The post-prognosis lifespan for those suffering with Glioblastoma (GBM) is approximately 13 months with current standard of care. Intratumoral heterogeneity is a common characteristic that hinders GBM treatment in the form of therapy resistant cell subsets and influence on cellular phenotypes. One cell subset in particular, glioma stem cells (GSCs), is frequently left behind in the brain parenchyma once the bulk of the tumor has been resected. Previous research has found that patient-derived GSCs displayed varying invasion responses with and without the presence of interstitial flow. Interestingly, GSCs from a single patient are heterogeneous, displaying differences among sub-colonies derived from the same parental line. To study the motility of cells under flow, PDMS microfluidics are commonly used. Unfortunately, this setup often involves active flow generation using pumps, limiting the number of cell lines that can be imaged at a time. To increase the throughput of GSC sub-colonies imaged simultaneously, we developed a bio-compatible, printable device fabricated to allow for passive, gravity-driven flow through a hydrogel that recapitulates the brain microenvironment, eliminating the need for pumps. Stereo lithography 3D printing was chosen as the manufacturing method for the device, and this facilitated design feature modification when prototyping, increased the potential complexity of future iterations, and avoided some of the hurdles associated with fabricating PDMS microfluidics. This printable imaging device allows for higher throughput live-imaging of cell lines to aid in the understanding of the relationships between intratumoral heterogeneity, invasion dynamics, and interstitial flow. / Master of Science / For those suffering with Glioblastoma, a high-grade brain cancer, the life span post treatment is approximately 13 months. The cells in this and many forms of cancer have physical and biological differences that make successfully eliminating the disease difficult. One of the cell types contributing to this are Glioma Stem Cells (GSCs) that are often left in brain tissue once most of the tumor has been surgically removed. Previous research has found that GSCs from different sources had different responses with and without the simulated or actual presence of flow in brain tissue. This was further complicated when different responses were observed in cells obtained when breaking apart one of the cell lines and propagating these into their own sub-colonies. The current standard for studying the movement of cells under flow is by using compact chips made of a clear silicone rubber. The setup with microfluidics typically requires connection to external tubing and pumps to create flow and this limits the amount of cell types that can be imaged at a time. In order to monitor more cells at a time we created a 3D printable device that uses gravity for flow to go through a gel that mimics brain tissue and these cells of interest. Resin 3D printing was used to make these small devices so that they could be easily re-designed for other experimental purposes in the future. Hopefully this device could be used to more rapidly gain an understanding of cell movement in GBM and other disease models.

Advances in genetics and fluorescent protein chemistry have enabled us to fuse fluorescent probes directly to biomolecules in stably growing organisms; making it easier to image the precise position and movement of cells in three dimensions. Fluorescent stains and dyes can be employed in a similar fashion to visualize nano-scale fluctuations in active cellular structures without fixation. While informative and exciting on a qualitatively level, microscopy truly becomes powerful when we can extract meaningful quantitative information. To accomplish this, custom MATLAB (Mathworks, Natick, MA) image analysis algorithms were developed to specifically measure the biophysical parameters related to pathogenesis and function in microbes and mammalian cells. These parameters can then be exploited in the development of biophysical models to validate current measurements, and make critical predictions about the system's behavior, often addressing quantities inaccessible by experimental methods. The following research chapters of this dissertation thoroughly describe how these techniques were developed and applied to study the biophysical mechanisms of bacterial and cellular invasion.