Date of Award

8-2026

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biomedical Engineering and Sciences

First Advisor

Christopher A. Bashur

Second Advisor

James R. Brenner

Third Advisor

Peshala Priyadarshana Thibbotuwawa Gamage

Fourth Advisor

Linxia Gu

Abstract

Endothelial cell (EC) dysfunction, driven by changes in mechanical stimuli within blood vessels, contributes to major life-threatening cardiovascular diseases. Essential factors influencing healthy EC function include fluid flow, shear stress, and gravity. Understanding how ECs respond to these stimuli remains limited due to insufficient systems for studying and observing them in this environment, because spaceflight research opportunities are scarce, and because microgravity simulation units impose strict constraints on samples. The use of hydrogels within bioreactor chambers can provide a stable environment that supports cell viability and often more closely replicates in vivo conditions. The goal of this study was to develop a hydrogel chamber system capable of actively perfusing ECs with media while rotating within a random positioning machine (RPM) to simulate microgravity conditions. This was achieved by using computer-aided design to 3D print custom components to hold hydrogels, media reservoirs, and the assembled perfusion system within the RPM unit. The system was validated by comparing finite element simulation predictions with experimentally observed outcomes. The complete perfusion setup was evaluated through leak testing and flow rate calibration. Cast gelatin hydrogels were tested for thermal stability at 37°C, post-crosslinking channel diameter, and cell adhesion. Lastly, the fully assembled system was mounted and operated on an RPM for 72 hours, and post-experiment imaging confirmed cell viability within the system. The ECs without perfusion appeared to have morphological differences when compared to the typical EC morphology in arteries, likely due to a lack of fluid flow. Overall, with this system, cells can be investigated under microgravity in conditions that more closely resemble the in vivo environment and enable long-term experiments through continuous perfusion of nutrients and oxygen. Future studies will compare differences between cell morphology and density following microgravity experiments conducted with and without perfusion.

Comments

Copyright held by author.

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