Highly sensitive photoelectrochemical aptasensor based on MoS2 quantum dots/TiO2 nanotubes for detection of atrazine

Abstract

Due to the potential hazards of atrazine, developing efficient and accurate detection methods in the environment is urgently needed. In this work, a simple and highly sensitive photoelectrochemical (PEC) aptasensor was constructed for detection of atrazine by exploring TiO2 nanotubes decorated with MoS2 quantum dots (MoS2 QDs/TiO2 NTs) as the photoelectrode and aptamer molecules as the recognition element. MoS2 QDs/TiO2 NTs were prepared with a facile one-step dipped method, and they exhibited high photocurrent response and good visible light absorption. Au nanoparticles (Au NPs) were then electrodeposited on MoS2 QDs/TiO2 NTs to anchor aptamer molecules through Au-S bond and improved the conductivity of the sensing platform. In presence of atrazine, the atrazine-aptamer complexes formed via atrazine-aptamer bonding on the photoelectrode, which increased the steric hindrance of the electron transfer and resulted in the change of the photocurrent density that was used to quantitatively determine atrazine. The designed PEC aptasensor shows outstanding analytical performance in detecting atrazine with high sensitivity and specificity, and a low detection limit of 1.0 pM has been achieved. Also, this PEC aptasensor was utilized to detect atrazine in the environmental water samples, including lake water, agricultural wastewater and sewage water.