Development of bFGF-chitosan matrices and their interactions with human dermal fibroblast cells

Chitosan (CH) is a naturally derived, biodegradable polymer of glucosamine with a variable frequency of N-acetyl-D-glucosamine units, and has been demonstrated to have numerous pharmacological and wound-healing properties. Biodegradable chitosan films were fabricated using a solvent casting technique and investigated for skin tissue-engineering applications. Basic fibroblast growth factor (bFGF) was incorporated into the CH matrices (1 microg/film) by 3 methods: adsorption, entrapment and covalent binding. Release rates and biological activity of the incorporated bFGF were monitored. Human dermal fibroblasts (HDF cells) were used as an in vitro model for cell response to CH and bFGF-CH films. Cell attachment, growth and acid-soluble collagen quantification were employed as an assessment of cell function. The fibroblasts were found to remain viable on the chitosan films and scaffolds. CH films without bFGF were compatible with HDF cells; however, the fibroblasts did not proliferate. The release profile of adsorbed and bound bFGF from CH films were similar (indicating that binding was not efficient) while entrapped bFGF was not released in the time frame studied. The concentration of bFGF released to the cell culture medium was not high enough to stimulate HDF proliferation. However, cell attachment was significantly increased in chitosan films with bFGF adsorbed onto the surface as compared to control surfaces. HDF cells grown on CH films produced significantly more collagen than those on control surfaces.