title: Modulated dye retention for the signal-on fluorometric determination of acetylcholinesterase inhibitor.
abstract: A novel fluorometric assay method based on target-induced signal on was developed for acetylcholinesterase (AChE) inhibitor with obviously improved detection sensitivity. In this method, the AChE molecules catalyzed the hydrolysis of acetylthiocholine (ATCl) to form thiocholine, which in turn can specifically react with fluorescent squaraine derivative, a specific chemodosimeter for thiol-containing compounds, resulting in fluorescence quenching and offering a low fluorometric background for the further detection of AChE inhibitor. In the presence of AChE inhibitor, the catalytic hydrolysis of ATCl is blocked, and then the squaraine derivative remains intact and shows signal-on fluorescence. The amount of the remaining fluorescent squaraine derivative is positively correlated with that of the AChE inhibitor in solution. This new designed sensing system shows an obviously improved sensitivity toward target with a detection limit of 5 pg mL(-1) (0.018 nM) for the AChE inhibitor, comparing favorably with previously reported fluorometric methods. To our best knowledge, this new method is the first example of fluorometric enzymatic assay for AChE inhibitors based on such a signal-on principle and using a specific reaction, which has potential to offer an effective strategy for the detection of AChE inhibitors.
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, People's Republic of China.
authors.forename: Shuzhen
authors.initials: S
authors.lastname: Liao
authors.forename: Wenting
authors.initials: W
authors.lastname: Han
authors.forename: Huazhi
authors.initials: H
authors.lastname: Ding
authors.forename: Dexun
authors.initials: D
authors.lastname: Xie
authors.forename: Hui
authors.initials: H
authors.lastname: Tan
authors.forename: Shengyuan
authors.initials: S
authors.lastname: Yang
authors.forename: Zhaoyang
authors.initials: Z
authors.lastname: Wu
authors.forename: Guoli
authors.initials: G
authors.lastname: Shen
authors.forename: Ruqin
authors.initials: R
authors.lastname: Yu
mesh_terms: D000110:Acetylcholinesterase / Q000378:metabolism*; D000122:Acetylthiocholine / Q000378:metabolism; D055162:Biocatalysis / Q000187:drug effects; D015374:Biosensing Techniques / Q000379:methods*; D002800:Cholinesterase Inhibitors / Q000032:analysis* / Q000494:pharmacology; D005456:Fluorescent Dyes / Q000737:chemistry*; D005470:Fluorometry / Q000379:methods*; D006868:Hydrolysis / Q000187:drug effects; D010261:Paraoxon / Q000032:analysis / Q000494:pharmacology
chemical_list: D002800:Cholinesterase Inhibitors; D005456:Fluorescent Dyes; D000122:Acetylthiocholine; D000110:Acetylcholinesterase; D010261:Paraoxon