All ETDs from UAB

Advisory Committee Chair

Ho-Wook Jun

Advisory Committee Members

Renato P Camata

Amjad Javed

Timothy M Wick

Document Type

Thesis

Date of Award

2011

Degree Name by School

Master of Biomedical Engineering (MBE) School of Engineering

Abstract

A growing trend in the area of bone tissue engineering is the development of materials that mimic the native bone extracellular matrix (ECM). This need is typically met through the creation of composites, which attempt to recapitulate both the organic and inorganic components of the native bone ECM. However, few composites have been created with organic ECM analogous components that are functionalized to direct cellular behaviors. Furthermore, a majority of these studies do not investigate how the ratio of the inorganic and organic components affects cellular behaviors. To address this issue, hydroxyapatite nanoparticles (HANPs) were dispersed within peptide amphiphile (PA) nanofibers tailored with the RGDS cellular adhesion motif (PA-RGDS) to create bone ECM analogous nanomatrix composites and their ability to enhance the osteogenic differentiation of human mesenchymal stem cells (hMSCs) was assessed. These nanomatrix composites were prepared at various HANP to PA-RGDS ratios by weight. The successful synthesis of these composites was first confirmed via scanning electron microscope (SEM) and transmission electron microscope (TEM). The long term cellularity and osteogenic differentiation of hMSCs was then assessed in response to these nanomatrix composites. The timed expression of genes representing the early, middle, and late stages of osteogenic differentiation were quantified via RT-PCR. Increasing HANP to PA-RGDS ratios correlated with enhanced osteogenic differentiation for hMSCs as demonstrated by the timed up-regulation of key osteogenic markers and decreased proliferative rates over time. Overall, these results demonstrate the importance of compositional modification for the regulation of cellular behaviors for bone tissue engineering applications.

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