A novel method of fabricating core-shell structure, comprising monodisperse polystyrene (PS) spheres as cores and Fe3O4 as shells, is demonstrated. The coating shell of magnetite (Fe3O4) crystallites was formed by con...A novel method of fabricating core-shell structure, comprising monodisperse polystyrene (PS) spheres as cores and Fe3O4 as shells, is demonstrated. The coating shell of magnetite (Fe3O4) crystallites was formed by controlled hydrolysis of aqueous solutions of iron ion with diethyleneglycol (DEG) either by the facile, electrostatic absorption between the polymer and iron compounds. Thickness of the shell could be easily changed in the range from 20 to 60 nm by using slow-injecting coating process. Structure and composition of iron compounds shell were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), thermo-gravimetric analysis (TG) and vibrating-sample magnetometer (VSM), indicating there are some differences between the Fe3O4-shell of the magnetic composite spheres and pure Fe3O4 particles, e.g. smaller crystallite size, lower magnetic transition temperature and weaker ferromagnetic character.展开更多
目的探讨应用超微超顺磁性氧化铁纳米颗粒(ultra-micro superparamagnetic iron oxide nanoparticle,USPIO)标记小鼠巨噬细胞株RAW264.7的最适浓度以及比较MRI中不同扫描序列在细胞吞噬功能评价中的敏感度差别。材料与方法用终浓度为0...目的探讨应用超微超顺磁性氧化铁纳米颗粒(ultra-micro superparamagnetic iron oxide nanoparticle,USPIO)标记小鼠巨噬细胞株RAW264.7的最适浓度以及比较MRI中不同扫描序列在细胞吞噬功能评价中的敏感度差别。材料与方法用终浓度为0、25、50、75、100、125μg/mL的USPIO分别与小鼠巨噬细胞共培养24 h后,细胞计数试剂法(CCK-8)计算细胞存活率以及USPIO对该细胞的半数抑制浓度(IC;);光学显微镜下观察细胞形态学变化;普鲁士蓝染色确认细胞对USPIO的吞噬效应;3.0 T MRI扫描细胞-琼脂糖凝胶模型,记录T1WI和T2WI序列的弛豫时间和弛豫率并计算弛豫时间降低率。结果当USPIO浓度为25μg/mL时,对细胞的存活率无影响,差异无统计学意义(P>0.05);当USPIO浓度≥50μg/mL时,细胞存活率随USPIO浓度增加显著降低(P均<0.05);USPIO对细胞的半数抑制浓度IC;为(186.5±7.2)μg/mL;当USPIO浓度为50μg/mL时,细胞形态开始皱缩、透光度减低;当USPIO浓度为25μg/mL时,普鲁士蓝染色呈显著阳性;MRI显示,与对照组相比,当USPIO浓度为25μg/mL时,细胞即见显著信号改变;随USPIO浓度增加,T1、T2弛豫时间显著缩短(P均<0.01),对应弛豫率R1、R2逐渐升高;相同USPIO浓度下,各组T2弛豫时间降低率显著高于T1弛豫时间降低率(P均<0.001)。结论浓度为25μg/mL的USPIO对细胞没有明显毒性作用,而且标记效率高、MRI即见显著信号改变与较好的成像效果,为标记巨噬细胞的最适浓度;MRI能用于细胞标记后的体外成像,T2WI序列在检测细胞吞噬USPIO后的信号变化优于T1WI序列。展开更多
文摘A novel method of fabricating core-shell structure, comprising monodisperse polystyrene (PS) spheres as cores and Fe3O4 as shells, is demonstrated. The coating shell of magnetite (Fe3O4) crystallites was formed by controlled hydrolysis of aqueous solutions of iron ion with diethyleneglycol (DEG) either by the facile, electrostatic absorption between the polymer and iron compounds. Thickness of the shell could be easily changed in the range from 20 to 60 nm by using slow-injecting coating process. Structure and composition of iron compounds shell were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), thermo-gravimetric analysis (TG) and vibrating-sample magnetometer (VSM), indicating there are some differences between the Fe3O4-shell of the magnetic composite spheres and pure Fe3O4 particles, e.g. smaller crystallite size, lower magnetic transition temperature and weaker ferromagnetic character.
文摘目的探讨应用超微超顺磁性氧化铁纳米颗粒(ultra-micro superparamagnetic iron oxide nanoparticle,USPIO)标记小鼠巨噬细胞株RAW264.7的最适浓度以及比较MRI中不同扫描序列在细胞吞噬功能评价中的敏感度差别。材料与方法用终浓度为0、25、50、75、100、125μg/mL的USPIO分别与小鼠巨噬细胞共培养24 h后,细胞计数试剂法(CCK-8)计算细胞存活率以及USPIO对该细胞的半数抑制浓度(IC;);光学显微镜下观察细胞形态学变化;普鲁士蓝染色确认细胞对USPIO的吞噬效应;3.0 T MRI扫描细胞-琼脂糖凝胶模型,记录T1WI和T2WI序列的弛豫时间和弛豫率并计算弛豫时间降低率。结果当USPIO浓度为25μg/mL时,对细胞的存活率无影响,差异无统计学意义(P>0.05);当USPIO浓度≥50μg/mL时,细胞存活率随USPIO浓度增加显著降低(P均<0.05);USPIO对细胞的半数抑制浓度IC;为(186.5±7.2)μg/mL;当USPIO浓度为50μg/mL时,细胞形态开始皱缩、透光度减低;当USPIO浓度为25μg/mL时,普鲁士蓝染色呈显著阳性;MRI显示,与对照组相比,当USPIO浓度为25μg/mL时,细胞即见显著信号改变;随USPIO浓度增加,T1、T2弛豫时间显著缩短(P均<0.01),对应弛豫率R1、R2逐渐升高;相同USPIO浓度下,各组T2弛豫时间降低率显著高于T1弛豫时间降低率(P均<0.001)。结论浓度为25μg/mL的USPIO对细胞没有明显毒性作用,而且标记效率高、MRI即见显著信号改变与较好的成像效果,为标记巨噬细胞的最适浓度;MRI能用于细胞标记后的体外成像,T2WI序列在检测细胞吞噬USPIO后的信号变化优于T1WI序列。
