Facile and Rapid Preparation of Injectable Collagen Hydrogel Mediated by EGCG Physical Crosslinking

Collagen is a highly favorable macromolecule for biomedical applications and is often made into functional forms via gelation. Conventional gelation approach relies on the self-assembly of collagen molecules via pH and temperature adjustment, which is slow and tedious, and often associated with poor physical strength. To overcome these challenges, we present a facile and rapid collagen gelation strategy using epigallocatechin gallate (EGCG), a natural polyphenol from green tea. Upon simple mixing with solubilized collagen, EGCG induced the spontaneous formation of stable and injectable hydrogels via hydrophobic and π-π interactions. Capitalizing on the hydrogel's thixotropic behavior and the established skin health benefits of collagen and EGCG, we investigated its translational potential. The hydrogel exhibited excellent skin compatibility, prolonged surface retention with moisturizing effects, and erosion-controlled codelivery of proteins and EGCG. Collectively, these findings highlight the potential of the collagen-EGCG hydrogel as a promising platform for topical applications.