Deciphering UVA/Riboflavin Collagen Crosslinking: A Pathway to Improve Biomedical Materials

Collagen crosslinking employing ultraviolet A rays and riboflavin (UVA/R) has emerged as a pivotal technique in clinical therapies, especially in ophthalmology since the 1990s. Despite its clinical adoption, the lack of clarity of the detailed mechanism and the imperative for a refined manufacturing process necessitates further investigation. This study advances the understanding of UVA/R crosslinked collagen, concentrating on identifying the primary crosslinking sites using seven synthetic peptides and exploring the pathways of riboflavin-mediated crosslinking. The results demonstrate that tyrosine residues are key crosslinking sites, and riboflavin plays a dual role as both a catalyst and a competitive inhibitor in the crosslinking process. Furthermore, the UVA/R crosslinked collagen matrix exhibits a more harmonious balance between stability and degradability compared with chemically crosslinked collagen matrices, coupled with superior mechanical properties and augmented biocompatibility. In vivo experiments further validate its excellent biocompatibility, reduced tissue inflammation, and promotion of tissue regeneration. The research provides crucial insights into collagen crosslinking mechanisms, paving the way for the development of sophisticated collagen-based biomaterials tailored for biomedical applications. This study unveils the intricate mechanisms of collagen crosslinking through ultraviolet type A light rays and riboflavin (UVA/R), emphasizing the essential roles of tyrosine residues and riboflavin in reinforcing the structure of the collagen matrix. It uncovers the augmented mechanical durability, improved biocompatibility, and minimized tissue inflammation of UVA/R crosslinked collagen, which has the promise of being a potential next-generation collagen-based biomaterial for tissue regeneration applications. image