Application of optically-induced-dielectrophoresis in microfluidic system for purification of circulating tumour cells for gene expression analysis- Cancer cell line model.

Tzu-Keng Chiu,Song-Bin Huang,Min-Hsien Wu,Yung-Chang Lin,Chia-Hsun Hsieh,Wen-Pin Chou,Hung-Ming Wang

doi:10.1038/srep32851

Tzu-Keng Chiu, Song-Bin Huang + Show 5 more

Open Access

https://doi.org/10.1038/srep32851

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Abstract

Circulating tumour cells (CTCs) in a blood circulation system are associated with cancer metastasis. The analysis of the drug-resistance gene expression of cancer patients’ CTCs holds promise for selecting a more effective therapeutic regimen for an individual patient. However, the current CTC isolation schemes might not be able to harvest CTCs with sufficiently high purity for such applications. To address this issue, this study proposed to integrate the techniques of optically induced dielectrophoretic (ODEP) force-based cell manipulation and fluorescent microscopic imaging in a microfluidic system to further purify CTCs after the conventional CTC isolation methods. In this study, the microfluidic system was developed, and its optimal operating conditions and performance for CTC isolation were evaluated. The results revealed that the presented system was able to isolate CTCs with cell purity as high as 100%, beyond what is possible using the previously existing techniques. In the analysis of CTC gene expression, therefore, this method could exclude the interference of leukocytes in a cell sample and accordingly contribute to higher analytical sensitivity, as demonstrated in this study. Overall, this study has presented an ODEP-based microfluidic system capable of simply and effectively isolating a specific cell species from a cell mixture.

Highlights

To achieve the goal mentioned above, it is necessary to isolate and purify the Circulating tumour cells (CTCs) from a blood sample with a certain quality requirement
The results revealed that the cells harvested from the optically induced dielectrophoretic (ODEP)-based CTC isolation protocol only detected the gene expression of epithelial cell adhesion molecule (EpCAM), a surface marker on cancer cells of epithelial origins, whereas no gene expression of the typical leukocyte surface marker CD45 was observed (Supplementary figure; Fig. S3)
The analysis of the anticancer drug-resistance gene expression of cancer patient’s CTCs could open a new horizon for achieving personalized chemotherapy. To accurately conduct such analytical work, the CTCs isolated from the blood sample of a cancer patient must be pure to exclude the possible interference of leukocytes in the cell sample tested

Summary

Introduction

To achieve the goal mentioned above, it is necessary to isolate and purify the CTCs from a blood sample with a certain quality requirement (i.e., high CTC purity). Immunomagnetic separation approaches are predominantly utilized for these tasks In these methods, magnetic beads coupled with CTC surface antigen [mainly the epithelial cell adhesion molecule (EpCAM) and cytokeratins (CKs)]-specific antibodies are commonly used to recognize and bind the CTCs13. The low CTC purity issue in negative (or even positive) selection-based CTC isolation schemes could in turn hinder the subsequent utilization of CTCs for the analysis of anticancer drug-resistance gene expression. To address this critical technical hurdle, we proposed to integrate the technique of optically induced dielectrophoretic (ODEP) force-based cell manipulation in a microfluidic system to further purify CTCs after a conventional CTC isolation process. In the analysis of the anticancer drug-resistance gene expression levels of CTCs, this method could potentially exclude the interference of leukocytes in the cell samples tested and contribute to higher analytical sensitivity

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Conclusion