Long- and short-ranged chiral interactions in DNA-assembled plasmonic chains

Abstract

Circular dichroism (CD) has long been used to trace chiral molecular states and changes of protein configurations. In recent years, chiral plasmonic nanostructures have shown potential for applications ranging from pathogen sensing to novel optical materials. The plasmonic coupling of the individual elements of such metallic structures is a crucial prerequisite to obtain sizeable CD signals. We here identify and implement various coupling entities—chiral and achiral—to demonstrate chiral transfer over distances close to 100 nm. The coupling is realized by an achiral nanosphere situated between a pair of gold nanorods that are arranged far apart but in a chiral fashion using DNA origami. The transmitter particle causes a strong enhancement of the CD response, the emergence of an additional chiral feature at the resonance frequency of the nanosphere, and a redshift of the longitudinal plasmonic resonance frequency of the nanorods. Matching numerical simulations elucidate the intricate chiral optical fields in complex architectures.

Local Growth Mediated by Plasmonic Hot Carriers: Chirality from Achiral Nanocrystals Using Circularly Polarized Light

“… 3 − 7 These can be fabricated through a variety of advanced fabrication techniques, using either top-down or bottom-up methods 5 , 8 to create chiral structures in two 9 − 14 and three dimensions 15 − 17 or assembling chiral complexes and aggregates in a solution, which is composed of biomolecules and initially nonchiral plasmonic NCs. 18 − 26 …”

Chiral plasmonic nanostructures: recent advances in their synthesis and applications

“…171 Very recently, Martens et al studied the long-and short-range chiral interactions in DNA-assembled plasmonic chains where the coupling was ensured by an achiral nanosphere situated between a pair of gold nanorods arranged far apart but in a chiral fashion using a DNA origami. 172 The transmitter particle caused strong enhancement of the CD response with the emergence of an additional chiral feature at the resonance frequency of the nanosphere. Lan et al have developed an approach for the tunable self-assembly of chiral DNA supramolecular architectures using a versatile DNA origami adapter.…”

Recent developments in the chiroptical properties of chiral plasmonic gold nanostructures: bioanalytical applications

“…The presence of gold nanosphere (Fig. 5a and c) in between Au NRs creates hotspots via near-field mechanism and produced enhanced CD response [39]. The interaction of these nanosystems with biomolecules for utilizing it as a biosensor is in chaos.…”