Fabrication of chondroitin sulfate-chitosan composite artificial extracellular matrix for stabilization of fibroblast growth factor

The development of a novel, three-dimensional, macroporous artificial extracellular matrix (AECM) based on chondroitin sulfate (ChS)-chitosan (Chito) combination is reported. The composite AECM composed of ChS-Chito conjugated network was prepared by a homogenizing interpolyelectrolyte complex/covalent conjugation technique through co-crosslinked with N,N-(3-dimethylaminopropyl)- N′-ethyl carbodiimide (EDC) and N-hydroxysuccinimide (NHS). In contrast to EDC/NHS, two different reagents, calcium ion and glutaraldehyde, were used to react with ChS or Chito for the preparation of ChS-Chito composites containing crosslinked ChS or Chito network in the matrix. The stability and in vitro enzymatic degradability of the glutaraldehyde-, EDC/NHS-, and Ca ²⁺-crosslinked ChS-Chito composite AECMs were all investigated in this study. The results showed that crosslinking improved the stability of prepared ChS-Chito AECMs in physiological buffer solution (PBS) and provided superior protective effect against the enzymatic hydrolysis of ChS, compared with their non-crosslinked counterpart. Because ChS was a heparin-like glycosaminoglycan (GAG), the ChS-Chito composite AECMs appeared to promote binding efficiency for basic fibroblast growth factor (bFGF). The bFGF releasing from the ChS-Chito composite AECMs retained its biological activity as examined by the in vitro proliferation of human fibroblast, depending on the crosslinking mode for the preparation of these composite AECMs. Histological assay showed that the EDC/NHS-crosslinked ChS-Chito composite AECM, after incorporated with bFGF, was biodegradable and could result in a significantly enhanced vascularization effect and tissue penetration. These results suggest that the ChS-Chito composite AECMs fabricated in this study may be a promising approach for tissue-engineering application.