MSE Colloquium: Marco Rolandi, University of Washington

Self-assembled polysaccharide nanofibers for biocompatible nanodevices Abstract: Significant advances in materials and nanofabrication afford electronic devices that can interface with living systems. These devices may revolutionize modern medicine with an entire new set of minimally-invasive diagnostics and personalized on-demand therapeutics. To this end, devices that can measure and control ionic and protonic currents are uniquely positioned. In nature, protonic (H+) and ionic (not electronic) currents are used to communicate information. Here, I will present our efforts in fabricating H+ conducting devices using self-assembled polysaccharide nanofibers (chitin, chitosan, and maleic-chitosan). These nanofibers are used to demonstrate a H+- field effect transistor with proton transparent PdHx contacts. In maleic chitosan nanofibers, H+ from the dissociated maleic acid groups move along the hydrated nanofiber hydrogen bond network (Grotthuss mechanism) with μ ≈ 4.9 x 10-3 cm2 V-1 s. The H+ flow is turned on or off by an electrostatic potential applied to a gate electrode. A simple model (and simulations) involving proton semi conductivity in these materials will be presented. To fabricate the bioprotonic transistor, we have developed nanofiber fabrication using replica molding and microcontact printing. Self-assembled nanofibers micro and nanostructures are produced with 2D and 3D features ranging from several microns to less than 35 nm. Efforts in facile manufacturing biophotonics components and biocompatible nanostructures to guide cell growth in tissue engineering will be discussed.

Date: Friday, March 9th 2012

Start Time: 3:00pm

End Time: 4:00pm

Location: 8 St. Mary's Street, Room 205


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