Bioinspired Materials and Devices with Naturally Derived Polysaccharides

ChEMS Seminar

Dr. Marco Rolandi

Assistant Professor

Department of Materials Science and Engineering

University of Washington, Seattle

The ability to precisely assemble biological and bioinspired molecules into organized structures has contributed to significant advances in bionanotechnology. These advances include materials, structures, and devices that interface with biological systems. Here, I will present three such examples with chitin nanofibers and derivatives. The first example is chitin nanofiber ink — a solution of squid pen β-chitin that self-assembles into ultrafine α-chitin nanofibers upon drying. Addition of silk fibroin to chitin nanofiber ink yields a self-assembled biocomposite of chitin nanofibers embedded in a silk fibroin matrix. This biocomposite mimics the nanostructure of the insect cuticle and has good mechanical and optical properties.  The second example is chitin nanofiber ink fabrication — chitin nanofiber micro- and nanostructures made with airbrushing, replica molding, and microcontact printing. Applications include micropatterned substrates for tissue engineering and microneedles for tuberculosis testing. The third example is bioprotonics — complementary field effect transistors with proton-conducting chitin derivatives containing acid and base functional groups. In these transistors, protons hop along the hydrogen bond network formed by the chitin derivatives and absorbed water (Grotthuss mechanism). Acids are H^{+ ­­} donors and bases are H⁺ acceptors for H⁺-type and OH^- (proton hole)-type conducting devices, analogous to n-type and p-type electronic semiconductors. In nature, protonic and ionic (not electronic) currents communicate information across cell membranes. As such, these biocompatible protonic devices are a versatile biotic-abiotic interface for bionanoelectronics.

Bio:

Marco Rolandi, Ph.D., is an Assistant Professor of Materials Science and Engineering at the University of Washington (2008) and the scientific founder of KitoTech Medical (2012). He received his Ph.D. in Applied Physics from Stanford University in 2005 and completed his postdoctoral training at the University of California, Berkeley in 2008. His research focuses on micro- and nano- biological and bionspired structures, their integration in biocompatible devices, and their translational applications. His work on bioprotonic transistors was highlighted in The New York Times, New Scientist, MRS 360, IEEE Spectrum, Materials Views, Engadget, Popular Science, and several other sites.