Electrochemical Impedance Characterization of Cell Growth on Reduced Graphene Oxide-Gold Nanoparticles Electrodeposited on Indium Tin Oxide Electrodes

The improved binding ability of graphene-nanoparticle composites to proteins or molecules can be utilized to develop new cell-based assays. In this study, we fabricated reduced graphene oxide-gold nanoparticles (rGO-AuNP) electrodeposited onto a transparent indium tin oxide (ITO) electrode and investigated the feasibility of the electrochemical impedance monitoring of cell growth. The electrodeposition of rGO-AuNP on the ITO was optically and electrochemically characterized in comparison to bare, rGO-, and AuNP-deposited electrodes. The cell growth on the rGO-AuNP/ITO electrode was analyzed via electrochemical impedance measurement together with the microscopic observation of HEK293 cells transfected with a green fluorescent protein expression vector. The results showed that rGO-AuNP was biocompatible and induced an increase in cell adherence to the electrode when compared to the bare, AuNP-, or rGO-deposited ITO electrode. At 54 h cultivation, the average and standard deviation of the saturated normalized impedance magnitude of the rGO-AuNP/ITO electrode was 3.44 +/- 0.16, while the value of the bare, AuNP-, and rGO-deposited ITO electrode was 2.48 +/- 0.15, 2.61 +/- 0.18, and 3.01 +/- 0.25, respectively. The higher saturated value of the cell impedance indicates that the impedimetric cell-based assay has a broader measurement range. Thus, the rGO-AuNP/ITO electrode can be utilized for label-free and real-time impedimetric cell-based assays with wider dynamic range.