Synthesis and characterization of elastic and macroporous chitosan-gelatin cryogels for tissue engineering

Elastic chitosan-gelatin cryogels of varying concentration of polymer precursors have been synthesized using glutaraldehyde as a crosslinking agent. The optimum co-polymer ratio of chitosan to gelatin was found to be 1:4 at the temperature of -12 degrees C for synthesis of chitosan-gelatin hybrid cryogels. chitosan-gelatin cryogels synthesized with low viscosity chitosan were morphologically better than those formed with medium and high viscosity chitosan. Pore diameters of chitosan-gelatin cryogels as measured by scanning electron microscopy (SEM) was in the range of 30-100microm. While mercury porosimetry analysis revealed the majority of pores of the scaffold lying in the range of 30-50microm. Porosity of chitosan-gelatin cryogels was found to be greater than 90% using Archimedes's principle. Unconfined compression tests showed significant elasticity of chitosan-gelatin cryogels and maintained their physical integrity even after compressing them up to 80% of their original length. The elastic modulus varied in the range of 36-39kPa. Cyclic deformation analysis performed by compression of chitosan-gelatin cryogels with varying strains (10, 20 and 40%) showed no cracking or any significant deformation. The degradation of chitosan-gelatin cryogels was found up to 13.58+/-1.52% at 37 degrees C within 8 weeks of incubation under sterile conditions and the cryogels swelled up to 90% of their capacity within two min. Efficient cell adherence, proliferation and extracellular matrix (ECM) secretion was observed by growing fibroblast (Cos-7) cell line on chitosan-gelatin hybrid cryogels which indicate potential of the material for tissue engineering applications.