All things truly come full circle as scientists take child’s play to its tiniest and most complex level.
Using Nanoscale building blocks and DNA “glue,” scientists have discovered how to construct 3D "superlattice" multicomponent nanoparticle arrays.
The discovery, first published in Nature Communications, is considered a step toward designing predictable composite materials for applications in medicine, catalysis and other energy technologies.
Each array’s arrangement is determined by the shapes of the building blocks used. Blocks are held together by strands of DNA that can attract or resist other blocks, allowing scientists to manipulate arrangements.
"If we want to take advantage of the promising properties of nanoparticles, we need to be able to reliably incorporate them into larger-scale composite materials for real-world applications," said physicist Oleg Gang, lead researcher at Brookhaven's Center for Functional Nanomaterials (CFN), a DOE Office of Science User Facility.
Gang has previously used complementary DNA tethers attached to nanoparticles to guide the assembly of a range of arrays and structures. This new work explores particle shape as a means of controlling the direction of these connections to achieve long-range order in large-scale assemblies and clusters.
Complementary and non-complementary DNA tethers were also used to manipulate the direction of connections, to attract and repel other particles respectively."The DNA permits us to enforce rules: spheres attract cubes (mutually); spheres do not attract spheres; and cubes do not attract cubes," Gang said. "This breaks the conventional packing tendency and allows for the system to self-assemble into an alternating array of cubes and spheres, where each cube is surrounded by six spheres (one to a face) and each sphere is surrounded by six cubes." Using octahedral blocks instead of cubes achieved a different arrangement, with one sphere binding to each of the blocks' eight triangular facets.
Further experiments with different types of DNA tethers proved flexible DNA strands were essential to pairing more unique particle shapes.
"The flexible DNA shells 'soften' the particles, which allows them to fit into arrangements where the shapes do not match geometrically," said Fang Lu, the lead author of the publication.
Excessive softness can result in unnecessary particle freedom, which can ruin a perfect lattice, she added.
"Ultimately, this work shows that large-scale binary lattices can be formed in a predictable manner using this approach," Gang said. "Given that our approach does not depend on the particular particle's material and the large variety of particle shapes available-many more than in a child's building block play set-we have the potential to create many diverse types of new nanomaterials."
What real world implications could this have? If the technology could create a new class of low cost catalysts, the implications could be big for the chemical industry and emission reducing green technologies.
For more information click here.
Let us know what you think in the comments below.