Using a novel, adipose-liver, two-organ, human-on-a-chip system, the metabolic disease non-alcoholic fatty liver disease was modeled. This model was then used to test the effects of the gut microbiome on NAFLD progression. Two products of the gut microbiome, Trimethylamine-n-oxide and butyrate, were selected as representatives of potentially harmful and potentially beneficial compounds. A dose response, adipocyte and hepatocyte monocultures controls, and HoaC systems were run for 14 days. Through this experimentation, it was found that a dysbiosis of the gut microbiome could be influencing NAFLD progression. Additionally, further development and discovery regarding adipose-liver systems was added to the ongoing conversation of HoaC systems and their usages.

The drug development process is lengthy and expensive, with a 90% failure rate among drugs entering clinical trials due to the inadequacy of predictive models in the initial phases of drug development. To overcome these limitations, there is a paradigm shift towards developing micro physiological systems often referred as Organ-on-a-Chip that have be shown to recapitulate organ level functions in vitro. However, despite their promise, these systems often have limited throughput, restricting their widespread use in the drug development process. The work outlined in this thesis aims to bridge this gap by integrating the physiological relevance offered by micro physiological systems with the high throughput capabilities of traditional 2D multi-well plate cultures. The thesis outlines the development of two novel micro physiological systems, engineered in a high throughput multi-well format called the IFlowPlate and AngioPlate. Both the platforms have an open-top design and unlike tradition microphysiological platforms does not need complex pump systems and have built-in connections to achieve perfusion making it more scalable and user-friendly. The IFlowPlate leverages the self-assembly capability of endothelial cells to create a perfusable vascular network. This platform technology was utilized in this work to achieve intravascular perfusion of colon organoids for the first time and demonstrated immune cell circulation and recruitment in response to injury. AngioPlate, the other platform that was developed as a part of this work, utilizes a pre-patterned scaffold completely embedded in native hydrogel matrix to guide cells in forming organ-specific geometries and tubular structures using a novel subtractive manufacturing technique. This platform allowed for fabricating complex and intricate networks to model vascularized terminal lung alveoli and renal proximal tubules. This work demonstrated for the first time that highly complex perfusable tissues embedded in hydrogel can be integrated with multi-well plates to mimic tissue specific structures and interfaces without the use of synthetic membranes or plastic channels. The built-in perfusion channel and the flexible hydrogel matrix allowed for the terminal lung alveoli model to be mechanically actuated to mimic breathing motions. The renal proximal tubule model was used to mimic glucose reabsorption in kidney and model renal inflammation. The latter part of this work focusses on further improving this platform to increase platform robustness and to allow for incorporating supporting cells such as fibroblasts into the hydrogel matrix. This allowed us to model tubular injuries in kidney such as cisplatin induced -nephrotoxicity and TGF- β1 induced- tubulointerstitial fibrosis. Furthermore this work also describes the development of a high-throughput TEER meter that can be integrated with the AngioPlate platform allowing for rapid, non-invasive measurement of renal epithelial barrier integrity. Given that both platforms are designed in a 384-well plate format, they are high throughput and compatible with existing technologies like high-content imaging systems, robotic liquid handling systems, and microplate readers allowing for widespread adoption across diverse research settings. It is anticipated that the contributions described in this work will significantly advance our understanding of disease propagation and accelerate drug development process. / Thesis / Candidate in Philosophy / Drug development is a complex and expensive process, often hindered by a high failure rate in clinical trials. This failure is partly due to the inadequacy of current predictive models in the early stages of development. To address this, researchers are turning to innovative microphysiological systems known as Organ-on-a-Chip, which mimic organ structure and functions in the lab. However, these systems have been limited in their use due to low throughput. To overcome this limitation, microphysiological systems in multi-well formats called the IFlowPlate and AngioPlate were developed through the works outlined in this thesis. These platforms are designed to be high-throughput, scalable, user-friendly, and are compatible with existing technologies, such as microplate readers, high-content imaging systems and robotic liquid handlers, making them accessible to a wide range of researchers. By combining the physiological relevance of microphysiological systems with the high-throughput capabilities, these platforms aim to transform the way we study diseases and test drugs.

<p>  </p> <p>Diabetes, a chronic condition characterized by elevated blood glucose levels, arises when pancreatic β-cells lose capacity to produce a robust, dynamic glucose-stimulated insulin secretion (GSIS) response. Accurate measurement of β-cell health and function <em>ex vivo</em> is thus fundamental to diabetes research, including studies evaluating disease mechanisms, novel drug candidates, and replacement β-cell populations. However, present-day dynamic GSIS assays typically represent end-point measurements, involve expensive commercial perifusion machines, and require time-consuming enzyme-linked immunosorbent assays (ELISA) for insulin detection. Microfluidic devices developed as accessible, low-cost alternatives still rely on secondary ELISAs and suspend islets in liquid medium, limiting their survival <em>in vitro</em>. Here, we present a novel, 3D-printed microphysiological system (MPS) designed to recreate components of <em>in-vivo</em> microenvironments through encapsulation in fibrillar type I collagen and restoration of favorable molecular transport conditions. Following computational-informed design and rapid prototyping, the MPS platform sustained collagen-encapsulated mouse islet viability and cytoarchitecture for 5 days and supported <em>in-situ</em> measurements of dynamic β-cell function. To rapidly detect insulin secretion from β-cells in the MPS, we then developed a highly sensitive electrochemical sensor for zinc (Zn2+), co-released with insulin, based on glassy carbon electrodes modified with bismuth and indium and coated with Nafion. Finally, we validated sensor detection of Zn2+ released from glucose-stimulated INS-1 β-cells and primary mouse islets, finding high correlation with insulin as measured by standard ELISA. Together, the 3D MPS and Zn2+ sensor developed in this dissertation represent novel platforms for evaluating β-cell health and function in a low-cost, user-friendly, and physiologically-relevant manner. </p>