Oxidase-mimicking activity of ultrathin MnO₂nanosheets in colorimetric assay of acetylcholinesterase activity

Abstract

In the present study, a novel colorimetric sensing platform was constructed for quantitative detection of acetylcholinesterase (AChE) activity and its inhibitor. Manganese dioxide (MnO) nanosheets as an oxidase-mimicking nanomaterial could directly oxidize 3,3',5,5'-tetramethylbenzidine (TMB) into oxTMB without the need for horseradish peroxidase and HO. When AChE was introduced, acetylthiocholine could be catalytically hydrolyzed to produce thiocholine, which easily triggers the decomposition of MnO nanosheets, causing the decrease of solution absorbance. Owing to the inhibition effect of organophosphorus pesticides, the enzymatic activity was suppressed, preventing the decomposition of MnO and resulting in the increase of absorbance. Under optimal conditions, the colorimetric platform shows sensitive responses to AChE and paraoxon in the range of 0.1-15 mU mL and 0.001-0.1 μg mL, respectively. The detection limits of AChE and paraoxon reached 35 μU mL and 1.0 ng mL, respectively. Furthermore, the MnO-TMB platform has been used to fabricate test strips for rapid and convenient visual detection of AChE and its inhibitor with highly promising performance.

Manganese Oxide Nanomaterials: Synthesis, Properties, and Theranostic Applications

“…The generated H 2 O 2 can effectively decompose MnO 2 with an absorption change. Similarly, a lot of other examples were reported about MnO 2 ‐based colorimetric biosensors …”

A Probe for Fluorescence Detection of the Acetylcholinesterase Activity Based on Molecularly Imprinted Polymers Coated Carbon Dots

“…The maximum inhibition rate of huperzine A was 82% and IC 50 value was 254 nM, which was similar to previous reports (260 nM). 24) Selectivity of the Assay for AChE Detection To test the selectivity of our proposed C-dots@MIP method, we measured various potential interference, including amino acids, proteins and some inorganic salts. As shown in Fig.…”

Colorimetric detection of gallic acid based on the enhanced oxidase‐like activity of floral‐like magnetic Fe3O4@MnO2

“…Much attention has been focused on manganese oxide (MnO 2 ), due to its chemical and physical properties and board application . Over the past decades, MnO 2 has been widely used to detect small biological molecules based on its oxidase activity, such as the detection of glutathione, acetylcholinesterase, and ascorbic acid, etc. However, the catalytic performance of MnO 2 is weak, and it is difficult to separate after the reaction process .…”