Nosocomial infection, including ventilator-associated pneumonia (VAP) affects more than 1 million people each year. The first step in VAP is colonization of the endotracheal tube; prevention of which has failed using traditional approaches such as antibiotic prophylaxis. This work looks at the development of anti-infective materials capable of resisting bacterial adherence. The strategy centres around the use of biocides (QACs) which target the negatively charged bacterial cell wall, disrupting cell structure and causing death. Chapter 2 examines the incorporation of 3 QACs into PVC via the solvent cast method. The materials resisted colonization but possessed poor mechanical properties. Chapter 3 examines an alternative method of incorporation, hot melt extrusion. The QACs and PVC were stable despite the application of heat but when combined, the QACs catalyzed the degradation of PVC and resulted in materials unsuitable for use in a medical device. Chapter 4 reconsiders the solvent cast method, but with ion pairs formed from quaternary ammonium cations and docusate anion. This produced ionic liquids with improved solubility in PVC, which improved the mechanical properties of the materials. However, the antimicrobial activity of the materials was not equivalent to that of the precursor QACs. Chapter 5 examines an alternate approach to the modification of PVC, by the production of an ultrahydrophobic surface. This did not prevent adherence but the materials showed no bacterial viability in adhered biofilm after 24 hours incubation. This was attributed to transition metals used to roughen the surfaces. Chapter 6 reports a second attempt at the exchange of anion paired with the quaternary ammonium cation, for sulfonate based anions. This produced films which showed improved mechanical properties and reduced bacterial adherence. This reduces the need for additional plasticisers, and these materials are suggested as suitable candidates for anti-infective ET tube biomaterials.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:557654 |
| Date | January 2012 |
| Creators | Kinnear, D. J. |
| Publisher | Queen's University Belfast |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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