Tag Archives: stimuli-responsive peptides

Better contrast agents for magnetic resonance imaging with nanoparticles

I wonder what’s going on in the field of magnetic resonance imaging. This is the third news item I’ve stumbled across related to the topic in the last couple of months. (Links to the other two posts follow at the end of this post.) By comparison, that’s the more than in the previous seven years (2008 – 2015) combined.

The latest research concerns a new and better contrast agent. From an Aug. 3, 2016 news item on Nanowerk,

Scientists at the University of Basel [Switzerland] have developed nanoparticles which can serve as efficient contrast agents for magnetic resonance imaging. This new type of nanoparticles [sic] produce around ten times more contrast than the actual contrast agents and are responsive to specific environments.

An Aug. 3, 2016 University of Basel press release (also on EurekAlert), which originated the news item, explains further,

Contrast agents are usually based on the metal Gadolinium, which is injected and serves for an improved imaging of various organs in an MRI. Gadolinium ions should be bound with a carrier compound to avoid the toxicity to the human body of the free ions. Therefore, highly efficient contrast agents requiring lower Gadolinium concentrations represent an important step for advancing diagnosis and improving patient health prognosis.

Smart nanoparticles as contrast agents

The research groups of Prof. Cornelia Palivan and Prof. Wolfgang Meier from the Department of Chemistry at the University of Basel have introduced a new type of nanoparticles [sic], which combine multiple properties required for contrast agents: an increased MRI contrast for lower concentration, a potential for long blood circulation and responsiveness to different biochemical environments. These nanoparticles were obtained by co-assembly of heparin-functionalized polymers with trapped gadolinium ions and stimuli-responsive peptides.

The study shows, that the nanoparticles have the capacity of enhancing the MRI signal tenfold higher than the current agents. In addition, they have an enhanced efficacy in reductive milieu, characteristic for specific regions, such as cancerous tissues. These nanoparticles fulfill numerous key criteria for further development, such as absence of cellular toxicity, no apparent anticoagulation property, and high shelf stability. The concept developed by the researchers at the University of Basel to produce better contrast agents based on nanoparticles highlights a new direction in the design of MRI contrast agents, and supports their implementation for future applications.

Here’s a link to and a citation for the paper,

Nanoparticle-based highly sensitive MRI contrast agents with enhanced relaxivity in reductive milieu by
Severin J. Sigg, Francesco Santini, Adrian Najer, Pascal U. Richard, Wolfgang P. Meier, and Cornelia G. Palivan. Chem. Commun., 2016,52, 9937-9940 DOI: 10.1039/C6CC03396B First published online 13 Jul 2016

This paper is behind a paywall.

The other two MRI items featured here are in a June 10, 2016 posting (pH dependent nanoparticle-based contrast agent for MRIs [magnetic resonance images]) and in an Aug. 1, 2016 posting (Nuclear magnetic resonance microscope breaks records).