Modified cotton gauze dressings that selectively absorb neutrophil elastase activity in solution

Dressings for chronic human wounds have been aimed at protection, removal o f exudate, and improved appearance. However since the time of ancient Greec e wound care and dressing strategies have primarily relied on empiricism. R ecent studies have shown that chronic wounds contain high levels of tissue and cytokine destroying proteases including collagenase and neutrophil elas tase. Therefore we sought to develop an effective wound dressing that could absorb elastase through affinity sequestration. Cotton gauze was modified by oxidation, phosphorylation, and sulfonation to enhance elastase affinity by ionic or active site uptake. Type VII absorbent cotton gauze was oxidiz ed to dialdehyde cotton which was subsequently converted in part to the bis ulfite addition product. Gauze preparations were also phosphorylated and ca rboxymethylated. Modified cotton gauzes were compared with untreated gauze for reduction of elastase activity in buffered saline. Solutions of elastas e that were soaked in oxidized, sulfonated, and phosphorylated cotton gauze showed reduced elastase activity. The initial velocities (v(o)) and turnov er rates of elastase showed significant decreases compared with solutions t aken from untreated gauze. The reduction in enzyme activity with dialdehyde cotton gauze was confirmed in solution by determining elastase inhibition with dialdehyde starch. The dialdehyde cotton gauze also decreased elastase activity in human wound fluid in a dose response relation based on weight of gauze per volume of wound fluid. Absorbency, pH, air permeability and st rength properties of the modified gauze were also compared with untreated c otton gauze. This report shows the effect of reducing elastase activity in solution with cotton containing aldehydic or negatively charged cellulose f ibers that may be applicable to treatment modalities in chronic wounds.