The particles are tracked with an MRI scanner, because their iron cores show up. When they are seen at at tumour site an electromagnetic pulse breaks the bond with the drug it is dragging. Blood vessels around tumours are generally widesr, so the particle size allows them to pass into tumours, without as much chance of the drug 'leaking' into other organs, and systems, and so prevent a number of side effects

This type of work is a sign that we are progressing.