The Combination of Immunomagnetic Bead-Based Cell Isolation and Optically Induced Dielectrophoresis (ODEP)-Based Microfluidic Device for the Negative Selection-Based Isolation of Circulating Tumor Cells (CTCs).

Po-Yu Chu,Min-Hsien Wu,Chia-Hsun Hsieh

doi:10.3389/fbioe.2020.00921

Abstract

Negative selection-based circulating tumor cell (CTC) isolation is able to harvest viable, label-free, and clinically meaningful CTCs from the cancer patients’ blood. Nevertheless, its main shortcoming is its inability to isolate high-purity CTCs, restricting subsequent CTC-related analysis. To address this issue, this study proposed a two-step optically-induced dielectrophoresis (ODEP) cell manipulation to process the cell sample harvested by negative selection-/immunomagnetic microbeads-based CTC isolation. The working mechanism is that the ODEP force acting on the cells with and without magnetic microbeads binding is different. Accordingly, the use of ODEP cell manipulation in a microfluidic system was designed to first separate and then isolate the cancer cells from other magnetic microbead-bound cells. Immunofluorescent microscopic observation and ODEP cell manipulation were then performed to refine the purity of the cancer cells. In this study, the optimum operating conditions for effective cell isolation were determined experimentally. The results revealed that the presented method was able to further refine the purity of cancer cell in the sample obtained after negative selection-based CTC isolation with high cell purity (81.6~86.1%). Overall, this study proposed the combination of immunomagnetic bead-based cell isolation and ODEP cell manipulation for the negative selection-based isolation of CTCs.

Highlights

Metastasis is the main cause of cancer morbidity and mortality (Mehlen and Puisieux, 2006)
The results revealed that the presented two-step optically-induced dielectrophoresis (ODEP) cell manipulation process was able to further refine the cancer cell purity of the sample obtained after a negative selection-based circulating tumor cell (CTC) isolation process with high cell purity (81.6 ̃86.1%)
At a given electric condition of 10 Vpp and 3 MHz, this outcome was experimentally confirmed by Figure 3B, in which the Jurkat cell and SW620 cancer cell were all attracted within the light image, whereas the magnetic microbeads with varied diameters were repulsed by the light image and located outside of the light image

Summary

Introduction

Metastasis is the main cause of cancer morbidity and mortality (Mehlen and Puisieux, 2006). Circulating tumor cells (CTCs) are those cells that have escaped from the primary tumor tissue into the vasculature and are subsequently present in the blood circulation or lymphatic system (Plaks et al, 2013). The presence of CTCs in the blood circulation is closely associated with cancer metastasis (Plaks et al, 2013). The fundamental study of CTCs has immense potential for revealing the mechanism behind metastasis. Such a discovery could help scientists develop novel therapeutic methods for cancer treatments. In terms of clinical utility, the CTCs obtained from cancer patients’ blood can act as a kind of liquid tumor biopsy, which are useful for various clinical applications [e.g., the selection of personalized therapeutic regimens (Yue et al, 2018), for the evaluation of therapeutic response (Otsuka et al, 2013), or for the detection of cancer disease status (Tsai et al, 2016)]

Methods

Results

Conclusion