Ph.D. Research Proposal - Tribological Assessment of Hydrogels for Replacing Damaged Articular Cartilage
Date: April 25, 2012
Time: 10:00 AM
Location: Bossone Research Enterprise Center, Room: 709
Doruk Baykal, M.S.
Advisors: Steven M. Kurtz, Ph.D., and Michelle Marcolongo, Ph.D.
Hydrogels, which are complex hydrophilic polymer networks swollen with water, have been researched to replace damaged articular cartilage tissue. The motivation is that hydrogels may maintain natural joint lubrication due to their biphasic nature, and their structure can be modified so that their mechanical properties mimic those of articular cartilage and reduce contact stresses. To date, a standard method to quantify wear properties of hydrogels has not been established. This proposal will define a novel and comprehensive methodology to practically evaluate hydrogels for cartilage replacement based on parameters relevant to implant longevity.
First, determining wear resistance of cartilage replacement materials is instrumental in predicting their in vivo performance. However, the quantification of wear of hydrogels by conventional weighing methods is problematic since gravimetric measurements cannot differentiate between mass changes caused by fluid movement as opposed to worn mass. In this proposal, a novel method to quantify wear rate of hydrogels based on submerged measurements will be presented.
Furthermore, the extent of detrimental effects on opposing cartilage surface caused by articulation against cartilage substitutes is an indicator of success in hemiarthroplasty and defect filling applications. Current methods of evaluating cartilage damage are time-consuming and usually not capable of monitoring wear with respect to change to a known parameter. A novel application of Fourier Transform Infrared Spectroscopy (FTIRS), which has been used to study structure of tissues, will be employed to model the progression of articular cartilage wear. Pin-on-Disk testing will be utilized to characterize the wear of cartilage against various hydrogels and these results will be compared with cartilage on cartilage articulation to screen for hydrogels that impart minimal damage on opposing cartilage.
Finally, the capacity of hydrogels to facilitate lubrication, similar in magnitude to that of articular cartilage, is believed to result in low wear and low friction in vivo. An anisotropic and biphasic hydrogel model to predict the lubrication properties of hydrogels based on their mechanical properties will be presented.
The Bossone Research Enterprise Center is located at the corner of 32nd and Market Streets.