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Characterization of Optically Active Biopolymers

Fiester, Steven E.
http://rave.ohiolink.edu/etdc/view?acc_num=kent1302187683

Abstract Details

2011, PHD, Kent State University, College of Arts and Sciences / Department of Biological Sciences.
All systems have a universal tendency toward disorder. Biological systems must therefore invest energy in order to maintain homeostasis. Salmonella flagella and g8p, the coat protein of fd bacteriophage, are two systems that use self-assembly to maintain order while minimizing this energy expenditure. Salmonella flagella are created through the self-assembly of flagellin protein monomers to form a filament. These flagellar filaments self-organize into bundles in order to form a rigid “propeller” for locomotion. The amino acid monomers of g8p form proteins that self-assemble through hydrophobic interactions around viral DNA (to protect the DNA from degradation). Both flagella filaments and g8p self-assemble with individual filaments aligning along a common direction, thus exhibiting liquid crystalline phases. Cross-polarized microscopy was used to characterize the liquid crystal textures in concentrated systems of flagella and g8p. Helical flagella possessed chiral nematic textures indicative of an arrangement of filaments approaching parallel alignment. Straight flagella possessed a nematic texture indicating a parallel alignment of filaments. Filaments with a smectic texture were observed in concentrated suspensions of g8p suggesting a layered organization of g8p. Atomic force microscopy and scanning electron microscopy supported these data, and suggested that g8p proteins further assemble into films such that the films wrap about a central axis to form filaments of concentric layers. As a possible application of liquid crystal biopolymers in vitro, the liquid crystalline phases of chitin, flagella and fd bacteriophage were investigated as potential sensors to detect bacteria. Sensor development exploited well documented changes of liquid crystal textures resulting from contaminating materials that exceed a critical size, thus appearing as defects in the respective liquid crystal textures. Salmonella cells and streptavidin-coated beads (as bacterial surrogates) were detectable at an initial concentration of 106 cells or beads/mL in chitin. Beads were not detectable to 106 beads/mL in liquid crystal phases of flagella or fd bacteriophage, likely due to the inherent flexibility of flagella and fd bacteriophage. This dissertation characterizes several biopolymers with different liquid crystal arrangements, characterizes their potential as sensors and offers numerous alternatives to traditional synthetic liquid crystals.
Christopher Woolverton, PhD (Committee Chair)
Douglas Kline, PhD (Committee Member)
Donald Gerbig, PhD (Committee Member)
Antal Jakli, PhD (Committee Member)
Scott Bunge, PhD (Committee Member)
Biology; Biophysics; Materials Science
liquid crystal; biopolymer; mesophase; bacteria detection; bent-core

Recommended Citations

Citations

  • Fiester, S. E. (2011). Characterization of Optically Active Biopolymers [Doctoral dissertation, Kent State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=kent1302187683

    APA Style (7th edition)

  • Fiester, Steven. Characterization of Optically Active Biopolymers. 2011. Kent State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=kent1302187683.

    MLA Style (8th edition)

  • Fiester, Steven. "Characterization of Optically Active Biopolymers." Doctoral dissertation, Kent State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=kent1302187683

    Chicago Manual of Style (17th edition)

kent1302187683
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© 2011, all rights reserved.
This open access ETD is published by Kent State University and OhioLINK.