A Foundational Study Of Heart Valve Tissue Engineering: exploration of Natural and Synthetic Scaffold Approaches

Open Access
Author:
Johnson, Katherine Lynn
Area of Honors:
Bioengineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Dr George Engelmayr, Thesis Supervisor
  • Peter J Butler, Honors Advisor
  • Margaret June Slattery, Faculty Reader
Keywords:
  • Tissue engineering
  • Bioengineering
  • heart valve
Abstract:
The objective of this project was to explore the possibilities of two different approaches to heart valve tissue engineering; naturally-derived and synthetic scaffolds. Since it has been shown that the mechanical properties of the native heart valve leaflet derive principally from collagen orientation, this project focused on collagen and cellular structures that were produced through each approach. In order to establish defined goals for the structural properties of the engineered constructs the first objective of this thesis was to obtain the mechanical properties and gain an appreciation of the structural properties of the native heart valve leaflets. This research investigated the cellular orientation within collagen matrigel scaffolds (i.e. a naturally-derived scaffold) and micromolded poly(glycerol sebacate) scaffolds (i.e. a synthetic scaffold). Fiber tracking software along with fast-Fourier transform-based software was used to analyze these orientations. In the case of the naturally-derived collagen gel scaffolds, a distinct difference in collagen and F-actin orientations were found between biaxially- and uniaxially-constrained gels. Specifically, a degree of orientation was seen in the uniaxial case, whereas a more random distribution of orientations was seen in the biaxial case. As for the synthetic, microfabricated PGS scaffolds, it was found that cells would preferentially align along the long-axis of the microfabricated scaffold pores. Collectively these results provide a foundation for future studies in heart valve tissue engineering exploring ways to mimic the native collagen and cell orientations in tissue constructs.