Gold screen-printed electrodes coupled with molecularly imprinted conjugated polymers for ultrasensitive detection of streptomycin in milk

Antibiotic resistance is a global health threat, challenging traditional treatments and complicating the food safety process. This study introduces an electrochemical detection method for streptomycin sulfate, utilizing gold screen-printed electrodes (Au-SPE) functionalized via electropolymerization of a custom-made naphthalene diimide-based conjugated monomer (Th2-NDI-PIA). This modification creates specific binding sites for streptomycin, allowing rapid detection of the antibiotic. The sensor's response to different concentrations of streptomycin was studied via Differential Pulse Voltammetry (DPV) in a wide linear range from 10-13 M to 10-9 M, with a limit of detection (LoD) of 0.190 ± 0.005 pM. The imprinted electrode demonstrates selectivity to other antibiotics, but also to common interferents that can be found in milk such as lactose, glucose, riboflavin, and bisphenol A. Successful proof-of-principle in whole cow milk highlights the sensor's efficacy in detecting antibiotic residues in food samples, offering a promising alternative for a rapid and portable detection technique.