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11-10 :: October 2011
nanotimes News in Brief
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number of beads, and the attached molecules or cells, to assemble “smart” tags with specified proper- ties, such as an affinity for a given protein at a speci- fic position in the array.
NIST is also interested in developing cellular and molecular tags for magnetic resonance imaging (MRI) studies in which individual cells, such as cancer cells or stem cells, would be tagged with a smart magnetic biomarker that can be tracked remotely in an MRI scanner, Moreland says. Automated spin valve chips might also be used in portable instruments for rapid medical diagnosis or DNA sequencing.
W.R. Altman, J. Moreland, S.E. Russek, B.W. Han and V. M. Bright: Controlled transport of superparamagnetic beads with spin-valves, In: Applied Physics Letters, Vol. 99, Issue 14, October 3, 2011, Article 143703 [3 pages], DOI:10.1063/1.3645615: http://dx.doi.org/10.1063/1.3645615
Top: Video clip of NIST/CU microchip manipulating ma- gnetic beads. The chip features two adjacent lines of 12 switches called spin valves. The beads float in a pool of saltwater above the valves. Individual val- ves are switched “on” to trap the beads, or “off” to release them, and thereby move the beads down a ladder formed by the two lines. The clip plays twice, the first time with the spin valves and a magnetic bead labeled. © Wendy Altman, National Institute of Standards and Technology and University of Colora- do Boulder