Imaging and Positioning of Objects at the Nanoscale

Fluorescence resonance energy transfer represents a mechanism to transport light energy at the nano-scale as is exemplified by nature’s light harvesting complexes. Here we used DNA origami to arrange fluorophores that transport excited state energy from an input dye to an output dye. We demonstrate that energy transfer paths can be controlled on the single-molecule level by the presence of a “jumper”-dye that directs the excited state energy either to a red or to an IR output dye. We used four-color single-molecule FRET with alternating laser excitation to sort subpopulations and to visualize the control of energy transfer.