Tuning inflammation response via adjusting microstructure of hydroxyapatite and biomolecules modification

Excellent biocompatibility and inflammatory regulation ability are essential to bone repair materials. Herein, Rod-like HAP with a diameter of 0.1 pm and Flake-like HAP with a width of 0.5-1 mu m were synthesized by hydrothermal method, and then combined with two kinds of biomolecules, Icariin and Kaempferol. Two kinds of HAPs have similar crystal structure, but different zeta potentials and specific surface area. Rod-like HAP possesses stronger loading capacity and internalization efficiency than Flake-like one. in vitro inflammation assay reveals that HAP particles up-regulate the expression of IL-1 beta, TNF-alpha, IL-6, IL-10, IFN-gamma and IL-2 cytokines. HAP particles loaded with Icariin or Kaempferol biomolecules up-regulate anti-inflammatory cytokines and down regulate the expression of inflammatory cytokines.