Development of hydrogel wound dressings using mixtures of polyvinyl alcohol and polysaccharide extract from durian fruit-hulls

Abstract

The purpose of this study was to develop hydrogel dressing prepared by physically cross-linked polyvinyl alcohol (PVA) with polysaccharide gel extracted from durian fruit-hulls (DG) using freeze-thaw technique. Processing parameters included freeze-thaw duration (freezing at -20 ℃ 18 hrs and thawing at 30 ℃ 6 hrs (F18T6) and freezing at -20 ℃ 24 hrs and thawing at 30 ℃ 24 hrs (F24T24)); freeze-thaw cycles (3,4and 5 cycles); mixing temperatures (room temperature: RT, 50 ℃, 70 ℃ and 90 ℃); thickness (1.00, 2.00 and 3.50 mm); and DG concentrations (2, 3 and 3.5%w/w). The DG/PVA hydrogel membranes were characterized by its water content, swelling property, surface properties, mechanical/structural behaviors and antimicrobial activity. DG/PVA hydrogels prepared by freeze-thaw process were light-tan in color and transparent while PVA hydrogels were transparent and colorless.DG/PVA hydrogels prepared byF24T24 (3 cycles) absorbed higher amount of water than F18T6 (3 cycles).Mixing hydrogel at RT resulted inhydrogel membranes with better water absorption capacity than mixing at higher temperatures. Thinner DG/PVA hydrogels absorbed higher amount of water per weight than thicker hydrogels but were more fragile and showed decreased strength after swelling. High freeze-thaw cycles resulted in the hydrogels with higher strength and ductility but less water absorption ability. With higher DG concentrations, membranes became stronger, were able to elongate and absorbed higher amount of water than at lower concentrations. F24T24 (3 cycles) and initial mixing at RT was the optimal condition for the preparation of DG/PVA hydrogels. By using this optimal condition, DG/PVA hydrogel with 3.5%w/w of DG and thickness of 3.50 mm showed high water content (90.10 ± 0.26%), high water absorption capacity at 13 hrs (250.96 ± 33.92%) and good mechanical properties with percent elongation of 237.77 ± 49.72%. Scanning electron photomicrographs of DG/PVA hydrogel showed folded structure with large pores, while PVA hydrogel structure composed of small fibers which created its elongated cavities. Storage condition affected overall properties of DG/PVA hydrogel. When stored at 4 ℃, hydrogel properties changed less than when stored at 30 ℃ and 40 ℃, 75%RH. Most importantly, DG/PVA hydrogel was able to inhibit bacterial growth while PVA hydrogel did not. DG/PVA hydrogels exhibited clear zone (23.3 ± 0.6 mm2) and translucent zone (31.3 ± 1.2 mm2) against Staphylococcusaureus and Escherichia coli, respectively. The addition of polysaccharide gel from durian fruit-hulls extract into polyvinyl alcohol hydrogel resulted in an improved membrane properties suitable for further development in biomedical applications.