Strong Collagen Hydrogels by Oxidized Dextran Modification

Collagen hydrogel has been regarded as an excellent biomaterial because it is an abundant and sustainable resource and has good biocompatibility and controllable cell-based biodegradability. However, the poor mechanical properties of collagen hydrogel are the main disadvantage preventing it from having wide applications. In this communication, we use aldehyde-functionalized dextran, which is prepared from the oxidation of another natural polymer dextran, as a macromolecular cross-linker to enhance the strength of the collagen hydrogel. The resulting collagen/aldehyde-functionalized dextran (Col/DAD) hydrogels are much stronger and show better thermostability than the pristine collagen hydrogel, as expected. The maximum compressive strength of the Col/DAD hydrogel is 32.5 ± 1.6 kPa, which is about 20 times more than that of the pristine collagen hydrogel. We also prove that our method maintains the good biocompatibility of the collagen hydrogel and does not bring the cytotoxicity often observed from conventional chemical cross-linking in the product. Therefore, the strong collagen hydrogel made by oxidized dextran modification may have a great potential in tissue engineering and other biomedical fields.