Effect of two crosslinking methods on the physicochemical and biological properties of the collagen-chitosan scaffolds

Chemical and physical crosslinking methods using glutaraldehyde (GA) and ammonium hydroxide (AH), respectively, were utilized to prepare chitosan (CS) and chitosan/collagen (CS-Co) hydrogels; these materials were then subjected to freeze-drying process to obtain 3D porous scaffolds. The effect of crosslinking methods on the physicochemical and biological properties of the scaffolds was studied. Results indicated that crosslinking method plays a key role on morphology, average pore size, pore size distribution, degradation and cytotoxicity of the scaffolds. Physically crosslinked scaffolds exhibited a homogeneous morphology with higher pore size and interconnectivity in comparison to other prepared scaffolds; also, these samples, showed a good biocompatibility. Scaffolds derived from hydrogels treated with acetone (AC) showed shrinkage, smaller pore size and higher degradation rates; finally, materials chemically crosslinked with glutaraldehyde presented cytotoxicity and exhibited a heterogeneous morphology. Overall, these results suggest that the scaffolds physically cross linked by means of AH, containing or not collagen (CS-AH and CS-Co-AH), are suitable for tissue engineering.