Novel fluorescence sensor based on BSA-engineered au NCs for quantitative visual detecting cypermethrin pesticides via smartphone imaging

Fluorescence assay for in situ and on-site monitoring of pyrethroid pesticides residues from plants is of great value but remains little research. In this study, a fluorescence biosensor Au NCs@BSA, is designed and constructed by embedding Au nanoclusters (Au NCs) in bovine serum albumin (BSA) to transmit on-the-scene cypermethrin pesticide residues messages. Harnessing orange emission and stimuli-responsive performance of Au NCs, as well as the specific strong binding ability of BSA to cypermethrin molecules, Au NCs@BSA is endowed with quantitative response to cypermethrin at μM level within 20 s through promoting fluorescence recovery in conjunction with the transformation of fluorescence images into digital signals. In addition, the interference experiment using common ions and other types of pesticides as coexisting interference substances demonstrated that the sensing system possesses brilliant selectivity and anti-interference ability. By combining the smartphone-based platform and convolutional neural network (CNN-model), different concentrations levels of cypermethrin were accurately identified in real samples. This study opens up a new avenue to engineer simple fluorescence assay for in situ and on-site capturing of the pyrethroid pesticide residue information, favoring the rapid development of agriculture food monitoring.