One way to deliver nanomedicines is to inject particles directly into target tissue or infuse them into the blood stream for systemic administration. The other approach is to develop particles that can move or swim through a medium. And that is the hope of scientists from University of Bordeaux who developed a new propulsion system for nanoparticles, based on a property of metallic objects to grow on one end while dissolving on the other.
For the first time, two researchers from the Bordeaux Institute of Molecular Sciences (CNRS/ENSCBP/Universités Bordeaux 1 and 4) have shown that such motion can be induced using a novel approach called bipolar electrochemistry. The chemists apply an electric field to metallic objects, which then have a different charge at each end, namely a positive charge at one end and a negative charge at the opposite end. This polarization is high enough for opposing redox chemical reactions to occur on both sides. Thus, the object is oxidized and dissolves at one end, while a metal salt present in the solution is reduced and metal is deposited at the other end, causing the object to expand. This process finally induces self-regeneration of the object while causing it to move. The motion brought about in this way is directed towards one of the two electrodes. Speed can be controlled by varying the potential difference between the electrodes.
The advantage of this method is that no conventional fuel is required to induce this motion. Moreover, such micromotors could be adapted so as to push other objects in a predetermined direction and disappear once their task is completed.
Press release: New propulsion system for micro-objects …
Abstract in Journal of American Chemical Society: Propulsion of Microobjects by Dynamic Bipolar Self-Regeneration