Fluid flow stimulation of engineered heart valve tissue

Smith, Emma; Taylor, Alexandra; Drasser, Rachel; Chabra, Casey

Student Work

Fluid flow stimulation of engineered heart valve tissue

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Currently, the only treatment for aortic valvular disease is a valve replacement, and replacement valves on the market have limitations, especially for pediatric patients who need to undergo multiple invasive surgeries in a lifetime. Tissue-engineered heart valves (TEHV) hold the possibility to grow with patients, by having host cells repopulate it, however, this mechanism of repopulation is not understood, and TEHVs have mechanical limitations that are not conducive to the valvular environment. The cells within the TEHVs are directly influenced by the blood flow through the valves, therefore the goal of this project is to study the cellular response to blood flow conditions. We designed a microfluidic bioreactor that can contain cells and a gel matrix where endothelial cells are seeded adjacent to the matrix so that they can migrate into it as they experience phenotypic changes due to exposure to shear flow conditions. To achieve this, we designed multiple microfluidic devices out of PDMS using photolithography and soft lithography increasing the height of our devices to 200 µm and post spacing, while containing the gel matrix. We also designed two gravity pumps that produce steady flow at shear stresses of 2.0 pascals and 0.2 pascals and updated a double gravity pump which produces oscillatory flow. Based on our results, our microfluidic designs can contain gel and can be used for further testing under our gravity pump systems, indicating that we successfully designed a device with double the height and space between posts, increasing the area by four times. Hence, a microfluidic bioreactor was created with an accurate shear stress pumping system and a microfluidic device that maximizes the space for cell migration.

This report represents the work of one or more WPI undergraduate students submitted to the faculty as evidence of completion of a degree requirement. WPI routinely publishes these reports on its website without editorial or peer review.

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