Document Type

Thesis

Date of Award

5-31-2012

Degree Name

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

Department

Biomedical Engineering

First Advisor

Treena Livingston Arinzeh

Second Advisor

George Collins

Third Advisor

Cheul H. Cho

Fourth Advisor

Rameshwar, Pranela

Abstract

Over the past few decades, tissue engineering approaches have pushed their way to the forefront of biotechnological research and development, serving a wide variety of applications. This research utilizes quantitative methods to analyze the outcome of two bone tissue engineering studies. In an in vivo study, the use of Negative Pressure Wound Therapy (NPWT) in combination with stem cell-loaded scaffolds was investigated for the repair of large bone defects. Quantitative histological analysis was performed by determining both the percentage of cells proliferating (BrdU), as well as cells expressing bone-specific markers of alkaline phosphatase (A L P) in the defect. Total cell number in the defect was also determined by nuclear staining (DA PI). The results at week 1indicated that the NPWT significantly increased cell numbers – compared to the non- treated control samples – within the defect. As a result, a direct correlation could be attributed between the use of N PWT and increased bone formation.

In a second study, tissue engineered scaffolds were evaluated for the cell adhesion and growth of mesenchymal stem cells (MSCs) and breast cancer cells (B CCs) . These scaffolds were investigated for use as a potential in vitro model to examine breast cancer cell dormancy in the bone/bone marrow microenvi ronment. Fibrous scaffolds, consisting of poly-ε-caprolactone (PCL), tricalcium phosphate (β-TCP), or hydroxyapatite (HA), were fabricated using electrospinning techniques. The β-TCP and HA components are soluble and stable forms of calcium phosphate respectively, and closely mimic the physiochemical properties of bone during active bone remodeling. Quantitative image analysis was performed using scanning electron microscopy images to determine fiber morphology, fiber diameter, and the degree of fiber alignment. These scaffolds consisted of either random or aligned fibers. Observations utilizing confocal microscopy identified MSC and BCC attached to the materials, and MSCs elongated along the aligned fibers. PicoGreen proliferation assay determined that all scaffolds supported the growth of MSCs over a two week period. The results demonstrate that the fibrous scaffolds may be a suitable three-dimensional substrate to examine BCC and MSC interaction. In summary, this thesis demonstrates the successful use of quantitative analyses in the characterization and outcome of two bone tissue engineering applications.

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