If you coat colloids with bits of specific DNA, you can use temperature to programme shapes that self-assemble. This could form the basis for new biomimetic materials, according to the authors in Nature.

For complex structures, you often need many building blocks, a bit like the different pieces of a jigsaw puzzle. That is sometimes inconvenient; preferably you would like to build complex structures with few components. New York and Paris physicists Angus McMullen, Maitane Muñoz Basagoiti, Zorana Zeravcic and Jasna Brujic looked at biology to see how proteins fold and assemble, and found a way to make complex structures with just two building blocks and some DNA strands.

They made colloid droplets of polydimethylsiloxane in water, which they could label with fluorescent groups resulting in yellow and blue droplets. They then decorated the colloids with four different strands of DNA up to 20 base pairs long, which can interact with each other depending on temperature. Between 45 and 75°C, the droplets form a chain (backbone) of alternating blue and yellow colloids. Between 40 and 45°C activate