Designing a simple and sensitive photoelectrochemical (PEC) sensor is crucial to addressing the limitations of routine analytical methods. The sensitivity of the PEC sensor, however, relies on the photoelectric material used. In this manuscript, composites of MoS2/rGO (MG) with a large area and layered structure are prepared by simple steps. This material exhibits sensitivity to visible light and demonstrates outstanding photoelectric conversion performance. The constructed PEC aptasensor using this material to detect aflatoxin B1 (AFB1) shows significantly higher sensitivity and stability compared to similar sensors. This may be attributed to the presence of surface defects in MoS2, which provide more active sites for photocatalysis. Additionally, graphene oxide (GO) is reduced to rGO by thiourea and forms a heterojunction with MoS2, enhancing charge carrier separation and interfacial electron transfer. Our research has revealed that the photocurrent intensity of the aptamer electrode decreases with an increase in AFB1 concentration, resulting in a “signal-off” PEC aptasensor. The detection limit of this aptasensor is 2.18 pg mL−1, with a linear range of 0.001 to 100 ng mL−1. This result will also provide a reference for the study of other mycotoxins in food.
The development of electrochemical dopamine (DA) sensor with anti-interfering ascorbic acid and uric acid is challenging due to the presence of their overlapping electrical signals. Herein, MoS 2 nanoflower assembled from ultrathin nanosheets were uniformly loaded on rGO substrate through one-step hydrothermal reaction. Then, the composite (MoS 2 /rGO) was modified on the surface of glassy carbon electrode (GCE) by a drop coating method, successfully assembling non-enzymatic electrochemical sensor for ultra-selective DA detection. The test results show that the MoS 2 /rGO/GCE probe exhibits good sensitivity (15.73 μA μM −1 cm −2 ), small limit of detection (13 nM) and wide range of detection (0.1 ∼ 110.0 μM) for DA in 0.1 M PBS medium (pH = 7.4), as well as good interference resistance, reproducibility and stability. This excellent sensing ability mainly stems from the synergistic effect of the prepared electrode material with abundant edge defects, small charge transfer resistance, large electrochemically active area, and more negative Zeta potential (–23.4 mV). Furthermore, the satisfactory and accurate detection of DA content in animal serums predicts its potential for practical applications in related biological aspects.
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