To implement a collision-based computer using DNA objects, we used DNA origami nanorobots as described previously. These robots…

“To implement a collision-based computer using DNA objects,
we used DNA origami nanorobots as described previously. These robots are controlled by a gate that opens in response to a correct combination of protein cues, which bind a sensing strand, typically an aptamer, and displace it from its complementary strand. Upon displacing the gate strands from each other, the robot undergoes a drastic conformational shift, exposing the payload inside it and making it available to engage target cells”

–http://life-sciences.biu.ac.il/files/life-sciences/media/nnano.2014.58.pdf