Imagine having a toothbrush that can tell if you’ve brushed enough by measuring the amount of halitosis in your mouth, or a microscopic drug capsule programmed to seek out and kill cancer cells, or a device asthma patients could use to detect an oncoming attack.
Alexander Star, a University of Pittsburgh chemistry professor, thinks about these futuristic devices a lot. He’s already proved the basic science behind their possible creation and, to him, that future doesn’t seem so far away.
“I’m looking forward to the day when every pharmacy has an asthma detector for sale, so then I can tell my kids, ‘Hey, I helped make that,'” Star said during a recent tour of his lab in Eberly Hall in Oakland.
For the last decade, including the last five years at Pitt, he has worked with carbon nanotubes – naturally occurring, and increasingly manmade, microscopic tubes of carbon that were truly identified just 20 years ago. They’ve been found to be 100 times stronger but far lighter than steel, wonderfully efficient conductors of electricity, and to have an amazing array of potential uses, everything from making tennis rackets stronger and lighter, to solving beguiling medical problems.
In a field that is one of the hottest in scientific research today, the 39-year-old Star is considered one of its, well, stars. The friendly but quiet Russian immigrant churns out top-level, oft-referenced discoveries of the basic science behind exactly what it is that carbon nanotubes are capable of doing.
“There are only a few people making significant progress towards figuring out how nanotubes work and he is one of them,” said Nosang Myung, a University of California at Riverside chemistry professor and a nanotube expert. “It’s a very competitive and fast-moving world right now, and he’s near the front of it.”
But the increasing commercial use of carbon nanotubes has also set off alarms in the scientific community. It’s all too aware of past proliferations of products, such as asbestos and DDT, that were later found to be dangerous.
So, in work that is still unusual in the field, Star is trying to learn about what impact carbon nanotubes might have on people and the environment, and how to more readily break them down so they don’t have any negative impact.
“I would hate to see nanotubes grow every year in use and 20 years from now someone says, ‘Hey, it’s bad,'” Star said. “I think it’s important to look up front while this application is still emerging.”
Among other awards and recognitions in recent years, Star this fall was named by the National Institute of Environmental Health Sciences as one of its eight Outstanding New Environmental Scientists for 2010. The prestigious award also brought with it a five-year, $2 million grant that will help him expand his lab and look further into the environmental impact of nanotubes.
“We’re looking for the best and the brightest in our institute with these awards, and we selected from those people who are the most innovative,” said Carol Shreffler, the health scientist administrator of the NIEHS’s Training and Career Programs, which oversees the award. “He has developed this area of expertise in a field that’s very competitive, and he’s very good at it.”
Star – close friends and family know him as “Sasha,” a common Russian nickname for Alexander – was born and raised in what is now the Republic of Kazakhstan. His family, which is Jewish, left for Israel in 1990 as barriers began to come down with the crumbling of the Soviet Union.
His mother, Regina, was a research chemist, and his father, Victor, was a clinical psychiatrist in the Soviet Union, though he didn’t work in the field in Israel. Star grew up speaking Russian, and then had to start picking up Kazakh. Before his family left for Israel, he had already decided to start learning English, in anticipation of a career in science. None of those languages helped him in Tel Aviv University where courses were taught in Hebrew.
“I’d sit through class, try to pick up what I could, and then spend the rest of the day in the library reading translated books to try to catch up,” he said.
Despite the language barrier, he got his undergraduate degree in 1994 and doctorate in 2000 from Tel Aviv University. That same year he, his wife, Anjela, and a then-young son (they also have a daughter now) left Israel for a post-doctorate post at UCLA, working in J. Fraser Stoddart’s lab.
It was there he first began working on nanotube sensors, work that “I was excited by from the beginning,” he said.
His mentor, Stoddart, still marvels at how quickly Star picked up on it.
“He had no previous experience with this type of science and it was like a duck taking to water,” said Stoddart, who now runs a lab at Northwestern University in Evanston, Ill. “He recognized then that it was futuristic and there was risk – but he has pulled it off.”
After two years at UCLA, Star spent four years at a private firm, Nanomix Inc., a California firm that is attempting to commercialize carbon nanotube-based sensor technology, before coming to Pitt.
He was hired away from Nanomix by Pitt at about the time the university was forming its new Petersen Institute of Nanoscience and Engineering. He was given funding for two student assistants in the beginning, but now has 10, and will add two or three more with his new grant.
Work in the lab is dominated by research into possible sensors, but 40 percent of the projects involve either environmental or medical applications.
Single-walled carbon nanotubes are particularly useful in Star’s work developing sensors because their electrical conductivity can be modified through interaction with chemical or biological species, which means once they’ve been sensitized to a specific gas, they can tell you if that gas is present.
And because the nanotubes are so small, you could theoretically have a variety of sensitized nanotubes in one device that detects for a variety of gases.
Using this technique, among Star’s many discoveries in the field, he has proven the basic science that could lead to the “bad breath toothbrush,” as he jokingly calls it, by using gold decorated single-walled carbon nanotubes to tell if too much hydrogen sulfide – an indicator of the presence of halitosis – is present.
“That was clever work,” Myung said.
A similar discovery found how carbon nanotubes could detect levels of nitric oxide in a breath that might indicate an asthma attack is coming on.
“Personally, I don’t see the limits of sensor work,” Star said.
His effort to create a nanocapsule is, perhaps, closest to Star’s own interests.
He was able to get the basic cup structure to form a capsule by adding nitrogen to the carbon nanotube production process, which, instead of a long tube, forms something like a cup. Two cups can be coded to be attracted to each other so they form a capsule. The challenge is to figure out a way to get microscopic amounts of a drug into the capsule and then teach the entire capsule to attack specific cancer cells and avoid healthy cells.
As a researcher, his mother “was to cure cancer, too, but it unfortunately killed her.”
She died in 2008 and the implications of his work are never far away.
His mentor, Stoddart, doesn’t doubt that Star may some day come up with some of the answers he’s seeking.
“In his own quiet way, he’s fearless,” he said. “Right now, he’s really only at the beginning of his career. Let’s just wait and give him five or 10 years. The sky is the limit.”
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