Signal amplified photoelectrochemical sensing platform with g-C3N4/inverse opal photonic crystal WO3 heterojunction electrode.

Abstract A novel photoelectrochemical (PEC) aptasensor based on the g-C 3 N 4 nanosheets modified WO 3 film with inverse opal photonic crystals (IOPCs) structure was developed. Oxytetracycline (OTC) aptamer was immobilized on the surface of composites through π-π interaction between g-C 3 N 4 and DNA nucleotide. Benefiting from the great optical absorption ability and photo-generated charge separation capacity, the g-C 3 N 4 /WO 3 IOPCs aptasensor exhibited excellent PEC response performance in an electrolyte containing 0.1 M ascorbic Acid (AA). After the recognition and capture of OTC, the configuration change of OTC-aptamer restrained the oxidation of AA by the photogenerated hole on the valance band of g-C 3 N 4 , resulting in photocurrent change. The results showed that the PEC aptasensor possessed a linear detection range from 1 nM to 230 nM and a detection limit of 0.12 nM (≈59.58 ng L−1) for the detection of OTC in water. The satisfactory detection results in real sample further revealed the potential of WO 3 IOPCs and its heterostructure for PEC analytical applications, and provided a novel approach for design of PEC platform. Graphical abstract Unlabelled Image Highlights • The g-C 3 N 4 /WO 3 inverse opal photonic crystals (IOPCs) were designed as photoelectrochemical (PEC) sensing platform. • The g-C 3 N 4 /WO 3 IOPCs possessed great optical absorption and fast charge separation. • The g-C 3 N 4 /WO 3 IOPCs PEC aptasensors were used to detect the OTC concentration in water. • It exhibited good reproducibility, high selectivity and excellent sensitivity. [ABSTRACT FROM AUTHOR]