A scientist at the Max Planck Institute for Intelligent Systems in Stuttgart was taken aback by an unexpected discovery: nanometer-sized diamond particles, intended for a completely different purpose, shone brighter in a magnetic resonance imaging experiment than the actual contrast agent, the heavy metal gadolinium. Could diamond dust, in addition to being employed in medication delivery to treat tumor cells, one day become a novel contrast agent for MRI? The researchers have recently published their findings in Advanced Materials.
Some of the world’s greatest discoveries were made by mistake. While the discovery of diamond dust’s potential as a future MRI contrast agent may not be considered a watershed moment in scientific history, its signal-enhancing properties are an unexpected discovery that may open up new possibilities: Diamond dust sparkles brightly even after days of injection. Does this suggest it could eventually replace the widely used contrast agent gadolinium?
For almost 30 years, this heavy metal has been utilized in clinical settings to detect malignancies, inflammation, and vascular anomalies. It increases the brightness of the image in impacted areas. Gadolinium, when injected into a patient’s bloodstream, travels not just to tumor cells but also to healthy tissue. It is kept in the brain and kidneys for months or years after the previous dosage. The long-term repercussions on the patient are currently unknown. Gadolinium has a number of additional adverse effects. The search for an alternative has been ongoing for many years.
Why the diamond dust shines bright in our MRI still remains a mystery to us. I believe the tiny particles have carbons that are slightly paramagnetic.
Prof. Metin Sitti
Could diamond dust, a carbon-based material, become a bearable substitute as a result of an unexpected discovery in a lab at the Max Planck Institute for Intelligent Systems in Stuttgart?
Dr. Jelena Lazovic Zinnanti was working on an experiment using nanometer-sized diamond particles for an entirely different purpose. The research scientist, who heads the Central Scientific Facility Medical Systems at MPI-IS, was surprised when she put the 3 to 5 nanometer particles into tiny drug-delivery capsules made of gelatin. She wanted these capsules to rupture when exposed to heat. She assumed that diamond dust, with its high heat capacity, could help.
“I had intended to use the dust only to heat up the drug carrying capsules,” Jelena recollects. “I used gadolinium to track the dust particles’ position. I intended to learn if the capsules with diamonds inside would heat up better. While performing preliminary tests, I got frustrated, because gadolinium would leak out of the gelatin — just as it leaks out of the bloodstream into the tissue of a patient. I decided to leave gadolinium out. When I took MRI images a few days later, to my surprise, the capsules were still bright. Wow, this is interesting, I thought! The diamond dust seemed to have better signal enhancing properties than gadolinium. I hadn’t expected that.”
Jelena took these findings further by injecting the diamond dust into live chicken embryos. She discovered that while gadolinium diffuses everywhere, the diamond nanoparticles stayed in the blood vessels, didn’t leak out and later shone brightly in the MRI, just as they had done in the gelatin capsules. While other scientists had published papers showing how they used diamond particles attached to gadolinium for magnetic resonance imaging, no one had ever shown that diamond dust itself could be a contrast agent.
Two years later, Jelena became the lead author of a paper now published in Advanced Materials.
“Why the diamond dust shines bright in our MRI still remains a mystery to us,” adds Jelena, who collaborated with Prof. Metin Sitti and researchers from the Physical Intelligence Department at MPI-IS, as well as Dr. Eberhard Goering from the MPI-IS’ adjacent institute, the MPI for Solid State Research. She can only speculate on the dust’s magnetic properties: “I believe the tiny particles have carbons that are slightly paramagnetic.” The particles may contain a flaw in their crystal lattice that causes them to be somewhat magnetic. This is why they respond similarly to T1 contrast agents like gadolinium. Furthermore, we don’t know whether diamond dust is possibly harmful, which must be thoroughly investigated in the future.
If diamond dust is found to be safe and well tolerated by patients, Jelena believes it has the potential to become a new contrast agent option for future MRI scans, where it would be deposited in tissue with abnormal vasculature, such as tumors, but not in healthy tissue.
