Quantitative visualization and detection of acetylcholinesterase activity and its inhibitor based on the oxidation character of ultrathin MnO2 nanosheets†
Acetylcholinesterase (AChE) is the key enzyme in the treatment of Alzheimer's disease (AD). In this study, we designed a novel visualization biosensing system for the quantitative detection of AChE and its inhibitors. The MnO2–OPD platform showed the broad detection of AChE ranging from 0.49–98 U L−1 and the LOD was 0.13 U L−1. Furthermore, the AChE–MnO2–OPD biosensing system was successfully applied to screen AChE inhibitors from a natural product library (Northwestern China Plant Natural Material Bank). 3,4-Dihydroxyphenylethanol (HJ-38), a natural product isolated from Zanthoxylum bungeanum pericarps, was found to be a potent AChE inhibitor with an IC50 of 2.8 μM and is comparable to the positive control tacrine with an IC50 of 1.3 μM. Furthermore, a cell-based assay confirmed the neuro-protective potential of compound HJ-38, which supported the practicability of the established AChE–MnO2–OPD biosensing system.