University of Connecticut |
New moves in nanotechnology
A chemistry professor in CLAS and his graduate students have published new results in Nature Nanotechnology showing how they isolated a particular type of carbon nanotube from a sample and manipulated it in a way that could have broad applicability in drug and gene delivery, electronic devices, and nanotechnology research. Prof. Fotios Papadimitrakopoulos and his graduate students found a way for a biological molecule, a form of vitamin B2, to wrap around a single-walled carbon nanotube – a tube so small that it has the highest curvature on earth. In addition, the journal hada report that scientists have created a membrane than can absorb up to 20 times its weight in oil. The research, led by an MIT scientist, included the work of collaborator and co-author Steven L. Suib, Board of Trustees Distinguished Professor of Chemistry and department head, and his former graduate student, Jikang Yuan, PhD ’07, who is now a postdoctoral fellow at MIT. The material that was used in the study was initially developed at UConn by Yuan, Suib says. It is a paper or membrane that can be recycled many times and has applications in oil recovery and the filtering and purification of water. It is made from an interwoven mesh of nanowires. Its super-hydrophobic characteristic – repelling water – enabled it to absorb oil from water. Its properties would enable it to absorb industrial discharges from sea water, the authors noted in the paper. “Given the global scale of severe water pollution arising from oil spills and industrial organic pollutants, this study may prove particularly useful in the design of recyclable absorbents with significant environmental impact,” they wrote. The Papadimitrakopoulos group’s discovery, meanwhile, had several important steps. Wrapping a carbon nanotube was a difficult achievement and instrumental to their research, since it eventually enabled them to isolate a particular type of nanotube from a sample that contained 50 different kinds.
Nanotubes that are alike can be interlocked to create a material that is extremely strong, even if each nanotube is as small as one micron. Homogenous nanotubes also have the same electrical and optical properties, and they form a material that is extremely pure. The research opens the possibility of wrapping nanotubes with proteins or other molecules, which would be useful in a variety of applications. “We have learned how to manipulate this molecule,” says Papadimitrakopoulos. Papadimitrakopoulos says that by separating like nanotubes, the research has provided a way to minimize the potential negative health impact of carbon nanotubes, which recently were associated with asbestos-like contamination in the lung linings of laboratory animals. In that recent study, it was shown that carbon nanotubes larger than 20 microns behaved like asbestos, while those smaller than 20 microns could be cleared out of the lungs, much like pollen. The carbon nanotubes that his research group works on are far smaller, at approximately one-micron in length.
Two undergraduates, William Kopcha, CLAS ’08, a chemistry major, and Christopher Badalucco, a physiology and neurobiology major who is a junior, also were involved in the research. Papadimitrakopoulos is a chemistry professor in CLAS, but his work is interdisciplinary, involving physics as well. He also serves as the associate director of the Institute of Materials Science and is a member of the Polymer Program. A nanobionics initiative that he leads was one of the flagship interdisciplinary programs to emerge from the College of Liberal Arts and Science’s strategic plan last year: http://www.clas.uconn.edu/strategicplanning/intd/toc7.html To hear Papadimitrakopoulos describe the research, go to the podcast: http://www.clas.uconn.edu/facultysnapshots/view.php?id=papadimitrakopoulos To read the paper in Nature Nanotechnology online, go to: To read the Suib report, go to: http://www.nature.com/nnano/journal/v3/n6/abs/nnano.2008.136.html
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