Magnetic Nanoparticles Fight Tumors

In years to come, drugs transported by magnetic particles could target and combat cancer cells much more effectively than in the past. In experiments on animals, physicians at the University Hospital of Erlangen, Germany, have demonstrated that chemotherapy of this kind is possible with practically no side-effects. They completely counteracted a tumor with one fifth of the usual drug dosages and without side-effects, because the agents were administered much more precisely than usual. Researchers from Siemens Corporate Technology (CT) supported the experiments by building a very small and powerful magnet. For the project "Local Chemotherapy with Magnetic Nanoparticles", the scientists PD Dr. Christoph Alexiou from the university clinic in Erlangen and Dr. Heinz-Werner Neumüller from CT have now been awarded the medical technology award of the "Health and Medicine in Erlangen Association" (Verein Gesundheit & Medizin).

The only treatment possible for tumors that cannot be surgically removed, because they are too close to blood vessels or have already formed metastases, for example, is to administer drugs that often have serious side-effects. Doctors want to use as little of an active agent as possible, and target it as well as possible, in order to protect healthy cells. One approach is "Magnetic Drug Targeting", in which magnetic particles roughly 100 nanometers in size transport an active agent. With a strong magnet, the particles are guided from outside into the target region of the tumor, and only there do they exert their toxic effect.

This requires magnets with highly non-uniform fields. In the past, such fields have usually been generated by large electromagnets weighing over 1.5 tonnes. Because of their weight, these magnets are permanently installed. Siemens researchers therefore designed and built a small, pivoting electromagnet that has an easily accessible pole tip and produces a large field gradient. The one-of-a-kind instrument weighs only 47 kilograms. This was made possible by the use of appropriate materials and a simulation-based optimization of the design.

Because of the huge reduction in weight and the optimized pole tip, the doctor can manipulate the new magnet very easily and position the pole tip precisely over the tumor. This makes it possible to safely treat even small cancerous ulcers. The research focuses on near-surface tumors like head, neck and skin carcinomas, and further pre-clinical studies are still needed. In the longer term, the physicians in Erlangen also hope to carry out clinical studies on patients. To help advance their research, they have placed an order with Siemens Corporate Technology for another magnet to be delivered in October.