Enhanced photoelectrochemical cytosensing of fibroblast-like synoviocyte cells based on visible light-activated ox-GQDs and carboxylated g-C3N4 sensitized TiO2 nanorods

Abstract

Herein, we demonstrated the protocol of a visible light induced photoelectrochemical cytoassay on the basis of TiO₂ nanorods/carboxylated g-C₃N₄/ox-graphene quantum dots coupling with a biospecific interaction for the ultrasensitive detection of fibroblast-like synoviocyte cells. The nanohybridization assembly of TiO₂ NRs, carboxylated g-C₃N₄ and ox-GQDs showed good PEC performance through the excellent electrical conductivity as well as the high photon-to-electron conversion efficiency and improved the sensitivity of the cytosensor. To perform the cytoassay, CD95 antibody, a marker of FLS cells, was conjugated onto the TiO₂ NR/carboxylated g-C₃N₄/ox-GQD modified electrode to trap the cell target by using EDC/NHS coupling reactions. The concentrations of FLS cells were determined by the decrease in photocurrent intensity resulting from the increase in steric hindrance from FLS cells. This strategy opens a simple perspective for the application of carboxylated g-C₃N₄ and ox-GQDs as light-harvesting architectures.