Interaction of antimicrobial polycationic polymer with bacteria and viruses in aqueous systems towards advanced antimicrobial material

New pathways need to be developed to overcome the increasing antibiotic resistance of pathogens. A better understanding of the mechanism and interaction is important to overcome the fast mutation cycles of pathogens. The sensibility of a biological system to charge and ionic strength is an approach to overcoming the natural barrier of microorganisms. For example, the mechanism of Colistin, a last resort antibiotic, is based on charge interactions. Therefore, the usage of physical chemistry methods to analyse structural and chemical changes in combination with microbiological assays gives a good fundament to provide additional insights.

Precision-synthesised polycationic polymers offer the ability to tailor chain length, and composition according to our needs. Therefore, they are ideal as model systems for interaction studies. One part of the thesis covers the research on poly[2-(methacryloyloxy)ethyl]trimethylammoniumchloride (pMETAC), a cationic polymer synthesised by atom transfer radical polymerisation (ATRP), and assembled with the bacteriophage Qbeta to study the interaction with small-angle x-ray scattering, dynamic light scattering and microscopic techniques. Antimicrobial assays will determine the efficiency of those assemblies towards the host bacterium.

Another part is to study the interaction of pMETAC with lipopolysaccharide (LPS). LPS are the outermost part of gram-negative bacteria and the first defending mechanism of the bacteria. The study builds up in complexity by using outer membrane vesicles towards direct interaction of pMETAC with the bacteria.

The outcome of the research is valuable for the development of antimicrobial bio-nanomaterials towards medical applications and phage therapeutics. The additional knowledge can be further applied to the design of novel antimicrobial surfaces.