Researchers found that magnetic nanoparticles could deliver heat directly to cancerous tumors, helping to increase the effectiveness of treatments such as radiotherapy or chemotherapy and reduce the necessary dose of the chemicals.
These microscopic balls of iron oxide heat up when exposed to magnetic fields, allowing them to apply heat to invasive tumors, the National Institute of Standards and Technology reported. Different particles deliver different doses of heat, and some heat up more quickly and easily than others, meaning the type of particle used in the treatment is important.
"You want to design your nanoparticles for the kind of cancer you're treating-whether it's localized or spread through the body," said NIST's Cindi Dennis. "The amount of electricity needed to create the field can be 100 kilowatts or more. That costs a lot of money, so we want to help engineer particles that will do the best job."
The research team looked at two kinds of iron-oxide nanoparticles that had different internal structures. In one, iron-oxide crystals were found to be stacked like a "brick wall," while the other boasted a more haphazard arrangement. They subjected both types of nanoparticles to an alternating magnetic field, and found the ones that were neatly stacked internally needed a stronger field to heat up.
The team found the different reactions were caused by regions of "different sizes and shapes" within the particles. These regions each hold "magnetic moments" that are uniform and point in the same direction, but the regions proved to misalign with each other. This behavior was extremely unexpected, and was found to strongly effect the particles' response to a magnetic field.
"Materials often behave unexpectedly on the nanoscale, and here we have another example of that. We expect it will help design better cancer treatments. A localized cancer could be treated with nanoparticles that give out lots of heat right away because the field can be focused on a small region," Dennis said.
The findings were published in a recent edition of the journal Advanced Functional Materials.
