Microwell Fabrication for Impedance and AC Measurements of Isolated Ventricular Cardiomyocytes

Electrophysiological behavior of human hearts have been extensively studied for hundreds of years. Even with elucidation of not just biological function, but also time and frequency-dependent current flow, the sheer intricacy of in vivo cardiac tissue function remains somewhat enigmatic. All while heart disease has been the leading cause of death in the United States for over a century, with its rates of occurrence still increasing annually [1]. Thus, new research techniques and tools to quantify cardiac function are still being pursued at smaller and smaller scales to decrease research/innovation time, cost, and diagnostic ambiguity. In fact, it remains incredibly scientifically-relevant to measure ionic current from single, isolated cells to quantify cells’ coupled electromechanical behavior. Among engineering studies, it is commonplace to use cultures of induced pluripotent STEM cells (iPSCs) to conveniently and uniformly mimic the behavior of a specific native cell type [2,3]. However, live cardiac cells from humans or animal models are non-uniform with exceptional capabilities of adaptation to varying electrical input (i.e., changing heart rate). This thesis outlines a novel microelectrode designed to measure impedance profiles for native murine left ventricular myocytes (LVMs) as utilized with cultured iPSC models. The main goal of this thesis is to synthesize and test this microelectrode optimized for quantifying impedance of hundreds of both living and dead LVMs in real-time. The results can be employed in many ways including, but not limited to, quantification of cell-electrode adhesion, cell-cell contacts, cell death, contraction rates, cardiotoxicity of drugs, and cell morphology.