(168q) Changes in Antimicrobial Efficacy Due to Ionic Binding of Modified Cellulose to Quaternary Ammonium Compounds

The Covid-19 pandemic emphasized the need for a long-term or a self-cleaning disinfectant for surfaces. Here we study the effects of ionicly bound oxone-mediated TEMPO-oxidized cellulose nanomaterials (OTO-CNMs) to quaternary ammonium compounds (QACs). OTO-CNMs are bio-compatible, renewable, non-toxic and have high adhesion. By incorporating OTO-CNMs as an excipient material for QACs it is necessary to understand the adhesion properties and antimicrobial efficacy of the new coating material. Antimicrobial effects were studied by minimum inhibitory concentration tests (MIC) in suspension and on carrier substrates with Escherichia coli. Didecyldimethylammonium chloride (DDAC) and cetrimonium bromide (CTAB) were chosen as model QACs. It was observed that binding QACs to OTO-CNM increased the minimum inhibitory concentration, representing a need for an increased amount of material to maintain antimicrobial efficacy. In suspension experiments with E.coli, DDAC’s MIC value increased by 180% when bound to OTO-CNM, similarly, CTAB’s MIC value increased by 92%. These trends are reflected in surface experiments where DDAC’s MIC increased by 93% and CTAB’s by 20%. While QAC efficacy has decreased post binding, shifts in adhesion properties may provide a longer lasting surface coating.