Inkjet-Printed Flexible Biosensor Based on Graphene Field Effect Transistor

In this paper, we present a graphene field effect transistor (FET) fabricated on a flexible Kapton substrate using 3-D inkjet printing for use as a biosensor to detect infectious organisms. Inkjet printing process of graphene film is described with sheet resistance as low as 110 Omega/sq. To suppress background noises, the biosensors are based on intensity changes of the ac signal as a function of the biological agents' concentration. Using the foodborne pathogen, Norovirus, as a proof-of-concept disease target, the value of S12 (i.e., the voltage gain from source to drain) at 10 GHz generates a linear response from 0.07 to 3.70 dB when the concentration of Norovirus protein increases from 0.1 to 100 mu g/ml. While further studies are needed to improve surface functionalization and sensitivity, the current study establishes a linear response over three orders of magnitude indicating that the flexible graphene FET sensor has a wide dynamic range for detection of biological targets that could ultimately be applied for detection of a variety of disease-causing pathogens.