In vitro efficacy and toxicology evaluation of silver nanoparticle‐loaded gelatin hydrogel pads as antibacterial wound dressings

The silver nanoparticle (nAg)‐loaded gelatin hydrogel pads were prepared from 10 wt % gelatin aqueous solution containing silver nitrate (AgNO 3 ) at 0.75, 1.0, 1.5, 2.0, or 2.5 wt % by solvent‐casting technique. These AgNO 3 ‐containing gelatin solutions, that had been aged for 15, 12, 8, 8, and 8 h, respectively, showed noticeable amounts of the as‐formed nAgs, the size of which increased with an increase in the AgNO 3 concentration (i.e., from 7.7 to 10.8 nm, on average). The hydrogels were crosslinked with a glutaraldehyde aqueous solution (50 wt %, at 1 μL mL −1 ). At 24 h of submersion in phosphate buffer saline (PBS) or simulated body fluid buffer (SBF) solution, about 40.5–56.4% or 44.4–79.6% of the as‐loaded amounts of silver was released. Based on the colony count method, these nAg‐loaded hydrogels were effective against Staphylococcus aureus , Escherichia coli , and Pseudomonas aeruginosa , with at least about 99.7% of bacterial growth inhibition. Unless they had been treated with a sodium metabisulfite aqueous solution, these hydrogels were proven, based on the indirect cytotoxicity evaluation, to be toxic to human's normal skin fibroblasts. Lastly, only the hydrogels that contained AgNO 3 at 0.75 and 1.0 wt % were not detrimental to the skin cells that had been cultured directly on them. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012