This method is less expensive and takes less time than conventional techniques.
Carbon nanotubes are rolled-up sheets of graphite only a few nanometers wide - about the width of a molecule of DNA. The researchers used these nanotubes ™ electrical properties to find a particular mutation in the gene that causes hereditary hemochromatosis, a disease in which too much iron accumulates in body tissues.
The size compatibility between the detector and the detected species - DNA molecules in this case - makes this approach very attractive for further development of label-free electronic methods, said Star, who is an assistant professor of chemistry at Pitt.
Star and his colleagues at Nanomix also tested fluorescently labeled DNA molecules in order to confirm that DNA had attached to the nanotube surfaces and was subsequently hybridized, or matched to its complementary DNA.
We have found that electrical measurement of carbon nanotube devices produce sensor results that are comparable to state-of-the-art optical techniques, Star said.
He added, The applications of our method for detection of other, more serious genetic diseases can be seen. Label-free electronic detection of DNA has several advantages over state-of-the-art optical techniques, including cost, time, and simplicity.
Our technology can bring to market hand-held, field-ready devices for genetic screening, as opposed to laboratory methods using labor-intense labeling and sophisticated optical equipment, Star said.
This research was partially supported by the National Science Foundation ™s Small Business Innovation Research program.
pitt
HIV is a particularly successful virus, and the size and shape variability which makes it so hard to image is assumed to play a role in its success. A puzzling question was how HIV, unlike other viruses, managed to be so varied without losing its crucial structure. The new image of the particle gave new insights into that conundrum. Instead of the central region of the virus organising its growth, as in most viruses, the virus membrane and the core interact so that the core stops growing only when it reaches the membrane ™s limit. The inner surface of the viral membrane directs ™ growth, which keeps the important parts of the structure consistent whilst allowing size variation.
This novel mechanism accommodates significant flexibility in lattice growth while ensuring the closure of cores of variable size and shape ™, said Professor Fuller. Identifying how the virus grows will allow us to address the formation of this important pathogen and understand how it accommodates its variability. This could inform the development of more effective therapeutic approaches. ™
The microscopy was performed at the Wellcome Trust Centre for Human Genetics in Oxford and The Max Planck Institut f r Biochemie in Martinsried, and was supported by the Wellcome Trust.
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