In this work, we propose a novel energy-transfer-based photoelectrochemical (PEC) platform for probing of protein-protein interaction, which associates intimately with zinc-dependent cleavage and substrate specificities in the enzymatic activities of botulinum neurotoxin (BoNT). Specifically, by using substrate protein SNAP-25 as the energy-transfer nanoprobe, an exciton-plasmon interaction (EPI) based strategy between CdS quantum dots (QDs) and Au nanoparticles (NPs) in a PEC system is constructed with the photocurrent declining. Interestingly, the EPI effect is then interrupted by the target botulinum neurotoxin serotype A light chain (BoNT-LCA) special cleavage of the probe SNAP-25, leading to the photocurrent recovery. Therefore, the enzymatic activity of BoNT-LCA could be sensitively detected with a detection limit of 1 pg/mL. Unlike conventional DNA-programable assembly, a protein probe is used to bridge the excitons and plasmons in this work, which provides a new route for the investigation of the EPI-based bioassay.

在这项工作中，我们提出了一种新型的基于能量转移的光电化学（PEC）平台，用于探测蛋白质-蛋白质相互作用，该平台与锌依赖性切割和肉毒杆菌神经毒素（BoNT）酶活性中的底物特异性密切相关。具体而言，通过使用底物蛋白SNAP-25作为能量转移纳米探针，在光电流下降的情况下，构建了PEC系统中CdS量子点（QDs）和Au纳米颗粒（NPs）之间基于激子-等离子体激元相互作用（EPI）的策略。有趣的是，EPI效应随后被探针SNAP-25的靶肉毒杆菌神经毒素血清型A轻链（BoNT-LCA）特异切割打断，从而导致光电流恢复。因此，可以以1 pg / mL的检出限灵敏地检测BoNT-LCA的酶活性。