Good news for nanomedicine: Quantum dots appear safe in pioneering study on primates
May 22, 2012
Transmission electron microscopy (TEM) images showing quantum dots after micelle encapsulation (Credit: Ling Ye, et al./Nature Nanotechnology)
A pioneering study to gauge the toxicity of quantum dots in primates has found the tiny luminescent crystals are safe over a one-year period, a hopeful outcome for doctors and scientists seeking new ways to battle diseases like cancer through nanomedicine.
In the study, scientists found that four rhesus monkeys injected with cadmium-selenide quantum dots remained in normal health over 90 days. Blood and biochemical markers stayed in typical ranges, and major organs developed no abnormalities. The animals didn’t lose weight. Two monkeys observed for an additional year also showed no signs of illness.
Quantum dots are tiny luminescent crystals that glow brightly in different colors. Medical researchers are eyeing the crystals for use in image-guided surgery, light-activated therapies and sensitive diagnostic tests. Cadmium selenide quantum dots are among the most studied, with potential applications not only in medicine, but as components of solar cells, quantum computers, light-emitting diodes and more.
The new toxicity study — completed by the University at Buffalo, the Chinese PLA General Hospital, China’s ChangChun University of Science and Technology, and Singapore’s Nanyang Technological University — begins to address the concern of health professionals who worry that quantum dots may be dangerous to humans.
The authors caution, however, that more research is needed to determine the nanocrystals’ long-term effects in primates; most of the potentially toxic cadmium from the quantum dots stayed in the liver, spleen and kidneys of the animals studied over the 90-day period.
“This is the first study that uses primates as animal models for in vivo studies with quantum dots,” said paper coauthor Paras Prasad, UB professor of chemistry and medicine, and executive director of UB’s Institute for Lasers, Photonics and Biophotonics (ILPB). “So far, such toxicity studies have focused only on mice and rats, but humans are very different from mice. More studies using animal models that are closer to humans are necessary.”
The cadmium build-up, in particular, is a serious concern that warrants further investigation, said Ken-Tye Yong, a Nanyang Technological University assistant professor who began working with Prasad on the study as a postdoctoral researcher at UB.
Because of that concern, the best in-vivo applications for cadmium-selenide quantum dots in medicine may be the ones that use the crystals in a limited capacity, said Mark Swihart, a third coauthor and a UB professor of chemical and biological engineering. Image-guided surgery, which could involve a single dose of quantum dots to identify a tumor or other target area, falls into this category.
Ref.: Ling Ye, et al. A pilot study in non-human primates shows no adverse response to intravenous injection of quantum dots. Nature Nanotechnology, 20 May 2012 DOI: 10.1038/nnano.2012.74
Comments (1)
by tedhowardnz
Study isn’t a lot of use unfortunately.
Stuff like asbestos doesn’t produce significant problems for up to 30 years after ingestion.
The problem with long term studies is, they take a long time ;)
Seems like lots of stuff has long term effects, like high doses of animal protein in our diets – might take 50 years, but then the cancers start showing up.
2 years ago I was diagnosed terminal melanoma, after a month of intensive study I went strict vegan, with high dose vitamin C supplement, and multivitamin/mineral. I just past what I was given a 2% chance of surviving until, and have been free of any trace of tumours for over a year now.
I’ve done a lot of reading in those 2 years.
It seems that the great social experiment of centralised food production with an emphasis on long shelf life (at the expense of freshness), and an emphasis on animal rather than vegetable protein, is the major cause of the observed increases in cancer and heart disease. But that is not information that is in the financial interests of any government or corporation to spread.
So we continue to focus on short term profits and money, rather on long term well-being of people.
Time a lot more people started to wake up, and started to look to their own long term self interest – which I very strongly suspect does not involve widespread early adoption of nanotechnology. Lots of organic fruits and veges from robotically tended gardens seems much healthier.
It seems to me that nanotechnology offers great promise for our long term future, and it also seems that it would be wise to keep it in the laboratory for a long time in most cases, at least until it was tested on at least two generations of long lived primates (not me please!).