Dual antimicrobial effects induced by hydrogel incorporated with UV-curable quaternary ammonium polyethyleneimine and AgNO3

Abstract

This study presents a simple method for fabricating a highly potent dual effect antibacterial hydrogel consisting of a UV-curable cationic polyethyleneimine (QUV-PEI) and embedded silver nitrate (AgNO3). In the first part of this study, polyethyleneimine (PEI) was reacted with 3-(acryloyloxy)-2-hydroxypropyl methacrylate (ACOM) to introduce methacryl functionality onto the backbone. UV-curable PEI was further quaternized by N-methylation with methyl iodate. Hydrogels based on QUV-PEI and AgNO3were found to have impressive biocidal properties. The antibacterial properties were assessed by spraying aqueous suspensions of bacterial cells on the surface, followed by air drying and counting the number of remaining viable cells (i.e. capable of growing into colonies). In a manner depending on the QUV-PEI content in the gel formulation, up to 99±1% of Escherichia coli and Staphylococcus aureus cells sprayed on the resulting hydrogel surfaces were killed. The inclusion of AgNO3 in the QUV-PEI based hydrogel not only enhanced the antimicrobial property against adherent bacteria but also led to the inhibition of bacterial growth in suspended culture via the long-term release of Ag/Ag(+) to the surrounding media. Cytotoxicity studies on human umbilical vein endothelial cells and MTS cell lines were also performed with hydrogels. These findings confirm that hydrogels are potentially useful as antimicrobial agents in a wide variety of applications.

Keywords: Antibacterial coating; Dual effect; Hydrogel; Polyethyleneimine; Silver.