Selective control of reconfigurable plasmonic metamolecules

Selective configuration control of plasmonic nanostructures has remained challenging using both top-down and bottom-up approaches in the field of active plasmonics. Here we demonstrate the realization of DNA origami-based... [ view full abstract ]

Selective configuration control of plasmonic nanostructures has remained challenging using both top-down and bottom-up approaches in the field of active plasmonics. Here we demonstrate the realization of DNA origami-based reconfigurable plasmonic metamolecules which can respond to a wide range of pH changes in a programmable manner (1). Such programmability allows for selective reconfiguration of different plasmonic metamolecule species coexisting in solution through simple pH tuning. Importantly, this approach enables discrimination of chiral plasmonic quasi-enantiomers as well as arbitrary tuning of chiroptical effects with unprecedented degrees of freedom (see Fig 1). Our work outlines a new blueprint for implementation of advanced active plasmonic systems, in which individual structural species can be programmed to perform multiple tasks and functions.

Figure 1. Enantioselective control of the chiral plasmonic metamolecules. (a) Selective reconfiguration process of the designated quasi-enantiomers. Left: At low pHs, the LH (red) and RH (blue) metamolecules coexist in equimolar amounts. LH and RH metamolecules are quasi-enantiomers, i.e., they are enantiomers as plasmonics object but functionalized with DNA locks with different TAT content. The mixture is quasi-racemic. Middle: Upon a pH increase, one type of the quasi-enantiomers (blue) undergoes a locked to relaxed transition. Right: Further pH increases result in both quasi-enantiomers being in the relaxed state. (b) Relative CD dependence on pH for a mixture of two quasi-enantiomers. (c) Relative CD dependence on pH for a quasi-racemic mixture composed of four different metamolecules in equimolar amount.

REFERENCES

1.       Kuzyk, A. et al. “Selective control of reconfigurable chiral plasmonic metamolecules” Science Advances Vol. 3, e1602803,  2017.