Use of Electric Field and Nanoscale Nozzle Achieves Significant Resolution in E-Jet Printing
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from the tip of the new growth straight through the substrate on which the material is growing. Tracking the surface evolution of the material provides insight into how the structure evolves and helps researchers understand the nanostructure formation mechanism. The creation of surface pole figures was particularly important in understanding the growth of nanoblades, as the surface morphology changed greatly with time. The surface pole figure technique was first outlined by Tang, a postdoctoral research associate in Wang’s group, in a 2006 issue of Applied Physics Letters. In that article, surface pole figures were created for nanorod growth. The researchers are now working to analyze nanoblade growth to provide additional insight into the growth patterns of these nanomaterials.
Researchers Look at Nanotubes Inside Living Animals T.K. Leeuw, K.M. Beckingham, R.B. Weisman, and colleagues at Rice Uni versity have confirmed that nearinfrared fluorescent imaging was capable of detecting DNA-sized, single-walled carbon nanotubes inside living fruit flies. “Carbon nanotubes are much smaller than living cells, and they give off fluorescent light in a way that researchers hope to harness to detect diseases earlier than currently possible,” said Bruce Weisman, professor of chemistry at Rice. “In order to do that, we need to learn how to detect and monitor nanotubes inside living tissues, and we must also determine whether they pose any hazards to organisms.” Researchers have studied how carbon nanotubes interact with tissues of rabbits, mice, and other animals, but Weisman and co-researcher Kathleen Beckingham, professor of biochemistry and cell biology, chose the fruit fly Drosophila melanogaster to attempt the detection of nanotubes inside a living animal. In the study, published in the September issue of Nano Letters (p. 2650; DOI: 10.1021/nl0710452), fruit fly larvae were raised on a yeast paste that contained carbon nanotubes. The flies were fed this food from the time they hatched throughout their initial feeding phase of 4–5 days. Fruit flies are ravenous eaters during this period and gain weight continuously until they are about 200 times heavier than hatchlings. Then they become pupae. As pupae, they do not eat or grow. They mature inside pupal cases and emerge as adult flies. “Developmentally, the first few days of a fruit fly’s life are critical,” Beckingham 888
said. “We provided larval flies with a steady diet of food that contained carbon nanotubes and checked their weight just after they emerged from their pupal cases. We found no significant differences in the adult weight of nanotube-fed flies when compared to control groups that were not fed carbon nanotubes.” The nanotube-fed larvae also survived to adulthood just as well as the control group. Using a custom-built microscope, the team aimed a red laser beam into the fruit flies. This excited a fluorescent glow from the carbon nanotubes as they emitted nearinfrared light of specific wavelengths. The researchers were then able to use a camera to view the
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