Multienzyme cascades analysis of α-glucosidase by oxygen deficient MoO_3-x

Recently, the enzymatic cascade reactions during the cellular process are widely used for fabricating robust biosensors and they have attracted extensive attention in analyzing various clinical biomarkers. The enzymatic cascades analysis is commonly based on the peroxidase (POD)/oxidase coupled system. However, the requirement of harsh acidic environment, poor stability and interference from the oxidase further limit their analytical practicability. Herein, novel chromogenic nanomaterials with H₂O₂ sensitive features are urgently required to replace the POD nanozyme in enzymatic cascades based bioanalysis.

Herein, oxygen deficient MoO_3-x with H₂O₂ sensitive features and near-infrared (NIR) absorption band have been ultra-fast synthesized and utilized for the enzymatic cascades analysis of α-Glucosidase's activity, and inhibitors screening. With the addition of 4-nitrophenyl-α-d-glucopyranoside, the simultaneous presence of α-Glucosidase and glucose oxidase (GO_x) would fade their dark blue color and decrease the NIR absorption. The α-Glucosidase's activity can be analyzed by the absorption at 770 nm, and their limit of detection is 8 × 10^-5 U/mL, indicating the superior performance of the proposed colorimetric assay. Moreover, this proposed α-Glucosidase assay is further utilized for inhibitors screening. Moreover, the activity of α-Glucosidase can also be analyzed by the smartphone and microplate reader through the agarose-based colorimetric portable kit.

This MoO_3-x involved enzymatic cascades assay would facilitate for the development of bio-analysis related to H₂O₂ generation or consumption. Moreover, this bio-analysis strategy will contribute to the development of other H₂O₂ sensitive chromogenic nanomaterials for the analysis of certain biomolecules and biological enzymes.