1. Electrochemical biosensor based on singlet oxygen generated by molecular photosensitizers.
- Author
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Ling, Pinghua, Sun, Xinyu, Chen, Nuo, Cheng, Shan, Gao, Xianping, and Gao, Feng
- Subjects
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REACTIVE oxygen species , *BIOSENSORS , *MULTIENZYME complexes , *SIGNAL detection , *ELECTROCHEMICAL analysis , *HYDROQUINONE , *PHOTOELECTROCHEMISTRY - Abstract
Here a sensing strategy with the integration of photosensitizer and electrochemical analysis was present. The photosensitizer, Zinc(II) tetraphenylporphyrin (ZnTCPP), was functionalized graphene oxide (GO) to form complex (ZnTCPP/GO) as the electrode material and generated singlet-oxygen (1O 2) in the presence of air under light illumination. Due to the special electronic structure of 1O 2 , hydroquinone (HQ) could react with 1O 2 to produce electrochemically-detectable products, benzoquinone (BQ). Meanwhile, the formed BQ could be reduced on the electrode, completing the redox cycling. The ZnTCPP/GO modified ITO electrode produces a stable and enhanced photocurrent signal under 420 nm irradiation in air-saturated buffer, compared with in N 2 -saturated buffer. On the other hand, l -glutathione (GSH) as a signalling molecule plays important role in physiological process, which was employed as model to investigated the sensing performance. Coupling with HQ oxidized by 1O 2 , a GSH sensor was constructed on the basis the redox cycling of HQ. A sensitive reduction of photocurrent is observed with the addition of GSH, due to the GSH could be oxidized by the generated 1O 2 to form GSSG. The biosensor displayed good performance in a broad concentration range of 0–150 μM, with a lower detection limit of 1.3 μM at an S/N ratio of 3, and could be used in practical application. This work affords a platform for constructing the biosensor with 1O 2 instead of enzyme via on/off light switching. Electrochemical biosensor based on singlet oxygen generated by molecular photosensitizers was designed for l -glutathione detection with signal amplification. [Display omitted] • A electrochemical biosensor based on singlet oxygen (1O 2) generated by molecular photosensitizers was designed. • Photosensitizers, Zinc(II) tetraphenylporphyrin, generated 1O 2 in the presence of air under light illumination. • The signal was amplified by hydroquinone which was oxidized by 1O 2 and then reduced on the electrode, completing the cycling. • The use of catalytic photosensitizers could instead of enzyme used in complex environment, and switch the light to control the signal. • The sensor showed good performance. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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