Show/Hide Menu
Hide/Show Apps
Logout
Türkçe
Türkçe
Search
Search
Login
Login
OpenMETU
OpenMETU
About
About
Open Science Policy
Open Science Policy
Open Access Guideline
Open Access Guideline
Postgraduate Thesis Guideline
Postgraduate Thesis Guideline
Communities & Collections
Communities & Collections
Help
Help
Frequently Asked Questions
Frequently Asked Questions
Guides
Guides
Thesis submission
Thesis submission
MS without thesis term project submission
MS without thesis term project submission
Publication submission with DOI
Publication submission with DOI
Publication submission
Publication submission
Supporting Information
Supporting Information
General Information
General Information
Copyright, Embargo and License
Copyright, Embargo and License
Contact us
Contact us
Enrichment of MCF7 breast cancer cells from leukocytes through continuous flow dielectrophoresis
Download
index.pdf
Date
2018
Author
Çağlayan, Zeynep
Metadata
Show full item record
Item Usage Stats
323
views
138
downloads
Cite This
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-care (POC) medical diagnostic tools, which offers low cost, rapid, and sensitive analysis of variety of clinical disorders, especially in resource-limited settings. Integration of microfluidic systems with on-chip mechanical and electronic parts have been enabled by Micro-Electro-Mechanical Systems (MEMS) technology, allowing low-cost fabrication of fully integrated microfluidic detection tools. Dielectrophoresis (DEP) is a technique used for separating particles with different sizes and/or dielectric properties. Fabrication of microelectrodes thanks to MEMS technology, allows DEP to be applied in biomedical applications such as manipulation, separation and enrichment of targeted cells from untargeted ones without any labeling. Among numerous applications, rare cell detection from blood occupies an important place in diagnostics of fatal diseases such as cancer. Because of the difficulties in detecting only a few rare cells inside of billions of blood cells in 1 ml blood, rare cell enrichment from blood becomes essential. Starting from this point of view, enrichment of CTCs from blood by using DEP is decided as the main objective of the thesis. One of the most critical issue related to successful design of a DEP-based enrichment device is that DEP spectra of the targeted particles should accurately be known. In this content, DEP spectrum analysis method was developed. This study presents an approach for analyzing the dielectrophoretic (DEP) spectra of biological cells without ascertaining their membrane and cytoplasmic properties. For the proof of DEP spectrum investigation of the biological cells with the proposed analysis method, MEMS-based DEP spectrum device was designed. In this design, reciprocal V-shaped planar electrodes were utilized to generate non-uniform electric field in the chamber that holds the cell solution. Fabrication flow for this design was developed and fabrication of these devices was performed. Testing of the proof of concept DEP spectrum devices was carried out with polymoprhonuclear leukocytes and mononuclear leukocytes obtained from 2 different healthy donors and MCF7 cells (human breast adenocarcinoma cell line) for 15 different frequencies in the range from 100 kHz to 50 MHz at 10 Vpp. The results reveal that at 1 MHz, a significant velocity difference occurs between MCF7 cells (33.99 μm/s) and leukocytes, mononuclear leukocytes (7.9 μm/s) and polymorphonuclear leukocytes (13.82 μm/s), which can be utilized as the working frequency for DEP-based enrichment of MCF7 cancer cells from WBCs as a future work. Considering the problems associated with the experimental setup, testing and post-processing of the proof of concept devices, the proposed DEP spectrum study was improved. The design of the device used in the improved DEP spectrum study was the same as the proof of concept device, except the gap between the electrodes was increased from 20 µm to 30 µm in order to generate more proper electric field gradient distribution on the surface. Testing of the improved analysis was carried out with leukocytes obtained from single donor and MCF7 cells at 10 Vpp for 9 different frequencies in the range from 500 kHz to 10 MHz, by considering the results presented for the proof of concept analysis. The results reveal that there are significant velocity differences occur between MCF7 cells and leukocytes at 500 kHz, 850 kHz and 1 MHz with the ratios 3.58, 3.37 and 3.12, respectively. With the improved DEP spectrum study, the examination method was automated and approximately 130 MCF7 cells were examined for each frequency value. By considering the results obtained from DEP spectrum analysis, DEP-based enrichment microfluidic device was designed. In this design, rectangular and evenly spaced planar electrodes rotated with a certain degree relative to the main flow (13º) were utilized at the bottom of parylene microchannel with 1000 µm in wide. The proposed structure performs the separation of the cells focused on the microchannel wall (with the help of hydrodynamic focusing principle) by using the positive dielectrophoresis (pDEP) method in the active DEP area. Fabrication flow for this design was developed and fabrication of these devices was performed. Testing of the fabricated devices was started with the selection of experimental parameters to examine hydrodynamic focusing and expected cell movements. Later, CTC enrichment experiments of the DEP-based enrichment devices were conducted with MCF7 and leukocyte mixture. Recovery rate result for MCF7 cells were calculated as 83.3% at 10 Vpp. Cell enrichment factor for these rare cells were calculated as 3, which means the desired rare cell ratio was increased to 3 fold at the output relative to the input.
Subject Keywords
Leucocytes.
,
Breast
,
Dielectrophoresis.
,
Cancer cells
,
Microelectromechanical systems.
URI
http://etd.lib.metu.edu.tr/upload/12623008/index.pdf
https://hdl.handle.net/11511/27963
Collections
Graduate School of Natural and Applied Sciences, Thesis
Suggestions
OpenMETU
Core
Capture of circulating tumor cells from blood on modified gold surfaces inside the microfluidic channels
Çetin, Didem; Külah, Haluk; Department of Biomedical Engineering (2019)
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...
Label-free enrichment of MCF7 breast cancer cells from leukocytes using continuous flow dielectrophoresis
Arslan, Zeynep Caglayan; Yalcin, Yagmur Demircan; Külah, Haluk (2022-04-01)
Circulating tumor cells (CTCs) present in the bloodstream are strongly linked to the invasive behavior of cancer; therefore, their detection holds great significance for monitoring disease progression. Currently available CTC isolation tools are often based on tumor-specific antigen or cell size approaches. However, these techniques are limited due to the lack of a unique and universal marker for CTCs, and the overlapping size between CTCs and regular blood cells. Dielectrophoresis (DEP), governed by the in...
Synthesis of poly (dl-lactic-co-glycolic acid) coated magnetic nanoparticles for anti-cancer drug delivery
Tansık, Gülistan; Gündüz, Ufuk; Department of Biology (2012)
One of the main problems of current cancer chemotherapy is the lack of selectivity of anti-cancer drugs to tumor cells which leads to systemic toxicity and adverse side effects. In order to overcome these limitations, researches on controlled drug delivery systems have gained much attention. Nanoscale based drug delivery systems provide tumor targeting. Among many types of nanocarriers, superparamagnetic nanoparticles with their biocompatible polymer coatings can be targeted to an intented site by an extern...
Characterization and promoter identification of metastasis associated protein 1 in human colorectal carcinoma cell lines
Tunçay Çağatay, Seda; Erson Bensan, Ayşe Elif; Department of Biology (2014)
Metastasis associated protein 1 (MTA1) is a member of the nuclear remodeling and histone deacetylase (NuRD) complex, which is known to repress the expression of several tumor suppressor genes and has been widely linked to tumor metastasis. 15-lipoxygenase-1 (15-LOX-1) is a lipid metabolizing enzyme that has tumor suppressive properties and is silenced by the NuRD complex in colorectal cancer (CRC). We have previously shown that reexpression of 15-LOX-1 inhibited metastasis in CRC, inhibited the inflammatory...
Reversal of breast cancer resistance protein mediated multidrug resistance in MCF7 breast adenocarcinoma cell line
Urfalı, Çağrı; Gündüz, Ufuk; Department of Biology (2011)
Resistance to various chemotherapeutic agents is a major problem in success of cancer chemotherapy. One of the primary reasons of development of multidrug resistance (MDR) is the overexpression of ATP binding cassette (ABC) transporter proteins. Breast cancer resistance protein (BCRP) belongs to ABC transporter family and encoded by ABCG2 gene. BCRP is mainly expressed in MDR1 (P-glycoprotein) lacking breast cancer cells. Overexpression of BCRP leads to efflux of chemotherapeutic agents at higher rates, the...
Citation Formats
IEEE
ACM
APA
CHICAGO
MLA
BibTeX
Z. Çağlayan, “Enrichment of MCF7 breast cancer cells from leukocytes through continuous flow dielectrophoresis,” M.S. - Master of Science, Middle East Technical University, 2018.