Controlled assembly of mesoscale structures using DNA as molecular bridges.

Mesoscale polyhedral structures from binary mixtures of microspheres of specific size ratios were prepared by using DNA as a molecular bridge. Carboxy-modified polystyrene beads were decorated with fluorescently labeled single-stranded DNA via carboxydiimide chemistry. Fluorescent resonance electron transfer in a confocal microscopy setting was utilized to corroborate DNA hybridization. Tetrahedrons were made by combining DNA-containing 0.818 and 0.211 mum beads, while octahedrons were obtained by bridging 0.818 and 0.364 mum beads. Confocal data in the reflection mode and SEM provide evidence for the formation of mesoscale building blocks.