Ultrasensitive and Selective Bacteria Sensors Based on Functionalized Graphene Transistors

We propose here a graphene biosensor based on the field-effect transistor (FET) architecture for continuous and real-time monitoring of bacteria, with beneficial features including facile operation, low-cost, selectivity, and high sensitivity. Our sensing device consists of the chemical-vapor-deposition (CVD) graphene monolayer, functionalized by the phage tail spike proteins (TSPs) that form specific binding sites to capture E. coli bacteria. We have investigated effects of surface functionalization and bacteria binding on the conductance of atomically thin graphene that determines transfer characteristics of a graphene FET (GFET). We have experimentally demonstrated that the concentration of E. coli bacteria can be selectively and accurately detected (at the single bacterium level) by a TSP-functionalized GFET. The proposed graphene biosensor may be of great interest for rapid, efficient detection of bacterial pathogens that could potentially pose a severe threat to human, animal, or plant health.