Concurrent formation of H- and J-aggregates of dyes with chiralities individually determined by G-quadruplex handedness

DNA templated dye assemblies pave an easy way to regulate the optical properties of molecular aggregates. G-quadruplexes (G4s) provide versatile DNA platforms for the dye assemblies since their foldings can be easily tuned by cation ions and sequences. In this work, we found that the G4 handedness can be used to control the aggregate chirality of a dye of 3,3'-diethylthiacarbocyanine (DiSC(2)(3)). The lefthanded and right-handed G4s can template the concurrent formation of the Jand H-aggregates of DiSC(2)(3) with emergence of the featured absorption spectra. However, the chiral J-aggregate of DiSC(2)(3) can be formed only on the left-handed G4s, while the chiral H-aggregate is otherwise grown only on the right-handed G4s, as confirmed by the induced circular dichroism (ICD) spectra with the characteristic splitting bands. Additionally, these G4s even at tens of nM level are efficient to produce these chiral aggregates, demonstrating the high sensitivity of G4s in creating these optically active dye assemblies. The possible growth sites of the aggregates are proposed by the sequence length dependent assemblies. Our work will provide a new way to control the chiral assemblies of dye aggregates via the G4 handedness. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

DNA templated dye assemblies can regulate the optical properties of molecular aggregates, with G-quadruplexes serving as versatile platforms for this purpose. The handedness of G4s can control the chirality of dye aggregates, with left-handed G4s facilitating the formation of J-aggregates and right-handed G4s favoring the growth of H-aggregates. The high sensitivity of G4s in creating chiral aggregates at low concentrations demonstrates their potential in controlling optically active dye assemblies.