Figure 3.

Different methods of cross-linking type I collagen scaffolds. Physical cross-linking includes UV irradiation and DHT heating treatments. Chemical cross-linking method is most commonly applied by combining EDC and NHS. In this combination, EDC activates aspartic acid and carboxyl groups of glutamic acid origin making them react with nucleophiles to form 0-length cross-links. Genipin induces cross-linking by initiating a nucleophilic attack on amine with two amino groups to form two amide bonds.