School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907, USA.
Lab Chip. 2015 Apr 7;15(7):1677-88. doi: 10.1039/c5lc00100e.
We report on-chip isolation and detection of circulating tumor cells (CTCs) from blood samples using a system that integrates a microchip with immunomagnetics, high-throughput fluidics and size-based filtration. CTCs in a sample are targeted via their surface antigens using magnetic beads functionalized with antibodies. The mixture is then run through a fluidic chamber that contains a micro-fabricated chip with arrays of 8 μm diameter apertures. The fluid runs parallel to the microchip while a magnetic field is generated underneath to draw the beads and cells bound to them toward the chip surface for detection of CTCs that are larger than the apertures and clear out free beads and other smaller particles bound to them. The parallel flow configuration allows high volumetric flow rates, which reduces nonspecific binding to the chip surface and enables multiple circulations of the sample fluid through the system in a short period of time. In this study we first present models of the magnetic and fluidic forces in the system using a finite element method. We then verify the simulation results experimentally to determine an optimal flow rate. Next, we characterize the system by detecting cancer cell lines spiked into healthy human blood and show that on average 89% of the spiked MCF-7 breast cancer cells were detected. We finally demonstrate detection of CTCs in 49 out of 50 blood samples obtained from non-small cell lung cancer (NSCLC) patients and pancreatic cancer (PANC) patients. The number of CTCs detected ranges from 2 to 122 per 8 mL s of blood. We also demonstrate a statistically significant difference between the CTC counts of NSCLC patients who have received therapy and those who have not.
我们报告了一种使用集成微芯片与免疫磁珠、高通量流体和基于尺寸的过滤的系统，从血液样本中分离和检测循环肿瘤细胞（CTC）的方法。使用抗体功能化的磁性珠针对样品中的 CTC 表面抗原进行靶向。然后将混合物通过一个包含微制造的芯片的流体腔运行，该芯片具有 8μm 直径的孔阵列。流体与微芯片平行运行，同时在下方产生磁场，将珠和与之结合的细胞吸引到芯片表面，以检测大于孔径的 CTC，并清除游离珠和与之结合的其他较小颗粒。平行流配置允许高体积流速，这减少了对芯片表面的非特异性结合，并使样品流体在短时间内多次循环通过系统。在这项研究中，我们首先使用有限元方法对系统中的磁场和流体力进行建模。然后，我们通过实验验证了模拟结果，以确定最佳流速。接下来，我们通过检测掺入健康人血液中的癌细胞系来表征该系统，并表明平均有 89%的掺入 MCF-7 乳腺癌细胞被检测到。最后，我们在 50 名非小细胞肺癌（NSCLC）和胰腺癌（PANC）患者的 49 份血液样本中证明了 CTC 的检测。每份 8 毫升血液中检测到的 CTC 数量从 2 到 122 不等。我们还证明了接受治疗和未接受治疗的 NSCLC 患者的 CTC 计数之间存在统计学上的显著差异。
