Hyaluronic acid-hydroxyapatite composite hydrogels for tissue filling and soft tissue regeneration

Hyaluronic acid (HA) is a widely used biomaterial for soft tissue filling and repair, while hydroxyapatite (HAp) promotes fibroblast activity and collagen deposition. In this study, we developed a composite HA@HAp hydrogel scaffold by blending HA with HAp. The HA@HAp hydrogel demonstrated good in vitro biocompatibility and promoted cell proliferation and collagen regeneration in vivo. Whole transcriptome RNA sequencing of subcutaneously injected HA@HAp hydrogels revealed that HA exhibits inert properties and inhibits proliferation and differentiation of cells in vivo, whereas HAp enhances cell metabolic activity and proliferation through multiple mechanisms. In a face filling model, HA@HAp hydrogels stimulated cell proliferation and collagen synthesis. In the skin defect model, HA@HAp hydrogels accelerated wound healing, reduced scar formation, and promoted collagen deposition. Altogether, HA@HAp hydrogels hold promise for enhancing soft tissue regeneration and improving therapeutic outcomes in tissue repair.