Scaffolds,
Matrices and Mice with Ears on Their Backs
Lu is among the many researchers trying to trick cells into forming dynamic replacement organs that can respond to the mechanical sophistication of the parts that they replace. Specifically, Lu is trying to discover how to organically rebuild the knee's anterior cruciate ligament (ACL) which is one of four stabilizing ligaments of the knee and prevents abnormal motion and rotation of the lower leg with respect to the thigh. Current treatment for repairing ACL's includes one of two options: surgeons can take a third of the patella tendon which runs from the knee cap to the shin bone, or take part of your hamstring and fold it over four times, and refashion either to perform approximately like the ACL. The obvious rub: to repair one ligament, doctors must degrade another. Lu hopes to circumvent that conundrum and if you have ever seen the fabled photos of a mouse with an ear on its back, and sort of understood the mechanics of what was going on there, then you are on your way to understanding what Lu is doing with her soft tissue research. While looking at the knee joint, you can see that the knee cap is covered in cartilage, and ligaments hold the joint together. Unfortunately, doctors have had extreme difficulty trying to repair cartilage when damaged. Instead, they have to go to another part of the body and get what is called an autograph, or another piece of cartilage and replace the damaged bits with it. To change this dynamic, researchers are trying to grow tissue from scratch, and then grafting it onto damaged areas. "By recreating the bone and the cartilage at the same time," explains Lu, "we can rebuild the system." To do this, Lu and her researchers design scaffolds and matrices and then lay tissue cells on them. In theory, tissue cells then adapt to the shape of that which they are laid upon. The crux of the matter though is twofold: how do you get skin cells or stem cells to behave like ligament cells in Lu's case, and how do you successfully cultivate cells outside the body? To answer these questions Lu dives into the world of the invisible and tries to discover the interface between soft and hard tissue. Working on a micron level, which is to say on a scale that makes the dot on this "i" seem positively gargantuan in comparison, Lu builds her scaffolds out of ceramic, glass, titanium, hydrogels, corals and degradable polymers. Her models need to be porous so that blood vessels can provide nutrients to the cells that are laid across the scaffold. "I'm humble," she says, "you have millions of years of evolutions going on and nature is the best optimizer. I can't design anything better than whatever we've got in our body." Her goal though, as she flips through 3D lithographic models that show different layers of her scaffolds, is to be able to provide customized models for different individuals while simultaneously optimizing mechanical, degradable and porous properties so that the body can eventually replace her scaffold with living tissue of its own. Next: Crazy English and Why Foreskin is King |
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Index: Dance the Bionic Electric Mice with Ears on their Backs Crazy English and Why Foreskin is King |
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The
Story of the Mouse It sounds
like something from a carnival sideshow: "The Mouse With A Human
Ear On Its Back." But it's real. It's alive. Source: AP |
