3D Graphene Based Electrochemical Biosensors

With the development of biological sensing technology, the study of non-enzymatic electrochemical biosensor becomes one of hot fields of electrochemical sensors. Due to high conductivity, good biocompatibility and free-standing structure, three-dimensional graphene foam(3DGF) is selected as electrode material to design non-enzymatic electrochemical biosensors for detecting glucose and hydrogen peroxide with high sensitivity, respectively. The main content can be divided into two parts:(1) The Ni(OH)2/3DGF composite was fabricated through in situ hydrothermal method. After characterization of the morphology and structure of the composite, the nonenzymatic electrochemical glucose biosensor was prepared with the composite. The results exhibited a good linear response for glucose from 1 μM to 1.17 mM with correlation coefficient of 0.999, detection sensitivity of 2.652 mA mM-1 cm-2 and lowest detection limit of 0.34 μM based on a signal-to-noise ratio of 3(S/N=3). Moreover, the sensor performed superior selectivity for detection of glucose.(2) The NiCo2O4/3DGF composite was fabricated through in situ hydrothermal method. The electrochemical glucose biosensor was prepared with the composite. The results exhibited a good linear response for glucose from 500 nM to 1.489 mM with correlation coefficient of 0.997, detection sensitivity of 2.129 mA mM-1 cm-2 and lowest detection limit of 0.42 μM based on a signal-to-noise ratio of 3(S/N=3). Moreover, the sensor performed superior selectivity for detection of glucose.(3) Sliver nanoparticles were composed on the 3DGF surface to prepare a new nonenzymatic H2O2 electrochemical biosensor. Employed the above biosensor, the current response is estimated to be linear with the H2O2 concentration in the range from 30 μM to 16.21 mM followed by correlation coefficient of 0.999. The detection sensitivity was calculated as 1.094 mA mM-1 cm-2, and the detected limitation was estimated to be 14.9 μM(S/N=3). Furthermore, the experiment results implied that the sensor exhibited excellent selectivity for H2O2.