U.S. researchers have developed a prototype device of a card-swipe for medical tests which could be used to check for hundreds of diseases simultaneously. It should act as 'a credit card-swipe machine to scan a card loaded with microscopic blood, saliva or urine samples.' The current prototype is about the size of a PC, but a future commercial version should look like a credit card reader. And according to the researchers, results could be available in minutes instead of hours or weeks. Besides health care, such a device has potential applications for homeland security or environmental monitoring. This device is based on giant magnetoresistance (GMR), a phenomenon discovered in 1988 by French and German researchers who shared the 2007 Nobel Prize in Physics, and which is used to read data on computer hard drives and by MP3 readers. But read more...
You can see on the left images and schematics of the GMR test station developed at the University of Utah: "(a) schematic showing the test station connections; (b) photograph of the test station; (c) photograph showing the area directly between the Helmholtz coils, which contains a Pyrex sample stick mounted directly above a GMR sensor." (Credit: University of Utah)
This research work has been led by Marc Porter, a Utah Science, Technology and Research (USTAR) professor of chemistry, chemical engineering and bioengineering. Porter worked with USTAR research scientist Michael Granger and other researchers in Iowa and Minnesota to develop the screening device.
And how does this system work? "The prototype card-swipe device consists of a GMR 'read head' and sample stick. Right now, the device is about the size of a PC. But Granger says that when it is developed commercially, the GMR sensor device will look like a credit card reader. Porter expects a more advanced version will start being used to test farm animals for diseases in about two years, and a version for human medical tests might begin clinical evaluation in five years, perhaps sooner if pursued by certified laboratories."
Such a device could also be used for homeland security applications. "A card swipe device could be taken into the field, where a sample card or stick 'could be dipped in groundwater, dried off and read in our device to look for E. coli, plague, smallpox or other suspects on the homeland security list,' adds Porter. Granger says cards with GMR sensors also could be used for environmental monitoring of various toxins or toxic chemicals in an office building's water or air."
Such a sensor device could be used to test 10 or 2,000 diseases simultaneously depending of its possible uses.
Here are some additional details. "The current prototype reader had four GMR devices: two sensors to detect changes to the magnetic fields of the sample spots, and two 'reference elements' to distinguish how magnetic measurements were affected by temperature changes as opposed to the presence of disease indicators in medical samples. The prototype does not yet look like a credit card reader or card-swipe device. Instead, it is used to 'read' a Pyrex glass sample stick about three-quarters-inch long and one-eighth-inch wide. Biological samples can be placed on the sample stick, which then is 'scanned much like a credit card reader,' Porter says."
This research work has been reported in the November 1, 2008 issue of the Analytical Chemistry journal in two articles about "Giant Magnetoresistance Sensors" (Volume 80, Number 21, Pages 7930–7939 and 7940–7946).
The first part is called "Internally Calibrated Readout of Scanned Magnetic Arrays" and here are two links to the abstract and to the full paper (PDF format, 10 pages, 1.22 MB), from which the above image has been extracted.
The second part is titled "Detection of Biorecognition Events at Self-Referencing and Magnetically Tagged Arrays." And here are the links to the abstract and to the full paper (PDF format, 7 pages, 1.43 MB).
Sources: University of Utah news release, October 29, 2008; and various websites
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