C.M. Spillmann, S. Buckhout-White, M.G. Ancona, P.D. Cunningham, J.S. Melinger, E.R. Goldman, I.L. Medintz
Naval Research Laboratory, United States
pp. 139 - 142
Keywords: photonic wire, DNA, energy transfer, FRET, exciton, fluorophore
Energy manipulation at the nanoscale is a key requirement to develop next-generation nanotechnologies ranging from biosensing to light harvesting, yet the design rules of these nanoscale systems must first be optimized to accomplish their intended task. We utilize structural DNA technology to build a number of multidimensional nanoscaffolds to examine directed exciton transfer between chromophores and achieve both spectrally and spatially resolved energy delivery via Förster resonant energy transfer (FRET). Combining a DNA scaffold with pendent organic fluorophores creates an ideal nanoscale photonic wire construct with control over several variables, including the choice and spacing of adjacent fluorophores pairs and their respective branching ratio. We evaluate several increasingly complex DNA-based nanostructures to understand the key parameters required to optimize exciton delivery among organic fluorophores via FRET. Experimental evaluation and modelling confirm the most effective means of exciton delivery are achieved with multiple interacting FRET pathways versus several independent channels. We also investigate a series of split- and dual-rail DNA constructs with pendent organic fluorophores to understand how the local DNA environment and homoFRET pathways affect exciton delivery and find that exciton transfer is indeed strongly influenced by the local environment due that alters the photophysical performance of individual fluorophores.