Preparation and cell compatibility evaluation of chitosan/collagen composite scaffolds using amino acids as crosslinking bridges

In this study, a novel freeze-gelation method instead of the conventional freeze-drying method was used to fabricate porous chitosan/collagen-based composite scaffolds for skin-related tissue engineering applications. To improve the performance of chitosan/collagen composite scaffolds, we added 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) and amino acids (including alanine, glycine, and glutamic acid) in the fabrication procedure of the composite scaffolds, in which amino acid molecules act as crosslinking bridges to enhance the EDC-mediated crosslinking. This novel combination enhanced the tensile strength of the scaffolds from 0.70 N/g for uncrosslinked scaffolds to 2.2 N/g for crosslinked ones; the crosslinked scaffolds also exhibited slower degradation rates. The hydrophilicity of the scaffolds was also significantly enhanced by the addition of amino acids to the scaffolds. Cell compatibility was demonstrated by the in vitro culture of human skin fibroblasts on the scaffolds. The fibroblasts attached and proliferated well on the chitosan/collagen composite scaffolds, especially the one with glutamic acid molecules as crosslinking bridges, whereas cells did not grow on the chitosan scaffolds. Our results suggest that the collagen-modified chitosan scaffolds with glutamic acid molecules as crosslinking bridges are very promising biomaterials for skin-related tissue engineering applications because of their enhanced tensile strength and improved cell compatibility with skin fibroblasts. (c) 2007 Wiley Periodicals, Inc.