Bioengineers Pioneer Techniques for Knee Repair

Each of these samples were 3D-
tailored to fit a specific rabbit femur
© Rice University

The technique was developed by Rice University bioengineer Kyriacos Athanasiou and postdoctoral researcher Jerry Hu. Using cells, they refined the technique to grow the entire articular surface of the lower femur. “This has significant ramifications because we are now beginning to talk, for the first time, about the potential treatment of entire arthritic joints and not just small defects," said Athanasiou.

The new self-assembly method involves a break from conventional wisdom in bioengineering; almost all previous attempts to grow replacement transplant tissues involved the use of biodegradable implants that are seeded with donor cells and growth factors. These implants, which engineers refer to as scaffolds, foster the tissue growth process by acting as a template for new growth, but they always present a risk of toxicity due to the fact that they are made of materials that aren't naturally found in the body.

In the newly reported findings, Athanasiou and Hu grew dime-sized disks of cartilage with properties approaching those of native tissue using nothing but donor cells. In a follow-up study due for publication soon, graduate student Christopher Revell refined the process to produce disks that are virtually identical to native tissue in terms of both mechanical and biochemical makeup.

In a third, and perhaps most impressive breakthrough, Athanasiou and Hu used the self-assembly approach to grow the entire articular surface of the distal femur. Each of these unbroken samples were tailored three-dimensionally to fit a specific rabbit femur. "If you told me 10 years ago that we would be making entire articular end caps via self assembly I would have said you were crazy," said Athanasiou. "The fact that we can do this is an indication of how far the discipline of tissue engineering has progressed."

MEDICA.de; Source: Rice University