Are Magnetic Nanoparticles Suitable for Cancer Therapy?

The particles, released into the blood stream, serve as a carrier for specific drugs; they then course freely through the blood stream, until they fall under the influence of a targeting magnetic field, which holds them on to the tumor where the loaded drug releases its active agent. Besides the pharmaceutical effect, as an added bonus the electromagnetic field generates heat in the accumulated particles, destroying the tumor. Both therapeutic concepts have the advantage of largely avoiding undesired side effects on healthy tissue. In an attempt to find and investigate appropriate nanoparticles, the researchers at PTB developed magnetorelaxometry, a measurement technique in which the nanoparticles are magnetized for a brief period by a strong magnetic field in order to measure their relaxation after the switch-off of the field by means of superconducting quantum interferometers (SQUIDs).

Following magnetorelaxometry, conclusions on the nanoparticle aggregation behavior can then be drawn. Results in other fields have already served to optimize the paint drying process in the automobile industry, the thermal design of furnaces, as well as the monitoring of glass forming processes. In examining the cancer fighting potential of nanoparticles, conclusions can be drawn from measurements of their suspensions in serum or in whole blood. For example, it could be shown that certain nanoparticles in the blood serum form clusters with a diameter of up to 200 nanometers; since this a clear indication of aggregation, such nanoparticles would not appear to be suitable candidates for such therapy.

However, the high technical effort connected with the use of helium-cooled magnetic field sensors is still standing in the way of using this method routinely in practice. In a joint project with Braunschweig Technical University (Germany), the researchers at PTB are attempting to transfer the technique to a simpler technology, based on fluxgate magnetometers.


Related Links:
Physikalisch-Technische Bundesanstalt
Braunschweig Technical University