Construction of a Au@MoS 2 composite nanosheet biosensor for the ultrasensitive detection of a neurotransmitter and understanding of its mechanism based on DFT calculations.

MoS 2 nanosheets can be applied as electrochemical biosensors to selectively and sensitively respond to the surrounding environment and detect various biomolecules due to their large specific surface area and unique physicochemical properties. In this paper, single-layer or few-layer MoS 2 nanosheets were prepared by an improved liquid phase stripping method, and then combining the unique material characteristics of MoS 2 and the metallic property of Au nanoparticles (AuNPs), Au@MoS 2 composite nanosheets were synthesized based on MoS 2 nanosheets. Then, the structure and properties of MoS 2 nanosheets and Au@MoS 2 composite nanosheets were comprehensively characterized. The results proved that AuNPs were successfully loaded on MoS 2 nanosheets. At the same time, on the basis of the successful preparation of Au@MoS 2 composite nanosheets, an electrochemical biosensor targeting dopamine was successfully constructed by cyclic voltammetry. The linear detection range was 0.5-350 μM, and the detection limit was 0.2 μM. The high-sensitive electrochemical detection of dopamine has been achieved, which provides a new idea for the application of MoS 2 -based nanomaterials in the biosensing of neurotransmitters. In addition, density functional theory (DFT) was used to explore the electrochemical performance of Au@MoS 2 composite nanosheets. The results show that the adsorption of Au atoms on the MoS 2 2D structure improves the conductivity of MoS 2 nanosheets, which theoretically supports the possibilities of its application as a platform for the ultrasensitive detection of neurotransmitters or other biomolecules in the field of disease diagnosis.