Imagine a small car with a nanomagnetic structure that can propel the human body (Individually Characterized biological vehicles) through an external magnetic field. Upon arrival at the destination, the car can release drugs or heat cancer cells without affecting healthy tissue. Scientists in various fields are working on this vision.
A multidisciplinary research group at the Universidad del País Vasco, Leioa, Spain, is researching the talents of so-called magnetotactic bacteria, which have the surprising ability to produce iron oxide oxide nanoparticles in their cells. These particles, about 50 nanometers in diameter (100 times smaller than blood cells), regulate the bacteria inside the chain. The Spanish team followed the idea of using such “magnetic bacteria” (Individually Characterized biological vehicles) as magnetic hyperthermic agents in cancer treatment: transferred to the cancer side, magnetic nanostructures were instead heated in external fields to burn cancer cells.
Today, researchers are working with a group of physicists led by Sergio Valencia at HZB to study these magnetic properties in detail. The success of all these applications depends on the magnetic properties of the individual nanomagnets. But because the signals coming from these super small magnetic structures are so weak, it is necessary to average the values across thousands of structures to get meaningful data.
Average amounts are not enough
Until now, these average values have only been measurable, which places certain design limitations on the nanomagnet applications themselves. But that has changed now. The Spanish physicist Lourdes Marcano came up with a new approach. “Now we can get accurate information about the magnetic properties of several individual nanomagnets at the same time,” he said.
Magnetic anisotropy for each particle
The method allows the measurement of magnetic properties of individual magnetic nanostructures, even if they are embedded in biological entities. The magnetic imaging of the MAXYMUS of BESSY II scanning X-ray microscope using theoretical simulations provides information on the so-called magnetic anisotropy of each nanoparticle in the microscope’s field of view. The method has been proven by determining the magnetic anisotropy of magnetic nanoparticles inside a bacterium. The magnetic anisotropy is an important parameter for controlling and steering magnetic nanoparticles as it describes how a magnetic nanoparticle reacts to external magnetic fields applied at an arbitrary direction.
Future standard lab technique
“Actually, magnetic imaging of magnetic nanoparticles inside a biological cell with enough spatial resolution requires the use of X-ray microscopes. Unfortunately, this is only possible at large scale research facilities, like BESSY II, providing sufficiently intense X-ray radiation. In the future, however, with the development of compact plasma X-ray sources, this method could become a standard laboratory technique,” says Sergio Valencia. The study was published in ACS Nano.
