A static/dynamic dual-strategy for synergistically enhanced POM@Polypyrrole nanozymes in oxidase-like sensing

The development of high-performance oxidase-like nanozymes is crucial for advancing biocatalysis and biosensing. Polyoxometalates (POMs) are promising candidates but suffer from high solubility and inefficient interfacial electron transfer. Conventional immobilization often overlooks the matrix's role in catalysis. Herein, a dual-strategy enhanced nanozyme was developed by in-situ oxidative polymerization of a mono-V-substituted phosphomolybdic acid H₅[PMo₁₁VO₄₀] (PMo₁₁V₁) into a conductive polypyrrole (PPy) matrix. The optimal composite PMo₁₁V₁@PPy-2 exhibits 2.2-fold higher oxidase-like activity than its conventional immobilized counterpart. Ultrasonic irradiation (100 kHz) further enhances its activity by ∼ 80% through improved mass transfer. Leveraging this synergy, a highly sensitive colorimetric biosensor for glutathione (GSH) detection was constructed, achieving a low detection limit (0.73 μM), a wide linear range (1-80 μM), excellent recovery in serum (99.4% to 100.6%), and high selectivity. This work demonstrates that rational integration of static material design with dynamic process engineering can overcome fundamental limitations in heterogeneous nanozyme catalysis, providing a generalizable strategy for developing high-performance enzymatic mimics for biomedical applications.