Poly(2-Hydroxyethyl Methacrylate) Sponges Doped with Ag Nanoparticles as Antibacterial Agents

Abstract

Poly(2-hydroxyethyl methacrylate) sponges doped with silver nanoparticles (Ag NP-PHEMA) were prepared by irradiation of aqueous solutions containing 2-hydroxyethyl methacrylate (HEMA) and silver nitrate in the presence of a cross-linking agent and a photoinitiator. The Ag NP-PHEMA sponges had polymer droplet morphology with interconnected pores, characteristic of PHEMA sponges prepared by polymerization-induced phase separation. The Ag NP-PHEMA sponges were yellow-brown, whereas PHEMA sponges were white. For formation of Ag NP-PHEMA, the size of the polymer droplets was larger and the rate of polymerization was increased compared to PHEMA sponges formed under similar conditions but in the absence of silver nitrate. Mechanical strength, as indicated by compression testing, was similar for Ag NP-PHEMA and PHEMA sponges. Nanoparticles slowly leached out of Ag NP-PHEMA sponges, exerting antibacterial activity against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) bacteria. Notably, Ag NPs that leached were nontoxic to human corneal epithelial (HCE-T) cells.