Wound debridement and antibiofilm properties of gamma-ray DMAEMA-grafted onto cotton gauzes

Cotton gauze fabric was functionalized with 2-(dimethylamino)ethyl methacrylate (DMAEMA) with the aim of developing wound dressings with antibiofilm activity and tunable debriding activity. Cotton-g-DMAEMA gauzes were prepared via one-step grafting (direct method) using Co-60 gamma-rays as source to initiate the polymerization process. The effects of absorbed dose, dose rate, and monomer concentration on the degree of grafting were evaluated in detail. Some cotton-g-DMAEMA gauzes were subsequently quaternized with methyl iodide. Grafting of DMAEMA and sequential quaternization were confirmed by FTIR-ATR spectroscopy; thermal properties were analyzed using TGA, and morphology by scanning electron microscopy. Grafting of DMAEMA gauzes enhanced blood absorption and collagenase activity, while further quaternization led to a remarkable inhibition of the proteinase activity. Their antimicrobial features were analyzed by evaluating their biofilm inhibiting and biofilm eradicating properties in an in vitro chronic wound model. Although the non-quaternized gauzes only displayed moderate biofilm inhibitory properties at best, the quaternized cotton-g-DMAEMA bearing the highest content of DMAEMA displayed strong biofilm inhibiting and biofilm eradicating properties. This indicates that quaternized cotton-g-DMAEMA gauzes are less prone to be colonized by bacteria and can notably reduce the number of colonies in an infected wound.