目的·构建一种负载骨形态发生蛋白2（bone morphogenetic protein-2，BMP-2）微球的新型抗菌和可注射水凝胶，检测其生物相容性、抗菌和促成骨性能。方法·通过微流控技术制备负载BMP-2的光交联明胶微球，将微球与巯基化的聚乙二醇[4-arm thiol-terminated poly (ethylene glycol)，4SH-PEG]混合，用Ag+交联4SH-PEG，制备含有微球的可注射4SH-PEG复合水凝胶（BMP/Gel/SH-Ag）。光学显微镜和扫描电子显微镜(scanning electron microscope, SEM)观察微球和水凝胶的微观形态；在100转/min、37 ℃的摇床中进行药物释放实验；使用针头直径为0.5 mm的注射器注射BMP/Gel/SH-Ag，评价其可注射性；通过琼脂扩散实验评价BMP/Gel/SH-Ag对金黄色葡萄球菌（Staphylococcus aureus，S. aureus）和大肠埃希菌（Escherichia coli，E. coli）的抗菌性能；通过CCK-8实验考察BMP/Gel/SH-Ag的生物相容性；通过骨髓间充质干细胞（bone marrow mesenchymal stem cells，BMSCs）的碱性磷酸酶（alkaline phosphatase，ALP）染色和钙结节染色评价其促成骨活性。结果·明胶微球外表光滑，粒径分布均匀（～350 μm）；BMP/Gel/SH-Ag呈现孔洞状的微观结构；在摇床中温育8 d ，BMP/Gel/SH-Ag中的BMP-2累积释放量为（81.8±3.6）%；BMP/Gel/SH-Ag可以用直径小至0.5 mm的注射器针头来注射，以产生水凝胶细丝；BMP/Gel/SH-Ag对S. aureus和E. coli有抑制作用；CCK8结果表明，BMP/Gel/SH-Ag具有良好的生物相容性；BMP/Gel/SH-Ag可提高BMSCs的ALP的表达和钙结节的含量。结论·该BMP/Gel/SH-Ag水凝胶在促进成骨和抗感染方面有良好的表现。

Objective · To construct a novel antibacterial and injectable hydrogel (BMP/Gel/SH-Ag) loaded with bone morphogenetic protein-2 (BMP-2) microspheres, and investigate its biocompatibility, antibacterial properties and bone-promoting properties. Methods · The photocrosslinked gelatin microspheres loaded with BMP-2 were prepared by microfluidics. The microspheres were mixed with 4-arm thiol-terminated poly (ethylene glycol) (4SH-PEG) and crosslinked with Ag+ to prepare injectable sulfhydrylated PEG hydrogels (BMP/Gel/SH-Ag). The micromorphology of microspheres and hydrogels was observed by light microscope and scanning electron microscope. The drug release profile was investigated at 37 ℃ in a shaker (100 r/min). The injectability of BMP/Gel/SH-Ag was evaluated by injecting hydrogel using a syringe with a tip diameter of 0.5 mm. The antibacterial activity of BMP/Gel/SH-Ag against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) was evaluated by agar diffusion test. The biocompatibility of BMP/Gel/SH-Ag was verified by CCK-8, and the bone-promoting activity was evaluated by alkaline phosphatase (ALP) assay and calcium nodule staining in bone marrow mesenchymal stem cells (BMSCs). Results · Gelatin microspheres had smooth appearance and uniform particle size distribution (～ 350 μm). BMP/Gel/SH-Ag had porous microstructure and can be injected with a syringe needle with a diameter of up to 0.5 mm in diameter to produce hydrogel filament. The cumulative release of BMP-2 from BMP/Gel/SH-Ag was (81.8±3.6)% after being incubated for 8 d. BMP/Gel/SH-Ag had obvious inhibitory effect on S. aureus and E. coli. CCK-8 results showed that BMP/Gel/SH-Ag had good biocompatibility. BMP/Gel/SH-Ag can increase the expression of ALP and the content of calcium nodules in rat BMSCs. Conclusion · The BMP/Gel/SH-Ag has good performance in promoting osteogenesis and anti-infection.