Magnetic Nanoparticles

A bright future in medicine

Magnetic nanoparticles are minute. This 15 nm Fe3O4 magnetic nanoparticle has a diameter about 1/7000th that of a human hair.

And the future for mNPs looks even brighter. With the design of 'theranostic' molecules, mNPs will play a crucial role in developing one-stop tools to simultaneously diagnose, monitor and treat a wide range of common diseases and injuries.

Multifunctional particles, modeled on viruses such as those that cause flu and HIV, are being researched and developed to carry signal-generating sub-molecules and drugs to particular targets. A sprinkling of tiny mNPs, an application of external magnetic force, and presto! — a new means of confirming specific ailments or releasing drugs at exact points within a living system.

A landmark selection of review articles published this week in IOP Publishing's Journal of Physics D: Applied Physics, 'Progress in Applications of Magnetic Nanoparticles in Biomedicine', shows just how far magnetic nanoparticles for application in biomedicine have come and what exciting promise they hold for the future.

The magnetic component of the direction-giving nanoparticles is usually an iron-based compound called ferric oxide wrapped in a biocompatible envelope, for example, a light coating of friendly fatty acids to provide stability during the particle's journey through one's body. For biomedicine, the mNPs are extremely useful because you can add specific signal triggering molecules to identify certain conditions, or dyes to help in medical imaging, or therapeutic agents to zap a tumor.

Already mNPs have sparked interest after being attached to stem cells and used in vivo to remedy heart injury in rats. On humans, in 2007, Berlin's Charité Hospital used a technique which involved mNPs, called hyperthermia, to destroy a particularly severe form of brain cancer in 14 patients. The technique — which took advantage of the fact that tumor cells are more sensitive to temperature increases than normal cells — sent mNPs acting as nano-heaters directly against the inoperable tumors and essentially cooked them to death.

Dr Catherine Berry, one of the review paper's authors from the Centre for Cell Engineering in Glasgow, writes, "One of the main forerunners in the development of multifunctional particles for theranostics is magnetic nanoparticles. Following recent advances in nanotechnology, the composition, size, morphology and surface chemistry of particles can all be tailored which, in combination with their magnetic nanoscale phenomena, makes them highly desirable."

In other words, nMPs have a big future in medicine.