K+/Sr2+/Na+ triple-doped hydroxyapatites/GelMA composite hydrogel scaffold for the repair of bone defects

One of the most important characteristics of desirable bone repair materials is to mimic the functions of human bones such as the storage/release of ions to maintain ionic homeostasis. In attempt to mimic natural Hydroxyapatite (HAP: Ca10(PO4)6(OH)2) in bones, HAP nanoparticles containing three abundant ions in human skeletal tissue (K+, Sr2+ and Na+) were designed and synthesized. The structures, morphologies, functional groups and cellular viability of the developed systems were examined to determine the precipitation conditions for generating pure phases of K+/Sr2+/Na+ triple-substituted nanoparticles. Notably, K+/Sr2+/Na+ triple-doped HAP nanoparticles were evaluated in vitro using osteoblasts cell line MC3T3-E1 to confirm the improved proliferation compared to bone cells grown with HAP without ion substitution. This study provides a bone material platform based on GelMA hydrogel that can deliver therapeutic ions in a biomimetic manner, and demonstrates the impact of ions on the osteogenic activity of cells.