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Engineering Cardiac Organoid Vascularization via Fluid Shear Stress and Vascular-Promoting Growth Factors

Cardiovascular disease (CVD) is the leading cause of death internationally. Efforts to decrease CVD death has been explored through stem cell technology, specifically organoid formation. Current cardiac organoid models lack the vascular networks for nutrient supply and maturation. In this study, pillar perfusion technology is used to fabricate cardiac organoids and induce vascularization via dynamic culturing and the addition of vascular promoting growth factors (GFs). In addition to this study, a millifluidic chip is engineered for shear stress application via flow simulations and experimental flow analysis. We successfully optimized the millifluidic chip to achieve fluid shear stress of 20mPa and validated through particle tracking velocimetry using 0.1um diameter beads under flow. The results of cardiac organoids displayed contraction and growth of endothelial cells (ECs) under dynamic flow with GFs. In addition, smooth muscle cells (SMCs) displayed growth via GFs in both dynamic and static culturing. Although vascular networks were not present in all conditions of this experiment, this thesis can serve a basis for searching other methods of inducing vascularization.
Date: August 2022
Creator: Huerta Gomez, Angello
System: The UNT Digital Library
Integrating a Brain Control Interface towards the Development of a Retrofitted, Low-Cost, Open Sourced, Electric Wheelchair (open access)

Integrating a Brain Control Interface towards the Development of a Retrofitted, Low-Cost, Open Sourced, Electric Wheelchair

The Emotiv Insight is a commercially available, low-cost, mobile EEG device that is commonly overshadowed by its costlier counterpart, the Emotiv EPOC. The purpose of this report is to investigate if the Emotiv Insight is a suitable headset to be used as a controlling factor in conjunction with an Arduino microcontroller and various electrical components that are used towards the development of an open-sourced, affordable electric wheelchair with the primary goal of providing those who either do not have the financial resources or the physical capability to operate a traditional wheelchair due to their disability a viable option to improve their quality of life. All of the C++ code, STL files used to fabricate the 3d-printed components are uploaded to a GitHub repository as open sourced files to allow individuals with access to a 3d-printer to either build the open sourced wheelchair for their personal use, or refine the design to suit their needs.
Date: August 2020
Creator: Ta, Christopher Ian
System: The UNT Digital Library
Bio-Inspired Designs to Reduce Human-Exoskeleton Interaction to Prevent Falls in an Aging Population (open access)

Bio-Inspired Designs to Reduce Human-Exoskeleton Interaction to Prevent Falls in an Aging Population

As a large generation ages, the collective financial and ethical responsibility to prevent egregious bodily harm through fall prevention and gait assistant exoskeleton devices increases. Risk for falls increases with age and the severity of the fall does as well. To support this elderly population, motorized exoskeletons can both increase stability as well as respond faster to fall scenarios, but current models do not more around the existing biological framework. Giving participants a range of motion in key pelvic areas can closely approximate synchronous rotation around the femoral head, while limiting an increase in their sagittal profile. Utilizing 3D printed components while incorporating existing orthic methods provide short production times on modular designs. Although primarily mechanically based, these designs consider electronic requirements and are capable for supporting movement for a 200 lbs. user at a brisk walking pace for 1 hour.
Date: August 2021
Creator: Gates, Edward Sean
System: The UNT Digital Library

Stem Cell Regulation Using Nanofibrous Membranes with Defined Structure and Pore Size

Electrospun nanofibers have been researched extensively in the culturing of stem cells to understand their behavior since electrospun fibers mimic the native extracellular matrix (ECM) in many types of mammalian tissues. Here, electrospun nanofibers with defined structure (orientation/alignment) and pore size could significantly modulate human mesenchymal stem cell (hMSC) behavior. Controlling the fiber membrane pore size was predominantly influenced by the duration of electrospinning, while the alignment of the fiber membrane was determined by parallel electrode collector design. Electric field simulation data provided information on the electrostatic interactions in this electrospinning apparatus.hMSCs on small-sized pores (~3-10 µm²) tended to promote the cytoplasmic retention of Yes-associated protein (YAP), while larger pores (~30-45 µm²) promoted the nuclear activation of YAP. hMSCs also displayed architecture-mediated behavior, as the cells aligned along with the fiber membranes orientation. Additionally, fiber membranes affected nuclear size and shape, indicating changes in cytoskeletal tension, which coincided with YAP activity. The mechanistic understanding of hMSC behavior on defined nanofiber structures seeks to advance their translation into more clinical settings and increase biomanufacturing efficiencies.
Date: August 2022
Creator: Blake, Laurence A
System: The UNT Digital Library