Kim_2023_Anal.Chim.Acta_1257_341171

We developed an electrochemical and fluorescent dual-mode sensor for assessing acetylcholinesterase (AChE) activity and inhibition by taking advantage of the high redox sensitivity of surface-coated mesoporous MnO(2)@polymer dot (MnO(2)@PD) towards AChE. The following phenomena constitute the basis of the detection mechanism: fluorescence resonance energy transfer (FRET) effect between MnO(2) and PD; catalytic hydrolysis of acetylthiocholine (ATCh) to thiocholine (TCh) by AChE expressed by PC-12 cells, inducing fluorescence restoration and change in the conductivity of the system due to MnO(2) decomposition; the presence of the inhibitor neostigmine preventing the conversion of ATCh to TCh. The surface-coated biosensor presents both fluorescence-based and electrochemical approaches for effectively monitoring AChE activity and inhibition. The fluorescence approach is based on the fluorescent "on/off" property of the system caused by MnO(2) breakdown after interaction with TCh and the subsequent release of PDs. The conductivity of the coated electrode decreased dramatically as AChE concentration increased, resulting in electrochemical sensing of AChE activity and inhibition screening. Real-time wireless sensing can be conducted using a smartphone to monitor the resistance change, investigating the potential use of MnO(2)@PD nanocomposites in biological studies, and offering a real-time redox-fluorescent test for AChE activity monitoring and inhibitor screening.