| In the light of problematic challenges in assessing the antimicrobial properties of medical materials and devices it is necessary and important to explore novel applications of existing analytical techniques. Isothermal microcalorimetry, whether as a static or modified flow-through system, was shown to have great potential with this area. The growth and metabolism of microbes, as with any other process, involves a change in enthalpy (heat). This is measurable using isothermal microcalorimetry, allowing real-time detection of growth and changes in metabolic performance of microorganisms. While there are a number of standard methods to assess microbial growth, for example, turbidometric measurements, calorimetry offers the benefits of being non- invasive, not dependent on sample transparency and being capable of measuring whole sections of medical devices. This work demonstrates the application of calorimetry in testing the efficacy of antimicrobial wound dressings both in freely suspended cultures (planktonic cells) and in sessile, matrix enclosed communities (biofilms). A flow-through system was developed by modifying existing ampoules to allow placement of 'test' tubing within, as well as to allow the flow of bacteria cultured in an external bioreactor. The flow-through system was designed as a testing system for putative products and materials aimed at reducing or eliminating device related biofilms. The calorimetric work described in this thesis was corroborated using classical microbiological methods with the aim of bridging the gap between these disciplines and to demonstrate the validity of calorimetry as a useful analytical method in microbiological studies. |
