Ultrasensitivity Detecting AChE through “Covalent Assembly” and Signal Amplification Strategic Approaches and Applied to Screen Its Inhibitor

Abstract

An ultrasensitivity detecting assay for acetylcholinesterase (AChE) activity was developed based on "covalent assembly" and signal amplification strategic approaches. After hydrolyzing thioacetylcholine by AChE and participation of thiol in a self-inducing cascade accelerated by the Meldrum acid derivatives of 2-[bis(methylthio) methylene] malonitrile (CA-2), mercaptans triggered an intramolecular cyclization assembly by the probe of 2-(2,2-dicyanovinyl)-5-(diethylamino) phenyl 2,4-dinitrobenzenesulfonate (Sd-I) to produce strong fluorescence. The limit of detection for AChE activity was as low as 0.0048 mU/mL. The detection system also had a good detecting effect on AChE activity in human serum and could also be used to screen its inhibitors. By constructing a Sd-I@agarose hydrogel with a smartphone, a pointof-care detection of AChE activity was achieved again.

Construction of logic gate computation for the assay of the nerve agent sarin based on an AChE-based dual-channel sensing system

“…Since the optical signal intensity of this sensing system depends on the AChE activity, this system is capable of serving as a universal sensing platform for the detection of AChE inhibitors. [28][29][30][31] Further, common interfering factors in the biosensing system, including common ions (Zn 2+ , Na + , K + , Cl − , ), amino acids (histidine, serine, cysteine, alanine), glutathione (GSH), glucose, citric acid, ascorbic acid, and bovine serum proteins, were selected for evaluating the selectivity of the sensing system to non-AChE inhibitors. Specically, under the same experimental conditions, the optical responses of the sensing system (AChE + ATCl + oxTMB + Ce 3+ -GSH-Au NCs) were tested in the presence of multiple interferents and GB, respectively.…”

Encapsulation of Enzymes into Hydrophilic and Biocompatible Metal Azolate Framework: Improved Functions of Biocatalyst in Cascade Reactions and its Sensing Applications

“…By introducing the specific inhibitor into the sensing platform with a certain concentration of the biocatalyst and substrate, the activity of the embedded enzyme would be hindered, resulting in a blocked cascade reaction [49] and accompanied by decline of the fluorescence signals. By plotting the inhibition rate [50] with the concentration of tacrine (a typical inhibitor of AChE), the typical S-shape curve was obtained (Figure 4E). The IC 50 value (concentration of the inhibitor when the inhibition rate is 50%) was 870.2 nm according to the fitting equation of the inhibition curve, which was consistent with the previous research in order of magnitude, [51] confirming the ability of screening inhibitors of this sensing platform based on MAF-7 and the encapsulated enzymes inducing the cascade catalysis.…”