Feature | November 26, 2013

Diamond Flaws Pave Way for Nanoscale MRI

mri systems contrast media diamonds nanodiamonds cambridge
November 26, 2013 — Researchers say they have achieved enough coherence of the magnetic moment inherent in the defects of miniscule diamond fragments to harness their potential for precise quantum sensors in a material that is biocompatible.
 
Nanoscopic thermal and magnetic field detectors, which can be inserted into living cells, could enhance our understanding of everything from chemical reactions within single cells to signaling in neural networks and the origin of magnetism in novel materials.
 
Atomic impurities in natural diamond structure give rise to the color seen in rare and coveted pink, blue and yellow diamond. But these impurities are also a major research focus in emerging areas of quantum physics.
 
One such defect, the nitrogen-vacancy center (NVC), consists of a gap in the crystal lattice next to a nitrogen atom. This system tightly traps electrons whose spin states can be manipulated with extreme precision.
 
Electron coherence, the extent to which the spins of these particles can sustain their quantum mechanical properties, has been achieved to high levels in the NVCs of large “bulk” diamonds, with coherence times of an entire second in certain conditions — the longest yet seen in any solid material.
 
However, in nanodiamonds — nanometer-sized crystals that can be produced by milling conventional diamond — any acceptable degree of coherence has, until now, been elusive.
 
Nanodiamonds offer the potential for both extraordinarily precise resolution, as they can be positioned at the nano-scale, and biocompatibility, as they have can be inserted into living cells. But without high levels of coherence in their NVCs to carry information, these unique nanodiamond benefits cannot be utilized.
By observing the spin dynamics in nanodiamond NVCs, researchers at Cavendish Laboratory, University of Cambridge, identified that it is the concentration of nitrogen impurities that impacts coherence rather than interactions with spins on the crystal surface.
 
By controlling the dynamics of these nitrogen impurities separately, they increased NVC coherence times to a record 0.07 milliseconds longer than any previous report, an order of significant magnitude that puts nanodiamonds back in play as an extremely promising material for quantum sensing. The results were published the journal Nature Materials.
 
"Our results unleash the potential of the smallest magnetic field and temperature detector in the world,” said Helena Knowles, M.Sc. and researcher on the study. “Nanodiamond NVCs can sense the change of such features within a few tens of nanometers — no other sensor has ever had this spatial resolution under ambient conditions. We now have both high spin coherence and spatial resolution, crucial for various quantum technologies."
 
Dhiren Kara, Ph.D. and researcher on the study, pointed out that the nanodiamond's biocompatibility can provide non-invasive optical access to magnetic changes within a living cell — essentially the ability to perform magnetic resonance imaging (MRI) and detect, for instance, a cell's reaction to a drug in real time.
 
"We may also be able to answer some key questions in material science, such as magnetic ordering at the edges of graphene or the origin of magnetism in oxide materials," said Kara.
 
"The pursuit of simultaneous high NVC coherence and high spatial resolution, and the fact that nanodiamonds couldn't deliver on this promise until now, has required researchers to invest in alternative means including advanced nanofabrication techniques, which tends to be both expensive and low-yield,” said Mete Atature, Ph.D. and director of the research. “The simplest solution — feasible and inexpensive — was in front of us the whole time."
 
For more information: www.phy.cam.ac.uk, www.rsna.org

Related Content

ACC late breakers
News | ACC| February 09, 2016
February 9, 2016 — The late-breaking clinical trial presentations have been announced for the 2016 American College o
Allegheny General Hospital, MRI, patients with implantable cardiac devices, safety and effectiveness
News | EP Lab| February 01, 2016
The findings of a major study led by cardiovascular imaging specialists at Allegheny General Hospital (AGH) suggest...
critical limb ischemia, amputations, MRI-based mapping, CLI, British Heart Foundation
News | Peripheral Arterial Disease (PAD)| January 28, 2016
A new imaging technique could reduce the need for amputation in patients with critical limb ischemia (CLI), according...
Siemens, Magnetom Amira MRI scanner, FDA clearance
Technology | Magnetic Resonance Imaging (MRI)| January 21, 2016
Siemens Healthcare announced that the U.S. Food and Drug Administration (FDA) has cleared the Magnetom Amira 1.5 Tesla...
MRI sensitivity, metamaterials, ITMO University, Advanced Materials

Artist's view of a biological object placed on a metasurface resonator. Image courtesy of Advanced Materials.

News | Magnetic Resonance Imaging (MRI)| January 20, 2016
A group of researchers from Russia, Australia and the Netherlands have developed a technology that can reduce magnetic...
Cath lab radiation dose reduaction, doseaware, raysafe

The Philips DoseAware Xtend system is an advanced version of the Unfors RaySafe system, combining real time radiation detection badges and a live video screen showing each person in the cath lab in a different color. The system reports their real-time exposure rate and cumulative dose since the start of a procedure. It shows changes in dose exposure the closer a person gets to the C-arm.

Feature | Cardiac Imaging| January 12, 2016 | Dave Fornell
Each year radiology vendors use the Radiological Society of North America (RSNA) meeting as a springboard to unveil t
recurrent stroke risk, low blood flow, vertebrobasilar region, NOVA, UIC
News | Stroke| December 23, 2015
Patients who have had a stroke in the back of the brain are at greater risk of having another within two years if blood...

Photo courtesy of Vital Images

News | ACC| December 22, 2015
December 22, 2015 — In 2015, results from the ITALIC and CvLPRIT trials, along with studies examining lifestyle facto
Philips, ScanWise Implant, MRI, MR conditional implants, RSNA 2015
Technology | Magnetic Resonance Imaging (MRI)| December 21, 2015
Philips Healthcare introduced ScanWise Implant, the industry’s first magnetic resonance imaging (MRI)-guided user...
Overlay Init