Primary cancers disseminate both single circulating tumor cells (CTCs) and CTC "clusters," the latter of which have been shown to demonstrate greater metastatic propensity and adverse impact on prognosis. Many devices developed to isolate single CTCs also capture CTC clusters, but there is translational potential for a platform specifically designed to isolate CTC clusters. Herein, we introduce our microfluidic device for isolating CTC clusters ("Microfluidic Isolation of CTC Clusters" or MICC), which is equipped with ∼10 000 trap chambers that isolate tumor cell clusters based on their large sizes and dynamic force balance against a pillar obstacle in the trap chamber. Whole blood is injected, followed by a wash step to remove blood cells and a final backflush to release intact clusters for downstream analysis. Using clusters from tumor cell-line and confocal microscopy, we verified the ability of the MICC platform to specifically capture tumor cell clusters in the trap chambers. Our flow rate optimization experiments identified 25 μl/min for blood injection, 100 μl/min as wash flow rate, and 300 μl/min as the release flow rate - indicating that 1 ml of whole blood can be processed in less than an hour. Under these optimal flow conditions, we assessed the MICC platform's capture and release performance using blood samples spiked with different concentrations of clusters, revealing a capture efficiency of 66%-87% and release efficiency of 76%-90%. The results from our study suggest that the MICC platform has the potential to isolate CTC clusters from cancer patient blood, enabling it for clinical applications in cancer management.

中文翻译：

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一种微流体装置，用于从未处理的血液样本中无标记地分离肿瘤细胞簇。

原发性癌症会播散单个循环肿瘤细胞 (CTC) 和 CTC“簇”，后者已被证明具有更大的转移倾向并对预后产生不利影响。许多为隔离单个 CTC 而开发的设备也捕获 CTC 簇，但专门设计用于隔离 CTC 簇的平台具有转化潜力。在此，我们介绍了用于分离 CTC 簇的微流体装置（“CTC 簇的微流体分离”或 MICC），该装置配备有约 10 000 个捕获室，可根据肿瘤细胞簇的大尺寸和针对柱状障碍物的动态力平衡来分离肿瘤细胞簇在陷阱室中。注入全血，然后进行清洗步骤以去除血细胞，最后进行反冲以释放完整的簇以进行下游分析。使用来自肿瘤细胞系的簇和共聚焦显微镜，我们验证了 MICC 平台特异性捕获捕获室中肿瘤细胞簇的能力。我们的流速优化实验确定血液注射流速为 25 μl/min，清洗流速为 100 μl/min，释放流速为 300 μl/min - 表明可以在不到一小时的时间内处理 1 ml 全血。在这些最佳流动条件下，我们使用掺有不同浓度簇的血液样本评估了 MICC 平台的捕获和释放性能，结果显示捕获效率为 66%-87%，释放效率为 76%-90%。我们的研究结果表明，MICC 平台有潜力从癌症患者血液中分离出 CTC 簇，使其能够在癌症管理中进行临床应用。