Season-ending injuries. Chronic joint pain. Debilitating osteoarthritis. Costly knee replacements.
What do these all have in common? Damaged cartilage.
Cartilage is the softer-than-bone fibrous material that’s found in your nose and around joints. It provides vital cushioning. But when damaged, cartilage doesn’t grow back. That all may change thanks to pioneering research at Northwestern University.
Ramille Shah and her team used a nanofiber gel that closely mimics the body’s natural collagen tissue. When combined with a common surgery, the bioactive material can help recruit stem cells and stimulate cartilage growth. She collaborated with her mentor Samuel Stupp, who developed the nanofibers in a research effort at Northwestern’s Institute for Bionanotechnology in Medicine, which he directs.
Successful in rabbits so far, the cartilage research could make long, painful recoveries and complicated surgeries a relic of the past.
Medill Reports interviewed Shah, a professor of materials science and engineering at Northwestern, to talk about her research and what it could mean for sports medicine and joint pain.
First of all, what is nanotechnology, and what kinds of fields does it impact?
Basically, nanotechnology works on very small scales, usually below 100 nanometers. The nanometer scale is one one-hundredth the size of a cell. (Learn more about the nanometer scale here.) Nanotechnology can affect every field you can think of, from transportation to food to textiles – even sunscreen.
How did you become interested in nanotech and orthopedics?
When I finished my PhD, I had a good background in regenerative medicine and tissue engineering, and I had worked with collagen. Nanomaterials was something that was on my radar, but I wanted to learn more about it. I got introduced to biomaterials as a senior at Northwestern, under Dr. Samuel Stupp. It really hooked me because I love research, and the outcome can potentially help someone improve their quality of life, especially if they’re in pain. Orthopedics sort of fell in my lap. My husband is an orthopedic surgeon, and he’s the one who actually introduced me to it,
How do you treat someone with damaged cartilage now?
Usually the first thing surgeons will try is called a microfracture technique, where they poke holes through the underlying bone. That allows blood from the bone marrow to come in and create a clot. It’s similar to when you get a cut. That blood clot works because it has all these growth factors, or proteins, that help regenerate the tissue.
But that’s not a perfect solution.
Right, because it causes cartilage with Type I collagen to grow, and not all cartilage is the same. The cartilage in your nose and the cartilage in your knee, for example, are very different. Nose cartilage usually has Type I collagen, and the area around your joints is made up of Type II collagen. With microfracture, usually the tissue that forms is Type I, so it doesn’t match what’s naturally there. In some cases, microfracture does relieve pain but, in a lot of other cases, it doesn’t do much.
So how does your gel encourage cartilage growth?
The gel is made up of these nanofibers that spontaneously assemble under specific conditions. So when you inject it into the body, as a fluid, it comes together and forms these long nanofibers that connect into a gel network. And collagen is fibrous, so the gel mimics what cells would normally see in the body. We also tailor an amino acid (compounds of the elements nitrogen, hydrogen, carbon, and oxygen that are the building blocks of proteins) to these fibers that’s bioactive. They bind to growth factors, or proteins, that help turn stem cells into cartilage cells.
Why doesn’t cartilage naturally grow back?
Good question. During development, cartilage is vascularized, meaning it has blood vessels running through it. But as you get older, those blood vessels go away. So if you damage it, it doesn’t grow back because there’s no bleeding. The other reason is that cartilage is very dense. So cells on the outside can’t migrate in, and cartilage cells don’t divide well. That’s why our medicine works. We’re supplying a scaffold, we’re supplying factors and we’re supplying a cell source by the microfracture procedure.
What kinds of injuries or surgeries could this change if it pans out?
With orthopedics, or sports medicine, it could definitely help athletes who have cartilage injuries. For example, if an athlete tears his or her ACL[a knee ligament], very often it comes with some sort of cartilage damage. It could also help elderly people, just because of the chronic wear and tear on their joints. Our new procedure is minimally invasive, it’s simple, and surgeons are already used to doing microfractures. It could decrease healing time, and with athletes, it could potentially decrease rehab time, too.
What are the next steps after successfully implanting the gel in animals?
First we need to reproduce this in a larger animal before going into clinical trials with people. It’s going to be a long process, but this first study at least showed proof that it can work, and hopefully it’ll show it again. It’s very promising.