Carbon Dot-Modified Branched TiO2 Photoelectrochemical Glucose Sensors with Visible Light Response

The development of a photoelectrochemical (PEC) sensorfor thesensitive and rapid detection of glucose is highly desirable. In PECenzyme sensors, inhibition of the charge recombination of electrodematerials is an efficient technique, and detection in visible lightcan prevent enzyme inactivation due to ultraviolet irradiation. Inthis study, a visible light-driven PEC enzyme biosensor was proposed,using CDs/branched TiO2 (B-TiO2) as the photoactivematerial and glucose oxidase (GOx) as the identification element.The CDs/B-TiO2 composites were produced via a facile hydrothermalmethod. Carbon dots (CDs) can not only act as photosensitizers butalso inhibit photogenerated electron and hole recombination of B-TiO2. Under visible light, electrons in the carbon dots flowedto B-TiO2 and further to the counter electrode throughthe external circuit. In the presence of glucose and dissolved oxygen,H2O2 generated through the catalysis of GOxcould consume electrons in B-TiO2, causing a decrease inphotocurrent intensity. Ascorbic acid was added to ensure the stabilityof the CDs during the test. Based on the variation of the photocurrentresponse, the CDs/B-TiO2/GOx biosensor presented a goodsensing performance of glucose in visible light, its detection rangewas from 0 to 9.00 mM, and the detection limit was 0.0430 mM.

Automated summary

In this study, a visible light-driven PEC enzyme biosensor was proposed for the sensitive and rapid detection of glucose. The biosensor utilized CDs/branched TiO2 (B-TiO2) as the photoactive material and glucose oxidase (GOx) as the identification element. The biosensor showed good sensing performance with a detection range of 0 to 9.00 mM and a detection limit of 0.0430 mM for glucose under visible light.