One of the key challenges in the fight against cancer is that potential treatments can often be worse than the disease. These treatments are so destructive that it takes a lot of effort to find one that will kill the cancer before it kills the patient. This means that treatments need to be as selective and controllable as possible.
The nanoparticle can be controlled by simply turning a magnetic field on and off. This means that its effects can be aimed at a specific area (if you have a focused magnetic field) and for a specific length of time. This level of targeting would reduce the severity of side-effects, allowing patients to receive stronger doses.
The zinc-doped iron oxide nanoparticle is attached to an antibody which binds tightly to death receptor 4, DR4. There are many copies of DR4 on the surface of the cancer cell and the nanoparticles can bind to them all, without any effect. When a magnetic field is applied, the nanoparticles move towards one another across the cell surface. This causes the DR4s to come together to form a complex. This is known as death-inducing signalling complex and it starts the chain reaction of events leading to apoptosis (programmed cell death).
This mechanism is actually a mimic of the one used by the TNF-related apoptosis inducing ligand (TRAIL). TRAIL has been investigated as a cancer treatment, however it degrades easily, a problem that is unlikely to affect the nanoparticles.
The paper, published in Nature Materials, looks at the effect on cancer cells in vitro and the effects on zebrafish. This research is still very much in the early stages and it will be quite some time before its effects on cancer in humans can be tested. However, it is a fine example of the novel ways that scientists are trying to fight cancer. It is the trickiest disease there is, and it will take a lot of ingenuity to tackle it.