This project focuses on the investigation of conformational dynamics of biomolecules using nanoscale electronic structures where the sensing element is a carbon nanotube or a nanotube network. Such sensors are small and fast (the active area is compatible with individual proteins or DNA) and are extremely sensitive since all the current flows at the surface of the nanotube conducting channel, and thus passes through the detection point. The objective of the research is to use these nanoscale electronic devices as bio-sensors and also explore their potential in real-time detection of conformational changes of biomolecules in a buffer environment. Three areas will be explored. First, duplex formation as well as the melting of the DNA duplex will be examined using oligomers of different lengths and sequences. Second, interactions between proteins will be studied using the biotin-streptavidin, ligand-receptor model system. The feasibility of detecting conformational changes will be explored using bacteriorhodopsin as a model system. Third, direct detection of protein binding to nanotubes, and the subsequent conformational changes, will be monitored in real time using devices where individual nanotubes span the source and drain of the electronic device. Experiments on electronic detection will be conducted hand-in-hand with spectroscopic measurements and with direct imaging of the devices. In the broader sense, electronic detection schemes may offer alternatives of optical detection in diverse areas of biotechnology, including gene chips and protein chips, and also medical diagnostics. The electronic detection schemes to be explored may complement other single molecule detection techniques, including optical methods, ESR and NMR techniques.
