Various chemical exchange systems exist in nature and are crucial in regulating important phenomena in biology and geochemistry. Attempts at replicating these using DNA nanotechnology have mainly focused on liquid-based systems. There exists no example of a DNA nanostructure that controls movement of molecules in the gas phase, leaving the potential of molecular robots to interact with different microenvironments unexplored. Taking inspiration from plant stomata, we propose a DNA origami polymer that facilitates light-inducible gas exchange through the membrane of a soap bubble.
The monomer is a square plate with a slit similar to a vending machine’s coin slot. To span the variable thickness of the membrane, monomers self-stack through shape complementarity, with the slits forming a central tunnel. The inside of the tunnel is lined with cholesterol to realize the hydrophobic environment required for gas transport. The structure has two distinct states that dictate whether gas molecules can pass or not: closed and open, the transition between which is controlled by DNA. When closed, the DNA strands form hairpins that cover the entirety of the tunnel, preventing gas flow. Due to their photoresponsivity, the hairpins unfurl under UV exposure, opening the whole tunnel for gas exchange.
Expansion of our structure’s functionality may enable nanorobots to perform biomimetic
photosynthesis, pH control of various environments, and even detection, capture, and subsequent
treatment of harmful gases.