A comparative study on EpCAM antibody immobilization on gold surfaces and microfluidic channels for the detection of circulating tumor cells

Cetin, Didem
Okan, Meltem
Bat, Erhan
Külah, Haluk
Detection of circulating tumor cells (CTCs) from the bloodstream holds great importance to diagnose cancer at early stages. However, CTCs being extremely rare in blood makes them difficult to reach. In this paper, we introduced different surface modification techniques for the enrichment and detection of MCF-7 in microfluidic biosensor applications using gold surface and EpCAM antibody. Mainly, two different mechanisms were employed to immobilize the antibodies; covalent bonding and bioaffinity interaction. Self-assembled monolayers (SAMs) formed on the gold surfaces were treated further for the immobilization of the antibody. The bioaffinity-based studies were performed with streptavidin and biotinylated EpCAM over the SAM coated surfaces. The cell attachment events were monitored using fluorescent microscope. Comparisons were made considering the length and functional end of alkanethiols and the positioning of the antibody. Then, these methods were integrated into a microfluidic channel system. Surface characterizations were performed with X-ray Photoelectron Spectroscopy, Atomic Force Microscopy, and contact angle measurements. The selectivity studies were carried out with EpCAM negative K562 leukaemia cell lines and the experiments were repeated for different types of surfaces, such as glass and polymer. Studies showed that long (n > 10) and aromatic ring containing alkanethiols lead to better cell capture events compared to shorter ones. Results obtained from the comparisons are of importance for the gold surface-based microfluidic biosensor designs aimed for CTC detection.
Colloids and Surfaces B: Biointerfaces


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Detection of circulating tumor cells (CTCs) from the bloodstream has a critical role in diagnosing and treatment of cancer. However, the number of CTCs in blood compared to other blood cells are extremely rare. In this thesis, various surface modifications strategies for detection of CTCs are studied in order to be used in the microfluidic detection systems. Functionalizing the gold surface with Self Assembled Monolayers (SAMs) used for attaching the EpCAM antibodies, which made possible to immobilize EpCAM...
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The detection of circulating tumor cells (CTCs) in blood is crucial to assess metastatic progression and to guide therapy. Dielectrophoresis (DEP) is a powerful cell surface marker-free method that allows intrinsic dielectric properties of suspended cells to be exploited for CTC enrichment/isolation from blood. Design of a successful DEP-based CTC enrichment/isolation system requires that the DEP response of the targeted particles should accurately be known. This paper presents a DEP spectrum method to inve...
Enrichment of MCF7 breast cancer cells from leukocytes through continuous flow dielectrophoresis
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Circulating tumor cells (CTCs) are cancerous cells detached from a primary tumor site and enter the bloodstream, causing the development of new tumors in a secondary site. Therefore, their detection in blood is critical to assess the metastatic progression and to guide the line of the therapy. However, the rarity of CTCs in the bloodstream and the lack of suitable detection tool hinders their use as a biomarker in malignancies. Recent advances in microfluidic technologies enabled development of point-of-car...
Citation Formats
D. Cetin, M. Okan, E. Bat, and H. Külah, “A comparative study on EpCAM antibody immobilization on gold surfaces and microfluidic channels for the detection of circulating tumor cells,” Colloids and Surfaces B: Biointerfaces, pp. 0–0, 2020, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/33220.