Imaging nanoparticles that give off light under a low-power laser could be used to safely pinpoint single cancer cells.
Some existing imaging systems use high-power laser light, at near infrared levels. But this means they can damage cells when used at the higher sensitivity needed to see deep into living tissue.
The U.S. Department of Energy’s Lawrence Berkeley National Laboratory, also known as the Berkeley Lab, has developed a new alloyed upconverting nanoparticle (aUCNP). The aUCNPs absorb light from ultra-low power lasers and then emit it as visible light. The lasers work on “near-infrared” wavelengths, which are safe for use in living tissues.
Researchers want to develop the technology further by coating the aUCNPs in substances that make them attach to a specific component of a single cell. This would allow the light to be used as part of a sophisticated imaging system that would not damage cells.
Researchers injected modified nanoparticles into the mammary fat pads of mice. They then recorded images of the light emitted by the particles.
The team found aUCNPs of 12 nanometers in diameter could be imaged through deep tissue in live mice. This was carried out at safe wavelength levels and did not appear to pose any toxicity to the cells.
More testing is now needed to know for sure if the particles can be used safely in humans. But researchers have called the results a “game-changer” in imaging.
Bruce Cohen, part of a science team at Berkeley Lab’s Molecular Foundry which is working with UC San Francisco researchers to adapt the nanoparticles for medical uses, explained.
“The challenge is: How do we image living systems at high sensitivity without damaging them? This combination of low-energy light and low-laser power is what everyone in the field has been working toward for a while,” he said.
In the future, this technology could potentially be used to guide high-precision surgeries and radiation treatments.
Berkeley Lab is currently working on nanoparticle coatings that would make them attach to cancer cells. This could lead to the ability to remove even tiny traces of cancer.
Dr. Mekhail Anwar, a radiation oncologist and an assistant professor at UC San Francisco, said current techniques used to locate cancers, such as mammograms, MRIs and PET-CT scans, lacked precise detail at very small scales.
He said: “We really need to know exactly where each cancer cell is. Usually we say you’re lucky when we catch it early and the cancer is only about a centimeter – that’s about 1 billion cells. But where are the smaller groups of cells hiding?”
Researchers are now developing an imaging sensor that would work with nanoparticles. It could be attached to surgical equipment to pinpoint cancer hot spots during surgical procedures.
Tian B, Fernandez-Bravo A, Najafiaghdam H, Torquato NA, Altoe MVP, Teitelboim A, Tajon CA, Tian Y, Borys NJ, Barnard ES, Anwar M, Chan EM, Schuck PJ, Cohen BE. Low irradiance multiphoton imaging with alloyed lanthanide nanocrystals. Nat Commun 2018; 9:3082.
DOE/Lawrence Berkeley National Laboratory (2018). Light-emitting nanoparticles could provide a safer way to image living cells. [online] Available at: https://www.eurekalert.org/pub_releases/2018-08/dbnl-lnc081418.php (accessed August 2018).