Fabrication of glutathione photoelectrochemical biosensor using graphene–CdS nanocomposites

A novel glutathione (GSH) photoelectrochemical biosensor was fabricated using the newly synthesized graphene–CdS (GR–CdS) nanocomposites. The GR–CdS nanocomposites were prepared by a fast, one-step, aqueous reaction. The as-prepared GR–CdS structure inherited the excellent electron transport of GR and facilitated the spatial separation of photo-generated charge carrier, therefore resulting in the enhanced photocurrent, and making it a promising candidate for developing photoelectrochemical biosensors. The proposed GSH sensor displays satisfactory analytical performance with an acceptable linear range from 0.01 to 1.5 mmol L−1 with a detection limit of 0.003 mmol L−1 at a signal-to-noise ratio of 3, and also shows an excellent specificity against anticancer drugs and can be successfully applied for GSH detection in real samples. The as-synthesized GR–CdS nanocomposites exhibited obviously enhanced photovoltaic properties, which could be extended to the detection of other enzymes and biomolecules, thus providing a promising platform for the development of photoelectrochemical biosensors.