Sequential antibiotic and growth factor releasing chitosan-PAAm semi-IPN hydrogel as a novel wound dressing

The aim of this study is to prepare a novel wound dressing material which provides burst release of an antibiotic in combination with sustained release of growth factor delivery. This might be beneficial for the prevention of infections and to stimulate wound healing. As a wound dressing material, the semi-interpenetrating network (semi-IPN) hydrogel based on polyacrylamide (PAAm) and chitosan (CS) was synthesized via free radical polymerization. Ethylene glycol dimethacrylate was used for cross-linking of PAAm to form semi-IPN hydrogel. The hydrogel shows high water content (～1800%, in dry basis) and stable swelling characteristics in the pH range of the wound media (～4.0–7.4). The antibiotic, piperacillin–tazobactam, which belongs to the penicillin group was loaded into the hydrogel. The therapeutic serum dose of piperacillin–tazobactam for topic introduction was reached at 1st hour of the release. Additionally, in order to increase the mitogenic activity of hydrogel, epidermal growth factor (EGF) was embedded into the CS–PAAm in different amounts. Cell culture studies were performed with L929 mouse fibroblasts and the simulated cell growth was investigated by 3-(4,5-dimethylthiazol-2-yl)-diphenyltetrazolium bromide assay. The successful sustained release behavior of CS–PAAm hydrogel for EGF maintained the presence of EGF in the culture up to 5?days and the highest mitochondrial activities were recorded for the 0.4?μg EGF-loaded/mg of hydrogel group. In conclusion, CS–PAAm semi-IPN hydrogel loaded with piperacillin–tazobactam and EGF could be proposed for an effective system in wound-healing management.