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Physics and Astronomy

Physics & Astronomy Colloquium

3:30 PM, Friday, September 24, 2010
Room 155, Chem-Phys Building

Dr. A. T. Charlie Johnson
Department of Physics and Astronomy
University of Pennsylvania

Adventures in Nanoscience: Biomimetic Chemical Sensors and DNA Translocation through Graphene Nanopores
Advances in synthesis and understanding of nanomaterials and the potent molecular machines of living organisms offer pathways to explore new frontiers at the interface of condensed matter physics and biophysics. We have recently focused on combinations of carbon nanomaterials, i.e., nanotubes (NT) and graphene, with single-stranded DNA or proteins. All-electronic vapor sensors can be made, where the biomolecule provides chemical recognition, and a nanotube or graphene transistor is used for electronic readout. The properties of these devices make them intriguing candidates for use in an "electronic nose" system whose architecture is inspired by that of the mammalian olfactory system. In a separate set of experiments we created a nanoelectronic interface to olfactory receptor proteins (ORs) that were embedded in synthetic nanoscale cell membrane analogues. The resulting devices transduce signals associated with odorant binding to ORs under ambient conditions and show responses that are in excellent agreement with results from established assays for OR-ligand binding. Finally, we report on DNA translocations through nanopores created in graphene membranes, an approach that may find application in DNA sequencing. Due to the thin nature of the graphene membranes, we observe larger blocked currents than for traditional solid-state nanopores. Use of graphene as a membrane material opens the door to a new class of nanopore devices in which electronic sensing and control are performed directly at the pore.

Refreshments will be served in CP 179 at 3:15 PM