<p> The goal of this research project was the development of a protocol for preparation of optically clear organic/inorganic hybrid materials that was amenable to entrapment of lipophilic biomolecules. The protocol involved the acid-catalyzed hydrolysis of mixtures of tetraethylorthosilicate (TEOS) with organosilane precursors, including methyltriethoxysilane (MTES), dimethyldimethoxysilane (DMDMS) and propyltrimethoxysilane (PTMS) in the presence and absence of the polymer additives poly(ethylene glycol) or poly(vinyl alcohol).</p> <p> The effect of organosilane precursors and polymer additives on the optical clarity, hardness and hydration stability of the resulting materials was characterized. It was determined that there was a limit to the amount of organosilane that could be added before the materials exhibited unacceptable characteristics. These limits were 20.0% (v/v) for MTES, 10.0% (v/v) for PTMS, and 5.0% (v/v) for DMDMS. Addition of PEG to these materials at levels up to 10.0% (w/v) resulted in good material characteristics. However, addition of PVA produced opaque materials with poor material properties. The internal environment of the materials was also probed using the environmentally sensitive fluorescent probes 7-azaindole (7AI) and prodan. These studies showed that the method of hydrolysis of the silane precursors and the aging conditions had a dramatic effect on the resulting material.</p> <p> The hybrid materials were used to entrap human serum albumin (HSA) and lipase to determine the effect of organic content on the biological function of these biomolecules. Both biomolecules retained a portion of their native function when entrapped in sol-gel-derived materials, and it was found that both proteins showed enhanced function in the presence of MTES. In the case of lipase, it was also determined that addition of PEG 600 at 10.0% (w/v in the gelation buffer) provided a dramatic increase in activity compared to materials without this additive, likely owing to a direct effect of the PEG on the stability of the entrapped protein.</p> <p> Following studies using bulk glasses, a protocol was developed for the preparation of optically clear sol-gel-derived thin films that was amenable to entrapment of biomolecules. The optimal method involved dipcasting of co-hydrolyzed materials containing 1.0 to 3.0% PEG. By careful control of the viscosity of the casting solution and the rate of film deposition, it was possible to form very stable thin films with excellent physical characteristics. These films were used to entrap the pH-sensitive, ratiometric fluorescent probe dextran-SNARF-1, resulting in a prototype of a fluorimetric pH sensor. Co-entrapment of the probe and lipase into sol-gel-derived thin films resulted in a rapid, reagentless biosensor prototype that could monitor changes in pH due to the enzyme-catalyzed hydrolysis of triglycerides. These results demonstrate that species entrapped in sol-gel derived thin films are suitable for biosensor development.</p> / Thesis / Master of Science (MSc)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/19206 |
| Date | 08 1900 |
| Creators | Rakic, Michael |
| Contributors | Brennan, John D., Chemistry |
| Source Sets | McMaster University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
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