Date of Award

Spring 2014

Document Type

Thesis

Degree Name

Master of Science in Biomedical Engineering - (M.S.)

Department

Biomedical Engineering

First Advisor

Cheul H. Cho

Second Advisor

Bryan J. Pfister

Third Advisor

George Collins

Abstract

Microencapsulation of cells is gaining popular interest in the field of biomedical engineering because it provides a more effective 3D scaffold that can mimic the cell microenvironment. The benefits of using microcapsules are biocompatibility, biodegradability, nontoxicity, and formation under mild gelation conditions. In this study, the ability of the alginate microcapsules to control the proliferation and differentiation of mouse OCT4-GFP embryonic stem cells is investigated. Microcapsules are produced by extrusion of alginate into a calcium chloride gelation bath with the aid of a co-axial air flow. It is shown that the size of the spheres is controlled based on needle gauge, air flow rate, and alginate concentration. Coating the microcapsules with a chitosan membrane improves stability over time as their swelling behavior is examined. The surface of the microcapsules is further characterized using Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). Permeability of the microcapsules is studied through the release rate of encapsulated bovine serum albumin (BSA) and fluorescein isothiocynate-dextran (FITC-dextran) over time. Finally, cell viability is tested by means of live-dead cell and resazurin assays of encapsulated cells. The proliferation and differentiation of encapsulated mouse OCT4-GFP embryonic stem cells are analyzed by flow cytometry. It is shown that encapsulated cells are able to remain viable and that the microcapsule microenvironment is able to control the proliferation and differentiation of mouse OCT4-GFP embryonic stem cells.

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