Figure 3

(a) Optical micrograph of a typical GraFET device before measurement; (b) SEM micrograph of device with the surface of graphene connected with gold electrode; (c) AFM image of bare graphene without antibody binding; (d) Resistance vs gate voltage plot of a prototypical GraFET device with an inset image of the device; (e) Resistance vs time graph monitored over a span of 4 weeks showed negligible change in the current response.