Absorption and swelling characteristics of silver (I) antimicrobial wound dressings

An important characteristic of moist wound dressings is their ability to swell and absorb exudates from the wound, while maintaining a moist atmosphere at the wound site. At the SRRC, we have previously developed antimicrobial silver-sodium-carboxymethylated (CM)-cotton printcloth from the sodium salt of CM-cotton, and silver-Ca-Na alginates from four commercially available alginate moist wound dressings. As part of ongoing research on silver antimicrobials, this report delineates the swellabilty of these silver antimicrobial dressings compared to commercially available calcium-sodium alginate dressings and printcloth (controls) in water and in 0.9% sodium chloride solution (saline) after 8 hours and after one week of immersion. Additionally, the swelling characteristics are correlated with the absorption of saline g/g of the dressing. Silver treated Sorbsan, Kaltostat, Curasorb, Algisite, and cotton-CM-printcloth showed a very significant increase in diameter of the fibers: NaCl 8 hr > water 8 hr > dry, albeit slightly less than the control alginate dressings. The majority of the swelling took place in the first eight hours of wetting, and continued wetting for one week caused little additional uptake of the solution. Fibers swell only in diameter and not in length. All the fibers had greater swelling in saline as compared with those in water. The proven swellabilty of these silver dressings, taken together with the known absorptive and antimicrobial properties of the dressings should make them suitable for treatment of exudative wounds that are at risk for infection. As more is learned about these dressings, clinical trials may be warranted to evaluate their efficacy.