Date of Award

2015

Degree Type

Thesis

Department

Chemical and Biomedical Engineering

First Advisor

Belovich, Joanne M.

Subject Headings

biomedical engineering chemical engineering

Abstract

Quantitative research concerning the impact of mechanical loading on the transport properties of bone has several critical applications. One such application is the effect of a microgravity environment, where the lack of mechanical forces on bone has been shown to negatively impact both growth and repair. A method has been developed in our lab that can potentially allow for the measurement of the effective permeability of large molecules (i.e., 300-15,000 Da in size) in bone tissue under both unloaded and mechanically loaded conditions. In proof-of-concept experiments, previous students have measured the effective diffusivity of the model solute, sodium fluorescein (376 Da) in a sample of unloaded bone tissue. A mechanical loading system has been modified to measure the effective permeability of sodium fluorescein for a bone beam undergoing four point bend testing in a bioreactor system in order to quantify the effect of mechanical loading on solute transport. The first goal of the present work was to validate that deflection of the bone beam was occurring at applied displacements of less than 40 æm. Once the deflection of the bone beam in the mechanical loading system was validated, the primary objective of measuring the transport parameter for sodium fluorescein in canine cortical bone under unloaded and loaded conditions could be achieved. The average value and standard error of this parameter for loaded samples was determined to be 3.70x10⁻⁸±1.31x10⁻⁸cm²s⁻¹ (n=5), and 6.59x10⁻⁹ ±2.46x1̄̄̄̄̄0⁻⁹ cm²s⁻¹ (n=4) for unloaded samples. Although a student's t-test showed that the loaded and unloaded values were not statisticly different p=(0.08), this is likely due to the small number of samples. these preliminary results do show that the transport parameter of sodium in cortial bone increased by more that factor of 5 with the sedition of mechanical loading

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