Preparation Of Graphene - Based Composites And Its Application In Electrochemical Biosensor

As the thinnest two-dimensional crystal, Graphene has been widely used in many fields,which owns a unique nano structure, large specific surface area, excellent photoelectric properties. Graphene nanocomposites have good biocompatibility and large specific surface area. Graphene nanocomposites as the basal modified electrodes material can keep the biological activity and improve load ability. The synergy of graphene nanocomposites can increase oxidation reduction rate and improve the detection sensitivity. In recent years, the research of biological sensors based on graphene nanocomposites has become an important field in electrochemical analysis.Conductive carbon black-graphene（CCB-GR） 3D carbon nanomaterial was fabricated by ultrasonic blending methods. CCB-GR 3D carbon nanomaterial modified glassy carbon electrode（CCB-GR/GCE） has been fabricated and was used for the determination of rutin.The CCB-GR/GCE showed excellent sensitivity with good stability toward the determination of rutin.Molybdenum disulfide/Graphene（MoS₂/Gr） composite was fabricated by chemical reduction method. Horseradish peroxidase/Molybdenum disulfide/Graphene（HRP/MoS₂/Gr） was also febricated. Based on aptamer recognition technology,aptasensor on HRP/MoS₂/Gr composites was fabricated and applied to the detection ofγ-interferon. MoS₂/Gr composites was negatively charged; HRP composites solution was positively charged; the two oppositely species should band together via electrostatic attraction to form HRP/MoS₂/Gr composites. γ-interferon aptamer combined on the HRP/MoS₂/Gr/GCE electrode surface formed γ-interferon aptasensor by electrostatic attraction and Ï€-Ï€ intermolecular force. In the solution, γ-interferon combined withγ-interferon aptamer, which made γ-interferon left from the surface of the electrode. Then the HRP on the aptasensor could produce electrochemical signal in MB-H2O2 system. Theγ-interferon aptasensor showed excellent sensitivity with good stability toward the determination of γ-interferon.Molybdenum disulfide/Graphene（MoS₂/Gr） composite was fabricated by chemical reduction method. Gold nanoparticles/MoS₂/Gr（Au NPs/MoS₂/Gr） composites-based aptasensor was fabricated via Au-S. Based on aptamer recognition by “signal-on” mode,aptasensor on Au NPs/MoS₂/Gr composites was fabricated and applied to the detection of lysozyme. The aptasensor presented excellent electrochemical performance.