In contrast to the single-functional enzymes such as superoxide dismutase and catalase, catalase-peroxidase (KatG) is a special natural enzyme with bifunctional activity that catalyzes the decomposition of hydrogen peroxide (H2O2) into both oxygen (O2) and radicals. Inspired by the unique catalytic activity of KatG, this study synthesized a two-dimensional (2D) tannic copper (CuTA) nanosheet with KatG-like catalytic activity, which is used for enhanced nanocatalytic tumor therapy by hypoxic modulations. CuTA presents a mixed-valence catalytic center (Cu2+/Cu+) through the stable coordination of copper ions with tannic acid, which endows the catalyst with exceptional electron transfer capabilities and dynamic redox cycling properties, thus providing excellent peroxidase-like activity to generate hydroxyl radicals (•OH) (Km = 18.8 µm, Vmax = 3.83 × 10-8 m·s-1), and catalase-like activity to generate O2 (Km = 96.95mm, Vmax = 12.37 × 10-7 m·s-1). Cell experiments demonstrate that catalytic O2 generation by CuTA alleviates the tumor hypoxia and therefore sensitizes cancer cells to the oxidative attack by catalytically generated •OH. In vivo experiments further confirm the significant antitumor efficacy of CuTA. This study highlights the promising potential of the KatG-mimic nanocatalyst in hypoxic modulation and hypoxic tumor treatment through coupled catalytic regulations.

The overuse of quinolone antibiotics (QNs) seriously endangers human health and the ecological environment. In this work, a copper dihydroxosulfate (Cu2(OH)2SO4) nanosheet exhibiting notable peroxidase-like (POD) and laccase-like (LAC) activities has been developed in basic deep eutectic solvents (DES). The unique physicochemical properties of QNs allow them to enhance the POD activity of Cu2(OH)2SO4, and with the extension of reaction time, this enhancement gradually intensifies. Conversely, when QNs are introduced into the LAC reaction system of Cu2(OH)2SO4, they significantly inhibit its LAC activity, with the degree of inhibition growing increasingly evident as the reaction time increases. A nanozyme sensing array has been developed via reaction dynamics to identify eight QNs. This method cleverly achieves self-calibration through two reverse signals, further improving the sensing performance of the sensor array. Moreover, through the optimization of various machine learning (ML), the precision of the concentration-independent recognition model built upon this array has been enhanced from 39.08% to 91.95%. This improvement is advantageous for the identification of unknown samples within actual samples. This work carries significant implications for enhancing the discrimination of QNs in complex samples.

Two selective methods were developed for detecting mercury ions (Hg2⁺) in food and water samples using catalytic fluorometry based on Au-Hg amalgamation with enhanced peroxidase-like activity. These approaches include (i) a laser-printed microfluidic paper-based analytical device (LP-µPAD) and (ii) a paper-based microcentrifuge tube test kit. The LP-µPAD was fabricated via commercial laser printing and integrated gold nanoparticles (AuNPs) with o-phenylenediamine (OPD) and hydrogen peroxide (H₂O₂). The test kit enabled Hg2⁺ detection in food by reducing Hg2⁺ to Hg⁰ with stannous chloride, facilitating Au-Hg amalgam formation in the detection zone. Both approaches utilized the Au-Hg amalgam to catalyze H₂O₂-mediated oxidation of OPD, generating fluorescent 2,3-diaminophenazine (DAP), further enhancing fluorescence intensity in proportion to Hg2⁺ concentrations. The LP-µPAD exhibited a detection range of 3.0-20.0µg L⁻1 with a limit of detection (LOD) of 1.65µg L⁻1, whereas the test kit provided a detection range of 0.1-1.0mg L⁻1 with an LOD of 0.08mg L⁻1. Both sensors showed high selectivity for Hg2⁺ over other ions and performed well in real sample analyses, aligning closely with results from conventional methods.

Oral ulcer, characterized by mucosal damage, is susceptible to bacterial infection, tissue inflammation, and slow healing. Traditional treatments for oral ulcers only target on single function, such as antimicrobial, anti-inflammatory, or wound-healing, limiting the therapeutic efficacy. In this work, a multifunctional nanotherapeutic approach is developed, integrating antibacterial, anti-inflammatory, and tissue-healing properties for the treatment of oral ulcers with bacterial infection. Outer membrane vesicles (OMVs) derived from probiotic Escherichia coli Nissle 1917 serve as biocompatible carriers to load platinum nanoparticles (Pt NPs) and curcumin (Cur), acting as multifunctional Cur@OMV-Pt (COP) nanocomposite for the treatment of oral ulcer. The probiotic OMVs enhance the delivery and promote tissue regeneration owing to their rich components and functional biomolecules. Pt NPs with peroxidase-like and catalase-like activities catalyze H2O2 to generate reactive oxygen species and oxygen, exerting chemodynamic antibacterial therapy while enhancing photodynamic therapy of curcumin with anti-inflammatory effects. The COP nanocomposite effectively addresses the challenges of methicillin-resistant Staphylococcus aureus-infected oral ulcer by synergistically enhancing antibacterial, anti-inflammatory, and tissue-healing responses. This work presents a promising strategy for clinical applications in the treatment of oral ulcers and other bacterial infections, particularly in complex microenvironments.

A novel dual-mode colorimetric and ratiometric fluorescence method for detecting isocarbophos based on S, N-CDs inhibiting Fe3O4@Cu-BTC nanozyme activity.

Multistimulus-responsive oxidative stress/ferroptosis combination anti-tumor nano-enzyme constructed based on glucose oxidase and PEG-PAA.

A catalase-like nanozyme of high activity and stability in acidic solutions for enzyme immobilization and chemoenzymatic cascade conversion of glucose to gluconic acid.

Ciprofloxacin-based zinc-doped carbon dots with peroxidase-like activity against Escherichia coli and biofilm eradication

Au-ag quantum dot nanozyme identified for multi-mode fluorescent, UV-vis and intelligent RGB monitoring and removal of toxic Hg2+ and S2- in food samples.

Multi-model immunochromatographic assay based on "three in one" Fe3O4@PDA@Pt nanocomposite for ultrasensitive detection of zearalenone in cereals.

A dual-readout immunosensor based on the peroxidase-like activity and fluorescence property of MIL-88-NH2@Pt

Trifunctional silver nanoparticle modified magnetic prickly-like nickel rods with magnetism, peroxidase-like and surface-enhanced Raman scattering activity for self-calibration dual-mode detection of 5-hydroxymethylfurfural in foods.

Unveiling a novel nanozyme cofactor: a highly activated Fe-CDs-derived colorimetric sensor array for comprehensive authentication of diverse tea products.

Multifunctional Prussian blue nanozymes ameliorate tendinopathy via modulating tissue homeostasis

Ultrasensitive detection of chloramphenicol using a performance-enhanced Fe/Zn-MIL-88B driven dual-mode biosensing platform.

Three birds with one stone: Integrated diagnosis and treatment platform for tetracycline based on Fe3O4QDs@ZIF-8 nanozyme.

Eu-Ce commensalism: A dual-functional nanozyme with enhanced peroxidase-like activity for the ultrasensitive and specific detection of phosphate ions

In this study, a novel nanocomposite was rationally engineered by embedding silver nanoparticles (AgNPs) into tannic acid-derived carbon spheres (Cs), followed by their distribution on graphene oxide (GO) sheets (AgNPs@Cs-TA@GO), aiming to enhance catalytic and antibacterial performance. The fabrication process was expedited using a microwave-assisted technique. The AgNPs@Cs-TA@GO nanocomposite with the core based on AgNPs with an average diameter of 21 nm showed significant peroxidase-like activity by oxidizing 3,3′,5,5′-tetramethylbenzidine to its oxidized form in the presence of H2O2. This compassionate H2O2 colorimetric detection allowed for quick identification of H2O2 in a broad range (0.6–9.0 ppm) with a low detection limit of 0.2 ppm (S/N = 3). The viability of this method was confirmed by qualitatively detecting H2O2 residual in aquaculture water samples. Additionally, the antibacterial assays, conducted using the agar well diffusion method demonstrated pronounced inhibitory effects against Vibrio parahaemolyticus ATCC 17802 (Gram-negative) and Staphylococcus aureus ATCC 25923 (Gram-positive), with inhibition zones of 46.1 and 49.3 mm, respectively. The rapid microwave-assisted incorporation of AgNPs into Cs within the GO network not only improves synthesis duration but also the catalytic and antibacterial performances as a result of minimized coagulation and promoting electron transfer on the AgNPs’ surface.

Cobalt single-atom nanozymes with peroxidase-like activity for the development of electrochemical and colorimetric dual-mode sensors for catechol detection

Smartphone-assisted portable swabs for thiram specific analysis based on target-regulated CuWO4 nanozyme activity combined with sample pretreatment.