Comparison of two proanthocyanidin cross-linked recombinant human collagen-peptide (RHC) - chitosan scaffolds.

Cross-linking plays an important role in tissue engineering, which involves the alternative of cross-linker and the way of components interaction. We compared two proanthocyanidin (PA) cross-linked recombinant human collagen-peptide - chitosan scaffolds: immerse cross-linking (I-CLS) and premix cross-linking (P-CLS). Both of the scaffolds presented homogeneous pore structure with mean pore size of 110-115 μm. The swelling ratio was decreased to 29.6 in I-CLS, but increased to 37.1 in P-CLS while porosity of the two scaffolds was reduced about 8% comparing to 94.3% before cross-linking. The cross-linked scaffolds exhibited enhanced resistance to enzyme degradation and improved compressive modulus (I-CLS > P-CLS). The scaffolds transformed from elastic region to plastic region until the strain reached 60%, and the stress was 40.5, 133.2 and 84.1 kPa of uncross-linking scaffold, I-CLS and P-CLS individually. Thermal stability indicated molecular bonding between PA and the scaffold components, simultaneously, Fourier transform infrared spectroscopy mainly presented hydrogen bonding between the protein amide carbonyl and the phenolic hydroxyl with a particular transform due to pyrrolidine rings of proline in P-CLS. Both of the I-CLS and P-CLS could promote human umbilical vein endothelial cells attachment and proliferation. The characterization suggested in situ biodegradable application of P-CLS, while a potential long-term utilization of I-CLS in tissue engineering.