Biomicrofluidics. 2011 Sep;5(3):32002-3200212. doi: 10.1063/1.3608133. Epub 2011 Sep 20.
A new strategy for magnetically manipulating and isolating adherent cells with extremely high post-collection purity and viability is reported. Micromolded magnetic elements (termed microrafts) were fabricated in an array format and used as culture surfaces and carriers for living, adherent cells. A poly(styrene-co-acrylic acid) polymer containing well dispersed magnetic nanoparticles was developed for creating the microstructures by molding. Nanoparticles of γFe(2)O(3) at concentrations up to 1% wt.∕wt. could be used to fabricate microrafts that were optically transparent, highly magnetic, biocompatible, and minimally fluorescent. To prevent cellular uptake of nanoparticles from the magnetic polymer, a poly(styrene-co-acrylic acid) layer lacking γFe(2)O(3) nanoparticles was placed over the initial magnetic microraft layer to prevent cellular uptake of the γFe(2)O(3) during culture. The microraft surface geometry and physical properties were altered by varying the polymer concentration or layering different polymers during fabrication. Cells plated on the magnetic microrafts were visualized using standard imaging techniques including brightfield, epifluorescence, and confocal microscopy. Magnetic microrafts possessing cells of interest were dislodged from the array and efficiently collected with an external magnet. To demonstrate the feasibility of cell isolation using the magnetic microrafts, a mixed population of wild-type cells and cells stably transfected with a fluorescent protein was plated onto an array. Microrafts possessing single, fluorescent cells were released from the array and magnetically collected. A post-sorting single-cell cloning rate of 92% and a purity of 100% were attained.
报道了一种新的策略，用于通过极高的收集后纯度和活力来磁性操作和分离贴壁细胞。制备了以阵列形式排列的微成型磁性元件（称为微筏），并将其用作活的贴壁细胞的培养表面和载体。开发了一种含有良好分散的磁性纳米粒子的聚（苯乙烯-共-丙烯酸）聚合物，用于通过成型来制造微结构。可以使用浓度高达 1wt.%的γFe2O3纳米粒子来制造具有光学透明性、高磁性、生物相容性和最小荧光的微筏。为了防止细胞从磁性聚合物中摄取纳米粒子，在初始磁性微筏层上放置了一层缺乏γFe2O3纳米粒子的聚（苯乙烯-共-丙烯酸）层，以防止细胞在培养过程中摄取γFe2O3。通过改变聚合物浓度或在制造过程中分层不同的聚合物，可以改变微筏表面的几何形状和物理性质。使用标准成像技术（包括明场、荧光和共聚焦显微镜）对接种在磁性微筏上的细胞进行可视化。将具有感兴趣细胞的磁性微筏从阵列上剥落，并通过外部磁铁高效收集。为了证明使用磁性微筏进行细胞分离的可行性，将具有荧光蛋白的稳定转染细胞的混合群体接种到阵列上。从阵列上释放并通过磁性收集具有单个荧光细胞的微筏。获得了 92%的单细胞克隆率和 100%的纯度。
