Biofilms are a significant problem for many industries including medical devices, the oil and gas industry, consumer product manufacturers and water distribution systems. Biofilms are communities of microbes that attach and grow on almost any surface. Biofilms are able to establish quickly in a matter of hours and can be very difficult to remove.
This thesis was focused on increasing the understanding of biofilm interaction with different substratum materials, for both the initial surface colonisation and for mature biofilm lifecycle stages using a Pseudomonas aeruginosa (PA) model. The surface energy and the surface roughness, for a number of substratums were investigated in this thesis. The effects of a number of proprietary and non-proprietary surface coatings which primarily changed surface energies and or topography were investigated.
This work has confirmed that surface energy is important in Pseudomonas bio-adhesion, with correlations observed in both the initial attachment of microbes, but also in high shear cleaning experiments for mature biofilms. Biofilm-substratum interfacial adhesion remains an important region even in mature biofilms, suggesting that surfaces that exhibit lower colonisation rates may also be easier to clean. Initial attachment studies confirm 1/3 less microbe attachment to polymer surfaces compared to metal surfaces; roughness was not a significant parameter.
PTFE-AF coatings on 316 stainless steel showed 88 percent decrease in initial microbe attachment coupled with enhanced cleanability. Industries currently using stainless steel in microbe applications could from benefit this coating; limiting future biofilm colonisation rates and improved cleanability.
It is demonstrated that Pseudomonas naturally colonises at low levels on selected transparent polycarbonate surfaces and given its good chemical compatibility and low cost would be an alternative to stainless steel.
A range of commercial surface coatings, which are meant to reduce microbial adhesion, were also tested in this thesis; this study could not affirm such claimed performance.Open Acces
