Objectives: To prepare Sr, Zn and Si-containing bioactive Sr2ZnSi2O7 (SZS) ceramic coating and evaluate its osteoimmunomodulatory properties on inflammation, osteoclatogenesis and osteogenesis.
Methods: SZS ceramic coating on Ti-6Al-4V were prepared by a plasma-spray coating method. Its osteoimmunomodulatory properties was evaluation using a immune cells/osteoblastic cells/biomaterials biomimic system. Ionic concentrations were detected by MS-ICP. Cell viability was detected by MTT. RT-qPCR and western blot were applied to detect the gene and protein expression respectively.
Results: The SZS coatings exhibited slow release of the bioactive ions, with significantly higher bonding strength than hydroxyapatite (HA) coatings. SZS coated Ti-6Al-4V elicited significant effects on the immune cells, inhibiting the release of pro-inflammatory cytokines and fibrosis-enhancing factors, while upregulating the expression of osteogenic factors of macrophages. It could also inhibit the osteoclastic activities. The RANKL/RANK pathway, which enhances osteoclastogenesis, was inhibited by the SZS coatings, whereas the osteogenic differentiation of BMSCs was significantly enhanced by the SZS coatings/macrophages conditioned medium, probably via the activation of BMP2 pathway.
Conclusion: SZS coatings can be a promising material for orthopaedic implant applications, and the strategy of manipulating the immune response by a combination of bioactive elements with controlled release has the potential to endow biomaterials with beneficial immunomodulatory properties.