PhD ceremony Mr. B.W. Peterson: Visco-elastic properties of biofilms

PhD ceremony: Mr. B.W. Peterson, 14.30 uur, Academiegebouw, Broerstraat 5, Groningen

Dissertation: Visco-elastic properties of biofilms

Promotor(s): prof. H.C. van der Mei, prof. H.J. Bosscher

Faculty: Medical Sciences

While mathematical models for biofilms have been available for many years, there has yet to be a definitive physical connection between mathematical terms and physical or biological functions. It was determined that a connection between the underlying properties of initially adhering bacteria and the resulting relaxation properties of biofilms exists. Stress relaxation of biofilms could be described mathematically in three Maxwell elements, which also linked to their structural composition and antimicrobial penetration. Extracellular DNA had a distinguishable role in biofilm stress relaxation, making it a primary target for future research into bioacoustics-associated treatments. Throughout this thesis, the length of the relaxation time constants was used to distinguish between Maxwell elements and determine their associations to biofilm structure and antimicrobial penetration. These time constants could be converted to frequencies for bioacoustics as a useful tool against bacterial biofilms, however we have not tested the efficacy of these frequencies. A potentially successful biofilm treatment would combine antimicrobials with a mechanical frequency that would resonate the bacterial biofilm while leaving neighboring cells and tissues unaffected.