Magnetic nanoparticles that could diagnose, monitor and then treat the wide range of common illnesses and injuries are on the way, according to research reviewed in a special cluster of papers [O'Grady et al., J. Phys. D: Appl. Phys. (2009) 42, 220,301, 224,001, 224,002, 224,003]

Researchers are attaching nanoparticles to sensory units that can be dragged to a target site using an external magnetic field, such as that from a permanent magnet. Also magnetic nanoparticles represent a new generation of contrast agents for medical imaging technology using MRI. Similar magnetic nanoparticles could carry a therapeutic agent to the site, whether that is a drug or a gene therapy vector. Indeed, they are arming white blood cells with magnetic nanoparticles to seek out and destroy a tumour or using them to target nerve channels to restore an ailing heart.

Indeed, magnetic nanoparticles have been tested in vivo to remedy heart injury in rats and in humans to destroy, through heat generated by the action of an AC magnetic field, to which tumour cells are more sensitive. This technique has been used to treat a particularly severe form of brain cancer in fourteen patients. A similar approach has been used in treating prostate cancer.

Magnetic nanoparticles are usually produced from the common iron oxide magnetite and then given a biocompatible coating, which provides stability and protection for the chemical particles and their companions as they are moved through the body. The coating is often comprised of fatty acids. It is a relatively simple matter to attach sensory molecules, dye indicators, or a pharmaceutical to the magnetic nanoparticles using various anchor groups.

Catherine Berry from the Center for Cell Engineering in Glasgow, UK is author of one of the cluster of papers entitled “Progress in functionalization of magnetic nanoparticles for applications in biomedicine.”

“One of the main forerunners in the development of multifunctional particles is Theranostics [therapeutic diagnostics] is magnetic nanoparticles, “Berry says,” Following recent advances in nanotechnology, the composition, size, morphology and surface chemistry of particles can all be tailored which, in combination with their nanoscale magnetic phenomena, makes them highly desirable.”

Kevin O'Grady of the University of York, UK, affirms in an editorial that there have been significant advances in this area since the last cluster review in J.Phys.D. published in 2003. He points out that, “none of these applications could have been realized without dramatic progress beyond the state of the art in 2003 in the areas of particle synthesis and functionalization.”