NANOPARTICLE ASSEMBLY Made to order

Several researchers have investigated the DNA-mediated assembly of crystal structures from non-spherical gold nanoparticles. A team of researchers led by C. A. Mirkin have synthetically realized the assembly of various anisotropic nanoparticles into ordered arrangements. They showed that anisotropic nanostructures initially form disordered aggregates and then, on thermal annealing, form ordered lattice structures. Another team is able to self-assemble hexagonal packing of gold rods, columns of triangular prisms and face-centered-cubic crystals of rhombic dodecahedrons. They also obtained both body-centered-cubic and face-centered-cubic crystals of gold octahedrons depending on the length of the DNA linkers, demonstrating the exciting possibility of customizing both the crystal structure and the lattice constants by simply changing the length of the DNA. They showed that the face-centered-cubic structure formed at long DNA linker lengths results from the increased flexibility of the longer DNA.