Luminescent Ruthenium(II) Polypyridyl Complexes as Nonviral Carriers for DNA Delivery

Metallohelix vectors for efficient gene delivery via cationic DNA nanoparticles

The design of efficient and safe gene delivery vehicles remains a major challenge for the application of gene therapy. Of the many reported gene delivery systems, metal complexes with high affinity for nucleic acids are emerging as an attractive option. We have discovered that certain metallohelices-optically pure, self-assembling triple-stranded arrays of fully encapsulated Fe-act as nonviral DNA delivery vectors capable of mediating efficient gene transfection. They induce formation of globular DNA particles which protect the DNA from degradation by various restriction endonucleases, are of suitable size and electrostatic potential for efficient membrane transport and are successfully processed by cells. The activity is highly structure-dependent-compact and shorter metallohelix enantiomers are far less efficient than less compact and longer enantiomers.

N, Revankar VK, Lokanath NK, Pinjari RV, Kumbar V, Bhat K. Synthesis, structural characterization and biological properties of cyclometalated iridium(iii) complexes containing [1,2,5]-thiadiazolo-[3,4-f]-[1,10]-phenanthroline

The iridium(iii) complexes have been structurally characterised and their interaction with DNA, cytotoxicity and cellular uptake have been investigated.

Tris-heteroleptic ruthenium(II) polypyridyl complexes: Synthesis, structural characterization, photophysical, electrochemistry and biological properties

Three water-soluble tris-heteroleptic ruthenium(II) polypyridyl complexes [Ru(bpy)(phen)(bpg)]²⁺ (1), [Ru(bpy)(dppz)(bpg)]²⁺ (2), and [Ru(phen)(dppz)(bpg)]²⁺ (3) (where bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline, dppz = dipyrido[3,2-a:2',3'-c] phenazine, bpg = 4b,5,7,7a-tetrahydro-4b,7a-epiminomethanoimino-6H-imidazo[4,5-f] [1,10] phenanthroline-6,13-dione) have been synthesized and characterized. Molecular structures of complexes 1 and 3 are confirmed by single crystal X-ray structure determination. Interaction of complexes 1-3 with DNA is explored by various spectroscopic techniques. The complexes 1-3 show solvent dependent photophysical properties. Complexes 2 and 3 show extensive "molecular light switch" effect for DNA. The complexes 1-3 are low toxic towards HeLa (human cervical cancer) and HL-60 (human promyelocytic leukemia) cell lines. Further, the cellular uptake of complexes 2 and 3 by cells shows that complexes mainly localised on the nucleus of the cells.

Optically active triptycenes containing hexa-peri-hexabenzocoronene units

We have successfully generated both left- and right-handed circularly polarized light using crystals prepared from a racemic triptycene containing hexa-peri-hexabenzocoronene units.

Ruthenium-containing supramolecular nanoparticles based on bipyridine-modified cyclodextrin and adamantyl PEI with DNA condensation properties

Exploring safe and highly efficient gene carriers made from biocompatible constituents has great prospects for clinical gene therapy. Here, a supramolecular gene delivery system was readily constructed by assembling adamantyl-modified polyethylenimine (PEI-Ada) units with a versatile ruthenium bipyridine-modified cyclodextrin (Ru-CD) through host-guest interactions. The photophysical and morphological features of the PEI-Ada@Ru-CD nanoparticles were systematically characterized by techniques including UV-vis absorption spectroscopy, fluorescence spectroscopy, transmission electron microscopy, dynamic light scattering, and zeta potential experiments. The small size and suitably positive zeta potential of the nanoparticles facilitated their cellular uptake and gene transfection. As expected, DNA interaction studies, which were performed using agarose gel electrophoresis and atomic force microscopy, showed that the ability of the nanoparticles to condense DNA was higher than that of the gold standard, i.e., PEI, at low N/P ratios. The design of these ruthenium-containing supramolecular nanoparticles based on bipyridine-modified cyclodextrin and adamantyl PEI has great prospects in the development of gene delivery vehicles.

Phosphorescent cyclometalated iridium(iii) complexes: synthesis, photophysics, DNA interaction, cellular internalization, and cytotoxic activity

Phosphorescent cyclometalated quinoline-appended iridium(iii) complexes undergo rapid cellular internalization and accumulate throughout the cell.

Chiral triptycene-pyrene π-conjugated chromophores with circularly polarized luminescence

Novel chiral triptycenes showing circularly polarized luminescence based on the supramolecular chirality induced in the hydrogen-bonded aggregate have been developed.

Efficient DNA condensation by ruthenium(ii) polypyridyl complexes containing triptycenyl functionalized 1,10-phenanthroline

A series of luminescent ruthenium(ii) polypyridyl complexes containing an extended aromatic moiety derived from triptycene and 1,10-phenanthroline were synthesized and their photophysical, theoretical, and biological properties were investigated.