M.Sc Thesis

M.Sc StudentVerberne Gabriel
SubjectTribology of Biological Tissues
DepartmentDepartment of Mechanical Engineering
Supervisors DR. Gregory Halperin
Full Thesis textFull thesis text - English Version


Wear processes occurring in synovial joints, mainly known as osteoarthritis (OA), affect many people worldwide. One of the symptoms of OA is wear of articular cartilage; it is thought that among other factors this may be due to failure of lubrication. Injections of bio-lubricants into human joints may maintain the proper functioning of the joint, thus postpone or even eliminate the need for total joint replacement. Phosphatidylcholines (PC), being major constituents of synovial fluid (SF) surface active phospholipids (SAPL), are natural candidates for investigation as additives for cartilage lubricants.

In the course of studying these nano-particles bio-lubricant additives (liposomes) it became necessary to find an efficient technique for quantitative evaluation of the effect of different liposomes on the wear of articular cartilage. Only few studies who deal with cartilage wear are found in the literature. Due to problems of acquiring suitable specimens and the complicated nature of the experiments, most of the studies concerning cartilage wear used cartilage-on-metal or animal cartilage-on-cartilage.

In the present study, wear tests were performed using human cartilage-on-cartilage under various working conditions. Several techniques of assessing the wear, such as changes in surface morphology using optical profilometry and variation in the content of Collagen and proteoglycans (PG) in the lubricating solution were studied. Of all these techniques the PG content analysis was found to be the most efficient one. The effect of liposomes on the wear of articular cartilage was studied. Wear tests were performed in the presence of different phospholipid-based liposomal bio-lubricating fluids. Wear was estimated by analyzing the PG content variation in the lubricating solutions used in the tests. It is shown that most liposome additive based lubricants induce less wear in comparison to inflamed synovial fluid (ISF) and ISF with an addition of hyaluronic acid (HA).