LAUSR

Background Inflammatory osteolysis, a major complication of total joint replacement surgery, can cause prosthesis failure and necessitate revision surgery. Macrophages are key effector immune cells in inflammatory responses, but excessive M1-polarization of dysfunctional macrophages leads to the secretion of proinflammatory cytokines and severe loss of bone tissue. Here, we report the development of macrophage-biomimetic porous SiO 2 -coated ultrasmall Se particles (porous Se@SiO 2 nanospheres) to manage inflammatory osteolysis. Results Macrophage membrane-coated porous Se@SiO 2 nanospheres(M-Se@SiO 2 ) attenuated lipopolysaccharide (LPS)-induced inflammatory osteolysis via a dual-immunomodulatory effect. As macrophage membrane decoys, these nanoparticles reduced endotoxin levels and neutralized proinflammatory cytokines. Moreover, the release of Se could induce macrophage polarization toward the anti-inflammatory M2-phenotype. These effects were mediated via the inhibition of p65, p38, and extracellular signal-regulated kinase (ERK) signaling. Additionally, the immune environment created by M-Se@SiO 2 reduced the inhibition of osteogenic differentiation caused by proinflammation cytokines, as confirmed through in vitro and in vivo experiments. Conclusion Our findings suggest that M-Se@SiO 2 have an immunomodulatory role in LPS-induced inflammation and bone remodeling, which demonstrates that M-Se@SiO 2 are a promising engineered nanoplatform for the treatment of osteolysis occurring after arthroplasty. Graphical Abstract