Development of microfluidic cell growth and stress response analysis platforms at single cell resolution

Cancer, as one of the evolutionary diseases, is among the major causes of death all over the world. In order to obtain quantitative data about development of cancer and its underlying mechanisms, it is significantly important to understand interactions of cancer cells and their surrounding microenvironment at single-cell resolution. In this respect, microfluidic platforms are capable of mimicking tumor microenvironment, while representing a versatile tool for lab-on-a-chip (LOC) applications. In this thesis, new microfluidic tools were presented to investigate behavior of single cells and their response to different chemicals. The context of this thesis includes design, simulation, microfabrication and tests of these microfabricated devices using human cancer cell lines. One of these microfluidic platforms was a cell culture device to culture cells fed by medium flow, while allowing their live-cell imaging at single-cell resolution. The second one was a microfluidic gradient generator, which is known as Christmas-Tree chemical gradient generator, was used to create gradient of chemicals to be induced grown cell culture in the microfluidic cell culture device. These microfabricated tools were modular, therefore, they might be used as independent devices or they could be integrated. The designs of the microfluidic devices were simulated using COMSOL multi-physics program. Soft-lithography was performed for their fabrication. The DsRed fluorescent protein expressing breast cancer cell line (MCF7) was used to test the performance of the developed microfluidic devices. As a result of this study, a bubble-free single-cell loading protocol for LOC platforms was successfully developed. Furthermore, cells were cultured; their proliferation rate was obtained using image processing. Last but not least, the cells cultured in the microfluidic cell culture device were exposed to sodium dodecyl sulfate (SDS) using the microfluidic gradient generator. The dose-dependent, SDS-induced death was quantitatively investigated using the integrated microfluidic platform.