Biomimetic phosphorylcholine-based antifouling electrochemical biosensor for tetracycline analysis in milk

Nonspecific adsorption occurring on the surface of electrochemical sensors seriously affects the sensitivity and accuracy of sensing and is particularly prominent when applied to complex food matrices. Construction of antifouling sensing surfaces by modifying antifouling materials is a promising approach to address surface biofouling. In this study, a biomimetic phosphorylcholine (PC-SH) was synthesized by a simple Michael addition reaction with a hydrophilic zwitterion group and a thiol group. Poly(sodium-p-styrene sulfonate) (PSS)-doped poly(3,4-ethylenedioxythiophene) (PEDOT) and Au NPs were used as the conductive substrate. As a result, PC-SH effectively enhanced the hydrophilicity of the sensing surfaces, and the biomimetic phosphorylcholine-based antifouling surface showed excellent antifouling ability both in three single protein solutions (signal suppression as low as 0.9 %) and milk samples (signal suppression as low as 0.5 %). The constructed antifouling biosensor was able to sensitively detect TC with a low limit of detection of 8.8 pg mL−1. More importantly, the biomimetic phosphorylcholine-based antifouling biosensor achieved satisfactory recoveries (96.9–107.6 %) in milk with dilution treatment only, which effectively avoided cumbersome sample pre-treatment and proved its promising application for antibiotic monitoring in complex food matrices.