Bioinspired Hydrogel Anchoring 3DP GeIMA/HAp Scaffolds Accelerates Bone Reconstruction

Seeking high biological activity and osteoinductive ability has always been an urgent problem for three-dimensional-printed (3DP) bony implants. Here, a 3DP methacrylic anhydride-modified gelatin (GelMA)/hydroxyapatite (HAp) scaffold with a high solid content of 82.5% was prepared and anchored by a functionalized polyphenol hydrogel. The scaffold and hydrogel were organically integrated into a bioinspired bony implant (HGH) by phenolic hydroxyl of hyaluronan derivatives conjugating amino groups of collagen I and GeIMA and further chelating calcium ions of HAp. Compared with a simplex 3DP scaffold, this freeze-dried HGH presented better water retention, delayed degradation, and mechanical stability. It could promote migration, proliferation, and osteogenic differentiation of bone marrow stem cells in vitro. One week of implantation showed that it promoted directional migration of endogenous stem cells and early osteogenesis and angiogenesis. After 15 week surgery of rabbit skull defects, the BV/TV value of HGH returned to 73% of the normal group level. This strategy provided a new research idea for bone regeneration.

Automated summary

This study developed a biologically inspired bony implant by preparing a 3DP methacrylic anhydride-modified gelatin/hydroxyapatite scaffold with high solid content and anchoring it with a functionalized polyphenol hydrogel. The implant showed improved water retention, delayed degradation, and mechanical stability compared to a simple 3DP scaffold. It also promoted migration, proliferation, and osteogenic differentiation of bone marrow stem cells in vitro, as well as direction migration, early osteogenesis, and angiogenesis in vivo.