Ampère Laboratory, CNRS-Université Claude Bernard Lyon 1-Ecole Centrale de Lyon, 69134 Ecully, France.
Biomed Microdevices. 2012 Oct;14(5):947-54. doi: 10.1007/s10544-012-9673-4.
Trapping of cells is essential to perform basic handling operations in cell-based microsystems, such as media exchange, concentration, cell isolation and cell sorting. Cell trapping by magnetophoresis typically requires cell labeling with magnetic nanoparticles. Here we report on endocytotic uptake of 100 nm magnetic nanoparticles by Human Embryonic Kidney 293 cells. The attraction of labeled cells by micro-magnet arrays characterised by very high magnetic field gradients (≤10⁶ T/m) was studied as a function of labeling conditions (nanoparticle concentration in the extracellular medium, incubation time). The threshold incubation conditions for effective magnetophoretic trapping were established. This simple technique may be exploited to minimise the quantity of magnetic nanoparticles needed for efficient cell trapping, thus reducing stress or nanoparticle-mediated toxicity. Nanoparticle internalization into cells was confirmed using both confocal and Transmission Electron Microscopy (TEM).
细胞捕获对于在基于细胞的微系统中执行基本操作至关重要，例如介质交换、浓缩、细胞分离和细胞分选。通过磁泳进行细胞捕获通常需要用磁性纳米粒子对细胞进行标记。在这里，我们报告了人胚肾 293 细胞对 100nm 磁性纳米粒子的内吞作用。通过微磁铁阵列对标记细胞的吸引力具有非常高的磁场梯度（≤10⁶T/m），作为标记条件（细胞外介质中纳米粒子的浓度、孵育时间）的函数进行了研究。确定了用于有效磁泳捕获的临界孵育条件。这项简单的技术可以用来最小化有效捕获细胞所需的磁性纳米粒子的数量，从而减少细胞的应激或纳米粒子介导的毒性。使用共聚焦和透射电子显微镜（TEM）都证实了纳米粒子进入细胞内。
