Research into DNA machines was pioneered in the late 1980s by Nadrian Seeman and co-workers from New York University.
This "selective stickiness" is a key advantage in the construction of DNA machines.
Strand A acts as a hinge so that the two "arms" — AB and AC — can move.
The DNA machine can be opened and closed repeatedly by cycling between strands D and E. These tweezers can be used for removing drugs from inside fullerenes as well as from a self assembled DNA tetrahedron.
The state of the device can be determined by measuring the separation between donor and acceptor fluorophores using FRET.