A highly bioactive THPC-crosslinked recombinant collagen hydrogel implant for aging skin rejuvenation.

Skin aging, a complex physiological progression marked by collagen degradation, poses substantial challenges in dermatology. Recombinant collagen emerges as a potential option for skin revitalization, yet its application is constrained by difficulties in forming hydrogels. We have for the first time developed a highly bioactive Tetrakis(hydroxymethyl) phosphonium chloride (THPC)-crosslinked recombinant collagen hydrogel implant for aging skin rejuvenation. THPC demonstrated superior crosslinking efficiency compared to traditional agents such as EDC/NHS and BDDE, achieving complete recombinant collagen crosslinking at minimal concentrations and effectively inducing hydrogel formation. THPC's four reactive hydroxymethyl groups facilitate robust crosslinking with triple helical recombinant collagen, producing hydrogels with enhanced mechanical strength, excellent injectability, increased stability, and greater durability. Moreover, the hydrogel exhibited remarkable biocompatibility and bioactivity, significantly promoting the proliferation, adhesion, and migration of human foreskin fibroblast-1. In photoaged mice skin models, the THPC-crosslinked collagen hydrogel implant notably improved dermal density, skin elasticity, and reduced transepidermal water loss, creating a conducive environment for fibroblast activity and healthy collagen regeneration. Additionally, it elevated superoxide dismutase (SOD) activity and displayed substantial anti-calcification properties. The THPC-crosslinked recombinant collagen hydrogel implant presents an innovative methodology in combating skin aging, offering significant promise in dermatology and tissue engineering.