The Research Of Highly Sensitive Biomedical Sensor Based On New Nanomatierials

Nanomaterials have been largely used in many areas in benefit of their unique physicochemical property. As the representative nanomaterial, Graphene has attracted tremendous attention resulted from the outstanding properties like high surface area, superior electric conductivity and good mechanical strength and so on. The process of maintain of intracellular redox homeostasis is affected by the reactive oxygen species (ROS) elimination. When living cells were stimulated by external elements, the intracellular redox homeostasis was destroyed and excreted ROS induced by stress reaction. However, an excess of ROS accumulation in cells gives rise to internal sabotage activity and leads to oxidative stress which was recognized as the root of caducity and diseases, resulting in destroying the balance of organic redox reaction and biological normal cells and tissues and causing a vary of pathological events such as neurodegeneration, alzheimer disease, autoimmune diseases and cancer. Therefore, the selective and accurate measure of H2O2 in cells and the dynamic observation of living cells are important to illuminate the mechanism of regulating signal transduction pathways and further exploit the potential application in clinical pathological diagnosis. Herein, we hypothesized to fabricate a highly sensitive nonenzymatic H2O2 biosensor to detect the H2O2 concentration released from different kinds of cells stimulated by extracellular matters and further to evaluate the oxidative stress of different living cells.The main content in this work have been shown below:We fabricated a new nanomaterial which consist of the reduced graphene oxide (RGO) nanocomposites decorated with Au, Fe3O4 and Pt nanoparticles (RGO/AuFe3O4/Pt), through physical adsorption and electrochemical deposition.Then, on basis of the new RGO/AuFe3O4/Pt nanomaterial, we prepared a sensitive H2O2 biosensor for evaluation of oxidative stress. The surface of as-prepared RGO/AuFe3O4/Pt nanocomposites modified glassy carbon electrode (GCE) was characterized by scanning electron microscopy (SEM), X-ray photoelectron spectrometer (XPS) to reveal their general morphology characterization and electrochemical property. We utilized the novel H2O2 biosensor to detect the H2O2 released from the living cells during the redox homeostasis disrupted by ascorbic acid and further evaluate the intracellular H2O2 concentration. The result of the research show that as-prepared RGO/AuFe3O4/Pt nanocomposites modified GCE obtains much higher current response on the H2O2 reduction process compared with the RGO/AuFe3O4NPs and Pt NPs modified GCE, exhibiting the high sensitivity, the fast response time, large linear range and low detection limit in the measurement of H2O2. There are more released H2O2 from three kinds of tumor than that of normal cell lines, the amount of H2O2 by human cervical cancer cell human hepatoma cell HepG2 was almost triple as much as that of the normal hepatic cells L02. This robust biosensor has shown great potential applications in the determination of H2O2 released from the living cells including cancer cells, which is significance in the development of ultrasensitive nonenzyme biosensors for clinical diagnostics to rapidly assess oxidative stress of different kinds of diseased cells.