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Advanced wound dressings that can deliver potent antibacterial action are still much in need, especially for treating wound infections caused by drug-resistant bacteria. In this research, we utilized electron beam (EB) irradiation to develop antibacterial hydrogel sheet dressings from poly(vinyl alcohol) (PVA) and silver nanoparticles (AgNPs) in a two-step processing and evaluated their bactericidal efficacy, as well as the AgNP release. The effect of the irradiation dose on the swelling, gel fraction, network parameters, and mechanical properties of the hydrogels was first determined to establish the optimal doses for the two-step processing. The prototypic hydrogel sheets were then formed in the first EB irradiation and served as a matrix for the AgNP synthesis by the reduction of the silver nitrate precursors during the second EB irradiation. The diffusion assay showed that the minimal inhibition concentration (MIC) of the AgNP-load hydrogels was 0.25 and 0.5 mg/cm2 against Escherichia coli and Staphylococcus aureus, respectively. At these MIC levels, the released AgNPs increased sharply before reaching the maximum, ~950 and 1800 ppb, at 24 h as analyzed by atomic absorption. Therefore, we successfully demonstrated that this two-step processing by EB irradiation provides a convenient platform to fabricate AgNP-loaded hydrogel dressings that can be further developed for wound healing. [ABSTRACT FROM AUTHOR]

Radiolytic synthesis provides a convenient and environmentally-friendly approach to prepare metallic nanoparticles in large scale with narrow size distribution. In this report, colloidal silver nanoparticles (AgNPs) were synthesized by gamma radiation using poly(vinyl alcohol) (PVA) or silk fibroin (SF) as stabilizers and were evaluated for their antibacterial properties. The conversion of metallic silver ions to silver atoms depended on irradiation dose and stabilizer concentration as determined by UV-Vis spectrophotometry and transmission electron microscopy. The uniformly dispersed AgNPs with diameter 32.3 ± 4.40 nm were evaluated as antiseptic agents in films composed of chitosan, SF, and PVA that were processed by irradiation-induced crosslinking. Using disc diffusion assay, the films containing 432 ppm AgNPs could effectively inhibit the growth of both Staphylococcus aureus and Pseudomonas aeruginosa. Therefore, we have demonstrated in our present study that gamma radiation technique can potentially be applied in the mass production of antibacterial wound dressings. [ABSTRACT FROM AUTHOR]