@phdthesis{oai:oist.repo.nii.ac.jp:00001341,
 author = {Hsieh-Fu, Tsai},
 month = {2020-04-02, 2020-04-02},
 note = {In biosystems, chemical and physical fields established by gradients guide cell migration, which is a fundamental phenomenon underlying physiological and pathophysiological processes such as development, morphogenesis, wound healing, and cancer metastasis. Cells in the supportive tissue of the brain, glia, are electrically stimulated by the local field potentials from neuronal activities. How the electric field may influence glial cells is yet fully understood. Furthermore, the cancer of glia, glioma, is not only the most common type of brain cancer, but the high-grade form of it (glioblastoma) is particularly aggressive with cells migrating into the surrounding tissues (infiltration) and contribute to poor prognosis. In this thesis, I investigate how electric fields in the microenvironment can affect the migration of glioblastoma cells using a versatile microsystem I have developed. I employ a hybrid microfluidic design to combine poly(methylmethacrylate) (PMMA) and poly(dimethylsiloxane) (PDMS), two of the most common materials for microfluidic fabrication. The advantages of the two materials can be complemented while disadvantages can be mitigated. The hybrid microfluidics have advantages such as versatile 3D layouts in PMMA, high dimensional accuracy in PDMS, and rapid prototype turnaround by facile bonding between PMMA and PDMS using a dual-energy double sided tape. To accurately analyze label-free cell migration, a machine learning software, Usiigaci, is developed to automatically segment, track, and analyze single cell movement and morphological changes under phase contrast microscopy. The hybrid microfluidic chip is then used to study the migration of glioblastoma cell models, T98G and U-251MG, in electric field (electrotaxis). The influence of extracellular matrix and chemical ligands on glioblastoma electrotaxis are investigated. I further test if voltage-gated calcium channels are involved in glioblastoma electrotaxis. The electrotaxes of glioblastoma cells are found to require optimal laminin extracellular matrices and depend on different types of voltage-gated calcium channels, voltage-gated potassium channels, and sodium transporters. A reversiblysealed hybrid microfluidic chip is developed to study how electric field and laminar shear can condition confluent endothelial cells and if the biomimetic conditions affect glioma cell adhesion to them. It is found that glioma/endothelial adhesion is mediated by the Ang1/Tie2 signaling axis and adhesion of glioma is slightly increased to endothelial cells conditioned with shear flow and moderate electric field. In conclusion, robust and versatile hybrid microsystems are employed for studying glioma biology with emphasis on cell migration. The hybrid microfluidic tools can enable us to elucidate fundamental mechanisms in the field of the tumor biology and regenerative medicine.},
 school = {Okinawa Institute of Science and Technology Graduate University},
 title = {チップ上の神経膠腫: 機械学習を用いたマイクロ流路中微小環境における神経膠腫細胞ガイダンスと細胞間相互作用の解析},
 year = {}
}