Fabrication Of Recombinant Human-source Collagen Scaffolds For Biomedical Tissue Engineering

Recombinant human-source Collagen (RHSC) was choosen as the main object obtained through high-density fermentation of genetic engineering bacteria Pichia pastoris. Firstly, separated and purified RHSC from suspension and characterized its sructure. Then, combined it with chitosan to prepare three-dimensional porous sponges using freeze-drying techniques. The strong antioxidant of proanthocyanidins (PA) was selected as cross-linking agent to improve the properties of sponges.1. The purity of RHSC reached electrophoresis degree after separation and purification, and characterization indicated that the purify was above 99%, while the recovery exceeded 93%. DSC, UV, FT-IR and NMR were detected to compare RHSC with type Ⅲ collagen. Results showed that RHSC has the characteristic structure of type Ⅲ collagen.2. We evaluated several factors during sponges fabrication and found that concentration of acid as well as weight ratio of RHSC and chitosan were the crucial effects to control the mricostructure of sponges. Chitosan-RHSC sponges with admirable physical and chemical properties were obtained after PA cross-linking. The pore size was about 110-160μm, the porosity exceeded 92%, and the water uptake reached to 3900%. The results of FT-IR showed that PA could form stable hydrogen bonds with the sponge matrix. DSC and TG analysis presented that the thermal stability of the sponges after cross-linking was increased. In vitro biodegradation exhibited enhanced resistance to enzyme degradation of the cross-linked sponges. The sponge also showed favourable biocompatibility containing cell ashesion, migration, proliferation and cell morphology detection.Therefore, the PA cross-linked chitosan-RHSC sponges was an alternative biomaterial which could promoted cell growth well. Even though the study is still at the initial stage of experiment, the sponge reveals its potential ultilization in tissue engineering.