Dual-Component Surface-Enhanced Raman Scattering Detection of Tetracycline Based on Aptamer-Regulated Catalytic Switch.

This paper presents a surface-enhanced Raman scattering sensing platform for sensitive detection of tetracycline (TTC) in food samples, in which dual-component signal enhancement is achieved by combining an aptamer-regulated catalytic switch with a structurally optimized substrate. The substrate consists of an ordered gold nanoparticle (AuNP) array conformally coated with a continuous MXene film via liquid-liquid interfacial assembly. A TTC-specific aptamer and catalytic nitrogen/silver co-doped carbon dots (CDN/Ag) are further integrated through controlled in-situ formation of AuNPs, enabling synergistic electromagnetic and chemical signal enhancement. The platform exhibits a wide linear range from 10-5 M to 10-12 M for TTC, with a limit of detection of 5.3 × 10-12 M, high selectivity, and robust performance in complex samples. Spike-recovery tests in milk yielded recoveries of 95.6%-126%, with relative standard deviations of 1.6%-5.1%, demonstrating the reliability and practical applicability of the sensor for food safety monitoring.