In Situ Enzymatically Generated Photoswitchable Oxidase Mimetics and Their Application for Colorimetric Detection of Glucose Oxidase.

ABSTRACT: In this study, a simple and amplified colorimetric assay is developed for the detection of the enzymatic activity of glucose oxidase (GOx) based on in situ formation of a photoswitchable oxidase mimetic of PO?(3-)-capped CdS quantum dots (QDs). GOx catalyzes the oxidation of 1-thio-?-d-glucose to give 1-thio-?-d-gluconic acid which spontaneously hydrolyzes to ?-d-gluconic acid and H?S; the generated H?S instantly reacts with Cd(2+) in the presence of Na?PO? to give PO?(3-)-stabilized CdS QDs in situ. Under visible-light (? ? 400 nm) stimulation, the PO?(3-)-capped CdS QDs are a new style of oxidase mimic derived by producing some active species, such as h?, (•)OH, O?(•-) and a little H?O?, which can oxidize the typical substrate (3,3,5,5-tetramethylbenzydine (TMB)) with a color change. Based on the GOx-triggered growth of the oxidase mimetics of PO?(3-)-capped CdS QDs in situ, we developed a simple and amplified colorimetric assay to probe the enzymatic activity of GOx. The proposed method allowed the detection of the enzymatic activity of GOx over the range from 25 ?g/L to 50 mg/L with a low detection limit of 6.6 ?g/L. We believe the PO?(3-)-capped CdS QDs generated in situ with photo-stimulated enzyme-mimicking activity may find wide potential applications in biosensors.

SUBMITTER: Cao GX 

PROVIDER: S-EPMC6273347 | biostudies-other | 2016 Jul

REPOSITORIES: biostudies-other