This dissertation focuses on the applications of solid supported phospholipid
membranes as mimics of the cellular membrane using lab-on-a-chip devices in order to
study biochemical events such as ligand-receptor binding and the chemical mechanism
for the preservation of the biomembrane. Supported lipid bilayers (SLBs) mimic the
native membrane by presenting the important property of two-dimensional lateral
fluidity of the individual lipid molecules within the membrane. This is the same
property that allows for the reorganization of native membrane components and
facilitates multivalent ligand-receptor interactions akin to immune response, cell
signaling, pathogen attack and other biochemical processes.
The study is divided into two main facets. The first deals with developing a
novel lipopolymer supported membrane biochip consisting of Poly(ethylene glycol)
(PEG)-lipopolymer incorporated membranes. The formation and characterization of the
lipopolymer membranes was investigated in terms of the polymer size, concentration
and molecular conformation. The lateral diffusion of the PEG-bilayers was similar to
the control bilayers. The air-stability conferred to SLBs was determined to be more effective when the PEG polymer was at, or above, the onset of the mushroom-to-brush
transition. The system is able to function even after dehydration for 24 hours. Ligandreceptor
binding was analyzed as a function of PEG density. The PEG-lipopolymer acts
as a size exclusion barrier for protein analytes in which the binding of streptavidin was
unaffected whereas the binding of the much larger IgG and IgM were either partially or
completely inhibited in the presence of PEG.
The second area of this study presents a molecular mechanism for in vivo
biopreservation by employing solid supported membranes as a model system. The
molecular mechanism of how a variety of organisms are preserved during stresses such
as anhydrobiosis or cryogenic conditions was investigated. We investigated the
interaction of two disaccharides, trehalose and maltose with the SLBs. Trehalose was
found to be the most effective in preserving the membrane, whereas maltose exhibited
limited protection. Trehalose lowers the lipid phase transition temperature and
spectroscopic evidence shows the intercalation of trehalose within the membrane
provides the chemical and morphological stability under a stress environment.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/5923 |
| Date | 17 September 2007 |
| Creators | Albertorio, Fernando |
| Contributors | Cremer, Paul S. |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | 4064450 bytes, electronic, application/pdf, born digital |
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