Self-Assembled DNA-Inorganic Nanoparticle Structures - DNA Nanotechnology: From Structure to Function - page 193

9.4 3-D Ordered Arrangements of Nanoparticles

Mediated by DNA

3-D nanoarchitectures with precise control in particle size, interparticle separation
and structure symmetry may exhibit novel optical, electronic, and magnetic proper-
ties that play important roles in a wide range of applications. Most interestingly,
they supply a robust structural platform for studying particle-molecule and/or
interparticle interactions.
The strategy that exploits the DNA mono-functionalized AuNPs as building
blocks mentioned above not only was applied in construction of dimeric and/or
trimeric structures but in assembly of complex 3-D nanoarchitectures. Alivisatos et
al. extended this strategy to build pyramidal grouping of AuNPs [ 49 ]. They modified
four sets of AuNPs with different single-stranded DNA, each of which travels
through three pyramid sides and traces out one face of the pyramid (Fig. 9.7 a). And
each third of each strand is complimentary to a third of each of the other strands. The
base-pair hybridization between these strands organized AuNPs into 3-D pyramidal
nanostructure as a result. Base sequence programmability is fully exploited in this
DNA-mediated assembly of mono-functionalized gold nanoparticles, whereas the
deliberate control in the geometry of the resulting nanoarchitecture is intrinsically
limited by the DNA self-assembled geometry. More sophisticated nanoarchitectures
will be constructed through DNA-based assembly strategy if the NPs are asymmetri-
cally functionalized with DNA strand and thereby have bifacial surface property that
allows for highly directional assembly. Mirkin reported a strategy to functionalize an
AuNP with two different DNA strands asymmetrically by using a magnetic sphere
as a geometric restriction template [ 50 ]. These asymmetric functionalized AuNPs
are subsequent assembled into cat paw, satellite, and dendrimer-like structures.
Lu achieved asymmetrically functionalized NPs with DNA by using Janus NPs as
building blocks that have two different hemispheres naturally [ 51 ].
DNA origami, arising from its spatially addressable structure, was also utilized
as template for directing the programmable assembly of nanoparticles into 3-D
nanostructures. Liedl and coworkers designed a DNA origami 24-helix bundle
that has nine helically arranged attachment sites [ 52 ]. The AuNPs of 10 nm in
size covered with DNA were hybridized with the complimentary DNA probes in
the origami (Fig. 9.7 b), thereby were assembled into helical nanoarchitectures.

Fig. 9.6 (continued) two single carbon nanotubes as a cross-junction structure. ( e ) Fabrication
process of QDs nanopatterns on DNA origami templates and corresponding AFM images (Part
( a ) reproduced from Ref. [ 12 ] with permission of John Wiley & Sons Ltd. Part ( b ) reproduced
from Ref. [ 45 ] with permission of John Wiley & Sons Ltd. Part ( c ) reprinted with permission
from Ref. [ 46 ]. Copyright 2011 American Chemical Society. Part ( d ) reprinted with permission
from Macmillan Publishers Ltd: Ref. [ 47 ], copyright 2010. Part ( e ) reproduced from Ref. [ 48 ] with
permission of John Wiley & Sons Ltd.)