M2 polarization of macrophage is an important immunomodulatory event that attenuates inflammation. To regulate the immune microenvironment in osteoporotic conditions for enhancing bone healing, strontium-doped nano-structure is fabricated on the surface of titanium implant via microarc oxidation and electrochemical deposition technology, followed by the addition of multiplayer coatings embedded with silk fibroin-based wogonin nanoparticles (Ti-MAO/Sr/LBLWNP ) by layer-by-layer self-assembly technique (LBL). It is found that Ti-MAO/Sr/LBLWNP can release wogonin and Sr2+ in a sustainable manner for more than 7 and 21 days. In vitro studies show that Ti-MAO/Sr/LBLWNP significantly upregulates the expression of CD206 while reducing the expression of CD86. Meanwhile, Ti-MAO/Sr/LBLWNP can promote the expression level of M2 macrophage anti-inflammatory factor (TGF-β1, Arg-1), which improves the proliferation and osteogenic differentiation of osteoblasts through paracrine signaling. Compared to bare titanium, Ti-MAO/Sr/LBLWNP significantly inhibits the expression of inflammatory factors around the implant and effectively promotes new bone formation at pre-implant interface after implantation for 4 weeks. This study provides a simple and effective method to develop functional titanium alloy materials for osteoporotic fracture repair.
Keywords: macrophage; osteoporosis; silk fibroin/wogonin nanoparticles; titanium implants.
© 2022 Wiley-VCH GmbH.