DNA-templated assembly of helical cyanine dye aggregates: a supramolecular chain polymerization.

Symmetrical cationic cyanine dyes assemble in cooperative fashion into helical supramolecular polymers using DNA as a template. The dyes assemble into cofacial dimers within the minor groove of the DNA and assembly of one dimer facilitates assembly of additional dimers directly adjacent to the first. Growth of the polymer ceases when the end of the DNA is reached or when the DNA sequence blocks dimerization of the dye. Thus, this process can be thought of as a supramolecular analogue of a chain polymerization. This Account describes how polymerization depends on the dye structure and DNA sequence and also summarizes the interesting optical properties exhibited by these chiral, helical materials.