title: 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 PO₄(3-)-capped CdS quantum dots (QDs). GOx catalyzes the oxidation of 1-thio-β-d-glucose to give 1-thio-β-d-gluconic acid which spontaneously hydrolyzes to β-d-gluconic acid and H₂S; the generated H₂S instantly reacts with Cd(2+) in the presence of Na₃PO₄ to give PO₄(3-)-stabilized CdS QDs in situ. Under visible-light (λ ≥ 400 nm) stimulation, the PO₄(3-)-capped CdS QDs are a new style of oxidase mimic derived by producing some active species, such as h⁺, (•)OH, O₂(•-) and a little H₂O₂, 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 PO₄(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 μg/L to 50 mg/L with a low detection limit of 6.6 μg/L. We believe the PO₄(3-)-capped CdS QDs generated in situ with photo-stimulated enzyme-mimicking activity may find wide potential applications in biosensors.
authors.affiliation: The Key Laboratory of Food Colloids and Biotechnology, Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, China. 18206180706@163.com.
authors.forename: Gen-Xia
authors.initials: GX
authors.lastname: Cao
authors.affiliation: The Key Laboratory of Food Colloids and Biotechnology, Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, China. wuxiuming821@163.com.
authors.forename: Xiu-Ming
authors.initials: XM
authors.lastname: Wu
authors.affiliation: The Key Laboratory of Food Colloids and Biotechnology, Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, China. dongym@jiangnan.edu.cn.
authors.forename: Yu-Ming
authors.initials: YM
authors.lastname: Dong
authors.affiliation: The Key Laboratory of Food Colloids and Biotechnology, Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, China. zaijunli@263.net.
authors.forename: Zai-Jun
authors.initials: ZJ
authors.lastname: Li
authors.affiliation: The Key Laboratory of Food Colloids and Biotechnology, Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, China. glwang@jiangnan.edu.cn.
authors.forename: Guang-Li
authors.initials: GL
authors.lastname: Wang
mesh_terms: D032701:Biomimetics; D015374:Biosensing Techniques; D002384:Catalysis; D003124:Colorimetry / Q000379:methods*; D004789:Enzyme Activation; D005949:Glucose Oxidase / Q000737:chemistry*; D008027:Light; D010088:Oxidoreductases / Q000737:chemistry*; D055668:Photochemical Processes; D056951:Photoelectron Spectroscopy
chemical_list: D010088:Oxidoreductases; D005949:Glucose Oxidase
keywords: colorimetric sensor; glucose oxidase; photoswitchable oxidase mimetics; visible light