Alex Star Named Outstanding New Environmental Scientist in U.S., Receives $2 Million to Investigate Nanotube Toxicity

Alex Star

The National Institute of Environmental Health Sciences selected University of Pittsburgh researcher Alex Star for one of eight 2010 Outstanding New Environmental Scientists awards for his investigations into the health effects of the tiny, ubiquitous carbon nanotube. As part of the award, Star, a professor of chemistry in Pitt’s School of Arts and Sciences, also received a five-year, $2 million grant to continue his work. He was recognized along with early-career researchers from such institutions as Brown University, the University of Chicago, and the University of North Carolina at Chapel Hill.

Star studies the toxicity of carbon nanotubes and natural methods for dissolving the highly durable materials. Carbon nanotubes are one-atom-thick rolls of graphite 100,000 times smaller than a human hair yet stronger than steel. They are used to reinforce plastics, ceramics, or concrete; are excellent conductors of electricity and heat; and are sensitive chemical sensors. However, a nanotube’s surface contains thousands of atoms that could react with the human body in unknown ways. Laboratory tests have suggested that nanotube inhalation could result in severe lung inflammation and fibrosis.

“The demand and use of carbon nanotubes has vastly increased. Accordingly, so has the potential for negative health and environmental effects linked to nanotubes,” Star said. “It is necessary to develop approaches for safely removing carbon nanotubes from the environment. This project will further a novel and effective technique for biodegrading carbon nanotubes with natural enzymes, neutralizing their toxicity.”

Star has led or been central to studies demonstrating that the enzyme peroxidase can biodegrade carbon nanotubes. In April 2010, Star was part of a Pitt-led international team that reported in Nature Nanotechnology that carbon nanotubes exposed to the human enzyme myeloperoxidase—emitted by white blood cells—did not produce the lung inflammation that intact nanotubes have been shown to cause. In December 2008, Star coauthored a report in Nano Letters demonstrating that carbon nanotubes spilled during manufacturing or in the environment deteriorate when exposed to the plant enzyme horseradish peroxidase.

With his recent award, Star will examine the environmental factors and the structural characteristics of nanotubes that make them vulnerable to peroxidases, as well as the molecular interactions that promote breakdown. In addition, he will work to identify and determine the potential toxicity of the remnants of dissolved nanotubes.

Star used the chemical sensing attributes of carbon nanotubes to develop an early-detection device for asthma attacks. Described in Nanotechnology in 2007, the device functions via carbon nanotubes that can detect minute amounts of nitric oxide preceding an attack. In 2009, Popular Mechanics named Star’s asthma sensor one of “20 Biotech Breakthroughs That Will Change Medicine.”