Date of Award

Spring 1-1-2011

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Mechanical Engineering

First Advisor

Frank S. Barnes

Second Advisor

Wei Tan

Third Advisor

Virginia Ferguson

Abstract

A torn anterior cruciate ligament (ACL) is a notorious injury among athletes. Current means of replacement and reconstruction are ineffective and often result in instability and osteoarthritis. Tears in the medial collateral ligament (MCL), on the other hand, are self-healing and do not require surgical intervention. The differences between ACL and MCL healing properties have been shown to exist mainly on the cellular and biochemical levels. For example, ACL fibroblasts have shown increased production of and sensitivity to the cellular messenger nitric oxide (NO) in response to injury [13]. Non-invasive enhancement of the self-healing capacity of ACL fibroblasts to more closely resemble that of MCL fibroblasts would have obvious therapeutic applications. In the past, many researchers have employed exogenous electromagnetic fields to non-invasively alter cellular properties. There are several devices currently on the market that use such fields to stimulate healing. In this study, radiofrequency electromagnetic fields with a perpendicular static field were applied to human ACL fibroblasts in vitro. The magnitude of the applied static field was equivalent to the geomagnetic field. Cellular proliferation increased by 20% within 48 hours (p < 0:01) compared to the control. Soluble collagen synthesis remained constant in confluent cultures, suggesting little effect on stationary cells. The purported mechanism of interaction is through modulation of radical lifetimes, related to the spin-radical-pair mechanism of much higher strength fields.

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