Recombinant human collagen type III microgel: an advanced injectable dermal filler for rejuvenating aging skin

Skin aging, characterized by reduced collagen regeneration, chronic inflammation and heightened skin cancer risk, poses a significant challenge. Collagen-based materials, employed as dermal fillers to smooth wrinkles, have attained extensive utilization. Nevertheless, traditional animal-derived collagen protein primarily presents concerns pertaining to disease risks, potential immunological reactions, and batch instability. Here, we introduced a highly durable 1,4-butanediol diglycidyl ether cross-linked recombinant human collagen type III (rhCol III) microgel as dermal filler for rejuvenating aging skin. The rhCol III microgel exhibited exceptional thermostability, mechanical strength and injectability. Subsequently, we established a UV-photoaging skin animal model and chose rhCol III microgel as a bioactive material for <i>in vivo</i> implantation, systematically comparing its biological effect with commercialized collagen I (Col I) derived from porcine skin (pCollagen) and hyaluronic acid through histological observation, immunofluorescence staining, hydroxyproline quantification and analysis of specific gene expression. Outcomes indicated rhCol III microgel prompted augmented production of Col I, collagen III (Col III) and elastic fibers, thereby contributing to the remodeling of the extracellular matrix (ECM). In summary, our investigation contributed to robust biosafety and rejuvenation of UV-induced skin photoaging by rhCol III under a single injection for 6 weeks. Despite the imperative ongoing efforts required for the successful translation from bench to clinic, the discernibly superior safety and efficacy of rhCol III microgel present an innovative methodology in combating skin aging, offering significant promise in medical cosmetology and tissue engineering.