A flexible biocompatible graphene sensor for real-time monitoring of PH and protein

This paper presents the preliminary results of graphene biosensors for the measurement of pH and protein concentration. Graphene is a semiconductor, and its conductivity can be modulated by the field effect of surrounding charged biomolecules and applied voltage. We used mechanical exfoliation to produce high-quality graphene, and monitored the change of conductance in the solutions of different pH and different protein concentration (bovine serum albumin, BSA). We observed negatively charge hydroxyl ions and BSA induces electron holes in graphene, making the Dirac point shift to the positive voltage, and changing its conductance.