Poly(vinyl chloride) is one of the most common polymeric biomaterials currently in use in healthcare devices such as endotracheal (ET) tubes. As is often the case, bacterial colonisation of the PVC surface represents a major issue, contributing to poor patient outcomes, increased hospital stays and, in some cases, death. Bacteria readily colonize such surfaces, forming biofilms highly resistant to antibiotic therapy. A prime example of this is the implication of the ET tube in the development of ventilator-associated pneumonia (VAP). Numerous attempts have been made at reducing the incidence of VAP via pharmacological and non-pharmacological methods; however, improvement of ET tube functionality is increasingly being seen as facile means of lowering this risk. This thesis presents a method for the permanent, covalent attachment of a range of molecules with the potential to limit bacterial adherence and survival on modified surfaces which present the opportunity to reduce the incidence of VAP. Fluorination of PVC surfaces was studied as a means of increasing hydrophobicity of the material and reducing surface energy in order to limit bacterial-polymer interaction, thereby reducing adherence and, ultimately, biofilm formation. Results showed that successful modification of less than a third of the PVC surface significantly reduced bacterial adherence. Immobilisation of hydrogel layers on PVC surfaces was also researched in order to permanently attached drug delivery depots. Data obtained indicated that pHEMA could be co-polymerized onto PVC and remain as a functional hydrogel, capable of delivering antibiotics directly to the site of biofilm formation. Incorporation of light-activated microbicidal molecules (photosensitizers) and quaternary ammonium salts, with a view to future development of similar surface functionalising compounds, revealed that both methods were capable of producing significant reductions in bacterial activity on ET tubes. In particular, photosensitizers offer an on-demand activity which could be utilised if VAP is suspected.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:579694 |
| Date | January 2012 |
| Creators | Cowley, John Francis |
| Publisher | Queen's University Belfast |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
Page generated in 0.0023 seconds