Biosensing by programmable proteins on graphene field effect transistor

Biosensing devices based on nanostructures and graphene facilitate label-free detection with sensitivities beyond traditional methods. Specific biorecognition relies on selective immobilization of analytes on the close vicinity of the sensor surface. We demonstrate single-step functionalization of graphene biosensors by using surface-active hydrophobin proteins that have been biologically fused with a receptor moiety. The fusion proteins self-align to form a dense and specifically oriented receptor monolayer and can be easily detached from the surface for sensor re-programming. Detection sensitivities in high ionic strength buffer are in femtomolar range both for small charged peptide analytes and for large immunoglobulin antibodies.