Gold nanoparticle-decorated MoSe, nanosheets as highly effective peroxidase-like nanozymes for total antioxidant capacity assay

A visual colorimetric detection strategy is reported for total antioxidant capacity (TAC) assay by using 3,3',5,5'tetramethylbenzidine (TMB) oxidation as chromogenic substrate based on gold nanoparticle-decorated MoSe2 nanosheets (Au@MoSe2). Au@MoSe2 nanostructures exhibit high peroxidase-like activity and can catalyze H2O2 to oxidize TMB. Based on inhibition effect of ascorbic acid (AA) on TMB oxidation, a facile and sensitive colorimetric method was developed for AA detection. Under optimal conditions, the proposed method showed a sensitivity for AA in a concentration range from 2 to 120 pM and limit of detection was 0.41 pM. Furthermore, the method was employed for TAC assay in actual samples, including commercial beverages and vitamin C tablets. This work represents a model in nanostructure design and will lead to further development of TAC assay in evaluation of antioxidant food quality.

Automated summary

A visual colorimetric detection strategy using gold nanoparticle-decorated MoSe2 nanosheets (Au@MoSe2) as catalysts is reported for total antioxidant capacity (TAC) assay. The method demonstrates high sensitivity for ascorbic acid (AA) detection based on the inhibition effect on chromogenic substrate oxidation. The proposed method also shows potential for TAC assay in evaluating antioxidant food quality.