Abstract

Cancer is considered to be the second cause of death in the Canada and other parts of the world. Separation of cancer cells from blood for early detection of cancer improves prognostics of survivals for most of types of cancer. In this thesis, design and fabrication of microdevices for living cell separation based on dielectrophoresis phenomena is presented. A novel microfluidic device for continuous separation of malignant cells from blood is fabricated and experimentally tested. The separation of breast cancer cells from blood using the microdevice is performed experimentally and reached close to 100% accuracy with a flow rate 01 mL/hr. Parallel configuration of the presented microdevice is recommended to increase the separation speed which will enable point-of-care tests. The effects of dielectrophoretic manipulation and carbon nanotubes on living cells are also investigated in the present work. The changes in genes expression due to the exposure to AC field of 10 kHz and 100 kHz and carbon nanotubes treatment are studied using microarray analysis. Results show that 75% of the studied genes were altered by the exposure to 10 KHz field and only 25% of the genes were slightly altered by the 100 kHz exposure. As a result, higher AC frequency in range of 100 kHz is recommended for dielectrophoretic applications. Moreover, important genes are reported to be altered by carbon nanotubes. Due to the fact that dielectrophoretic separation of living cells requires knowledge of the strength and distribution of electric field, analytical solutions for dielectrophoretic force over non-uniform interdigitated electrodes and for moving dielectrophoretic phenomenon are derived. Novel method to approximate the function that describes the potential profile between adjacent electrodes is reported. Excellent agreement is found by comparing the analytical solution with numerical and experimental results. A number of designs for the microfluidic chip were completed and experimental work carried out with living cells form cell lines being separated from blood. The experimental results suit the analytical findings and the method could be used in clinical studies.