Electronic detection of specific protein binding using nanotube FET devices

We have used nanoscale field effect transistor devices with carbon nanotubes as the conducting channel to detect protein binding. A PEI/PEG polymer coating layer has been employed to avoid nonspecific binding, with attachment of biotin to the layer for specific molecular recognition. Biotin-streptavidin binding has been detected by changes in the device characteristic. Nonspecific binding was observed in devices without the polymer coating, while no binding was found for polymer-coated but not biotinylated devices. Streptavidin, in which the biotin-binding sites were blocked by reaction with excess biotin, produced essentially no change in device characteristic of the biotinylated polymer-coated devices.