Glutaraldehyde\nCross-Linking of Salt-Induced Fibrinogen\nHydrogels

Covalent cross-linking is a common strategy to improve\nthe mechanical\nproperties of biological polymers. The most prominent field of application\nof such materials is in medicine, for example, in the form of bioprinting,\ndrug delivery, and wound sealants. One biological polymer of particular\ninterest is the blood clotting protein fibrinogen. In the natural\nprocess, fibrinogen polymerizes to fibrous hydrogel fibrin. Although\nthe material shows great potential, its costs are very high due to\nthe required enzyme thrombin. Recently, we introduced several approaches\nto trigger a thrombin-free fibrillogenesis of fibrinogen to a fibrin-like\nmaterial. Inspired by the natural pathway of blood clotting in which\ncovalent cross-linking stabilizes the clot, this “pseudofibrin”\nis now developed even further by covalently cross-linking the fibers.\nIn particular, the effect of inexpensive glutaraldehyde on fiber morphology,\nrheological properties, and irreversible gel dissolution is investigated.\nAdditionally, new insights into the reaction kinetics between fibrinogen\nand glutaraldehyde are gained. It could be shown that the fibrous\nstructure of pseudofibrin can be retained during cross-linking and\nthat glutaraldehyde significantly improves rheological properties\nof the hydrogels. Even more important, cross-linking with glutaraldehyde\ncan prevent dissolution of the gels at elevated temperatures.