The Synthesis Of Graphene Hybrid Nanosheets And Its Analytical Application

Chapter1:In this chapter, we introduced the properties and synthesis of graphene and the way of graphene functionalization, the constitute and development of biosensor and electrochemical glucose biosensor based on graphene nanosheets, the principle of interaction between aptamer and target molecular and the characterization and classification of aptasensor.Chapter2:In this chapter, we demonstrated a new class of high-quality graphene-based nanocomposites:metal coordination polymer-graphene nanosheets (MCPGNs). The as-obtained nanocomposite was characterized by TEM, SEM, AFM etc. Furthermore, the asprepared MCPGNs exhibit better conductivity and electrocatalytic activity for H2O2reduction than graphene. The direct electrochemical behavior prove the MCPGHs/GOD exhibit biological activity. Based on these excellent properties, a sensitive electrochemical biosensing platform for glucose was fabricated. This novel biosensor displays a linear response range between50nM and1mM with a detection limit of5nM and good selectivity. The recovery of glucose in1%real human serum was97%～104%. Our work not only provides a facile, effective and general route for the synthesis of a variety of MCP-graphene nanohybrids, but also sets an example for fabricating an electrochemical biosensor with this new kind of nanohybrid as an enhanced material and can be easily extended to other biosensors.Chapter3:This chapter presents a facile approach for the preparation of Orange Ⅱ functionalized graphene nanosheets (O-GNs). O-GNs is chracterized by Uv-Vis spectra, TEM and AFM. The successful attachment of Orange Ⅱ on the surface of graphene nanosheets not only prevents the agglomerates of the as-formed graphene nanocomposite in aqueous media, but also endows graphene nanosheets with excellent electroactive property. Integrating the unique properties of the as-prepared O-GNs (high conductivity, high specific surface area and electroactive function) with high affinity and specificity of aptamer, a new label-free electochemical biosensing concept is demonstrated for the "signal-on" detection of targets such as thrombin and lysozyme. The present O-GNs-based aptasensor exhibits good current response to the above proteins. The linear ranges for thrombin and lysozyme are1.0×10-12-4.0×l0-10M and5.0R10-12-7.0×10-10M, with the detection limit of3.5×10-13M and1.0×10-12M, respectively and shows good selectivity against common proteins. The recovery of thrombin in1%real human serum was95.8%～103%. In contrast to the common laborious and expensive labeling approaches, the present O-GNs based aptasensing process is highly simple, cost-efficient and does not need label and modification of aptamers or introduce additional electrochemical probes.