Abstract
Abstract
This study reports a multifunctional sensing platform that integrates molecular recognition by γ-cyclodextrin (γ-CD), nanozyme catalytic activity, and Raman enhancement within a single nanoparticle system for the detection of fenthion, a widely used organophosphate pesticide in agriculture. Unlike conventional single-mode assays, this sensor platform provides both colorimetric and SERS readouts, offering enhanced versatility and sensitivity. The γ-CD host–guest interaction drives nanoparticle aggregation upon fenthion binding, simultaneously suppressing peroxidase-like oxidation of 3,3′,5,5′‑tetramethylbenzidine and attenuating surface-enhanced Raman scattering (SERS) signals. The dual readouts enable quantitative analysis with detection limits of 7.8 ppb (SERS) and 0.618 ppm (colorimetric). Practical applicability was demonstrated in tomato samples, achieving a SERS detection limit of 0.18 ppm. This cost-effective dual-mode platform demonstrates the potential of γ-CD nanozymes for pesticide residue monitoring by combining simple colorimetric screening with more sensitive SERS-based quantification, offering a complementary approach for food safety and environmental surveillance applications.