AVS 49th International Symposium
    Biomaterials Tuesday Sessions
       Session BI+SS-TuA

Paper BI+SS-TuA10
Antibacterial Coatings of Immobilised Furanones

Tuesday, November 5, 2002, 5:00 pm, Room C-201

Session: Molecular Recognition Surfaces
Presenter: H.J. Griesser, University of South Australia
Authors: H.J. Griesser, University of South Australia
S. Al-Bataineh, University of South Australia
B.W. Muir, CRC for Eye Research and Technology, Australia
H. Thissen, CRC for Eye Research and Technology, Australia
M. Willcox, CRC for Eye Research and Technology, Australia
Correspondent: Click to Email
The formation of bacterial biofilms and subsequent infections can cause serious complications in the use of biomedical devices such as catheters, and broadly effective technology is lacking. Nature has, however, addressed very effectively the problem of microbial colonisation of surfaces. For instance, the red alga Delisea pulchra secretes brominated furanones that prevent its microbial colonisation. These compounds are thought to interfere with bacterial quorum sensing by their chemical similarity with homoserine lactone, an important bacterial regulator. We have immobilised various furanones onto synthetic surfaces and tested the efficiency of such coatings in bacterial colonisation assays. A broadly applicable covalent immobilisation strategy involves nitrene chemistry, with light-activated reaction between furanones and azido aniline coupled onto a surface hydrogel interlayer. This allows coupling of furanones without reactive substituents but is non-selective with regard to molecular orientation and location of attachment. Other strategies require functionalised furanones, for example reaction between a hydroxylated furanones and surface isocyanate groups; such furanones can be more difficult to synthesize. Work to date has produced substantial reductions in bacterial colonisation, but not to the high degree required in clinical applications. Investigations now focus on the interactive effects of furanone molecular composition, immobilisation chemistry and surface density. An interesting finding is that these compounds are effective when surface immobilised although the classical microbiological model of homoserine lactone action requires entry into the microbial interior. This dichotomy calls for detailed surface characterisation of furanone coatings, including study of whether the entire population of surface-bound molecules is indeed covalently linked and thus non-diffusible and acting via a different mechanism to stifle bacterial colonisation.