DNA G-Quadruplexes as a Template To Direct Cyanine Dyes To Form H-Aggregates and Application of the Self-Assembly Entity as a New G-Quadruplexes Ligands Screening Platform

The organization of organic chromophores to form H-/J-aggregates can result in new biomaterials with unique properties and applications. DNA-template self-assembly is one of the most attractive strategies to guide the formation of chromophore aggregates. However, the DNA templates are mainly limited to canonical nucleic acids structures [single (ss)- and double (ds)-stranded DNA]. DNA G-quadruplexes (GQs), with distinct and various structural features, were rarely exploited to guide the formation of dye aggregates. In this study, we present the spontaneous assembly of cyanine dye IR786 to form H-aggregates on DNA GQs exclusively, but no IR786 aggregates formed by adjusting the experimental parameters or on ss-/ds-DNA. Furthermore, on the basis of the assembly entity (GQs-IR786), an adaptive GQs-FID (fluorescence intercalator displacement) assay for screening of GQs ligands was developed. In contrast with the existing GQs-FID screening schemes, this assay displayed attractive performance in many aspects (such as turn-on signal output, broad screening range, and time saving). All these results have undoubtedly demonstrated the great values of DNA GQs as a template to guide the formation of dye aggregates. We hope that more GQs structures would be exploited as templates to expand the variety of functional materials in the future. Moreover, the specifically formed H-aggregates of IR786 on GQs are significant for GQs' detection, and we also expect that this GQs-FID assay would be further studied and finally applied to screen GQs ligands in a high-throughput manner in the future.