Nanoengineering Cartilage Repair
People who suffer from arthritis and athletes who have torn cartilage may one day find relief through nanotechnology. At MIT’s Center for Biomedical Engineering, researchers led by Alan Grodzinsky ‘69, SB/SM ‘71, ScD ‘74 and Shuguang Zhang are developing a cartilage repair technique that may eliminate the need for prosthetic joints and complicated surgery. They are growing cartilage cells in a nanoengineered gel that they ultimately hope to use to replace the damaged tissue in human joints.
The procedure relies on a new class of biomaterials based on self-assembling peptides, or protein fragments. Zhang discovered the peptides several years ago. When the peptides are mixed in just the right way, they automatically assemble themselves into specific nanoscale structures such as sheets and interweaving fibers. Scientists can take advantage of this behavior to develop extraordinary new materials. In the case of cartilage repair, the researchers coaxed the peptides into a water-based gel; the peptide gel acts as a “scaffold” for cartilage cells. Injected into small spaces such as joints, the peptide scaffold holds transplanted cartilage cells in place. It allows the tissue to grow and take hold while the framework itself slowly disintegrates, leaving healthy tissue behind.
The design flexibility of the peptide gel offers a critical advantage over other materials that might have been used, Grodzinsky says. By tinkering with the molecular structure of the peptides, scientists can tailor the gel’s performance to specific needs. For instance, they could add growth factor hormones that would hasten tissue regeneration. The researchers plan to begin testing the material in animal joints by the end of this year. With luck, the technique may be available for treatment of injured people within five to 10 years.