Web edition: January 28, 2011
Print edition: February 12, 2011; Vol.179 #4 (p. 32)
In January the American Association for the Advancement of Science hosted a panel in Washington, D.C., on the emerging field of convergence, which integrates engineering, the physical sciences and life sciences to solve problems in health care, energy and other sectors. Speakers described the movement as an integration of disciplines that will require changes to the peer review system, funding mechanisms, the structure of academic departments and the training of science's next generation. Science News writer Rachel Ehrenberg attended and excerpted comments by Robert Langer, an MIT engineer who develops materials for biomedical applications.
So how are materials moved into medicine?... Almost always, the way that this happened is medical doctors, clinicians, when they wanted to solve a medical problem, would go to their house and find an object that somehow resembled the organ or tissue they wanted to fix and they'd use it on a person.
So for example, in 1967 the clinicians at the [National Institutes of Health] wanted to make an artificial heart and they asked what object kind of resembles a heart in their house, and they thought of a lady's girdle. And they picked the material in a lady's girdle to make the artificial heart out of. And actually, today, 43 years later, that's still what the artificial heart's made out of. But the artificial heart, as you know, hasn't worked very well. And the biggest reason for that is when blood hits the surface of the artificial heart, the lady's girdle material, it forms a clot. The clot goes to the patient's brain, they get a stroke and they die. But if you think about it, something designed to be a lady's girdle probably isn't the best material to put in contact with blood. And this problem pervades all of medicine. Dialysis was sausage casing, vascular graft — that's artificial blood vessel — was a surgeon in Texas going to a clothes store to see what he could sew well with. Breast implants: One was a lubricant, another actually a mattress stuffing.
When I was a chemical engineer in the early '70s, rather than go into the oil industry — which almost all of my colleagues did — I actually worked with [medical researcher] Judah Folkman. I went to a surgery lab and that's where I learned this. I saw that's how all this would happen. So, some of the things that we started thinking about were, could we bring engineering … to solve these issues? What we started thinking about was to ask from an engineering, chemistry and biology standpoint, what do you really want? And then, could you just synthesize the material? So one material we created was a new set of biodegradable polymers [for time-release drug delivery and other applications].
A second example might be in the area of minimally invasive surgery. This new example hasn't yet been used clinically, but we've published one paper in Science and another in Nature…. Let's say somebody had minimally invasive surgery, and you wanted to put a[n] ... object like a medical device in them that was bulky. So what you could do someday, we hope, is you could take a material that might be like a string at room temperature and go through this little hole that you're doing minimally invasive surgery in, and [the material] would convert to a bulky object simply by a temperature change or maybe a fiber-optic–light change.
So that's one approach. The second approach that we started thinking about really is the epitome of convergence, and that's tissue engineering…. The idea is that you could take virtually any cell type, create a polymer scaffold material that could help guide these cells, grow them in what we call bioreactors and make different tissues…. I'll speculate: 30 or 40 years from now somebody wants plastic surgery, and they want a new nose. So my guess is 30 or 40 years from now, you go to a computer screen and any nose you want you can actually pick out…. So let's say somebody wants a regular nose, you could use … computer-aided design to design a regular nose. But let's say somebody wants an upturned nose. Well, that wouldn't be so hard. We would just take a little bit of this off. Let's say they want a hooked nose. I mean they probably wouldn't, but if they did, we'd give them a little more polymer.
Even though that sounds like science fiction, we're already doing it…. Jay Vacanti, my collaborator, he actually treated this little boy who was 12 years old at the time using these principles…. This little boy doesn't have a chest covering his heart. But like other 12-year-olds, he liked to play baseball. But you could imagine if he ever got hit in the chest with the ball he could die. So we actually made a scaffold for him with his own cells and made him a new chest.
The third example … and this is still experimental — someday maybe this could even help people with spinal cord damage…. What we did is actually take neuronal stem cells, put them on a polymer scaffold and implant these in rats … and they are doing better…. This is now actually in primate trials as we hope to someday move it to humans.