In this presentation we describe the self-assembly of supramolecular DNA lattices formed from the hybridization of metal-centered building blocks each containing multiple DNA "arms." Lattices differ fundamentally from DNA dendrimers or other DNA assemblies since each monomer building block attaches to the growing supramolecular lattice at more than one defined site. The result of lattice assembly is a regular array of DNA sequences, similar to a macroscopic crystal. In these designs of metal-centered lattices the metal ligand complex functions as a central "hub" and permits the attachment of two, four, or six DNA arms. The lattices formed from these building blocks will be linear, tetrahedral or octahedral, respectively (for the latter, see below). Lattices formed from monomers containing four or six DNA arms will be three-dimensional structures. Monomers are synthesized by a modification of conventional solid-phase based DNA synthesis. Assembly of defined structures or high molecular weight lattices is monitored by gel analyses.
In the simplest approach to lattice formation there is one building block with multiple identical and self-complementary DNA sequences. A more general system, as described in this presentation uses two building blocks with complementary DNA arms to generate lattices of virtually any desired sequence. The ligand present in the monomers also provides a method of assembling an array of metal centers precisely positioned by the DNA "spacers." Variations in the DNA sequence of the monomers should permit the incorporation of multi-component protein complexes, ligands, or other nucleic acids by binding to the DNA scaffold of the lattice. In addition to sequence composition and the properties of the metal center, sequence length also impacts the nature of the assembly; the longer the sequences, the larger the pores present in the lattice. Nanometer sized pores can be easily imagined. These metal-centered assemblies, DNA sequence, and/or pore size provide entry into new types of ordered and self-assembled biomaterials.