Jin Xiaoxia, Zhao Yang, Richardson Aaron, Moore Lee, Williams P Stephen, Zborowski Maciej, Chalmers Jeffrey J
Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH 43210, USA.
Analyst. 2008 Dec;133(12):1767-75. doi: 10.1039/b802113a. Epub 2008 Sep 9.
Magnetic separation in biomedical applications is based on differential magnetophoretic mobility (MM) of microparticulate matter in viscous media. Typically, the difference in MM is obtained by selectively labeling the target cells with superparamagnetic iron oxide nanoparticles (SPIONs). We have measured the MM of monodisperse, polystyrene microspheres (PSMs), with and without attached SPIONs as a model of cell motion induced by nanoparticle magnetization, using variable H field and cell tracking velocimetry (CTV). As a model of paramagnetic microparticle motion, the MM measurements were performed on the same PSMs in paramagnetic gadolinium solutions, and on spores of a prokaryotic organism, Bacillus globigii (shown to contain paramagnetic manganese). The CTV analysis was sensitive to the type of the microparticle magnetization, producing a value of MM independent of the applied H field for the paramagnetic species, and a decreasing MM value with an increasing field for superparamagnetic species, as predicted from theory. The SPION-labeled PSMs exhibited a saturation magnetization above H approximately = 64,000 A m(-1) (or 0.08 tesla). Based on those data, the average saturation magnetizations of the SPIONs was calculated and shown to vary between different commercial sources. The results demonstrate sensitivity of the CTV analysis to different magnetization mechanisms of the microparticles.
生物医学应用中的磁分离基于粘性介质中微粒物质的微分磁泳迁移率（MM）。通常，通过用超顺磁性氧化铁纳米颗粒（SPIONs）选择性标记靶细胞来获得MM的差异。我们使用可变H场和细胞跟踪测速法（CTV），测量了有无附着SPIONs的单分散聚苯乙烯微球（PSMs）的MM，以此作为纳米颗粒磁化诱导细胞运动的模型。作为顺磁性微粒运动的模型，在顺磁性钆溶液中的相同PSMs以及原核生物球形芽孢杆菌的孢子（已证明含有顺磁性锰）上进行了MM测量。CTV分析对微粒磁化类型敏感，对于顺磁性物质，产生的MM值与施加的H场无关，而对于超顺磁性物质，MM值随场强增加而降低，这与理论预测一致。SPION标记的PSMs在H约 = 64,000 A m(-1)（或0.08特斯拉）以上表现出饱和磁化强度。基于这些数据，计算了SPIONs的平均饱和磁化强度，并表明其在不同商业来源之间有所不同。结果证明了CTV分析对微粒不同磁化机制的敏感性。
