Date of Award

8-2012

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Bioengineering

Advisor

Dean, Delphine

Committee Member

Desjardins , John

Committee Member

Nagatomi , Jiro

Abstract

Articular cartilage is essential part of the human body that aids in support and locomotion. It has unique biochemical and biomechanical properties that allow it to act as a shock absorber to disperse and distribute loading of the joints. However, it has a limited capacity to repair itself because it is not vascularized and must receive its nutrients from the surrounding synovial fluid. Articular cartilage damage can lead to many pathological conditions, including osteoarthritis. Currently, there are many surgical treatment methods that repair some of the damage if it is localized, but for widespread degradation seen in osteoarthritis, there are no effective means of reparative treatments. Research has been ongoing to find a cure for this degeneration, and recently there has been focus on the potential of using nanoparticles as a drug delivery method in treating articular cartilage damage. Nanoparticles could be used to deliver growth factors, drugs, or genes to attempt to restore the tissue to its native state. However, the permeation of nanoparticles due to physiological loading of articular cartilage must first be characterized.
To conduct experiments on articular cartilage, a means of providing physiological compressive loading had to be established. After consulting the literature, a custom-designed dynamic compression loading apparatus was constructed. It was controlled using an electro-mechanical linear actuator, specifically an eccentric cam, to provide various loading conditions of frequency and strain. It was determined that the device could consistently and accurately provide axial loading in the physiological range for articular cartilage applications.
To characterize the permeation of nanoparticles in articular cartilage, experiments were carried out with cartilage exposed to gold nanoparticles under various loading conditions using the custom designed compression device. The tissue was then observed with electron microscopy to observe the presence of gold nanoparticles. The images taken qualitatively indicated the extent of gold nanoparticle permeation on the surface and inside the cartilage. It was seen that the gold nanoparticles were only observed in the dynamically compressed tissue in varying amounts. The cartilage tissue under higher frequency axial loading in the physiological range showed a greater amount of nanoparticle permeation. However, more work needs to be done to understand the zones of the articular cartilage that are affected by the convective transport and permeation of the gold nanoparticles.

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