Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
MIT-Harvard Center for Excitonics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Nat Mater. 2018 Feb;17(2):159-166. doi: 10.1038/nmat5033. Epub 2017 Nov 13.
Natural light-harvesting systems spatially organize densely packed chromophore aggregates using rigid protein scaffolds to achieve highly efficient, directed energy transfer. Here, we report a synthetic strategy using rigid DNA scaffolds to similarly program the spatial organization of densely packed, discrete clusters of cyanine dye aggregates with tunable absorption spectra and strongly coupled exciton dynamics present in natural light-harvesting systems. We first characterize the range of dye-aggregate sizes that can be templated spatially by A-tracts of B-form DNA while retaining coherent energy transfer. We then use structure-based modelling and quantum dynamics to guide the rational design of higher-order synthetic circuits consisting of multiple discrete dye aggregates within a DX-tile. These programmed circuits exhibit excitonic transport properties with prominent circular dichroism, superradiance, and fast delocalized exciton transfer, consistent with our quantum dynamics predictions. This bottom-up strategy offers a versatile approach to the rational design of strongly coupled excitonic circuits using spatially organized dye aggregates for use in coherent nanoscale energy transport, artificial light-harvesting, and nanophotonics.
自然光捕获系统使用刚性蛋白质支架在空间上组织密集堆积的发色团聚集体，以实现高效、定向的能量转移。在这里，我们报告了一种使用刚性 DNA 支架的合成策略，该策略可类似地对具有可调谐吸收光谱和在自然光捕获系统中存在的强耦合激子动力学的密集堆积的离散氰基染料聚集体进行空间组织。我们首先表征了可以在 B 型 DNA 的 A 链中空间模板化的染料聚集体的大小范围，同时保持相干能量转移。然后，我们使用基于结构的建模和量子动力学来指导由 DX 平铺内的多个离散染料聚集体组成的高阶合成电路的合理设计。这些编程的电路表现出具有突出圆二色性、超辐射和快速离域激子转移的激子输运特性，与我们的量子动力学预测一致。这种自下而上的策略为使用空间组织的染料聚集体来设计强耦合激子电路提供了一种通用方法，可用于相干纳米尺度能量传输、人工光捕获和纳米光子学。
