Quartz crystal microbalances, (QCM), are high frequency oscillators, capable of nanogram mass resolution in both air and liquid environments. ~ work has produced data showing the feasibility of using the QCM for monitoring interactions in liquids for several types of systems and has allowed comparison with surface plasmon resonance (SPR) where appropriate. Bulk phase changes in viscosity and density have been used in the development of a QCM agglutination assay for the Staphylococcus epidermidis infection which has reduced diagnosis periods by a factor of twelve. Direct interactions at the crystal electrode have been employed when studying bacterial adhesion to protein treated gold surfaces. It was shown that suspensions containing as little as I x 10-2 cellsml-1 could be recognised using the QCM system. A novel boronic acid - vicinal diol interaction mechanism has been employed as a model for receptor-ligand binding. New boronic acid disulphide and short chain thiol derivatives have been synthesised and the formation of self assembled monolayers of the~e compounds monitored, both on the gold QCM electrodes and on the gold films of SPR slides, the assembly mechanism being shown to fit a two stage model shown by other workers for straight chain thiols. Monolayer orientation was confirmed using SPR, by the binding of a range of saccharides and the diol containing enzyme cofactor nicotinamide adenine dinucleotide. The enzymes lactate dehydrogenase and glucose-6-phosphate dehydrogenase have been shown to interact with bound NAD using both a novel flow injection system with QCM detection and SPR. The low molecular weight saccharide, glucose, was shown to bind reversibly to GDH on the surface of a QCM and the potential for kinetic stu4ies recognised. This was taken one step further with a preliminary investigation into sensing within real fluids, using diluted and spiked human seruin samples.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:299222 |
| Date | January 1997 |
| Creators | Pavey, Karl David |
| Publisher | University of Brighton |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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