At the supramolecular level, scientists at the Technical University of Munich (TUM) have created an artificial motor with remarkable power. A small ribbon composed of unique chemicals powers this wind-up motor. This ribbon can push objects because it aligns itself and acts like a little fin when energy is applied. This is the first time that a chemical fuel is used to power it.
Up until now, only biology had been able to explain how chemical energy could be transformed into rotational energy at the supramolecular level, or for small things made up of many molecules. Archaea, or primitive bacteria, travel around by rotating their flagella, which are small structures that resemble fins, using the chemical fuel ATP. This procedure has not yet been replicated synthetically. Future applications of the new technology might include, for instance, nanorobots that can swim through blood arteries to find cancerous cells.
By adjusting the amount of fuel injected, the researchers were able to regulate the ribbons’ spinning speed. The structure of the ribbons’ molecular building blocks can also affect the rotational direction, which can be either clockwise or anticlockwise.
Chemical fuel drives the rotation
Several micrometers long and only a few nanometers wide, the peptide ribbons were created by a group under the direction of Brigitte and Christine Kriebisch and Job Boekhoven, a professor of supramolecular chemistry. They acquire structure and start to rotate when chemical fuel is introduced, when the ribbons curl up into tiny tubes. You may even watch this process in real time under a microscope.
By adjusting the amount of fuel injected, the researchers were able to regulate the ribbons’ spinning speed. The structure of the ribbons’ molecular building blocks can also affect the rotational direction, which can be either clockwise or anticlockwise. The study’s findings were released in the Chem journal.
Crawling on surfaces
In collaboration with Prof. Matthias Rief, TUM Professor of Molecular Biophysics, who develops cutting-edge optical measurement techniques, the researchers discovered that the ribbons move micrometer-sized objects by exerting sufficient force on their surroundings. One of the most crucial outcomes for real-world applications is figuring out the force.
For instance, tiny “micro-walkers” that can crawl across surfaces are produced when multiple revolving ribbons are joined at a central point. These micro-walkers may eventually be employed for medical purposes, including as delivering medications throughout the body, provided they undergo additional advancements. Because it would be detrimental to the organism, the fuel now in use is not appropriate for this.
