Nano-gold plasmon coupled with dual-function quercetin for enhanced photoelectrochemical aptasensor of tetracycline

•A novel and label-free “signal-off” PEC aptasensor for tetracycline were developed.•LSPR of nano-Au and dual-function quercetin for enhanced photocurrent responses.•The PEC aptasensor exhibited excellent performances in detecting tetracycline.•The novel strategy paves a new way for the improvements in PEC sensing. A simple and novel photoelectrochemical (PEC) aptasensor for tetracycline (Tc) was developed using the enhanced photocurrent response strategy by localized surface plasmon resonance (LSPR) of nano-Au and dual-function quercetin. With the photoexcitation of simulated light, the increased photocurrent for nano-Au/TiO2 than that of pure TiO2 nanoparticles is attributed to the hot electrons from excited Au nanoparticles. Also, quercetin was chosen as both photosensitizer and electron sacrificial agent for the enlarged photocurrents and thus the high sensitivity of the PEC aptasensor. The excellent selectivity is assigned to the specific binding of Tc to its aptamer. On the optimized condition, the PEC response was linear with the concentration of Tc in the range from 0.3 to 1600nmolL−1 with a detection limit of 0.1nmolL−1. The same concentration of other conventional organics did not interfere in the detection of Tc and the recovery was between 93.7% and 105.3%. Finally, the PEC aptasensor was successfully for the detection of Tc in liquid milk samples with good performance in wide linear range, low cost, high selectivity and sensitivity. Also, it provided an alternative approach to the detection of Tc.