TiO2–graphene complex nanopaper for paper-based label-free photoelectrochemical immunoassay

Abstract

A novel strategy was reported for the preparation of TiO2 nanobelts by the acid-assisted hydrothermal method. Complex nanopaper based on the TiO2 nanobelts and graphene was fabricated via a modified paper-making process. The as-prepared TiO2–graphene structure inherited the excellent electron transport of graphene 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 (PEC) biosensors. Thus, an advanced PEC biosensing platform for the detection of carcinoembryonic antigen was proposed at relatively low applied potential on screen-printed working paper-electrode using the as-prepared TiO2–graphene complex nanopaper. The complex nanopaper with good biocompatibility showed high PEC intensity and satisfactory stability, all of which held great promise for the fabrication of PEC biosensors with improved sensitivity. Furthermore, the TiO2–graphene complex nanopaper based PEC biosensor in this study was anticipated to provide the chance for the design of high-performance PEC biosensors for the detection of other enzymes and biomolecules.