Construction of visible light-induced renewable electrode for monitoring of living cells

Abstract Ultraviolet (UV) light-induced photocatalysts have been utilized to construct renewable electrode to solve the problem of electrode fouling and passivation. However, considering the damages of UV irradiation to environments and biosystems, it is of great significance to develop and apply visible light-induced photocatalysts for biosensing. But for intrinsic visible light photocatalysts, the high electron-hole recombination rate results in the poor photocatalytic performance. Herein, we design the poly(3,4-ethylenedioxythiophene) (PEDOT)-modified TiO 2 /CdS nanocomposites electrode, which can be efficiently renewed under visible light irradiation for living cell detection. The formation of TiO 2 /CdS heterojunction structure greatly enhances photocatalysis in visible light region by promoting separation of photogenerated electron–hole pairs. Additionally, the absorption in visible light of PEDOT further accelerates the electrode renewal. PEDOT coating provides a sensitive biosensing interface for electrochemical detection, and meanwhile prevents the cytotoxicity of CdS to cells. This allows electrochemical monitoring of nitric oxide release from living cells and subsequent visible light-induced electrode regeneration, demonstrating great potential of this renewable electrodes in biosensing.