Date of Award

Fall 2014

Document Type

Thesis

Degree Name

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

Department

Biomedical Engineering

First Advisor

George Collins

Second Advisor

Treena Livingston Arinzeh

Third Advisor

Bryan J. Pfister

Fourth Advisor

Bruno A. Mantilla

Abstract

The human body contains a vast array of soft and hard tissues, each with their own unique set of physical, chemical, mechanical, and electrical properties. It is the combination of these tissues that allows the human body to function as it does. However, these tissues are subject to wear, fatigue, and injury and thus can potentially limit the functions of the body. Therefore, tissue engineering has sought various natural and synthetic materials that can be used for fabrication of cellular scaffolds that have the ability to promote cellular attachment, proliferation, differentiation, and eventual whole tissue formation for replacement and repair of damaged human tissues.

The objective of this thesis is to develop an apparatus that is capable of producing a graded heterogeneous fiber scaffold, and its subsequent application towards the development of a scaffold which mimics the cartilage-bone ECM interface. The scaffold is a combination of fibers made from three separate solutions: 1) gelatin-NaCS in dH2O and ethanol, 2) gelatin-NaCS-HA/β-TCP in dH2O and ethanol, and 3) PCL-HA/β-TCP in methylene chloride and dimethylformamide. The fibers produced from the electrospinning of these solutions are intended to mimic the extracellular matrix of hyaline cartilage, calcified cartilage, and subchondral bone, respectively. A co-electrospinning technique, utilizing a grounded rotating mandrel, is used to create the fiber grade through the depth of the scaffold.

A combination of light microscopy, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and fluorescence microscopy are used to determine several scaffold parameters including: fiber diameter, inter-fiber spacing, fiber alignment, the presence of specific material components, and the confirmation of the presence of two distinct sides to the scaffold. Ideally, the scaffold has the potential of promoting cellular differentiation of mesenchymal stem cells into chondrocytes and osteoblasts on separate halves of the same scaffold. However, several hurdles remain that could impede complete differentiation of two cell types on the scaffold, the largest being the absence of a differentiation media that is both osteogenic and chondrogenic. Nevertheless, this work serves as a foundation for the development of electrospun scaffolds that look to generate more than one tissue type.

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