Electrochemical aptasensor for ultrasensitive detection of PCB77 using thionine-functionalized MoS2-rGO nanohybrid

The authors describe a PCB77 aptasensor based on the use of thionine (Thi) functionalized MoS2-rGO as a platform for aptamer immobilization. Differential pulse voltammetry and cyclic voltammetry were used to monitor the electrochemical properties of proposed aptasensor and investigated the importance of MoS2-rGO/Thi as an aptasensing platform in the measurement of PCB77, a type of polychlorinated biphenyl, as a model molecule. The electrochemical response is based on a decrease of DPV response of Thi before and after the interaction of aptamer with the target (PCB77). Based on the calibration curve, the very low detection limit of 80 ag mL−1 and a very wide linear range of 0.3 fg mL−1–0.1 ng mL−1 were obtained, which is the widest linear range and lowest detection limit among the previous methods reported in the literature. The reproducibility of this aptasensor was 4.2%. Moreover, the effective determination of the PCB 77 by our MoS2-rGO/Thi-based sensor in the complex environmental water and soil samples was realized, which displays a good application possibility.