Tuning of 2D cultured human fibroblast behavior using lumichrome photocrosslinked collagen hydrogels

Abstract

Collagen is extensively used in fabrication of hydrogels for biomedical applications but needs improvement after its isolation from tissues due to slow gelation and poor mechanical properties. Crosslinking could tailor such properties. Collagen has previously been crosslinked by chemical or photochemical methods. Chemical crosslinkers are often toxic, and the crosslinking reaction is difficult to control. Photochemical crosslinkers are usually biocompatible compounds that are activated upon irradiation. Riboflavin (vitamin B2), a photochemical crosslinker of collagen, photodegrades to lumichrome upon irradiation. Cyclodextrins have previously been used to increase the aqueous solubility of lumichrome and regulate collagen self-assembly. In this study, lumichrome dissolved by cyclodextrin complexation was used as a photochemical crosslinker of collagen. Lumichrome photocrosslinking reduced the gelation time to 10 s, compared to 90 min for physical crosslinking. The formed hydrogels exhibited increased elasticity, water absorption properties and water holding capacity compared to physically crosslinked collagen hydrogels and riboflavin photocrosslinked collagen hydrogels. Fibroblasts achieved a myofibroblastic phenotype when cultivated in 2D on lumichrome photocrosslinked gels as observed from histology. These biocompatible photocrosslinked hydrogels could have potential applications in biomedical applications, such as wound healing.