A host guest interaction enhanced polymerization amplification for electrochemical detection of cocaine

Highlights: • Firstly, it was reported for cocaine detection based on host−guest chemistry and atom transfer radical polymerization (ATRP). • Ultra-high efficiency was discovered in the synthesized macroinitiator β−CD−Br₁₅. • This biosensor was successfully achieved in biological samples. Cocaine (Coc) is one of the illegal drugs and is harmful to digestive, immune, cardiovascular and urogenital systems. To achieve drug abuse control and legal action, it is essential to develop an effective method for cocaine analysis. In this work, an aptasensor has been developed using atom transfer radical polymerization (ATRP) based on host−guest chemistry for electrochemical analysis of cocaine. The NH₂−DNA (Apt1) was immobilized on the indium tin oxide (ITO) electrode via addition reaction, and Fc−DNA (Apt2) was introduced to ITO relying on the specific recognition of cocaine. The Apt2 can initiate host−guest chemistry between Apt2 and ATRP initiators (β−CD−Br₁₅), then the β−CD−Br₁₅ further triggers ATRP. Moreover, ATRP avoids the sluggish kinetics and poor coupling capability sustained. The result shows a sensitive and selective analysis of cocaine within a linear range from 0.1 ng/mL to 10 μg/mL (R² = 0.9985), with the detection limit down to 0.0335 ng/mL. Thus, this strategy provides a universal method for the analysis of illegal drugs.