Visible light-driven photoelectrochemical enzyme biosensor based on reduced graphene oxide/titania for detection of glucose

Developing a rapid and sensitive photo-electrochemical (PEC) sensing platform for glucose detection is highly desirable. Herein, a visible light-driven PEC enzyme biosensor for sensitive detection of glucose was proposed, employing reduced graphene oxide/titania (TiO2) nanotubes (RGO/TNTs) as photoactive materials and glucose oxidase (GOD) as the identification element. The RGO/TNTs composites were synthesized via a facile hydrothermal process. Notably, the unique nanostructure system significantly increases the absorption in the visible region and effectively separates the photo-generated electron–hole pairs, which is essential for promoting the PEC activity. In the presence of dissolved oxygen, the GOD immobilized on the modified electrode could specifically catalyze the electro-oxidation of glucose to produce H2O2, resulting in an increase of photocurrent intensity. Based on the variation of the photocurrent response, the constructed PEC enzyme biosensor exhibited high sensitivity with a wide linear range from 10–2 to 10 mM and a low detection limit of 5.0 μΜ. Meanwhile, the potential applicability of the PEC enzyme biosensor was evaluated by detecting glucose in human serum samples, and satisfactory results were obtained. The PEC enzyme biosensor based on RGO/TNTs composites successfully realized the sensitive detection of glucose and displayed good selectivity, high stability and satisfactory repeatability.