Chiral Ru(ii) complexes act as a potential non-viral gene carrier for directional transportation to the nucleus and cytoplasm

Guanine-rich DNA sequences can spontaneously fold into four-stranded structures called G-quadruplexes (G4s). G4s have been identified extensively in the promoter regions of several proto-oncogenes, includingc-myc, as well as telomeres. G4s have attracted an increasing amount of attention in the field of nanotechnology because of their use as versatile building blocks of DNA-based nanostructures. In this study, we report the self-assembly ofc-mycG-quadruplex DNA controlled by a pair of chiral ruthenium(ii) complexes coordinated by 2-(4-phenyacetylenephenyl)-1H-imidazo[4,5f][1,10]phenanthroline (PBEPIP), ?-[Ru(bpy)(2)(PBEPIP)](ClO4)(2)(?-RM0627, bpy = bipyridine) and Delta-[Ru(bpy)(2)(PBEPIP)](ClO4)(2)(Delta-RM0627).?-RM0627could promote the high-order self-assembly ofc-mycG-quadruplex DNA into a nanowire structure, whereas Delta-RM0627could induce DNA condensation into G-quadruplex aggregates. Moreover,in vitrostudies on human liver carcinoma HepG2 cells showed that the nanowire ofc-mycG-quadruplex DNA promoted by?-RM0627could be localized in the nuclei of cells, whereas the nanoparticle ofc-mycG-quadruplex DNA generated by Delta-RM0627was taken up and localized in the cytoplasm. This study provides examples of the enantioselective self-assembly of G4 DNA molecules controlled by chiral ruthenium(ii) complexes and suggests the potential applications of assembled nanostructures as non-viral DNA vectors for gene therapy.