Two-Dimensional Graphene Optoelectronic Probes for DNA Detection

With high charge-carrier mobility and large surface-area-to-volume ratio, graphene has become one of the most promising materials for biological and biomedical applications. Here, we demonstrate that graphene field-effect transistors combined with scanning photocurrent microscopy are ideal platforms for detecting DNA molecules. When negatively-charged DNA molecules are attached to graphene surface, significant photocurrent signals can be detected due to the local conductivity change in graphene. Our experimental results show that DNA-induced photocurrent response of graphene can be modulated by adjusting the electrochemical potential through an electrolyte gate. This study indicates that two-dimensional graphene optoelectronic probes can be used to explore the local electrostatic environment change with high electrical sensitivity.