Graphene, with its unique electrical properties and biocompatibility, has become a material of choice for the development of biosensor platforms. In this study, a microelectrode array based on reduced graphene oxide (rGO) was constructed and used as a platform for electrical monitoring of cell–substrate adhesion. The rGO-based sensor arrays were designed in order to facilitate sensor pads comparable to the size of individual cells. The sensor chips were fabricated in a scalable manner via site-specific immobilization of graphene oxide flakes onto microelectrode pairs followed by reduction to rGO. The sensor chips were mounted on a measurement platform equipped with a fluidic cell. Electrical characteristics were recorded and field-effect behavior was confirmed. Sensors reacted to changes of pH value in the solution. Finally, as a proof-of-concept, the graphene oxide-based sensing platform was used for electrical cell–substrate impedance sensing of individual HEK293 cells in culture.
Schematic view of the rGO-based sensor chip for electrical cell–substrate adhesion assays.