Vignesh Muthuvijayan

This study explores the potential of gallic acid incorporated chitosan (CS/GA) 3D scaffolds for tissue engineering applications. Scaffolds were prepared by freezing and lyophilization technique and characterized. FTIR spectra confirmed the presence of GA in chitosan (CS) gel. DSC and TGA analysis revealed that the structure of chitosan was not altered due to the incorporation of GA, but thermal stability was significantly increased compared to the CS scaffold. SEM micrographs showed smooth, homogeneous, and microporous architecture of the scaffolds with good interconnectivity. CS/GA scaffolds exhibited approximately 90% porosity on average, increased swelling (600-900%) and controlled biodegradation (15-40%) in PBS (pH 7.4 at 37°C) with 1 mg/mL of lysozyme. CS/GA scaffolds showed 2-4 fold decrease in CFUs (p < 0.05) for both gram positive and gram negative bacteria compared to the CS scaffold. Cytotoxicity of these scaffolds was evaluated using NIH 3T3 L1 fibroblast cells. CS/GA 0.25% scaffold showed similar viability with CS scaffold at 24 and 48 h. CS/GA scaffolds (0.5-1.0%) showed 60-75% viability at 24 h and 90% at 48 h. SEM images showed that an increased cell attachment was observed for CS/GA scaffolds compared to CS scaffolds. These findings authenticate that CS/GA scaffolds were cytocompatible and would be useful for tissue engineering applications.

The aim of this article was to develop silk protein (SF) and l-proline (LP) loaded chitosan-(CS) based hydrogels via physical cross linking for tissue engineering and wound healing applications. Silk fibroin, a biodegradable and biocompatible protein, and l-proline, an important imino acid that is required for collagen synthesis, were added to chitosan to improve the wound healing properties of the hydrogel. Characterization of these hydrogels revealed that CS/SF/LP hydrogels were blended properly and LP incorporated hydrogels showed excellent thermal stability and good surface morphology. Swelling study showed the water holding efficiency of the hydrogels to provide enough moisture at the wound surface. In vitro biodegradation results demonstrated that the hydrogels had good degradation rate in PBS with lysozyme. LP loaded hydrogels showed approximately a twofold increase in antioxidant activity. In vitro cytocompatibility studies using NIH 3T3 L1 cells showed increased cell viability (p < 0.01), migration, proliferation and wound healing activity (p < 0.001) in LP loaded hydrogels compared to CS and CS/SF hydrogels. Cell adhesion on SF and LP hydrogels were observed using SEM and compared to CS hydrogel. LP incorporation showed 74-78% of wound closure compared to 35% for CS/SF and 3% for CS hydrogels at 48 h. These results suggest that incorporation of LP can significantly accelerate wound healing process compared to pure CS and SF-loaded CS hydrogels. Hence, CS/LP hydrogels could be a potential wound dressing material for the enhanced wound tissue regeneration and repair. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1401–1408, 2017.