Capture of circulating tumor cells from blood on modified gold surfaces inside the microfluidic channels

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Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Bilimleri Enstitüsü, Türkiye

Tezin Onay Tarihi: 2019

Tezin Dili: İngilizce

Öğrenci: DİDEM ÇETİN

Eş Danışman: Erhan Bat

Danışman: Haluk Külah

Özet:

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 protein expressing MCF-7 breast cancer cells. Cell binding events were monitored using fluorescent microscopy and antibody attachments through covalent binding and bioaffinity analyzed on different alkanethiol and polyethylene glycol (PEG) thiol SAM formations. The comparison between techniques was made considering the length and functional end of SAMs, homogeneous surface coverage, elimination of the nonspecific binding, positioning of the antibody and steric hindrance effect. Surface characterizations of SAMs and antibody attached surfaces were performed with X-ray Photoelectron Spectroscopy, Atomic Force Microscopy, and contact angle measurements. The selectivity to EpCAM protein was tested with K562 leukaemia cells. The experiments were repeated for other possible microfluidic surfaces, such as glass and polymer. Results obtained from the comparisons are found useful for improvement on the antibody immobilization techniques for CTC capture on biosensor designs