The development of programmable molecular machines has taken an important step forward. Researchers at the Technical University of Munich (TUM) have developed an exceptionally reliable and stable DNA origami switch that can be controlled electrically and used to regulate molecular functions. The nanoswitch remained fully functional over several hundred thousand switching cycles. Several researchers from the Cluster of Excellence BioSysteM played a key role in the project.
The switch is based on DNA origami, a technique in which DNA strands are folded into precisely defined nanoscale structures. Using this approach, the team designed a DNA switch with two stable states. A short electrical pulse is sufficient to change the structure from one state to the other within milliseconds. Once switched, it remains in its new position without requiring any further energy input.
This represents an important step toward the development of molecular machines. Such systems must not only be switched in a controlled manner but also operate reliably over long periods. The new switch demonstrates exactly these properties. In the experiments, individual components remained stable for hours, exceeded 200,000 switching cycles and, in a second experimental setup, continued to switch reliably even after around one million activation events.
“With our design, we were able to demonstrate that a DNA-based switch can not only be controlled quickly and precisely, but is also exceptionally durable,” says Prof. Friedrich Simmel, Professor of Physics of Synthetic Biological Systems at the TUM School of Natural Sciences. “This makes it more realistic to use DNA-based components as functional elements of molecular machines in the future.”
The research team has already demonstrated two possible applications. In one experimental setup, the switch was coupled to gold nanorods, allowing an optical signal to be switched on and off depending on the position of the DNA switch. In a second experiment, the researchers used the switch to alternately expose or block a binding site for other DNA strands. This enabled them to control the speed of the binding process.
The study therefore presents more than just a single new nanocomponent. It also provides a basis for systematically investigating the durability, wear and potential failure mechanisms of molecular switches. First author Florian Rothfischer says: “In the future, electrically controlled DNA systems like these could become interesting for molecular information processing, optical nanodevices and the targeted control of chemical reactions.”
The experiments were carried out under controlled laboratory conditions using specialized measurement setups. The results demonstrate that the concept functions reliably under these conditions. However, further development will be required before potential technical applications outside laboratory environments become feasible.