ETH Zurich: Magnetic nanoparticles for use as contrast agents

Licensing opportunity

Researchers at ETH Zurich have developed magnetic nanoparticles for use in magnetic resonance imaging and for targeting therapeutics.

The particles are ultra-stable under physiological conditions and at elevated temperatures. These stable shells can have additional functions added for targeting and multimodal imaging. The latter can be achieved by coupling, for example of fluorophore, positron emission tomography (PET) or single photon emission computed tomography (SPECT) labels to the iron oxide cores.

The addition of electronegative groups to catechol rings greatly enhances their affinity towards oxides in general, and iron oxide surfaces in particular. Vastly enhanced individual oxide nanoparticle stability is obtained, especially under physiological conditions and at elevated temperatures, when these anchors, covalently linked to a spacer molecule, are adsorbed to form a monolayer shell around the nanoparticle.

Furthermore, because these high affinity anchors bind densely and irreversibly to ironoxide nanoparticles, the shell thickness can be tailored by adjusting the molecular weight of the dispersant molecule. An additional advantage is that these low molecular weight dispersants of flexible chemical composition can be grafted to oxide nanoparticle surfaces without the need for in situ chemical reactions.

It is possible to covalently bind different functional elements such as fluorophores, radiotracers, and/or ligands to the magnetic nanoparticle surface at controlled density.

In summary, the technology offers a number of functions and benefits:

• Easy mix and match method to stabilise and add functions to iron oxide nanoparticles;

• Significantly increased nanoparticle stability in body fluids, such as blood and lymph fluid (in vivo and in vitro);

• The particles are biocompatible;

• The ultra-stable magnetic nanoparticles can be stored as a powder and easily be re-dispersed.

They are suitable for use as:

• Contrast agents for biomedical imaging;

• Targeting magnetic particles to tumours for subsequent heat ablation treatment;

• For use in magnetic cell separation;

• For intra- and extracellular molecular capture and separation.

A patent has been applied for, EP Ref. No T-09-057.