Photoelectrochemical Biosensing Approach for Alcohol Determination by "Wiring" of Alcohol Oxidase Photonically with P(SNS-NH2)/AOx/CNT/[Ru(bpy)(3)](2+) Modified Electrodes

A photoelectrochemical alcohol biosensor was designed through photonic wiring of alcohol oxidase (AOx) onto conducting polymer of 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)benzenamine (SNS-NH2) and carbon nanotubes (CNTs) modified gold slides. The photoelectrochemical biosensors utilize a photonically wired electrode that oxidizes primary alcohols to aldehydes. Three different alcohols namely methanol, ethanol, and n-propanol were used as the substrates. In the presence of different concentrations of primary alcohol, the photocurrents were obtained by irradiating of the photoelectrochemical cell containing P(SNS-NH2)/AOx/CNT/[Ru(bpy)(3)](2+) electrode as the anode under air. The bipyridine complex [Ru(bpy)(3)](2+) was used to activate photoinduced electron-transfer reaction and it acted as a redox mediator to activate the bioelectrocatalytic functions of AOx. Therefore, it was shown the photonic electron-transfer wiring of AOx with the electrode. Sensitivity experiments, optimum pH value, operational stabilization and shelf life of the photoelectrochemical biosensor were investigated. Finally, the photoelectrochemical biosensors were used for alcohol detection in real samples.