Wang says the handheld device could be the smallest protein array reader in the world.
By means of magnets
The specialty of Wang's research group at Stanford is magnetic nanotechnology. Magnetism is rare in biological systems, so any magnetic signal in a blood serum sample stands out like a flare in the night sky. By tagging cancer proteins with tiny magnetic particles, rather than electrically charged or glowing particles as in other detectors, the new system can obtain a clearer signal from a smaller number of cancer proteins.
At the heart of the detector is a silicon chip, designed by the paper's lead author, Sebastian Osterfeld, a Stanford materials science and engineering doctoral student. The chips have 64 embedded sensors that monitor for changes in nearby magnetic fields. Attached to these sensors are "capture antibodies," painstakingly selected by Heng Yu, formerly a postdoctoral fellow at Stanford Genome Technology Center, and Richard Gaster, a student in a combined program of doctorate and medical degrees.
The sensor's "capture antibodies" grab specific cancer-related proteins as they float by and hold onto them. Then a second batch of antibodies is added to the mix. They latch onto magnetic nanoparticles as well as the cancer biomarkers that are being held captive by the sensors. Thus when the MagArray sensors detect the magnetic field of nanoparticles, they've found cancer markers as well.
In the paper, the researchers estimate that they could detect levels of the human chorionic gonadotropin protein at a level about 400 times lower than the level required for detection by current commercial kits known by the acronym ELISA, in which captured cancer proteins are tethered to color altering or fluorescent labels.
At Stanford Medical Center, the detector is viewed a
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| Contact: David Orenstein davidjo@stanford.edu 650-736-2245 Stanford University Source:Eurekalert |