A photoelectrochemical aptasensor of ciprofloxacin based on Bi24O31Cl10/BiOCl heterojunction

A photoelectrochemical (PEC) aptasensor was designed and constructed by Bi 24 O 31 Cl 10 /BiOCl heterojunction as a photoelectric active material for realizing the determination of trace ciprofloxacin (CIP) in water. Compared with Bi 24 O 31 Cl 10 , Bi 24 O 31 Cl 10 /BiOCl heterojunction possessed the improvement of light harvesting and the enhancement of photocurrent signal. The formation of heterojunction between Bi 24 O 31 Cl 10 and BiOCl can accelerate the transportation efficiency and inhibit the recombination rate of photoinduced carriers. Based on the excellent PEC performance, CIP aptamer was introduced on the modified Bi 24 O 31 Cl 10 /BiOCl/indium tin oxide (ITO) electrode for fabricating a PEC aptasensor. Owing to the combination between aptamer and CIP, CIP-aptamer complex can block the transfer of charge, leading to the reduction of photocurrent response. The PEC aptasensor possessed high sensitivity with a wide detection range (5.0~1.0 × 10 4 ng L −1 ) and a low detection limit (1.67 ng L −1 , S/ N = 3). The PEC aptasensor with good selectivity and reproducibility has been applied to the determination of CIP in water. Graphical abstract