High-throughput separation of circulating tumor cells by dielectrophoretic filtration

通过介电泳过滤高通量分离循环肿瘤细胞

• 批准号: 419882983
• 负责人: Professor Dr.-Ing. Georg Pesch
• 金额: --
• 依托单位: School of Chemical and Bioprocess Engineering
• 依托单位国家: 德国
• 项目类别: Research Fellowships
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/419882983?language=en
• 关键词: throughput; separation; circulating; tumor; cells

The separation of particles according to properties other than size or density is a highly relevant task but one that cannot be solved universally. Such separation requires a deterministic force that acts much stronger on the target particle than on all other particles of a mixture; consequently, it becomes increasingly difficult to separate particles that show only slightly different properties. A due to its diagnostic value in liquid biopsy significant example is the separation of circulating tumor cells (CTC) from whole blood. Several different approaches are currently investigated for this separation while most of them rely on specific surface markers on the tumor cells. This however limits the universal applicability, as the presence of these surface markers on all cells is questionable. Dielectrophoresis (DEP), a highly adaptable and selective electrokinetic separation technique, has already shown to be successful for the detection of CTC in a blood sample. Because the DEP force scales linearly with the spatial inhomogeneity of the electric field square, most contemporary DEP applications are realized using microelectrode structures and micro channels. This is necessary to generate forces that are strong enough in order to achieve separation.Together with our working group, I have pioneered the concept of dielectrophoretic filtration, which is capable of bridging the inherent DEP throughput gap. In this, the required field inhomogeneities are induced in the pore structure of a porous medium (which could be, for example, a macroscopic monolithic ceramic foam). This allows for selective and electrically switchable retention (trapping) of target particles from a mixture in the separation matrix. Consequently, compared to conventional DEP separators, we can operate the process using larger channels and higher throughputs. So far, we have tested this concept on model particle systems. In this project, I want to investigate the feasibility of the DEP filtration process for the selective retention of cancer cells from peripheral blood mononuclear cells (PBMC). Microfluidic model filters are used to find suitable separation parameters (throughput, applied voltage, field frequency) to separate a leukaemia cell line (RPMI-8226) and a breast cancer cell line (MCF-7) from T-cells. Subsequently, the target cell concentration will be decreased towards clinically relevant values and the separation process will be transferred towards separation in porous alumina foams as DEP filtration matrix. This project brings us a step closer towards solving a very relevant and difficult separation problem but it also explores the possibilities for selective separation of biological cell systems using the DEP filtration concept.

根据性质而不是大小或密度来分离颗粒是一项高度相关的任务，但不能普遍解决。这种分离需要一种确定性的作用力，这种作用力作用在目标粒子上，比作用在混合物的所有其他粒子上要强得多；因此，分离只表现出轻微不同性质的粒子变得越来越困难。由于其在液体活检中的诊断价值，重要的例子是从全血中分离循环肿瘤细胞(CTC)。目前研究了几种不同的分离方法，其中大多数依赖于肿瘤细胞上的特定表面标记。然而，这限制了普遍适用性，因为这些表面标记在所有细胞上的存在是值得怀疑的。介电泳法(DEP)是一种适应性强、选择性强的电动分离技术，已被成功地应用于血液样本中CTC的检测。由于DEP力与电场平方的空间不均匀性成线性关系，因此目前大多数DEP应用都是通过微电极结构和微通道来实现的。这是产生足够强大的力量以实现分离所必需的。与我们的工作组一起，我开创了介电过滤的概念，它能够弥合固有的DEP吞吐量差距。在这种情况下，在多孔介质(可以是宏观的整体陶瓷泡沫)的孔结构中诱导所需的场不均匀。这允许从分离基质中的混合物中选择性地和电可切换地保留(捕获)目标粒子。因此，与传统的DEP分离器相比，我们可以使用更大的通道和更高的吞吐量来操作该过程。到目前为止，我们已经在模型粒子系统上测试了这一概念。在这个项目中，我想研究DEP过滤工艺选择性地从外周血单个核细胞(PBMC)中保留癌细胞的可行性。利用微流控模型过滤器寻找合适的分离参数(通量、外加电压、电场频率)，将白血病细胞系(RPMI-8226)和乳腺癌细胞系(MCF-7)从T细胞中分离出来。随后，目标细胞浓度将降低到临床相关值，分离过程将转移到作为DEP过滤基质的多孔氧化铝泡沫中的分离。这个项目使我们朝着解决一个非常相关和困难的分离问题更近了一步，但它也探索了使用DEP过滤概念选择性分离生物细胞系统的可能性。