The ability to pattern three-dimensional microscale cultures opens new avenues for examining the effect of nonplanar mechanical environments on mammalian cells and tissues. Our lab has developed a method for generating suspended tissues with spatial control using open microfluidic principles called Suspended Tissue Open Microfluidic Patterning, or STOMP. STOMP utilizes spontaneous capillary flow and capillary pinning to pattern suspended, multi-region tissues. Using similar microfluidic principles as STOMP, we have developed a method to pattern large (cm-scale) models via semi-open microfluidic channels called Suspended Nonplanar and Planar, or SNaP, geometries. I design these devices with computer-aided design, fabricate components on stereolithography 3D printers, pattern devices with standard pipettes, and culture resulting tissues for short- and long-term time periods to model biological scenarios. With the broad statement that human tissue is generally nonplanar in mind, my research focuses on three different geometries of tissue, 1) a sinusoidal wave, 2) a transwell-like mogul, and 3) a multi-region dome, where each nonplanar geometry enables a different biomedical investigation. The sinusoidal wave construct allows us to ask if cells embedded in tissues with varying frequencies of undulation experience changes to cell morphology due to the topology of their environment; the transwell-like mogul enables investigation of cell proliferation of cells grown at or within an air-liquid interface; and the multi-region dome facilitates the study of tissue interfaces where a diseased region of cells meets a healthy region of cells, all within a single contiguous tissue. I am currently exploring these questions through multiple cultures where different device versions and/or multiple cell types are engaged to collect biological readouts which demonstrate SNaP as a translatable platform for the investigation of questions in biomechanics and regenerative medicine.

Less than 10% of drugs successfully transition from preclinical to clinical trials, principally due to the inability of currently used 2-dimensional models to simulate the 3-dimensional structure and function of human tissues. To develop 3D in vitro models of human vasculature for more efficacious screening of anti-atherosclerosis drugs, I created a device for constructing a perfusable tissue containing a lumen by leveraging open microfluidic patterning methods developed by our group: suspended tissue open microfluidic patterning (STOMP). The device can be used to pattern tissue with a hollow luminal structure lined with endothelial cells, which can be perfused via hollow posts the tissue is suspended between. Using surface tension-driven flow, a liquid hydrogel precursor solution flows through the open microfluidic channel and around the two hollow posts. After gelling, the tissue anchors to the post, contracts away from the sides of the microfluidic channel, and the STOMP device is removed. By adding a second STOMP device that can surround the first tissue another cell-laden hydrogel can be patterned around the first tissue, encapsulating it. To form a lumen in cardiac tissue, I will pattern the inner region with human umbilical vein endothelial cells (HUVECs) in an enzymatically degradable polyethylene glycol hydrogel, surrounded by human induced pluripotent stem cell-derived cardiomyocytes in fibrin hydrogel. Enzymatic degradation of the core region will form a cavity through which HUVECs will remodel the cavity walls, forming an endothelial lining. I will assess lining formation by adding fluorescent dextran to cell media being perfused through the device and measuring fluorescence through confocal microscopy in the surrounding region over time, allowing me to evaluate the permeability of the membrane to compare with physiological values. This model can then be used to screen treatments for atherosclerosis to study how drugs interact with cells in a 3D microenvironment.