Hydrophilic Quaternary Ammonium Ionenes—Is There an Influence of Backbone Flexibility and Topology on Antibacterial Properties?

The antimicrobial properties of polycations are strongly affected by the structural features such as the backbone flexibility and topology (isomerism) through the polymer ability to attain proper conformation in interaction with the cell membrane. In this paper, a synthesis and biocidal properties evaluation of ionenes characterized by different backbone topology (isomerism) and flexibility are presented. The findings reveal influence of variation in topology on activity against different microorganisms, and general positive effect of improved flexibility. Furthermore, one of the obtained ionenes displays degradable properties in near physiological environment (phosphate‐buffered saline pH 7.4, 37 °C). The degradation proceeds via Hofmann elimination reaction and the products are not of acidic character. For the first time a new class of degradable ionenes with a high antimicrobial potential is presented. Flexibility and isomerism of polymeric backbone in series of quaternary ammonium ionenes is discussed in context of antimicrobial activity. Determined minimal inhibitory concentrations values are low showing substantial dependence from structural parameters. Almost all tested ionenes display negligible hemolytic activity. Two of tested ionenes are degradable in phosphate‐buffered saline pH 7.4 at 37 °C via Hofmann elimination reaction.