The importance of circulating tumor cells (CTCs) as biomarkers has been greatly increased for early diagnosis and detection of cancer metastases. Along with a single form of CTCs, CTC clusters have recently attracted much attention due to their characteristics, such as suppression of apoptosis and survival from immune responses with high metastatic potential. Thus, it is highly necessary to investigate not only single cells but clustered cells at the same time to perform precise analysis of the current cancer state and develop suitable treatment. However, no cancer marker-free microfluidic devices have been realized to trap single cells and clusters at the same time in a single device yet. In this paper, we introduced a novel microfluidic device utilizing a microwell-on-electrode (MOE) array to realize simultaneous trapping of a single cell and clustered cells at a single cell/cluster level. Cell-sized microwells fabricated on interdigitated electrodes efficiently arrayed single cells with high trapping efficiency and single-cell occupancy (more than 90%) using dielectrophoresis (DEP). This high single cell trapping performance of MOE allows arraying of single clusters by trapping one of the cells that constitute a cluster. The feasibility of the MOE device for simultaneous arraying of single cancer cells and clusters was demonstrated by trapping a mixture of single cancer cells and clusters and measuring the size distribution of trapped clusters, which was almost identical with that of introduced cell population. Our work demonstrated that the developed MOE device can be one of the promising methods for trapping single cancer cells as well as clusters on a single device for cancer diagnosis and performing further analyses at a single cell/cluster level.

中文翻译：

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一种电活性微孔阵列器件实现同时捕获单个癌细胞和簇

循环肿瘤细胞 (CTC) 作为生物标志物的重要性已大大提高，用于癌症转移的早期诊断和检测。与单一形式的 CTC 一样，CTC 簇最近因其特性而备受关注，例如抑制细胞凋亡和从具有高转移潜力的免疫反应中存活。因此，非常有必要同时研究单细胞和成簇细胞，以对当前的癌症状态进行精确分析并开发合适的治疗方法。然而，目前还没有一种无癌症标记物的微流体装置能够在单个装置中同时捕获单个细胞和簇。在本文中，我们介绍了一种利用电极上微孔 (MOE) 阵列的新型微流体装置，以实现在单个细胞/簇水平上同时捕获单个细胞和簇状细胞。在叉指电极上制造的细胞大小的微孔使用介电泳 (DEP) 有效地排列了具有高捕获效率和单细胞占有率（超过 90%）的单细胞。MOE 的这种高单细胞捕获性能允许通过捕获构成簇的细胞之一来排列单个簇。通过捕获单个癌细胞和簇的混合物并测量捕获的簇的大小分布，证明了 MOE 装置同时排列单个癌细胞和簇的可行性，这与引入的细胞群几乎相同。