Magnetic fields control "nanorackets"
NanoNewsNet based on Radboud University materials: Magnetic field opens and closes nanovesicleChemists and physicists from the St. Radbod University of Nijmegen (Netherlands) have learned how to open and close nanoparticles using magnets.
This process is reproducible and can be controlled remotely, allowing, for example, the targeted transport of drugs in the body.
The idea of the scientists is to create nanos for the targeted transportation of medicines. The interim results of their study are published in the open access journal Nature Communications (van Rhee et al., Polymersome magneto-valves for reversible capture and release of nanoparticles).
Experimental nanobubbles (polymersomes) are assembled from diamagnetic amphiphilic block copolymers with highly anisotropic magnetic sensitivity and look like the smallest cup-shaped structures. They have already managed to be loaded with medicines and opened far from the injection site. But this was done using a chemical process, for example, osmosis. Researchers from the Institute of Molecules and Materials (Institute for Molecules and Materials) of Radbod University have proven the effectiveness of another method.
They stretched the bubble by aligning the molecules of its wall using strong magnets. Since the strength of the magnetic field is strictly related to the size of the bubbles, the control of deformation is facilitated. Thus, for the first time, scientists managed to make this process reversible: without a magnetic field, the bubbles are closed and open when it is turned on. After disabling the field, they return to the closed state.
Without magnetic field (0 T, left), bubbles
they have a small hole. In a strong
magnetic field (20 T), they are deformed,
as a result, a large hole is formed.
(Photo: Radboud University Nijmegen)
"Our fellow chemists recently published an article about a kind of nanorackets – bubbles that move due to the ejection of combustion products. At first, we only wanted to see if it was possible to give the movement of these rockets a certain direction using magnetic fields, but to our surprise, during these experiments, bubbles opened. This gave a start to our research," Peter Christianen tells about his work.
"Suppose you fill a vial with fuel and medicines, and then move it, creating a small hole that allows only fuel to escape. After that, you can unload the remaining cargo at the destination," explains how, ultimately, these two areas of research can be combined, chemist Daniela Wilson (Daniela Wilson).
Without a magnetic field, the bubble is closed (1),
and when it is turned on, it opens (2) and can be loaded.
After disabling the field, the bubble returns to the closed state.
When the magnetic field increases, it opens again, releasing its load (3 and 4).
(Fig. Radboud University Nijmegen)
However, the new method still requires fine tuning. Scientists will try to find out to what extent the bubble is deformed by a magnetic field of a certain strength. In addition, they are going to experiment with different types of molecules of its walls.
"The bubbles we use now are unsuitable for use in the human body, and we are looking for suitable molecules. In addition, we hope to find materials for which the same effect is possible with a weaker magnetic field, such as in MRI. Then this technology can be used in clinics, using MRI scanners for this purpose. In any case, the first step has been taken: we have demonstrated that the method works," adds Wilson.
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