PMSE 89 |
| We have synthesized robust hybrid bio / inorganic thin films, membranes and monoliths that incorporate biological species such as proteins, enzymes, liposomes, planar lipid bilayers and whole cells. These species are entrapped in a crosslinked gel matrix by vaporization of inorganic (e.g., tetramethoxy silane) and organic (e.g., acrylic acid) precursors. Using this method, thin-film electrodes were modified with a silica film encapsulating the enzyme horseradish peroxidase. Chrono-amperometric measurements clearly indicate the response of the enzymes when substrate was provided. Enzymes such as laccase have also been entrapped for potential application in bio-fuel cells. Proton pumping is observed in entrapped liposomes containing bacteriorhodopsin upon exposure to light. Ultra-thin (10-100 nm) lamellar, hybrid lipid-silica films with incorporation of gramicidin have been also been synthesized. X-ray diffraction, transmission electron microscopy and neutron reflectivity techniques indicate the d-spacing of these films to be around 54 Å. Whole cells have also been entrapped using this process and a high viability of the cells was obtained after the gelation process. Strengths of the process are low temperature synthesis, short times for gelation, independence of pH and ionic strength, and a wide choice of precursors. These materials exhibit excellent mechanical stability, long shelf life, low-toxicity, biocompatibility and efficient molecular transport. These materials have potential for a broad range of applications including biosensors, drug-delivery, bio-fuel cells (enzymatic, whole cell), micro reactors (cells), separations and photonic devices. |
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Hierarchically Ordered Functional Materials
8:30 AM-12:00 PM, Monday, August 20, 2007 Westin Boston Waterfront -- Grand Ballroom E, Oral
Division of Polymeric Materials: Science & Engineering |