Establishment Of Micro Valve And Liquid Membrane Double-Controlled Microflu1dic System And Its Application In The Study Of Breast Cancer Cell Interaction

Breast cancer is the most common malignancy which accounts for23%of total cancersin the world and cause14%deaths. Breast cancers can not only metastasize to distant vitalorgans but also be self-seeded by their derived CTCs; however, the dynamic interaction andco-existence between the two types of breast cancer cells have not yet been fully explained.Research on migration, infiltration and co-existence of the two types of breast cancer cellsmay give help for a better understanding of tumor progression and oncotherapy after self-seeding.Traditional cell migration appoaches such as Boyden/Transwell chamber and wound-healing assays are convenient to conduct for this purpose; however, each of these assays hasinherent limitations. In this study, we investigated the MDA-MB231and MDA231-LM2human breast cancer cells using a microvalves and liquid membrane double-controlledintegrated micrfluidics. Liquid membranes were prepared by precisely controlling the widthof microgaps and the flow rate of running flows in the designated channels. The cells alongthe liquid membranes which served as leading edge for migration remained intact and themigration can be triggered through increasing the flow rate.The flow rate assay and CFD simulation results demonstrate that5μl min^-1and10μlmin^-1can be adopted to effectively form and cancel the liquid membranes in a microchip with20μm microgaps. Cells viability analysis indicates that both MDA-MB231(MDA231) andMDA231-LM2(LM2) cells cultured in this microdevice took on good macrophages and theircell viability reach to99.1%and99.3%respectively. Investigating the migration abilityreveals that co-cultured MDA231and LM2are both attractive to each other, while themigration distance, area and cell number of LM2are all larger than MDA231cells; what'smore, the migration ability of both the two types of cells under monoculture werestrengthened by the other's secretory products. LM2cells can infiltrate their adjacentMDA231cell population and the number of the infiltrating cells increase from fast to slowduring a culture period of60h; additionally, the larger ratio of LM2to MDA231results infaster infiltration. The immunocytochemistry assay suggests that Fascin^-1 highly expressed inthe in cytoplasm and cellular protrusions of both MDA231and LM2cells, implying that Fascin^-1 functions in the organization of cytoskeleton and migration dynamics other thandirect cell communication. These findings will be beneficial in understanding the profoundinfluence of self-seeding on tumor progression, as well as exploring more specializedmicrofluidic platforms aiding the future researches on cell-cell interactions in a biomimeticcontext of physical or pathological conditions for more biological subjects.