Label-free cell separation is a promising method in the field of stem-cell research to obtain desired cell populations. Here, we report on phospholipid polymer-coated microfluidic channels with immobilized antibodies as devices for the capture of cells expressing target antigens in a label-free manner. We fabricated a microfluidic channel containing immobilized antibodies against vascular endothelial growth factor receptor 2 (Flk1), a potential marker for cardiac, angiogenic, and hematopoietic cell regeneration. A series of investigations was carried out to elucidate the effect of the immobilized antibodies on the adhesion behavior of the Flk1-expressing cell subpopulation derived from induced pluripotent stem cells. Increasing the immobilized antibody density (0.18–5.0 10⁹ ligands mm⁻²) led to an increased number of cells adhering to the channel. The antibody-immobilized polymer-coated surface suppressed nonspecific cell adhesion, which was swept away by a weak shear flow, and captured Flk1-expressing cells under a wall shear stress of 1.7 Pa. Flk1 expression was 2.8-fold higher in the cells that adhered than in those that did not adhere. Therefore, an optimal antibody density and sweeping flow are required for effective label-free separation of Flk1-positive cells.

无标记细胞分离是干细胞研究领域中获得所需细胞群体的一种有前途的方法。在这里，我们报道了固定化抗体的磷脂聚合物包被的微流控通道，作为以无标记方式捕获表达靶抗原的细胞的装置。我们制造了一条微流控通道，其中包含针对血管内皮生长因子受体2（Flk1）的固定抗体，该抗体是心脏，血管生成和造血细胞再生的潜在标记。进行了一系列研究，以阐明固定化抗体对衍生自诱导性多能干细胞的Flk1表达细胞亚群粘附行为的影响。增加固定的抗体密度（0.18–5.0 10 ^9个配体mm ^-2）导致粘附到该通道的细胞数量增加。固定有抗体的聚合物包被的表面抑制了非特异性细胞粘附，该粘附被弱剪切流所扫除，并在1.7 Pa的壁剪切应力下捕获了表达Flk1的细胞。在粘附的细胞中Flk1的表达高2.8倍比那些没有坚持的人。因此，有效的Flk1阳性细胞的无标记分离需要一个最佳的抗体密度和清扫流量。