Solution-gated graphene field effect transistor for TP53 DNA sensor with coplanar electrode array

This study presents a solution-gated graphene field effect transistor (GFET) for a TP53 DNA sensor using a unique coplanar electrode array integrated with a microfluidic chip. The integrated microfluidic channel controls the exact amount of solution to be delivered. The cancer-related gene, TP53, was applied over the graphene active layers to monitor the sensing performance of the solution-gated GFET. After immobilization of the probe DNA, we hybridized the target DNA with different concentrations (10 μM–1 nM) onto each electrode array. The limit of the detection value obtained herein was 1 nM. To validate the selectivity, when the noncomplementary and one-mismatched DNA molecules were injected into the microchannel, the Dirac point shift values were not significant. The shift of the Dirac point occurs owing to the doping effect caused by the negative charges of the DNA over the graphene surface. When the measurements were reproduced in eight other electrode pairs in the array structure, the transfer curves presented similar Dirac point values, i.e., approximately ±1 mV, indicating the stability of the device. The developed solution-gated GFET sensor provides a reliable measurement of the electrical characteristics and a multiplex detection for cancer diagnostics using a large area of the graphene platform.