Advertisement

If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.

ENJOY UNLIMITED ACCES TO C&EN

Materials

Quantum Dots Linger In Mouse Tissue

Fluorescence imaging reveals that the flashing nanoparticles can persist for years in mice, although the long-term toxicity is still uncertain

by Aaron A. Rowe
June 22, 2009 | A version of this story appeared in Volume 87, Issue 25

[+]Enlarge
Credit: James Fitzpatrick
This two-photon fluorescence image of a mouse lymph node shows quantum dots that have lingered there for two years.
Credit: James Fitzpatrick
This two-photon fluorescence image of a mouse lymph node shows quantum dots that have lingered there for two years.

Quantum dots could become fantastic contrast agents for medical imaging, but the glittering nanoparticles typically are made from toxic metals, and researchers don't know how long they remain in the body or whether they gradually dissolve. To shed light on those questions, Marcel P. Bruchez and colleagues of Carnegie Mellon University injected ZnS-coated CdSe quantum dots into mice and examined them with fluorescence imaging techniques (Nano Lett., DOI: 10.1021/nl901534q). Within days, the dots were undetectable in liver tissue, but they remained in bone marrow for months. Two years later, new images disclosed that some quantum dots still lingered in the animals' lymph nodes. The nanoparticles' emission spectra changed considerably, however, raising the possibility that they partially dissolved. The researchers conclude that quantum dots don't spill their metal contents quickly enough to pose an acute health risk, but it is unclear if the nanoparticles might cause chronic metal toxicity. They argue that quantum dots should be engineered to exit the body rapidly and should not be made from toxic metals, even if they have a sturdy shell.

Article:

This article has been sent to the following recipient:

0 /1 FREE ARTICLES LEFT THIS MONTH Remaining
Chemistry matters. Join us to get the news you need.