A bio-chemical application of N-GQDs and g-C3N4 QDs sensitized TiO2 nanopillars for the quantitative detection of pcDNA3-HBV

Herein, TiO2 nanopillars (NPs)/N-doped graphene quantum dots (N-GQDs)/g-C3N4 QDs heterojunction efficiently suppressed the photogenerated charges recombination and improved photo-to-current conversion efficiency. The introduced N-GQDs and g-C3N4 QDs could result in more effective separation of the photogenerated charges, and thus produce a further increase of the photocurrent. TiO2 NPs/N-GQDs/g-C3N4 QDs were firstly applied as the photoactive materials for the fabrication of the biosensors, and the primers of pcDNA3-HBV were then adsorbed on the TiO2 NPs/N-GQDs/g-C3N4 QDs modified electrode under the activation of EDC/NHS. With increase of the pcDNA3-HBV concentration, the photocurrent reduced once the double helix between the primers and pcDNA3-HBV formed. The developed photoelectrochemical (PEC) biosensor showed a sensitive response to pcDNA3-HBV in a linear range of 0.01 fmol/L to 20 nmol/L with a detection limit of 0.005 fmol/L under the optimal conditions. The biosensor exhibited high sensitivity, good selectivity, good stability and reproducibility.