Characterization of Cortical Precursor Cells’ Responses to BMP4 Gradient in a Microfluidic Device Student: Eric Kuo Mentor: Edwin S. Monuki & Noo Li Jeon Morphogen gradients are fundamental to animal development, and morphogen defects are primary causes of human brain malformations. Nonetheless, tremendous controversy remains about the mechanisms by which morphogen gradients act on the developing brain. To date, studies on this issue have relied on traditional cell culture tools, which are inefficient and biologically limited as models of natural gradients. In this study, a microfluidic culture device has been engineered and optimized to address these limitations. The device is used to simulate an in vivo environment by generating several diverse, stable, and continuous gradient profiles onto cultured cells in which its behaviors can be captured by time-lapse microscopy. The specific morphogen protein used in this study is BMP4 (Bone Morphogen Protein). Our finding indicates cells exposed to high BMP4 concentration induces cell death and suppresses cell proliferation. Also, it appears that BMP4 us a chemo-attractant for the mNSC (mouse Neural Stem Cells), which has never been reported in the literature. We have generated a real-time optical assay on cell death and on proliferation in a morphogen gradient that has revealed novel insights on the slope of the gradient and new roles of BMP4 in the developing cerebral cortex.