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Monday, November 3rd, 2014

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    12:00a
    Outside-the-box thinker

    When an aspiring mechanical engineer on a budget wants a top-of-the-line guitar, what does he do? He makes it himself, of course.

    At age 13, Nathan Spielberg — now an MIT senior — began building his first guitar, a process that consumed his attention for eight hours a day, every weekend, for 3 1/2 years. Reminiscing now, he calls it a full-time hobby, but it was also pure inspiration: Strumming away on what was once a mere block of wood, Spielberg grew to appreciate the potential to turn an abstract idea into a functional object.

    As a mechanical engineering major at MIT, he has held onto this tenet, but turned his attention to a new means of production: 3-D printing. Until recently, Spielberg worked in the MIT Media Lab with Neri Oxman, the Sony Corporation Career Development Assistant Professor of Media Arts and Sciences, and PhD student Steven Keating. There, he focused on optimizing system designs that can handle large-scale printing projects, like houses.

    As Spielberg sees it, 3-D printing has two extremes: At one end is rapid prototyping, which allows researchers to design, print, and experiment — and then design, print, and experiment again — many times faster than traditional manufacturing. On the other end is express, large-scale construction of single objects. That’s where his research with Oxman comes in.

    Outside the box

    Ordinarily, 3-D printing occurs inside a box — limiting the size of printable objects to that of the printer’s housing. But in the Media Lab, Spielberg literally thought outside the box: He worked on creating a robotic arm — out of that from a boom truck, used to fixed power lines — that would be able to maneuver back and forth, printing objects as large as walls, layer by layer.

    It’s analogous to how an office printer’s cartridge runs back and forth, but on a much grander scale: An aim of Spielberg’s research was not only to print walls, but to do so with considerable mobility, enabling immediate transport to a construction site, streamlining delivery and increasing construction efficiency.     

    The printed object, in this case, is actually a mold made of insulation that becomes a full-on wall once filled with concrete. Being made of insulation, however, the molds have their own functionality beyond providing the external shape for a wall: They don’t have to be removed once the concrete is poured, since they can act as embedded insulation for the house.

    Because of the scale of the work, Spielberg encountered some obstacles. For instance, he says, “You need really precise movement on the robotic arm end to get each layer exactly straight, and to build something that looks like a functional house, which is really hard to do with a construction crane. If you’ve ever seen someone working on the power lines, they’re usually swaying in the wind. There are a lot of inherent engineering and physics problems with this that we’re trying to solve.”

    From walls to nanoscale chips

    This fall, Spielberg jumped to the other end of the 3-D printing spectrum, moving from walls to nanoscale fluidic chips. He is now working in the lab of A. John Hart, the Mitsui Career Development Associate Professor of Mechanical Engineering, to manufacture what’s known as a “lab on a chip.”

    Currently, when a doctor wants to run a series of blood tests on a patient, he or she collects several vials of blood and sends them to a hospital laboratory for dozens of individual tests. Several hours or days later, the lab returns the results.

    Among other functions, a lab on a chip can theoretically take a minuscule sample of blood, run all of the required tests at once inside tiny channels embedded in the chip, and produce nearly instantaneous results. Spielberg even sees the technology as a potential tool in military environments.

    “It’s totally a convenience thing,” he says. “Imagine if you were in the military and you’re trying to screen for some disease, but you don’t have a lab with you. You can pull out this device, take a quick sample of blood, get almost instant feedback in a super-small form, and be on your way.”

    Once again, Spielberg’s role in the lab is with optimizing the 3-D printer that makes the device. The current method for creating labs on a chip is labor-intensive, and, much like manufacturing a standard computer chip, starts with creating silicon wafers, which act as a template for the final product.

    Even though he is only a few months into his new lab position with Hart, Spielberg is already working toward eliminating this clunky process, enabling the same type of efficient manufacturing he tackled at the Media Lab.

    An early introduction to research

    Growing up in Louisville, Ky., Spielberg first encountered the power of research when his 11-year-old brother was diagnosed with dystonia, a neurological disorder characterized by uncontrollable muscle contractions. 

    “He started limping, and progressively couldn’t walk to the point where he was bedridden,” Spielberg says. “Throughout that process, it was really hard because there’s not a lot you can do. One of the hardest things is feeling helpless.”

    But Spielberg broke through the helplessness: Piggybacking on the fundraising bracelet trend of a few years ago, he sold silicone bracelets, raising $60,000 to fund research on his brother’s disease. Then, as a high-school student, Spielberg became involved in some of the research his fundraising supported; the experience provided a perspective unlike what he already knew from designing guitars.

    “I didn’t do a ton of hands-on stuff,” he says, “but it was really interesting to learn about how they were trying to solve this problem from a biological standpoint, because I was more used to solving problems from a mechanical standpoint.”

    The story ultimately had a happy ending: Spielberg’s brother enrolled in a clinical trial, receiving pacemaker implants in his chest that could intercept aberrant signals from his brain before they reached his muscles. His brother can now walk almost perfectly, and can even play basketball with his friends.

    “That was, and is, so amazing to me — that research has the potential to totally give a person their life back,” Spielberg says.

    And as for the homemade guitar? Spielberg says he left it in Louisville for safekeeping. Nonetheless, he’s a member of a recently formed rock band with a fellow mechanical engineering major and two computer science majors, keeping music and science tied together in his life.

    “There’s something about art and music that offer a form of self-expression that’s sometimes hard to attain in other forms of work,” Spielberg says. 

    3:00p
    New way to make batteries safer

    Every year, nearly 4,000 children go to emergency rooms after swallowing button batteries — the flat, round batteries that power toys, hearing aids, calculators, and many other devices. Ingesting these batteries has severe consequences, including burns that permanently damage the esophagus, tears in the digestive tract, and in some cases, even death.

    To help prevent such injuries, researchers at MIT, Brigham and Women’s Hospital, and Massachusetts General Hospital have devised a new way to coat batteries with a special material that prevents them from conducting electricity after being swallowed. In animal tests, they found that such batteries did not damage the gastrointestinal (GI) tract at all.

    “We are all very pleased that our studies have shown that these new batteries we created have the potential to greatly improve safety due to accidental ingestion for the thousands of patients every year who inadvertently swallow electric components in toys or other entities,” says Robert Langer, the David H. Koch Institute Professor at MIT and a member of MIT’s Koch Institute for Integrative Cancer Research, Institute for Medical Engineering and Science (IMES), and Department of Chemical Engineering.

    Langer and Jeffrey Karp, an associate professor of medicine at Harvard Medical School and Brigham and Women’s Hospital, are the senior authors of a paper describing the new battery coatings in this week’s edition of the Proceedings of the National Academy of Sciences. The paper’s lead authors are Bryan Laulicht, a former IMES postdoc, and Giovanni Traverso, a research fellow at the Koch Institute and a gastroenterologist at MGH.

    Small batteries, big danger

    About 5 billion button batteries are produced every year, and these batteries have become more and more powerful, making them even more dangerous if swallowed. In the United States, recent legislation has mandated warning labels on packages, and some toys are required to have battery housings that can only be opened with a screwdriver. However, there have been no technological innovations to make the batteries themselves safer, Karp says.

    When batteries are swallowed, they start interacting with water or saliva, creating an electric current that produces hydroxide, a caustic ion that damages tissue. This can cause serious injury within just a couple of hours, especially if parents don’t realize right away that a child has swallowed a battery.

    “Disc batteries in the esophagus require [emergency] endoscopic removal,” Traverso says. “This represents a gastrointestinal emergency, given that tissue damage starts as soon as the battery is in contact with the tissue, generating an electric current [and] leading to a chemical burn.”

    The research team began thinking about ways to alter batteries so they would not generate a current inside the human body but would still be able to power a device. They knew that when batteries are inside their housing, they experience a gentle pressure. To take advantage of this, they decided to coat the batteries with a material that would allow them to conduct when under pressure, but would act as an insulator when the batteries are not being compressed.

    Quantum tunneling composite (QTC), an off-the-shelf material commonly used in computer keyboards and touch screens, fit the bill perfectly. QTC is a rubberlike material, usually made of silicone, embedded with metal particles. Under normal circumstances, these particles are too far apart to conduct an electric current. However, when squeezed, the particles come closer together and start conducting. This allows QTC to switch from an insulator to a conductor, depending on how much pressure it is under.

    To verify that this coating would protect against tissue damage, the researchers first calculated how much pressure the battery would experience inside the digestive tract, where movements of the tract, known as peristalsis, help move food along. They calculated that even under the highest possible forces, found in patients with a rare disorder called “nutcracker esophagus,” the QTC-coated batteries would not conduct.

    “You want to know what’s the maximum force that could possibly be applied, and you want to make sure the batteries will conduct only above that threshold,” Laulicht says. “We felt that once we were well above those levels, these coatings would pass through the GI tract unchanged.”

    After those calculations were done, the researchers monitored the coated batteries in the esophagus of a pig, and found no signs of damage.

    “A relatively simple solution”

    Because QTC is relatively inexpensive and already used in other consumer products, the researchers believe battery companies could implement this type of coating fairly easily. They are now working on developing a scalable method for manufacturing coated batteries and seeking companies that would be interesting in adopting them.

    “We were really interested in trying to impose design criteria that would allow us to have an accelerated path to get this out into society and reduce injuries,” Karp says. “We think this is a relatively simple solution that should be easy to scale, won’t add significant cost, and can address one of the biggest problems associated with ingestion of these batteries.”

    Also, because the coating is waterproof, the researchers believe it could be used to make batteries weather-resistant and more suitable for outdoor use. They also plan to test the coating on other types of batteries, including lithium batteries.

    Edith Mathiowitz, a professor of medical science at Brown University who was not involved in the research, says she believes this approach is a “brilliant idea” that offers an easy fix for the potential dangers of battery ingestion.

    “What I like about it is that it’s a simple idea you could implement very easily. It’s not something that requires a big new manufacturing facility,” she says. “And, it could be useful eventually in any type of size of battery.”

    The research was funded by the National Institutes of Health.

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