NIST/NIH micromagnets show promise as colorful 'smart tags' for magnetic resonan...( BOULDER Colo.-Customized microscopic...)

BOULDER, Colo.-Customized microscopic magnets that might one day be injected into the body could add color to magnetic resonance imaging (MRI), while also potentially enhancing sensitivity and the amount of information provided by images, researchers at the National Institute of Standards and Technology (NIST) and National Institutes of Health (NIH) report. The new micromagnets also could act as "smart tags" identifying particular cells, tissues, or physiological conditions, for medical research or diagnostic purposes.

As described in the June 19 issue of Nature,* the NIST and NIH investigators have demonstrated the proof of principle for a new approach to MRI. Unlike the chemical solutions now used as image-enhancing contrast agents in MRI, the NIST/NIH micro-magnets rely on a precisely tunable feature-their physical shape-to adjust the radio-frequency (RF) signals used to create images. The RF signals then can be converted into a rainbow of optical colors by computer. Sets of different magnets designed to appear as different colors could, for example, be coated to attach to different cell types, such as cancerous versus normal. The cells then could be identified by tag color.

"Current MRI technology is primarily black and white. This is like a colored tag for MRI," says lead author Gary Zabow, who designed and fabricated the microtags at NIST and, together with colleagues at the National Institute of Neurological Disorders and Stroke, part of NIH, tested them on MRI machines.

The micromagnets also can be thought of as microscopic RF identification (RFID) tags, similar to those used for identifying and tracking objects from nationwide box shipments to food in the supermarket. The device concept is flexible and could have other applications such as in enabling RFID-based microscopic fluid devices (microfluidics) for biotechnology and handheld medical diagnostic toolkits.

The microtags would need extensive furthe
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