3-mercaptopropionic acid agent-based biosensor system using gold-screen printed electrode for aflatoxin B1 detection

A novel electrochemical biosensor was constructed for the ultrasensitive detection of aflatoxin B1 (AFB1) in food samples. The biosensor design was based on a 3-mercaptopropionic acid (3-MPA)-modified self-assembled monolayer (SAM) constructed on disposable gold screen-printed electrodes (SPE-Au). Covalent attachment of anti-AFB1 antibodies was achieved on the functionalized electrode surface, and the modification process at each stage was analyzed using CV and EIS techniques. 3-MPA concentration was optimized to enhance analytical performance. The biosensor exhibited a wide linear detection range of 0.1-250 pg/mL with a calculated limit of detection (LOD) of 0.94 pg/mL and limit of quantification (LOQ) of 3.14 pg/mL. It also demonstrated high reproducibility and excellent selectivity toward AFB1. Finally, the biosensor was successfully applied to real food samples, including milk, rice, peanuts, and chili pepper, confirming its reliability and potential for practical food safety monitoring.