Strontium ion cross-linked alginate-g-poly (PEGMA) xerogels for wound healing applications: in vitro studies

Alginate-g-polyethylene glycol methacrylate xerogels cross-linked with strontium ions (AGPMS) were developed for wound healing applications. Grafting improved the mechanical properties of alginate xerogel significantly. Strontium cross-linking further strengthened the xerogel. There was a 4.4 fold increase in tensile strength of AGPMS xerogel compared to that of strontium cross-linked alginate. The amount of Sr²⁺ was quantified to be 5.144 mg/g of the xerogel and its release in phosphate buffer (pH 7.4) was 55 ± 3.18% by 72 h. An ionic concentration of 1.2 to 3 mmol.L^-1 strontium had influence on keratinocyte migration and proliferation. The wound healing activity of AGPM2S2 by scratch wound assay showed 30 ± 4.3% wound closure within 4 h and complete closure by 24 h in HaCaT cells, but only 13.17 ± 4.5% and 68.54 ± 3.4% respectively at 4 and 24 h for non-treated cells. The material also promotes collagen deposition from fibroblast cells which further improves the suitability of the material as a wound care biomaterial.