Enhancement of sensitivity for dichlorvos detection by a low-weight gelator based on bolaamphiphile amino acid derivatives decorated with a hybrid graphene quantum dot/enzyme/hydrogel

Chontica, Sahub and Jesicca L., Andrews and James P., Smith and Maya A., Mohamad Arif and Boosayarat, Tomapatanaget and Jonathan W., Steed (2021) Enhancement of sensitivity for dichlorvos detection by a low-weight gelator based on bolaamphiphile amino acid derivatives decorated with a hybrid graphene quantum dot/enzyme/hydrogel. Materials Chemistry Frontiers (2021). pp. 1-12.

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Abstract

Developing the sensitivity of an optical biosensor motivates the exploration of an amplification strategy for the incorporation of a biosensor system in a supramolecular hydrogel. We developed novel fluorescent hybrid materials comprising graphene quantum dots and enzymes supported by L-phenylalanine derived bis(urea) supramolecular hydrogels (GQDs/Enz/Gels) for detection of organophosphates. The addition of acetylcholinesterase (AChE) and choline oxidase (ChOx) during the formation of self-assembled GQDs/Gel materials resulted in enzyme-functionalized gel networks. Significant turn-off fluorescence of the encapsulated GQDs in the hydrogels was due to hydrogen peroxide generated from the active enzymatic reaction. The addition of insecticide dichlorvos to the GQDs/Enz/Gels resulted in the recovery of fluorescence in proportion to the concentration of dichlorvos, with a detection limit of 2.61 × 10−8 M which outperforms those in solution by 100-fold improvement and a wider linear range of 1.25 × 10−8–1.25 × 10−4 M compared to those of the biosensor in solution. These hybrid hydrogels show promising sensitivity to the detection of oxy-form organophosphate pesticides and expectedly offer scope for the development of rapid and environmentally friendly techniques.

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