聚六亚甲基胍TiO2纳米管的抑菌性能及机制研究

Antibacterial properties and mechanism of TiO2 nanotube loaded with polyhexamethylene guanidine

目的在人工关节置换钛假体材料表面原位合成负载抗菌剂聚六亚甲基胍(polyhexamethylene guanidine,PHMG)的二氧化钛(TiO2)纳米管,通过体外、体内实验研究负载PHMG的TiO2纳米管的抗菌性能,为具有良好抗菌性能人工关节假体材料的开发提供新的思路。方法采用阳极氧化法制备TiO2纳米管,并于其表面负载抗菌剂PHMG。体外实验时分别将纯金属钛箔、TiO2纳米管钛箔和负载PHMG的TiO2纳米管钛箔与金黄色葡萄球菌ATCC 29213悬液共培养研究其抑菌性能。体内实验时将24只新西兰大白兔股骨扩髓并注入0.1 ml 108 CFU/ml的金黄色葡萄球菌悬液制备感染模型后,分别将纯金属钛棒、TiO2纳米管钛棒和负载PHMG的TiO2纳米管钛棒植入新西兰大白兔右侧股骨髓腔,研究体内的抑菌性能。结果通过阳极氧化制备的TiO2纳米管孔径为(46.4±5.9)nm,钛箔TiO2纳米管长度为300~500 nm,钛棒TiO2纳米管长度为500~1000 nm,于其表面分别负载(3.46±0.40)mg与(1.27±0.28)mg PHMG。体外PHMG释放实验表明,该药物的释放分为两个阶段:初始突释释放阶段和相对缓慢释放阶段,为早期抑制细菌入侵和后期持续抑菌提供保障。体外和体内抑菌实验表明,载有PHMG的TiO2纳米管能够抑制细菌黏附与定植,减少感染。结合临床病理分析表明PHMG-TiO2纳米管植入组无明显病理变化,骨髓腔内可见大量有核细胞和网状结缔组织,并且在髓腔内可见正常的骨髓组织。结论负载PHMG的TiO2纳米管对金黄色葡萄球菌有良好的抗菌性能,作为一种人工关节假体材料具有极大的研究意义和开发价值。

Objective Titanium dioxide(TiO2)nanotubes loaded with polyhexamethylene guanidine(PHMG)were synthesized in situ on the surface of artificial joint replacement implant.Antibacterial properties of PHMG-loaded TiO2 nanotubes were evaluated by in vitro and in vivo experiments,which could provide a new idea for the research of artificial joint prosthesis with good antibacterial properties.Methods The TiO2 nanotubes were prepared by anodization,and the antibacterial agent PHMG was loaded onto the surface.Pure titanium foils,TiO2 nanotube foils and PHMG-loaded TiO2 nanotube foils were co-cultured in staphylococcus aureus ATCC 29213 suspension to evaluate the in vitro antibacterial properties.0.1 ml 108 CFU/ml Staphylococcus aureus suspension was injected into the medullary cavities of 24 New Zealand rabbits after intramedullary reaming.Pure titanium rods,TiO2 nanotube rods and PHMG-loaded TiO2 nanotube rods were implanted into the medullary cavities of the right femurs of the New Zealand rabbits respectively to study the in vivo antibacterial properties.Results The TiO2 nanotubes were fabricated by anodization with pore diameter(46.4±5.9)nm.Total(3.46±0.40)mg and(1.27±0.28)mg PHMG were coated onto the surface of TiO2 nanotube foil(length,300-500 nm)and rod(length,500-1000 nm).In vitro release experiments showed that the drug release was divided into two phases:the initial burst release and the relatively slow release phase,which provided protection for early inhibition of bacterial invasion and sustained bacteriostasis.In vitro and in vivo bacteriostatic studies showed that TiO2 nanotubes loaded with PHMG can inhibit bacterial infection,colonization,and reduce the risk of bacterial infection.The clinicopathological analysis showed that no obvious pathological changes were observed in the PHMG-TiO2 nanotube implant group;a large number of nucleated cells and reticular connective tissues were observed in the bone marrow cavity,and also normal bone marrow tissues were further observed in the medullary cavity.Conclusions The PHMG-loaded TiO2 nanotubes have excellent antibacterial properties against S.aureus,demonstrating great research significance in the prevention of periprosthetic infection.