Using DNA nanostructures to harvest light and create energy transfer and harvesting systems

DNA is a biocompatible scaffold that allows for the design of a variety of nanostructures, from straightforward double stranded DNA to more complex DNA origami and 3-D structures. By modifying the structures, with dyes, nanoparticles, or enzymes, they can be used to create light harvesting and energy transfer systems. We have focused on using Forster resonance energy transfer (FRET) between organic fluorophores separated with nanometer precision based on the DNAs defined positioning. Using FRET theory we can control the direction of the energy flow and optimize the design parameters to increase the systems efficiency. The design parameters include fluorophore selection, separation, number, and orientation among others. Additionally the use of bioluminescence resonance energy transfer (BRET) allowed the use of chemical energy, as opposed to photonic, to activate the systems. Here we discuss a variety of systems, such as the longest reported DNA-based molecular photonic wires (> 30 nm), dendrimeric light harvesting systems, and semiconductor nanocrystals integrated systems where they act as both scaffold and antennae for the original excitation. Using a variety of techniques, a comparison of different types of structures as well as heterogeneous vs. homogenous FRET was realized.