Abstract
Abstract Cancer cells initially originate from normal cells that obtain the ability to proliferate aberrantly and become malignant. A subpopulation of these malignant cells has many characteristics of normal stem cells, including self-renewal and differentiation. Also these cells have a potential of growing clonally into tumors and express markers of normal stem cells. Thus, these cells called cancer stem cells (CSCs). Tumor progression and recurrence after surgery or chemotherapy are the main reasons for mortality of cancers. On the other hand, the growing evidence shows that the existence of cancer stem cells is the main cause of cancer resistance to therapy, so it is becoming increasingly important to study CSCs. The ability to identify, isolate, propagate and molecularly characterize CSC subpopulations could improve the discovery of cancer stem cell biomarkers and expand the understanding of the molecular mechanisms that regulate self-renewal and differentiation. Confocal microscopy and microfluidic chip are two novel technologies for imaging and isolation of cells respectively. In this study we used confocal microscopy to investigate the expression pattern of several cancer stem cells markers (CD133, CD44 and Claudin-4) in 2-Dimentional and 3-Dimentional models. The scope of this thesis is to investigate the expression pattern of three cancer stem cell markers using cancer stem confocal microscopy. Then we selected the most expressed marker as a target for immunomagnetic-based cell separation by microfluidic chip technology to isolate CSCs among tumor cells. In this study we used HCT-8 colorectal cancer cell line to generate 2-D monolayer cells, 3-D sphere cells. Our chip possesses 500 micropost structures fabricated by photocrosslinking polymerization of polyethylene glycol diacrylate under the exposure of UV light. These microposts contain iron nanoparticles inside of their structure when a piece of strong magnet placed under the chip, a big magnetic force will be induced in the microposts and give them the ability to capture pre-labeled cells. Tumor cells were treated by antibodies against cancer stem cell markers and then magnetic Dynabeads against these antibodies; consequently the cultured cells labeled with magnetic Dynabeads could be isolated by the chip with approximately 50% of efficiency.