Tinkering on the Atomic Scale
Michael Strano has always been a tinkerer. As kids, he and his brothers fiddled with the old radios and electronic parts that filled their basement. “My dad owned his own electronics shop, so he saw value in any broken piece of electronics and would harvest it for parts,” he says.
Strano is still tinkering, but now on the atomic scale. His ideas for research projects seem nearly endless. Currently, he is working on applications that include new approaches to solar energy, novel water purification systems, and a tattoo that could change how diabetics monitor the disease.
Strano, the Charles and Hilda Roddey Associate Professor of Chemical Engineering, works with graphene, a form of carbon with dimensions on the nanoscale. A sheet of the material, which resembles chicken wire, is only one atom thick. Graphene, in turn, can be made into different shapes, from particles to the tiny cylinders about 10,000 times thinner than a human hair known as carbon nanotubes.
At those dimensions, “magic” happens, Strano says. Graphene and its nanoparticles and nanotubes are so small that they confine and restrict the movement of electrons. “If you start to put electrons in spaces commensurate with their size, you get new and unusual properties.”
“And really, that’s all an engineer needs — new properties. Then we try to apply them to global challenges.”
In one theme of his research, Strano is looking at new approaches to solar energy, work that is funded in part by the MIT Energy Initiative (MITEI). For example, he and his team have developed minuscule antennae that can concentrate 100 times more solar energy than the
conventional photovoltaic cell used in solar panels.
Key to the work are two different nanotubes, one nested within the other. Each antenna contains about 30 million of the composite nanotubes. It then absorbs solar energy, concentrates it, and funnels it to a small spot, roughly like rain from a roof pouring through a downspout into a water barrel. As a result, today’s large solar panels could be replaced by much smaller ones. Among other advantages, this would lower the capital investment for such panels, he said.
Strano is also developing novel sensors. He is especially excited about a tattoo of nanoparticles that could become “a new paradigm for monitoring diabetes,” he says. The tattoo takes advantage of nanoparticles’ ability to fluoresce under infrared light. In this case, they are engineered to be sensitive to glucose, or blood sugar. A watch-like wearable monitor can then detect the amount of fluorescence, which is proportional to the amount of glucose.
Such a tattoo could allow the continuous monitoring of a person’s blood sugar, which would help prevent the wide swings in blood-sugar concentration that over time cause the complications associated with diabetes. Strano believes the tattoo could last for a decade. Most existing continuous glucose sensors operate for a few days at best.
Strano has many more ideas for research on and applications of nanomaterials. “I feel like I’m limited only by the number of people in my lab to help me work on them,” he says.