectivity, g-C₃N₄ nanozyme catalysis, and low-cost PAD architecture delivers a user-friendly, field-deployable platform for rapid amoxicillin screening, promising significant potential to bolster antibiotic stewardship and mitigate overdose-related health risks across clinical, environmental, and food-safety applications.

An electrochemical immunosensor was developed based on silver-ruthenium nanoparticles functionalized NH2-MIL-88B (NH2-MIL-88B/Ag@Ru) composites for sensitive detection of cardiac troponin I (cTnI). The NH2-MIL-88B/Ag@Ru composites shows synergistic peroxidase-like activity with Km values of 0.737 mM- 1 for hydrogen peroxide (H2O2) and 0.55 mM- 1 for 3,3',5,5'-tetramethylbiphenylamine (TMB). Additionally, the electrode surface is modified using a one-step electrodeposition reduction of graphene with chloroauric acid trihydrate (rGO-AuNPs) to increase the effective specific surface area and facilitate charge transfer. By integrating NH2-MIL-88B/Ag@Ru composites as a signal amplification tracer and proportionally optimized rGO-AuNPs as the sensing platform, the resulting electrochemical immunosensor exhibits a wide linear detection range from 20fg/mL to 200 ng/mL for cTnI, with a detection limit of 2.15fg/mL. Furthermore, in a doxorubicin (DOX)-induced myocardial injury model, this sensor demonstrated excellent practicality paired with the PalmSens 4 portable analyzer. Detection results were consistent with commercial enzyme-linked immunosorbent assay (ELISA), and serum sample recoveries were excellent. This study provides a feasible strategy for the rapid and sensitive detection of cTnI, demonstrating potential for clinical application.

Ultra-sensitive self-powered patulin detection via CoOOH nanozyme-glucose oxidase bioconjugate and DNA walker-catalyzed nucleic acid frameworks.

Prussian blue nanoparticles-based dual-mode immunochromatographic assays for norfloxacin detection in animal-derived foods

Trace detection of copper ions with high specificity is critical for early warning indicators and public health governance due to its involvement in multiple physiological processes within the human body. Unlike previous research that was only based on the localized surface plasmon resonance (LSPR) properties of MoO3-x, this work presents a novel colorimetric sensing platform exploiting the peroxidase-like activity for sensitive copper detection. This mechanism provides higher specificity than conventional methods through the specific coordination of Cu2+ with MoO3, which forms a bond that facilitates electron transfer. Furthermore, Cu and Mo exhibit a synergistic catalytic effect. The strong substrate adsorption affinity of Cu, combined with the stable redox-active sites provided by Mo, results in an optimized electronic configuration and an accelerated catalytic process. This process enhances the generation of reactive oxygen species in the presence of H2O2, thereby catalyzing the oxidation of the 3,3',5,5'-tetramethylbenzidine (TMB) substrate with a colorimetric response. To enhance the analytical reliability and practical applicability, we employed a portable optical device for colorimetric signal analysis and a smartphone-based red-green-blue (RGB) colorimetric analysis platform. These methods show high sensitivity, with detection limits of 4.61 nM (colorimetry), 6.35 nM (portable device), and 9.91 nM (RGB analysis), significantly below the U.S. EPA regulatory limit (20 μM). Validation using real samples (wheat and corn) confirms the platform's robustness in environmental monitoring and food safety applications, offering a cost-effective, rapid and simple method for copper detection.

Reactive oxygen species (ROS) in the tumor microenvironment (TME) are key factors involved in inhibiting tumor cell proliferation. This study developed a hollow mesoporous silica-Prussian blue (HMSNs-PB) nanozyme delivery platform loaded with metformin (HPB@MET), which enhances ROS levels within tumor cells through peroxidase-like (POD) activity. Moreover, in the acidic microenvironment of tumors, HPB@MET disintegrates, and the released MET causes mitochondrial dysfunction and increased electron leakage, ultimately promoting the abnormal accumulation of ROS in the TME. In vitro experiments demonstrate that HPB@MET achieves peak cellular uptake at 72 h and significantly inhibits tumor cell proliferation through its exceptional ROS-generating capacity. In the K7M2 osteosarcoma model (initial tumor volume 80 mm3), HPB@MET increased the tumor inhibition rate from 55% with HPB to 76.5%, with median survival extended to 57 days, indicating that HPB@MET synergistically suppresses tumor cell proliferation via POD activity and mitochondrial dysfunction, effectively suppressing osteosarcoma progression. These results indicate that this nanozyme-drug delivery platform can synergistically promote ROS generation in the TME, effectively inhibiting OS and providing a key technological approach for the efficient treatment of this disease.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12896-025-01057-2.

Iron oxide nanoparticles (IONPs) have attracted great attention for different environmental applications, mainly due to their magnetic, enzymatic and adsorption properties. In this study, IONPs functionalized with Betula pendula extract (FIONPs) were synthesized by a simple and green method and fully characterized using FE-SEM, EDS, XRD, TGA, DLS, VSM, and FTIR. The monodisperse and colloidal FIONPs represented a crystal structure and spherical shape, an average hydrodynamic size of 118.4 nm with PDI of 0.52 and zeta potential value of -28.4, and also high saturation magnetization value of 45.3 emu g−1. The in vitro studies revealed high biocompatibility of FIONPs on the human cell lines and their potent antibacterial effects on S. aureus and E. coli. FIONPs also displayed high peroxidase-like activity with a specific activity of 0.50 mmol min−1 mg−1. UV-Vis spectroscopy showed more than 99% removal of crystal violet and methylene blue in the batch experiments in the presence of FIONPs, while HPLC analysis revealed more than 98% degradation of antibiotic cefixime and chlorpyrifos pesticide. Degradation mechanism of chlorpyrifos was further studied by LC-MS analysis and biocompatibility of degradation products was evaluated in vitro. The overall results indicated high potential of FIONPs for pollutant removal from water.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-22455-8.