Fabrication of N-GQDs and AgBiS2 dual-sensitized ZIFs-derived hollow ZnxCo3-xO4 dodecahedron for sensitive photoelectrochemical aptasensing of ampicillin

A sensitive photoelectrochemical (PEC) aptasensing platform based on Nitrogen-doped graphene quantum dots (N-GQDs) and AgBiS2 dual-sensitized Zn/Co bimetallic oxide (ZnxCo3-xO4) dodecahedron as a matrix was constructed for the ultrasensitive detection of ampicillin (AMP). Concretely, the ZnxCo3-xO4 dodecahedron derived from ZnCo-ZIFs retained the unique hollow porous structure, which provided large specific surface and efficacious active sites, and thereby significantly enhancing the light utilization and shortening the photoelectrons transmission path. Both N-GQDs with the up-conversion effect and eco-friendly AgBiS2 with optimal band gap for solar absorption were utilized to dual-sensitize ZnxCo3-xO4 dodecahedron to further strengthen the PEC performance. Subsequently, the aptamer recognition technology was integrated with the modified photoelectrode, adopting AMP-aptamer to catch the target AMP, accompanied the hole oxidation of bind AMP causing the remarkable increase of photocurrent signal, the AMP could be specific and sensitive detect. Under optimized conditions, the photocurrent of developed aptasensor increased linearly displayed large liner response of 0.5 pmol/L - 10 nmol/L with a detection limit of 0.25 pmol/L (S/N = 3). Besides, the novel PEC AMP-sensoring exhibited excellent reproducibility, perfect stability and selectivity, which could open a potential avenue for antibiotic residues detection in environmental media.