Active DNA nanorotors on Nanopores
The hallmark of life is the rise of order from chaos. Such order is created and maintained by nano machinery composed of biological molecules known as proteins. They convert various types of energy sources into transmembrane ion gradients, then to ATP that can be used by other motor protiens. At center of this process is the ATP synthase that converts chemical potential from the ion (usually proton) gradient to ATP. Despite the success of building machinery at almost all scales that powers our society for centuries, making an artificial counterpart of such sophisticated nanometer-sized bio-motors remains challenging.
At the centre of such a quest is to build up the mechanism that allows artificial nano-machines to consume local free energy, like the biological motors, to perform work. Generations of scientists, including chemists, physicists, and synthetic biologies have been trying to answer this question from different perspectives. Scientists have built various type of molecular machines whose motion can be regulated, such as molecular switches, mechanically interlocking molecules, and self-assembled DNA structures.
However, most of these systems could only exhibit dynamics by the deliberate alteration of external experimental conditions, such as the addition of chemical compounds, periodic exposure to light, or the alternation of external electric fields. Modulation steps that are manually applied by the external operator sequentially pushing them into a new equilibrium state at every intervention. The biologists, on the other hand, try to repurpose the biological molecular motors that has built-in functions of consuming energy to other jobs, however, doesn’t teach us the knowledge of how to build such active nanomachines themselves.
Is there a way to design and build these type of active nanomachines from bottom up, with complete control and understanding, while enable their autonomous directional motion as their biological counter parts?
In our latest paper in Nature Physics, I together with a team of scientists from Cees Dekker’s group, Hendrik Diets’s group (TU Munich, Germany), Ramin Golestanian’s group (Göttingen, Germany) joined the forces, provided a bran-new solution: DNA origami active rotor powered by nanoscale flows.
In this paper, we explored this bran-new energy transduction mechanism using a minimalistic DNA origami structure, essentially an elastic rod made out of DNA. The Elastic DNA rod docks onto a nanoscale opening in a solids-state membrane, self-organise into a chiral shape because of its mechanical properties, and start autonomously converting transmembrane ion- or electrical potential into rotary work.
This is also the first proof of concept work where we show that a nanoscale flow from nanopores can but coupled onto chiral DNA origami structures, making them active nano rotary machines. With this knowledge, people can start design a whole new kind of nanomachines (see our most recent preprint on a designed DNA turbine). It also opens up the door towards building nanoscale engines in physiologically relevant environments, a critical step towards active nanorobot that can perform complex task in life.
Realated post: DNA nanoturbine