DNA nanotechnology enables straightforward fabrication
of user-defined
and nanometer-precise templates for a cornucopia of different uses.
To date, most of these DNA assemblies have been static, but dynamic
structures are increasingly coming into view. The programmability
of DNA not only allows for encoding of the DNA object shape but also
it may be equally used in defining the mechanism of action and the
type of stimuli-responsiveness of the dynamic structures. However,
these “robotic” features of DNA nanostructures are usually
demonstrated for only small, discrete, and device-like objects rather
than for collectively behaving higher-order systems. Here, we show
how a large-scale, two-dimensional (2D) and pH-responsive DNA origami-based
lattice can be assembled into two different configurations (“open”
and “closed” states) on a mica substrate and further
switched from one to the other distinct state upon a pH change of
the surrounding solution. The control over these two configurations
is achieved by equipping the arms of the lattice-forming DNA origami
units with “pH-latches” that form Hoogsteen-type triplexes
at low pH. In short, we demonstrate how the electrostatic control
over the adhesion and mobility of the DNA origami units on the surface
can be used both in the large lattice formation (with the help of
directed polymerization) and in the conformational switching of the
whole lattice. To further emphasize the feasibility of the method,
we also demonstrate the formation of pH-responsive 2D gold nanoparticle
lattices. We believe this work can bridge the nanometer-precise DNA
origami templates and higher-order large-scale systems with the stimuli-induced
dynamicity.