Date of Award

12-2014

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Bioengineering

Committee Member

Dr. Dan Simionescu, Committee Chair

Committee Member

Dr. Agneta Simionescu

Committee Member

Dr. Martine LaBerge

Abstract

Tissue engineered constructs have proven to possess comparable mechanical and physical characteristics to autologous tissues making them suitable replacements fordiseased anatomy when autologous tissue transplants are unavailable. However, difficulty in reseeding the constructs with cells prevents the tissue-engineered scaffoldsfrom becoming an adequate, equivalent replacement for diseased tissues when compared to autologous transplants. Cells adhere to the outer surfaces of scaffolds but are incapable of penetrating the constructs to provide complete cellularization. If cells were able to populate the inner layers of the tissue, then they could likely diffuse into the intimal and external layers of the construct to create a fully colonized scaffold. We propose the use of microneedles to inject cells into the inner layers of scaffolds to evenly repopulate entire constructs with cells. With recent advancements in microfabrication, arrays of microneedles, less than a millimeter in height, can be fabricated simply and cost effectively. These microneedle arrays can be attached to a syringe to allow injection of cells into the interior of thescaffold. Unlike traditional hypodermic needles, these microneedle arrays will allow for accurate and customizable penetration depth as well as a customizable distance between adjacent needles. With this microtechnology, anatomically accurate distances between neighboring cells can be achieved, an option that has never been previously available. To validate the use of microneedles for bulk cell seeding, the group injected cells into both decellularized carotid arteries and decellularized aortic cusps using three different arrays of microneedles. We then determined the overall cellular density in the tissue using histological methods. Mechanical damage was quantified throughmechanical testing.

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