APPLICATIONS OF TECHNOLOGY:
- NMR spectroscopy and imaging to
- determine the chemical composition of a gas or liquid
- detect biohazards and toxic chemicals
- measure flow of gases or liquids in capillaries or micro-analysis systems, such as lab-on-a-chip devices
- conduct scientific or medical sampling
- Microfluidic assays of
- hyperpolarized noble gases (such as 129Xe, 3He, 83Kr)
- gases and liquids polarized using dynamic nuclear polarization or parahydrogen techniques
- Much lower cost than other magnetic resonance techniques
- Compact; user friendly set up
- No need for tracers
- Can be used at any temperature
Many microfluidic flow measurements rely on optical (laser) devices to detect fluorescent or radioactive markers, requiring the injection of tracers such as fluorescent microspheres to characterize a sample’s flow or analytes (e.g., glucose levels in a blood sample). These techniques, however, can contaminate the sample, resulting in inaccurate data, while other recent improvements have the additional problem of temperature management. Although nuclear magnetic resonance (NMR) detectors or sensors promise to overcome the complications associated with laser or radioactivity detectors, there is still a need for an NMR detector that is both small and sensitive enough to analyze microfluidic samples.
To address this need, Alexander Pines, Dmitry Budker, and their colleagues at Berkeley Lab have discovered that anisotropic magnetoresistive (AMR) sensors—including solid-state giant magnetoresistive (GMR) and magnetic tunnel junction (MTJ) sensors—can provide the high sensitivities needed for use with NMR remote detection to profile microfluidic flow of liquids or gases in tubes ranging in size from 1 millimeter to about 100 nanometers in diameter. They can also assay very small amounts of a substance in the nanoliter range. The Berkeley Lab researchers found that ample sensitivity in solid-state magnetoresistive sensors can be achieved by a novel use of an existing sensor’s design, allowing the sensor to be in close proximity to the sample without compromising the strength of the magnetic field needed to accurately characterize the sample.
Because it is ideally suited for applications that use remote NMR—a technique in which NMR signal encoding and detection are carried out independently by two different devices—the technology does not require expensive magnets to generate the spin polarization necessary for NMR detection, nor does it require any magnets or radio-frequency hardware for detection. This eliminates the most expensive and bulkiest components of an NMR apparatus.
The invention is not limited to use in a room-temperature environment, unlike other microfluidic techniques. The Berkeley Lab technology may also allow researchers to differentiate between chemical species or to simultaneously track two or more species within a sample, which is not possible with currently available microchips.
STATUS: Issued U. S. Patent #8,547,095. Available for licensing or collaborative research.
FOR MORE INFORMATION:
Verpillat, F., M.P. Ledbetter, S. Xu, D.J. Michalak, C. Hilty, L.-S. Bouchard, S. Antonijevic, D. Budker, and A. Pines, “Remote detection of nuclear magnetic resonance with an anisotropic magnetoresistive sensor,” Proceedings of the National Academy of Sciences, 105(7), 2271-2273, (February 19, 2008).
REFERENCE NUMBER: IB-2212
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