Significantly Accelerated Osteoblast Cell Growth on TiO₂/SrHA Composite Mediated by Phenolic Compounds (BHM) from Hippocampus kuda Bleeler

The microstructure of hydroxyapatite is known to influence cellular behavior, can be used as a substrate for osteoblast growth, and exploited as a drug-release platform. However, easy delamination and self-decomposition of hydroxyapatite caused by poor adhesion with substrates are the main problems currently. In this paper, we successfully fabricated titanium dioxide/strontium-doped hydroxyapatite (TiO2/SrHA) composite scaffolds by self-generated strontium-substituted hydroxyapatite microspheres in TiO2 nanotubes. Moreover, the active compound 1-(5-bromo-2-hydroxy-methoxyphenyl)-ethanone (BHM) from Seahorse (Hippocampus kuda Bleeler) was loaded in this scaffold, and the controlled release kinetics of BHM was studied. It was found that in the first 5 h, the release concentration and time of BHM had a good linear relationship, and the correlation coefficient reached 0.98. TiO2/SrHA/BHM composites exhibited favorable cytocompatibility at a given concentration of BHM (20 μmol/L). Compared to pure SrHA, TiO2 nanotubes, and traditional TiO2/SrHA composites, superior cytocompatibility (cell adhesion and proliferation) of MC3T3-E1 was obtained on TiO2/SrHA/BHM composites. The expression levels of osteogenic marker genes such as alkaline phosphatase, osteopontin, osteocalcin, runt-related transcription factor 2, and collagen I are also upregulated to varying degrees. This TiO2/SrHA composite scaffold-mediated phenolic compound BHM could be applied in bone tissue repair.