Antibacterial Photocurable Acrylic Resin Coating Using a Conjugate between Silver Nanoclusters and Alkyl Quaternary Ammonium

Ligand-protected silver nanoclusters (Ag NCs) have been gaining interest as antibacterial agents because of their ultrasmall sizes (<2 nm), their high antibacterial activity, and the variety of ligand species. The incorporation of Ag NCs into polymer resins is a desirable approach to achieve high durability and the long-term antibacterial activity of Ag NCs-based antibacterial coatings. However, the Ag NC-based antibacterial agents reported thus far are all water-soluble, and they have not been employed to generate antibacterial resins coatings because of the hydrophobic nature of the resins. Herein, we report for the first time Ag NC-based antibacterial photocurable acrylic resin coatings prepared by incorporating the conjugate of dihydrolipoic acid-capped Ag NCs with tetraoctylammonium (TOA) (TOA-Ag NCs). Given TOA's organosolubility, TOA-Ag NCs readily dissolved in the acrylic resin. The Ag NC-based antibacterial resin coatings displayed efficient antibacterial activity descending from the double antibacterial action of Ag NCs and TOA. This activity was maintained for a long time even after exposure of the coatings to aqueous environments. The cytotoxicity of the Ag NC-based antibacterial resin coatings was evaluated by measuring NIH3T3 cell proliferation and the expression of F-actin and vinculin, and data supported the low cytotoxicity of the coatings. These novel Ag NC-based antibacterial resin coatings have promising potential biomedical applications, for instance in healthcare/medical devices, for hospital infection prevention, and in implantable devices.