Antibacterial coatings based on microgels containing quaternary ammonium ions: Modification with polymeric sugars for improved cytocompatibility

The availability of biocompatible, anti-bacterial coatings is of extreme importance for the development of biomedical devices. However, it has proven to be difficult to achieve both biocompatibility and bactericidal properties simultaneously. In the present work, as a novel, alternative approach, a quaternary ammonium salt-based poly(N-isopropylacrylamide) (QAS-PNIPAM) microgel was used both as the bactericidal agent and as an anchor system for the attachment of a cyto-compatibility-enhancing component. QAS-PNIPAM microgels were first prepared as thin films on silicon wafer. The QAS component of the film, as well as having strong inherent bactericidal properties, also provided binding sites for attachment of a glycopolymer containing sulfonate groups via attractive electrostatic interactions. It was shown that introduction of the sugar units improved the cytocompatibility of the microgel film without compromising its bactericidal efficacy. It is proposed that such microgel coatings may serve more generally as intermediates for the attachment of biofunctional components to biomaterial surfaces.