Date of Award

2013

Degree Type

Thesis

Department

Chemical and Biomedical Engineering

First Advisor

Kothapalli, Chandra

Subject Headings

Biomedical engineering, Tissue scaffolds, Myocardium -- Regeneration, Extracellular matrix

Abstract

Heart failure accounts for over 5 million cases in the U.S. A major onset of this is myocardial infarction, which causes the myocardium to loose cardiomyocytes and transform into a scar tissue. Given that the adult infarcted cardiac tissue has a limited ability to regenerate, alternative methods to restore the damaged area need to be developed. The goal of these approaches is to design an optimal scaffold that can retain and deliver cardiomyocytes at the site of damaged myocardium. This tissue engineering approach would allow cardiac reconstruction by replacing the lost cardiomyocytes, delivering the required biomolecules, as well as remodeling the extracellular matrix (ECM). In this study we investigate the effects of a variety of ECM substrates on the attachment, survival and ECM production by cardiomyocytes. We cultured rat cardiomyocytes for 21 days in eleven different substrates, including nanofiber coated plates and 3D hydrogels. Cell attachment and survival rates were analyzed both quantitatively and qualitatively. ELISA and fluorometric assays were performed to quantify the synthesis and release of ECM protein molecules by the cells under various culture conditions. The matrix protein deposition was also qualitatively analyzed using immunofluorescence staining and imaging. Finally, the production of MMPs-2, 9 and TIMP-1 by these cells was quantified and correlated to matrix synthesis under respective culture conditions. The observations of this study were that the total protein content quantified within PCL nanofiber scaffolds was significantly higher compared to that within hydrogels. Collagen concentration played an important role in cardiomyocyte survival. Among all cases tested, 2 mg/ml collagen-I (CI-2) provided the highest cell survival rate. Additionally, laminin-coated PCL nanofiber scaffold provided the most suitable environment for cardiomyocytes to result in the highest number of beating cardiomyocytes. However, the maximum beating frequencies were noted in cells cultured on collagen

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