Green Agarose Hydrogel Implants With High Biocompatibility for Skin Repair and Regeneration in Photoaged Skin

ABSTRACT Skin aging is a multifaceted process marked by the destruction of skin structure and the diminishment of skin function, significantly impacting both physical and mental health. Injectable hydrogels are promising for skin repair, but chemical crosslinking in most hydrogels can cause cytotoxicity, whereas agarose hydrogels avoid crosslinking yet face injectability challenges. We have herein developed green agarose hydrogel implants with high biocompatibility for skin repair and regeneration in photoaged skin. The hydrogel is prepared by utilizing agarose's ability to dissolve at high temperatures and gel at low temperatures. This process yields implants with particle sizes predominantly ranging from 100 to 150 μm. The agarose hydrogel implant exhibits excellent injectability, with a steady injection force curve consistently around 4 N. The agarose hydrogel implant promotes the proliferation of human dermal fibroblasts and does not induce hemolysis or pyrogenic reactions. In a photoaging mouse model, the agarose hydrogel implant improves skin density and hydration, reduces transepidermal water loss, and stimulates collagen regeneration. This agarose hydrogel implant provides a novel approach to repairing aged skin and holds significant potential in the fields of skin health and tissue regeneration.