Author ORCID Identifier

https://orcid.org/0000-0001-7558-4221

Year of Publication

2018

Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation

College

Engineering

Department

Chemical and Materials Engineering

First Advisor

Dr. Bradley J. Berron

Abstract

Surface functionalization of living cells for cell therapeutics has gained substantial momentum in the last two decades. From encapsulating islets of Langerhans, to cell laden gels for tissue scaffolds, to individual cell encapsulation in thin hydrogels, to surface adhesives and inert surface camouflage, modification of living cell surfaces has a wide array of important applications. Here we use hydrogel encapsulation of individual cells as a mode of protection from mechanical forces for high throughput cell printing, and chemical stimuli for the isolation of rare cells in blood.

In the first study, we review methods of surface functionalization and establish a metric of potential target biomarkers for circulating tumor cell (CTC) isolation. For extended applications in cancer detection through a fluid biopsy, common surface antigen densities were quantitatively assessed in relation to peripheral blood mononuclear cells (PBMCs) for potential targets of cell specific encapsulation. We then look to commercialization of our process after considering biopsy volumes and cell therapy dose sizes. Undesired batch-to-batch variation in our in-house synthesized photo-initiator could be eliminated by the use of fluorescein, a commercial fluorochrome of similar initiating power to our current eosin initiating system. Fluorescence and hydrogel generation were compared indicating a fluorescein conjugate has comparable power to that of our in-house conjugated eosin. Parameters involving the number of cells and fluid volumes processed were then analyzed systematically. Key parameters were studied to determine optimal equipment and protocol for clinically relevant batch sizes. The final study looks at the mechanical protection provided by thin hydrogel encapsulation. With growing interests in 3D bioprinting and goals of viable whole organ printing for transplant, high resolution and high throughput printing is a growing need. 3D bioprinting presents intense mechanical stimuli in the process that cells must endure. Here we analyze how hydrogel encapsulation reinforces the cellular membrane allowing cells to withstand the damaging forces associated with bioprinting.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2018.512

Funding Information

This work was supported by the National Science Foundation Career Award grant awarded to BJB (NSF-1351531), and the NIH award R01 HL127682-01.

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