DNA Walking Devices - DNA Nanotechnology: From Structure to Function - page 262

12.4 DNA Walking Devices in Other Forms

In addition to DNA hybridization and enzyme triggering, DNA walker could also be
powered by other fuels such as metal ions or pH. Willner and coworkers reported a
construction of two DNA machines activated by H C /OH or Hg2 C ions/cysteine as
external triggers [ 28 ]. The system consisted of four interlinked footholds, acting as
a track, and a walker, which was rigidified onto the track by several complementary
nucleic acids as connectors (Fig. 12.7 ). The connectors had two special designs,
one sequence of which responded to Hg2 C ions and made it dissociate with
former foothold and associate with another. The other special design of connectors
made it respond to H C , the result of which was the connector's formation of the
i-motif structure. Also the walker could move back under the stimuli of cysteine
or OH . The devices also could perform a reversible bipedal walking function or a
clockwise/anticlockwise stepper function on a DNA wheel.
All of the DNA walkers mentioned above were to show our ability to control
the DNA strands. But what are their applications? Liu and coworkers demonstrated
that a DNA mechanical device—a DNA walker moving along a DNA track—can be
used to perform a series of amine acylation reactions in a single solution without any

Fig. 12.7 inputs with its fluores-

cence analysis as the output (Reproduced from Ref. [ 28 ] with permission of John Wiley & Sons
Ltd.)

The bipedal walker activated by Hg2 C /cysteine and H C /OH