The aim of this research programme was to examine the potential of photosensitiser incorporated copolymers in creating an anti-infective biomaterial for ocular use. A range of copolymers with varying amounts of the monomers HEMA, MAA and MMA were successfully manufactured and impregnated with the cationic porphyrin, TMPyP via a dipping method with exploited the electrostatic interactions between TMPyP and the anionically charged copolymers. It is desirable to surface-localise the TMPyP incorporation as much as possible, so that it may exert its antimicrobial effect at the material surface where required, and may also limit the impact ofTMPyP upon the optical transparency of the copolymer. Increasing the amounts of MMA in the copolymers led to an increase in surface localisation, as shown with confocal microscopy. This subsequently improved the antibacterial activity of the copolymers with optimal efficacy found for the blend containing 10%MAA, 10%MMA and 80% HEMA . Commercially available contact lenses were also impregnated with photosensitisers. Confocal microscopy showed the degree of localisation of the photosensitisers and bacterial adherence testing demonstrated that these lenses were active against gram-positive ocular pathogens, showing that an anti-infective contact lens was successfully made. Solutions of photosensitisers were tested against various bacterial pathogens, both alone and in combination with other antibacterial agents such that synergistic activity could be assessed. It was demonstrated that TMPyP is an effective antibacterial agent when used alone. However, it was further shown that the combinations of TMPyP with polymyxin B and also with chlorhexidine displayed synergistic properties. The concentration of TMPyP required to bring about bacterial kill was significantly reduced in the presence of polymyxin B/chlorhexidine whilst also reducing the time required for bacterial disinfection. The use of such solutions could have potential for the development of novel MPS.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:602498 |
| Date | January 2013 |
| Creators | McGlinchey, Seana Marie |
| Publisher | Queen's University Belfast |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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