The immune response of peri-titanium (Ti) implants, which is mainly determined by the surface properties of the Ti implant, may lead to a prolonged healing period and even implantation failure. The phosphate chemical conversion (PCC) technique is an effective method for simultaneously regulating the crystallographic morphological and elemental compositions of Ti implant surfaces. However, whether the PCC coating induces an immune response or further affects osteogenesis is unclear. In this study, we prepared three kinds of PCC-coated Ti implants, i.e., Sr-Zn-P A (strontium zinc phosphate with rectangular blocky crystals), Sr-Zn-P B (strontium zinc phosphate with lamellar crystals) and Sr-Ca-P (calcium strontium phosphate), which were composed of different phosphate crystals or had different morphologies. Although all PCC-coated Ti implants showed good biocompatibility with both rat bone marrow mesenchymal stem cells (rBMMSCs) and rat macrophages, different effects on rBMMSC osteogenesis and macrophage polarization were found in this study: 1) Sr-Zn-P B preferentially induced rBMMSC osteogenesis and M2 polarization to a greater extent than the other implants because of its surface morphology and ion release; 2) under three culture conditions (coculture, transwell and conditioned medium), Sr-Zn-P B was found to enhance the production of anti-inflammatory and pro-osteogenic factors via M2 polarization; 3) characterization of the osteogenesis and immune response in rat subcutaneous models and rat femoral defect models revealed that Sr-Zn-P B could perform well in osteoimmunomodulation in vivo; and 4) through RNA sequencing analysis, the up-/downregulation of several signaling pathways was identified as a potential reason for M2 polarization on Sr-Zn-P B. In conclusion, this study demonstrates that Sr-Zn-P B is a promising scaffold for osteoimmunomodulation and provides new insight into bone defect repair.

钛钛（Ti）植入物的免疫反应主要由Ti植入物的表面特性决定，可能会导致愈合时间延长甚至植入失败。磷酸盐化学转化（PCC）技术是一种有效的方法，可同时调节Ti植入物表面的晶体学形态和元素组成。然而，尚不清楚PCC涂层是诱导免疫反应还是进一步影响成骨作用。在这项研究中，我们准备了三种PCC涂层的Ti植入物，即Sr-Zn-P A（具有矩形块状晶体的磷酸锶锌），Sr-Zn-P B（具有层状晶体的磷酸锶锌）和Sr- Ca-P（磷酸钙锶），由不同的磷酸盐晶体组成或具有不同的形态。尽管所有PCC涂层的Ti植入物均与大鼠骨髓间充质干细胞（rBMMSCs）和大鼠巨噬细胞均表现出良好的生物相容性，但在这项研究中发现了对rBMMSC成骨和巨噬细胞极化的不同影响：1）Sr-Zn-P B优先诱导rBMMSC由于其表面形态和离子释放，成骨作用和M2极化程度比其他植入物更大。2）在三种培养条件下（共培养，transwell和条件培养基），发现Sr-Zn-P B通过M2极化增强抗炎和促成骨因子的产生；3）在大鼠皮下模型和大鼠股骨缺损模型中对成骨和免疫反应的表征表明，Sr-Zn-PB在体内的骨免疫调节中表现良好。和4）通过RNA测序分析，