G-quadruplex-based fluorescent sensing platform for thiamethoxam detection: integrating multiple signal amplification strategies.
Thiamethoxam, a widely utilized neonicotinoid insecticide, has been extensively applied in agricultural practices, leading to various adverse effects on human health, such as neurotoxicity, developmental issues, and endocrine disruption. Therefore, establishing a comprehensive and standardized surveillance framework for the quantitative determination of thiamethoxam residues in environmental compartments and food matrices is critical for mitigating its chronic toxicological risks to human health. We developed a biosensor for thiamethoxam detection, which leverages the target-induced formation of G-quadruplexes and subsequent Thioflavin T fluorescence enhancement based on Exonuclease III-driven shear amplification and the hybridization chain reaction. Under optimized conditions, this biosensor exhibited a detection range from 10 pg mL-1 to 1 µg mL-1 and a detection limit of 8.7 pg mL-1. Furthermore, the successful detection of thiamethoxam in real samples confirms the biosensor's practical applicability and reliability.