A NOVEL L-GLUTAMIC ACID LOADED CHITOSAN HYDROGEL AS AN IDEAL DRESSING MATERIAL FOR TREATING DIABETIC WOUNDS
Vignesh Muthuvijayan1, Ponrasu Thangavel1, Balaji Ramachandran1, Suguna Lonchin
1Indian Institute of Technology Madras, India CSIR-Central Leather Research Institute, India
Hydrogels have been extensively studied for wound healing applications. Here, we have developed a novel hybrid hydrogel using chitosan (CS) and L-glutamic acid (LG) via physical cross-linking. We prepared chitosan hydrogels with different concentrations of L-glutamic acid (0%, 0.25%, 0.5%, and 1.0%), using 2% solutions of chitosan. Glycerol (50%) was added as a plasticizer to improve elasticity of the hydrogels. Scanning electron microscopy images showed smooth surface for CS hydrogels and fibrous architecture with sponge like rough surfaces for the CS+LG hydrogels. These hydrogels showed good in vitro biodegradation in PBS using 1 mg/mL of lysozyme. FTIR spectrum of CS+LG hydrogels showed characteristic peaks for LG confirming the blending with chitosan. Swelling ratio of hydrogels showed that they absorbed water more than 3 times their original weight. DSC study shows that the CS+LG hydrogels has higher glass transition temperatures compared to CS hydrogel. Thermogravimetric analysis also strongly substantiates these findings with four gradual weight losses from room temperature to 600°C. CS+LG hydrogels showed higher thermal stability than the CS hydrogel. To evaluate the biocompatibility of these hybrid hydrogels, we studied in vitro cell viability, cell attachment and proliferation using NIH 3T3 fibroblast cells. CS+LG hydrogels showed good viability and cell attachment. Therefore, these hydrogels were used as a wound dressing material in rats during diabetic wound healing. CS+LG hydrogels reduced the frequent wound dressing and inflammation. It accelerated cellular activity to heal the wounds faster, with minimal scar formation. These CS+LG hydrogels reduced the epithelialization time and enhanced the rate of wound contraction in diabetic rats. It also increased the collagen content and crosslinking of collagen. Hence, increased shrinkage temperature was observed. Histopathological findings also revealed these results like fibroplasia, collagen deposition and angiogenesis. Hence, CS+LG hydrogels could be an effective wound dressing material for chronic wounds like diabetic wounds.