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.


Biological Chemistry

Nanoparticles Keep Immune Cells From Doing Their Job

Macrophages fail to ingest pathogenic bacteria after exposure to iron oxide nanoparticles

by Journal News and Community
July 29, 2013 | A version of this story appeared in Volume 91, Issue 30

Credit: ACS Nano
Macrophages ingest far fewer Streptococcus pneumoniae (blue) after exposure to iron oxide nanoparticles (right).
This is a confocal microscopy image of macrophages before and after being exposed to iron nanoparticles.
Credit: ACS Nano
Macrophages ingest far fewer Streptococcus pneumoniae (blue) after exposure to iron oxide nanoparticles (right).

In studying the potential health effects of nanoparticle exposure, scientists rely on cell death as a key indicator. But new research suggests that nanoparticles might require additional safety testing. Brian D. Thrall of Pacific Northwest National Laboratory and his colleagues treated immune cells with iron oxide nanoparticles and showed that although the cells appeared healthy in standard toxicology tests, they struggled to perform one of their key jobs: engulfing pathogenic bacteria (ACS Nano 2013, DOI: 10.1021/nn402145t). The researchers exposed macrophages from mouse bone marrow to superparamagnetic iron oxide nanoparticles. They then added a lipopolysaccharide to the culture, which the macrophages treat as bacteria, and measured the cells’ gene expression with a micro­array chip device. The nanoparticles altered the expression of 1,044 genes by at least 50%. The most troubling changes, Thrall says, took place in oxidative stress and inflammation pathways, which play significant roles in macrophages’ ability to detect and clear bacteria. Indeed, when the researchers mixed the macrophages with Streptococcus pneumoniae, macrophages exposed to nanoparticles struggled to take up the pathogen, ingesting just half as much as unexposed cells.


This article has been sent to the following recipient:

Chemistry matters. Join us to get the news you need.