Design, Fabrication and Optimization of Microfluidic Chambers for Neurobiology Research

In vitro culture systems have improved our understanding of human neurobiology and disease. For example, in vitro platforms such as organotypic brain slices and dissociated cultured neurons represent powerful screening systems for dissection of molecular pathways underlying dysfunction of neuronal activity. Similarly, tissue slice co-cultures that permit the evaluation of inter-neuronal function across brain regions have been well established. Also, studies with primary neuronal cell cultures indicate that disruption of intracellular axonal transport of molecules critically affects the survival and function of neurons. Despite significant progress in medicine, biology and engineering; there is still a widespread need for precisely defined culture systems to facilitate a better understanding of neuronal cell function and screen new therapeutic drugs or methods to treat neurodegenerative diseases. In this work we propose that an enhanced understanding of specific pathways underlying neuronal activity, in both normal and disease states, demands the use of research-specific experimental tools such as microfluidic culture chambers optimized for a precise manipulation and observation of the local tissue or cellular microenvironments of neuronal processes. By using a multidisciplinary approach to create a synergy of cell biology, engineering, and neuroscience, we tailored micro/nano-scale design strategies to control extrinsic aspects of the local neural tissue/cell microenvironment. Specifically, we developed perfusion-based microfluidic devices that allow both precise control of the tissue microenvironment and localized chemical stimulation of organotypic brain slices for either acute or long term experiments. Additionally, we developed a suite of cell-based compartmentalized microfluidic chips to isolate different neuronal subcellular compartments (i.e., either somatodendritic or axonal domains) into separate and precisely defined biochemical microenvironments. The devices allow independent genetic or pharmacological manipulation in each specific neuronal compartment, extended long-term fluidic isolation between different biochemical microenvironments, on-chip immunocytochemistry, and live cell imaging of subcellular localization and axonal transport of neuronal proteins. Importantly, these tools are aimed at potential drug testing and medium to high throughput screening. It is hoped that the technology developed in this work will aid investigations and discoveries related to neuronal functions and diseases.