Synthesis of in-situ formable hydrogels with collagen and hyaluronan through facile Michael addition

To mimic the natural extracellular matrix (ECM) and to facilitate tissue regeneration, in-situ formable collagen/hyaluronan composite hydrogels were prepared by a facile approach via Michael addition reaction, with maleilated collagen (Col-MA) and thiol derivatized hyaluronan (HA-SH). The hydrogels were denoted as CHG-1, CHG-2, CHG-3 and CHG-4 by vinyl/free thiol molar ratio (f) of 1:1, 1:2, 1:3 and 1:4, respectively. Results showed that with decrease of the f values, the gelation time decreased from 43s to 15s, Young's modulus increased from 1671.65Pa to 9105.86Pa, and the swelling ratio increased from 1.5 to 12.7. SEM images of the air-dried samples revealed that the chemical modification process did not denature the collagen, and the interwoven collagen fibrils were indeed observed. Cell culture confirmed that the CHG facilitated the growth and proliferation of MC3T3-E1. Cells displayed spreading morphology and formed nearly aligned cell layers with the extension of culture time. Therefore, it is suggested that CHG can be used as injectable materials for tissue regeneration.