Development of High Performance Electrochemical and Physical Biosensors Based on Chemically Modified Graphene Nanostructured Electrodes
A solvothermal technique with extra treatment was performed to synthesize high quality chemically modified graphene (CG). An environmentally friendly reducing agent, glucose, was used to obtain biocompatible chemically modified graphene. After acidic treatment of glucose treated chemically modified graphene (GCG), contamination free CG sheet was produced. CG suspension was cast on the surface of the plain biosensor surface and nylon filter paper. Pt nanoparticles (PtNP) were deposited on the CG decorated surface by cyclic voltammogram technique. Chitosan - glucose oxidase (chit-GOx) composite and nafion were then integrated by dropped casting technique on the CG/PtNP modified surface. This as-prepared biosensor showed high electrochemical activity for the detection of glucose in phosphate buffered saline (PBS) solution. It exhibited excellent analytical properties including a short response time (4 s), high sensitivity (69.44 μA/mMcm−2), and wide detection range (0.002–12 mM) for glucose sensing. The repeatability, reproducibility, interference phenomena and the stability of the developed sensors were also investigated. The CG based electrode was also evaluated for use as a dry electrode for ECG signal monitoring. The performance of the dry electrode was excellent in comparison to the conventional wet electrodes.