Detection of Exosomes Using Liquid-Gated Graphene Field Effect Transistor Biosensors

In this paper, liquid-gated graphene field effect transistor (LG-GFET) biosensors are demonstrated for exosomes sensing. Since the exosome is negative charged and thus served as n-type doping effect to graphene, the conductivity of the LG-GFET will varied loading with different exosome concentration. Therefore, exosomes concentration can be distinguished by detecting drain-source current (Ids) variation of LG-GFETs. The experimental results show that, compared to the blank group without exosomes, the change of Dirac-point gate voltage (VCNP) by using static method and saturation Ids by using dynamic method is larger than 80% and 18.8%, receptively. Moreover, the change rates of VCNP and saturation Ids versus exosomes concentrations are also investigated, which shows more than 7% and 12.5%, respectively. It is worthy to find out that it is only 30 seconds for LG-GFET biosensors to detect exosomes concentrations using dynamic method. These results indicate that LG-GFET biosensors can achieve rapid and sensitive detection of exosomes and provide an effective tool for clinical application and medical diagnostics.