Natural and synthetic polymeric antimicrobials with quaternary ammonium moieties: a review

Abstract

The excessive use of antibiotics has led to the development of antimicrobial resistance and, in turn, to the inefficiency of actual drugs. Therefore, scientists have recently focused on conceiving new antimicrobials with a longer duration of action and a minimum environmental toxicity, such as polymers modified with quaternary ammonium moieties. Indeed, these quaternary ammonium moieties have a net positive charge that interacts better with and inhibit negatively charged microorganisms. This article reviews natural and synthetic polymers modified with quaternary ammonium moieties with focus on biocompatible polymers. Polymers include cashew gum, cellulose, chitosan, dextran, polylactide, pullulan, starch, polyamidoamine, polyurethane, polysiloxane, polymethacrylate and polyethylene. The interaction of new antimicrobials with a wide range of bacteria and fungi is controlled by microenvironmental factors and polymer properties. The use of other functional groups or chemical compounds in synergy with quaternary ammonium moieties is actually emerging to improve the efficiency.