Utilizing HomoFRET to Extend DNA‐Scaffolded Photonic Networks and Increase Light‐Harvesting Capability

Abstract

hybridization allows functionalized elements, such as quantum dots, [3,4] gold nanoparticles, [5][6][7] and fluorophores [8,9] to be arranged with nanoscale precision at specific locations on DNA templates. The versatility of this approach allows for the creation of complex multidimensional shapes where the (collective) activity of pendant molecules can be evaluated in pursuit of new functionalities. Furthermore, commercial availability of synthetic DNA, along with a variety of open access design tools allow for the relatively rapid design and preparation of structural DNA templates. [10,11] Over the last decade, researchers have demonstrated a variety of DNA nanostructures that have potential for applications ranging from biosensors and biocomputing to energy harvesting. [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] For energy harvesting based applications in particular, the designs look to mimic the functional properties of light harvesting complexes from bacteria and green plants, exploiting Förster resonance energy transfer (FRET) as the underlying mechanism that moves and directs excitonic energy. [30,31] In these excitonic networks, FRET is typically between two different fluorophores (hetero-FRET) with differing excited state levels and its one-way downhill nature is used to control the directionality. [32][33][34] In order to make such devices widely applicable, an overarching and continuous functional goal is to increase their ability to harvest excitonic energy and then transfer it over multiple steps both across extended portions of the spectra and physical space.In pursuit of these same goals, we have explored a variety of DNA-based architectures displaying different densities and combinations of fluorophore types. [4,35] A purely linear doublestranded (ds) DNA scaffold displaying single copies of seven sequential donor-acceptor dyes manifested poor end-to-end energy transfer efficiency (E ee ) due to an intermediary dye acting as a strong energy sink rather than a viable relay. [36] An effective way to overcome this issue was demonstrated based on the use of DNA dendrimers. [36] These utilized AF488, Cy3, Cy3.5, Cy5, and Cy5.5 dyes assembled into sequential four or five-dye FRET cascades based on dendrimeric structures with 2:1, 3:1, and even 4:1 donor:acceptor ratios based on branching ratio. Evaluating the performance across all these assemblies revealed that although the 3:1 dendrimer performed the best, DNA-based photonic wires that exploit Förster resonance energy transfer (FRET) between pendant fluorophores to direct and focus excitonic energyhave high research interest due to their potential applications in light harvesting, biocomputing, and biosensing. One important goal with these structures is to increase their ability to harvest energy and then transfer it over multiple steps both across extended portions of the spectra and physical space. Toward these goals, incorporating extended homogeneous or homo-FRET sections into three unique FRET cascade DNA dendrimer ar...

Enhancement of Energy Transfer Efficiency with Structural Control of Multichromophore Light‐Harvesting Assembly

“…While MCSs tend to have inherent structural heterogeneity, the distributions of structural parameters of those systems were not considered in previous studies. [7,[28][29][30][31][32]37] Structural heterogeneity can originate from both (i) the rapid structural fluctuation of orientation factor and interchromophore distance around each of their average values and (ii) the static distribution of structural parameters such as D-A distance and orientation factor of all donors. To consider the structural heterogeneity of MCSs, we performed the simulations for calculating FRET in the model MCSs while considering two cases for each of Δ DA (and Δ DD ) and 2 , which are two major parameters that govern FRET , resulting in four cases in total.…”

Integrating DNA Photonic Wires into Light‐Harvesting Supramolecular Polymers

“…Different strategies have been developed to facilitate the processes of light harvesting and energy transfer. In particular, FRET efficiency can be significantly improved by increasing the maximal length of the photonic wires through a homo‐FRET mechanism . Alternatively, DNA photonic wires have been appended to quantum dots .…”

DNA-organized artificial LHCs – testing the limits of chromophore segmentation

“…[13][14][15][16][17][18][19][20][21][22] In such systems, light is collected by precisely arranged donor chromophores and the absorbed energy is transferred to a suitable acceptor. [23][24][25][26][27][28][29][30] The light-harvesting properties resulting from the supramolecular assembly of phenanthrene and pyrene molecules within the scaffold of the DNA duplexes was demonstrated before. 17 In this type of LHC, the phenanthrene units serve as donor chromophores.…”