DNA-Directed Artificial Light-Harvesting Antenna

Abstract

Designing and constructing multichromophoric, artificial light-harvesting antennas with controlled interchromophore distances, orientations, and defined donor-acceptor ratios to facilitate efficient unidirectional energy transfer is extremely challenging. Here, we demonstrate the assembly of a series of structurally well-defined artificial light-harvesting triads based on the principles of structural DNA nanotechnology. DNA nanotechnology offers addressable scaffolds for the organization of various functional molecules with nanometer scale spatial resolution. The triads are organized by a self-assembled seven-helix DNA bundle (7HB) into cyclic arrays of three distinct chromophores, reminiscent of natural photosynthetic systems. The scaffold accommodates a primary donor array (Py), secondary donor array (Cy3) and an acceptor (AF) with defined interchromophore distances. Steady-state fluorescence analyses of the triads revealed an efficient, stepwise funneling of the excitation energy from the primary donor array to the acceptor core through the intermediate donor. The efficiency of excitation energy transfer and the light-harvesting ability (antenna effect) of the triads was greatly affected by the relative ratio of the primary to the intermediate donors, as well as on the interchromophore distance. Time-resolved fluorescence analyses by time-correlated single-photon counting (TCSPC) and streak camera techniques further confirmed the cascading energy transfer processes on the picosecond time scale. Our results clearly show that DNA nanoscaffolds are promising templates for the design of artificial photonic antennas with structural characteristics that are ideal for the efficient harvesting and transport of energy.

Robust self-replication of combinatorial information via crystal growth and scission

“…Similarly, the method for crystal replication we have demonstrated could also be applied to the discovery of functional materials: DNA crystals can serve as templates for proteins, small molecules, and nanoparticles (42), allowing the use of this system for the exploration via directed evolution of photonic or plasmonic nanostructures (43,44) or of how the specific nanoscale arrangements of proteins gives rise to specific biological function (45). And while DNA crystals are more complex than most natural crystals, crystal growth processes and strong mechanical forces are varied and ubiquitous, suggesting the plausibility of a natural crystal growth process and environment that together support crystal information replication.…”

FRET efficiency and antenna effect in multi-color DNA origami-based light harvesting systems

“…[1][2][3][4][5] In the endeavor to harvest the sun light by mimicking the natural photosynthesis, articial light harvesting systems have been created, in which the excitation energy is channeled from multiple donor molecules to just a few or a single acceptor. [6][7][8][9][10] These articial light harvesting systems have been designed in one, 11 two 12 and three 13 dimensions. Apart from photosynthesis the concept of light harvesting is also exploited for analytical purposes to enhance the uorescence emission of luminescent probes and in this way improve the sensitivity of sensors.…”

“…DNA origami structures have been used to create highly sensitive SERS substrates by attaching gold nanoparticle dimers, [23][24][25] to analyze DNA strand breaks induced by low energy electrons 26,27 and UV photons 28 and to arrange different uo-rophores 29,29,30 at precise distances to create nanoscale photonic devices which can be used for example as photonic wires, 15,18 to resolve conformational changes of biomolecules, [31][32][33][34] as logic gates 35,36 and articial light harvesting complexes. 8,10,18 The light harvesting efficiency is in this context typically expressed as an antenna effect (AE), i.e. the intensity of A emission when D is excited compared to the A intensity when it is directly excited.…”

“…the intensity of A emission when D is excited compared to the A intensity when it is directly excited. 6,8,10,16,37,38 An antenna is therefore formed when AE is higher than 1, i.e. A is getting brighter by collecting light at lower wavelength compared to the direct excitation wavelength.…”

Sequential growth of long DNA strands with user-defined patterns for nanostructures and scaffolds

“…Extended DNA nanostructures have shown promise as structural scaffolds that can organize patterned arrays of cargo, with potential in plasmonics 25 , catalysis 26,27 , artificial light harvesting 28 and nanoelectronics 29,30 . These applications require fine control over the placement and order of specific functional groups, which can be challenging at the nanometre scale.…”