Aptamer-Based Molecule-Responsive SERS System for Highly Efficient Detection of Cocaine.

Illicit drug abuse has brought big challenges to public health, because it has caused severe damage to the human central nervous system. The development of a rapid, quantified, and on-site detection of illicit drugs is of key importance for the control of drug abuse. However, it remains challenging due to biological sample interference and difficulties in achieving specific recognition of the drug molecule. Here, we report a molecule-responsive two-component surface-enhanced Raman scattering (SERS) platform for the capture and detection of illicit drugs. Under optimized conditions, the system demonstrates a linear response to cocaine concentrations ranging from 1 ppb to 10 ppm (R2 > 0.99), with an ultralow detection limit of 1.5 ppb. Successful application in spiked bovine serum validates the method's robustness against complex biological matrices. This work establishes a novel paradigm for detecting trace-level illicit drugs with significant forensic potential. The design principle might be applied to other chemical detection.