Pt-VS2-MXene nanozyme for on-site pesticide and H2O2 sensing: Bridging computational insights and experiment

초록

The excessive use of chlorpyrifos (CPS), a widely applied organophosphate pesticide, has caused serious environmental and food contamination, necessitating rapid and selective detection. Likewise, sensitive detection of H2O2 in living cells is crucial given its role in reactive oxygen species-mediated signalling, cell growth, and apoptosis. In this study, we synthesized peroxidase-mimetic nanozyme, Pt nanoparticles on edge-defect V2C MXene decorated with VS2 (VS2-MXene) via chemical reduction and solvothermal processes for ultrasensitive CPS and H2O2 detection. The defect-engineered Pt-VS2-MXene nanozyme exhibits markedly enhanced peroxidase-like activity (90.6 U mg(-1)), exceeding Pt-VS2 (40.5 U mg(-1)), Pt-MXene (64.9 U mg(-1)), and VS2-MXene (26.8 U mg(-1)), and substantially outperforming conventional nanozymes. Taking into account the ability of CPS to inhibit the peroxidase-like activity of Pt-VS2-MXene and suppressing its catalytic oxidation of chromogenic 3,3 ',5,5 '-tetramethylbenzidine (TMB), we constructed a smartphone-integrated paper-based analytical device (PAD) for real-time CPS detection. The PAD sensor enables ultrafast (similar to 3 min), visual, and on-site CPS quantification, achieving a detection limit of 0.64 nM with a broad linear range of 10-140 nM, and excellent recovery of 105.2 %-108.2 % in real wastewater samples. Additionally, Pt-VS2-MXene exhibits exceptional catalytic activity, with a strong affinity for TMB (K-m = 0.0231 mM, V-max = 0.169 mu M s(-1)), enabling ultra-sensitive H2O2 detection (LOD = 0.08 nM) with the wide linear range of 10-900 nM and real-time monitoring of H2O2 secretion from HeLa cells. This work creates sensitive PADs that can be used in biosensing, environmental monitoring, and medical diagnostics.

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