Butler Kimberly S, Adolphi Natalie L, Bryant H C, Lovato Debbie M, Larson Richard S, Flynn Edward R
Department of Pathology, University of New Mexico Health Sciences Center, 1 University of New Mexico, Albuquerque, NM 87131, USA.
Phys Med Biol. 2014 Jul 7;59(13):3319-35. doi: 10.1088/0031-9155/59/13/3319. Epub 2014 May 29.
As new magnetic nanoparticle-based technologies are developed and new target cells are identified, there is a critical need to understand the features important for magnetic isolation of specific cells in fluids, an increasingly important tool in disease research and diagnosis. To investigate magnetic cell collection, cell-sized spherical microparticles, coated with superparamagnetic nanoparticles, were suspended in (1) glycerine-water solutions, chosen to approximate the range of viscosities of bone marrow, and (2) water in which 3, 5, 10 and 100% of the total suspended microspheres are coated with magnetic nanoparticles, to model collection of rare magnetic nanoparticle-coated cells from a mixture of cells in a fluid. The magnetic microspheres were collected on a magnetic needle, and we demonstrate that the collection efficiency versus time can be modeled using a simple, heuristically-derived function, with three physically-significant parameters. The function enables experimentally-obtained collection efficiencies to be scaled to extract the effective drag of the suspending medium. The results of this analysis demonstrate that the effective drag scales linearly with fluid viscosity, as expected. Surprisingly, increasing the number of non-magnetic microspheres in the suspending fluid results increases the collection of magnetic microspheres, corresponding to a decrease in the effective drag of the medium.
随着基于磁性纳米颗粒的新技术不断发展以及新的靶细胞被识别出来，迫切需要了解对于从流体中磁性分离特定细胞而言重要的特征，这在疾病研究和诊断中是一种日益重要的工具。为了研究磁性细胞收集情况，将涂覆有超顺磁性纳米颗粒的细胞大小的球形微粒悬浮于：（1）甘油 - 水溶液中，其被选定以近似骨髓的粘度范围；以及（2）水中，其中总悬浮微球的3%、5%、10%和100%涂覆有磁性纳米颗粒，以模拟从流体中的细胞混合物中收集稀有的磁性纳米颗粒涂覆细胞。磁性微球被收集在磁针上，并且我们证明收集效率与时间的关系可以使用一个简单的、基于经验推导的函数来建模，该函数具有三个具有物理意义的参数。该函数能够对实验获得的收集效率进行缩放，以提取悬浮介质的有效阻力。该分析结果表明，有效阻力如预期那样与流体粘度呈线性关系。令人惊讶的是，增加悬浮液中非磁性微球的数量会导致磁性微球的收集量增加，这对应于介质有效阻力的降低。
