Bacterial infections are a serious problem for patients with burns and other wounds.
Such burn wound infection accounts for the pathogenic bacteria by colonising onto
burned areas. Therefore, the need for detection and inhibition of such bacterial
colonisation requires a methodology for sensing/killing pathogenic bacteria.This research project aims to design a ‗smart‘ wound dressing system which can respond
to the microbiological environment of the wound via a simple colour change and will
release antimicrobials only when required. Two strains of pathogenic bacteria
Staphylococcus aureus (MSSA 476) and Pseudomonas aeruginosa (PAO1) were used in
the study. The non-pathogenic bacterium E.coli (DH5α) was used as a control organism
as it does not secrete virulence factors and therefore does not lyse membranes of vesicles.
The key contributions of this thesis are outlined below.Firstly, an initial responsive nanocapsule system was studied. The fundamental work
with giant unilamellar vesicles proved such a responsive system can provide
antimicrobial properties when antimicrobial agents were encapsulated within the
vesicles.Secondly, partially polymerised vesicles—polydiacetylene/phospholipid vesicles were
then developed to improve vesicle stability. The vesicle system was optimised by
varying molar concentration of diacetylene monomers (TCDA) in order to obtain
relatively stable vesicles as well as sensitivity to the toxins secreted by the pathogenic
strains. Measurements proved that the polydiacetylene/phospholipid vesicles can
respond to pathogenic bacteria when fluorescent dye/antimcirobials were encapsulated
in the vesicles.Finally, a simple prototype dressing was constructed. Plasma polymerised maleic
anhydride (pp-MA) deposited onto non-woven polypropylene was shown to be a good
method to stabilise vesicles via covalent bonding. Vesicle adhered to pp-MA non-woven
polypropylene showed the ability to inhibit/kill the pathogenic strains, quantified by the
Japanese Industry Standard assay and also gave a fluorimetric colour response in the
presence of pathogenic bacteria when a fluorescent dye is encapsulated within vesicles.
Other simple prototypes were also attempted by using hydrogels (gelatine and collagen)
to maintain vesicle stability as well as promote tissue healing.
|Date of Award||1 Nov 2011|
|Supervisor||Toby Jenkins (Supervisor)|
- phospholipid/polydiacetylene vesicles
- responsive nanocapsules
- burn wound infection