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Title: Understanding and exploiting biomolecular interactions at interfaces
Author: Batchelor, M. R.
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2007
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Force spectroscopy was used to measure adhesion forces between SAM-modified surfaces. A simple test system was investigated before applying the technique to the antibiotic, vancomycin, and its target cell-wall peptide sequence L-Lys-D-Ala-D-Ala. Unsuccessful attempts were made to investigate this interaction directly by coupling vancomycin to an AFM tip. Nonetheless, specific interaction forces were observed between two surfaces exposing L-Lys-D-Ala-D-Ala when vancomycin was present in the intervening solution. This has been ascribed to the initial formation of vancomycin/ L-Lys-D-Ala-D-Ala complexes, and subsequent dimerisation of bound vancomycin when the surfaces are brought into contact. The rupture forces are therefore thought to be associated with dimer breakage. A second project aimed to develop a DNA-based nano-positioning system. This bottom-up approach to nano-fabrication requires the adsorption of a bivalent analyte from solution at a pattern-boundary between two surface-bound probes. SPR spectroscopy was used to measure the binding constants for 10-base hybridisation of single-stranded DNA analytes with single-stranded surface-bound DNA probes. An increased binding strength was observed where G-quadruplex structures could form between different bound analytes. An in-situ method for the controlled formation of dual probe surfaces was established. By tailoring the solution conditions, and devising a system of interconnected analytes, strong and specific bivalent binding onto surfaces composed of one or two probe types was observed. Monovalent binding onto these surfaces was shown to be highly reversible, with near-complete removal achieved by rinsing with buffer. These SPR studies pave the way for in-situ microscopic techniques to be employed. This could allow the direct visualisation and manipulation of specifically adsorbed analytes at a boundary between patterned probes.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available