Antimicrobial and physicomechanical natures of silver nanoparticles incorporated into silicone-hydrogel films

Abstract Purpose The effects of silver nanoparticles (AgNPs) incorporated in silicone-hydrogel films on their physicochemical properties and microbial activity were investigated. Methods Silicone-hydrogel composite films (SiHCFs) were prepared by in-situ chemical reduction of silver ions added in different concentrations (0, 10, 20, 30, 40, 60, and 80 ppm) followed by ultraviolet (UV) casting. The reduction of silver ions into AgNPs was confirmed by transmission electron microscopy (TEM) and absorption spectroscopy over ultraviolet and visible (UV–vis) wavelengths. Incorporation of AgNPs into SiHCFs was confirmed by UV–vis absorption spectroscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) spectroscopic mapping. The physico- mechanical properties of the SiHCFs were evaluated. Antimicrobial activity and biofilm formation of Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus were assessed. Results TEM, UV–vis absorption, SEM, and EDX mapping showed that silver ions were reduced in the mixture of co-polymerizing monomers and incorporation of AgNPs into SiHCFs was achieved. Mechanical properties of the SiHCFs were enhanced with increasing AgNPs concentration without affecting their chemical and thermal properties. SiHCFs exhibited transmittance greater than 90% at a wavelength 600 nm. Bacterial growths in the solutions bathing the SiHCFs with increasing silver concentration were 95, 78, 4, 2, 0, 0, 0% respectively, for Escherichia coli ; 95, 82, 4, 0.6, 0, 0, 0% for Pseudomonas aeruginosa ; and 93, 79, 4, 0.5, 0, 0, 0% for Staphylococcus aureus . Conclusions Incorporation of AgNPs into SiHCFs demonstrated sufficient release of AgNPs to inhibit bacterial growth and reduce biofilm formation, with collateral enhancement of some mechanical properties of SiHCFs.