15 research outputs found
Self-Assembly of a 2D DX Array
<p>Each rod represents a DNA duplex. The geometric complementarity represents the sequence complementarity of sticky ends.</p
Schematic Representation of Self-Assembly of a Sierpinski Triangle Based on XOR Operation
<p>The values in the bottom row are the inputs.</p
Basic DNA Structures for Self-Assembly
<p>(A) A four-arm junction and (B) its three-dimensional structure; (C) a DNA DX; and (D) a DNA TX.</p
A Smart DNA Tetrahedron That Isothermally Assembles or Dissociates in Response to the Solution pH Value Changes
This communication reports a DNA
tetrahedron whose self-assembly
is triggered by an acidic environment. The key element is the formation/dissociation
of a short, cytosine (C)-containing, DNA triplex. As the solution
pH value oscillates between 5.0 and 8.0, the DNA triplex will form
and dissociate that, in turn, leads to assembly or disassembly of
the DNA tetrahedron, which has been demonstrated by native polyacrylamide
gel electrophoresis (PAGE). We believe that such environment-responsive
behavior will be important for potential applications of DNA nanocages
such as on-demand drug release
Solution-Phase Synthesis of DNA Amphiphiles for DNA Micellar Assembly
Hydrophobic moieties of amphiphilic DNAs can help DNAs
penetrate
cell membranes, but the conjugation of hydrophobic moieties to DNAs
in solution phase remains challenging. Herein we report a solution-phase
synthesis method to conjugate hydrophobic molecules to DNAs. This
method is simple and efficient. The resulted amphiphilic DNAs can
spontaneously assemble into micelles, which may serve as nanocarriers
for cellular delivery of nucleic acids and water-insoluble drugs
Artificial, Parallel, Left-Handed DNA Helices
This communication reports an engineered DNA architecture.
It contains
multiple domains of half-turn-long, standard B-DNA duplexes. While
each helical domain is right-handed and its two component strands
are antiparallel, the global architecture is left-handed and the two
component DNA strands are oriented parallel to each other
Fluorescence and Energy Transfer in Dye-Labeled DNA Crystals
DNA
crystals make it possible to organize guest molecules into
specific periodic 3D patterns at the nanoscale, and thereby to create
novel macroscopic objects with potentially useful functionality. Here,
we describe the fluorescence and energy transfer properties of DNA
crystals that are self-assembled from DNA tensegrity triangles with
covalently attached Cy3 and Cy5 dyes. When compared to reference DNA
strands in solution, the fluorescence measurements indicate that the
dyes in the crystal experience a more homogeneous environment, resulting
in a 2-fold increase in Cy3 quantum yield and single-exponential Cy3
fluorescence decays. Energy transfer in a network of coupled Cy3 and
Cy5 dyes in the DNA crystal is demonstrated experimentally. Numerical
simulation finds the experiments to be consistent with a Förster
model of the dyes in the periodic crystalline environment, and particularly
if the transition dipoles are assumed random in orientation but static
on the time scale of the excitation decay
Self-Assembly of Responsive Multilayered DNA Nanocages
Here
we report the assembly of multilayered DNA nanocages. The
layers can be separated in response to a chemical cue, ATP. This is
an effort to increase the structural complexity of DNA nanocages.
The structures have been characterized by native polyacrylamide gel
electrophoresis, atomic force microscopy, and cryogenic electron microscopy.
We envision that the layer-by-layer assembly strategy used in this
study can be easily applied to other DNA nanocages to form Russian-doll-like
semisolid structures, while the chemically activated layer separation
makes a contribution to the development of “smart” DNA
nanocages
Reversibly Switching the Surface Porosity of a DNA Tetrahedron
The ability to reversibly switch the surface porosity
of nanocages would allow controllable matter transport in and out
of the nanocages. This would be a desirable property for many technological
applications, such as drug delivery. To achieve such capability, however,
is challenging. Herein we report a strategy for reversibly changing
the surface porosity of a self-assembled DNA nanocage (a DNA tetrahedron)
that is based on DNA hydridization and strand displacement. The involved
DNA nanostructures were thoroughly characterized by multiple techniques,
including polyacrylamide gel electrophoresis, dynamic light scattering,
atomic force microscopy, and cryogenic electron microscopy. This work
may lead to the design and construction of stimuli-responsive nanocages
that might find applications as smart materials
Effects of Structural Flexibility on the Kinetics of DNA Y‑Junction Assembly and Gelation
The
kinetics of DNA assembly is determined not only by temperature
but also by the flexibility of the DNA tiles. In this work, the flexibility
effect was studied with a model system of Y-junctions, which contain
single-stranded thymine (T) loops in the center. It was demonstrated
that the incorporation of a loop with only one thymine prominently
improved the assembly rate and tuned the final structure of the assembly,
whereas the incorporation of a loop of two thymines exhibited the
opposite effect. These observations could be explained by the conformation
adjustment rate and the intermotif binding strength. Increasing DNA
concentration hindered the conformational adjustment rate of DNA strands,
leading to the formation of hydrogels in which the network was connected
by ribbons. Therefore, the gel can be treated as a metastable state
during the phase transition