Department of Biomedical Engineering, Ulsan National Institute of Science and Technology (UNIST) , UNIST-gil 50, Ulsan, 689-798, Republic of Korea.
Anal Chem. 2014 Nov 18;86(22):11349-56. doi: 10.1021/ac5035049. Epub 2014 Oct 30.
Circulating tumor cells (CTCs) have gained increasing attention owing to their roles in cancer recurrence and progression. Due to the rarity of CTCs in the bloodstream, an enrichment process is essential for effective target cell characterization. However, in a typical pressure-driven microfluidic system, the enrichment process generally requires complicated equipment and long processing times. Furthermore, the commonly used immunoaffinity-based positive selection method is limited, as its recovery rate relies on EpCAM expression of target CTCs, which shows heterogeneity among cell types. Here, we propose a centrifugal-force-based size-selective CTC isolation platform that can isolate and enumerate CTCs from whole blood within 30 s with high purity. The device was validated using the MCF-7 breast cancer cell line spiked in phosphate-buffered saline and whole blood, and an average capture efficiency of 61% was achieved, which is typical for size-based filtration. The capture efficiency for whole blood samples varied from 44% to 84% under various flow conditions and dilution factors. Under the optimized operating conditions, a few hundred white blood cells per 1 mL of whole blood were captured, representing a 20-fold decrease compared to those obtained using a commercialized size-based CTC isolation device. In clinical validation, normalized CTC counts varied from 10 to 60 per 7.5 mL of blood from gastric and lung cancer patients, yielding a detection rate of 50% and 38%, respectively. Overall, our CTC isolation device enables rapid and label-free isolation of CTCs with high purity, which should greatly improve downstream molecular analyses of captured CTCs.
循环肿瘤细胞 (CTC) 因其在癌症复发和进展中的作用而受到越来越多的关注。由于 CTC 在血液中的稀有性，因此有效的靶向细胞特征描述需要富集过程。然而，在典型的压力驱动微流控系统中，富集过程通常需要复杂的设备和较长的处理时间。此外，常用的基于免疫亲和性的阳性选择方法受到限制，因为其回收率依赖于靶 CTC 的 EpCAM 表达，而 EpCAM 表达在细胞类型之间存在异质性。在这里，我们提出了一种基于离心力的大小选择性 CTC 分离平台，该平台可以在 30 秒内从全血中分离和计数 CTC，具有高纯度。该设备使用 MCF-7 乳腺癌细胞系在磷酸盐缓冲液和全血中的混合物进行了验证，平均捕获效率达到 61%，这是典型的基于大小的过滤。在各种流动条件和稀释因子下，全血样品的捕获效率从 44%到 84%不等。在优化的操作条件下，每 1 毫升全血中可捕获几百个白细胞，与商业化的基于大小的 CTC 分离设备相比，减少了 20 倍。在临床验证中，来自胃癌和肺癌患者的每 7.5 毫升血液中的标准化 CTC 计数从 10 到 60 不等，分别为 50%和 38%。总体而言，我们的 CTC 分离设备能够快速、无标记地分离高纯度的 CTC，这将大大提高捕获 CTC 的下游分子分析。
