Bole Yu

Highly Charged Ruthenium(II) Polypyridyl Complexes as Lysosome‐Localized Photosensitizers for Two‐Photon Photodynamic Therapy

Photodynamic therapy (PDT) is a noninvasive medical technique that has received increasing attention over the last years and been applied for the treatment of certain types of cancer. However, the currently clinically used PDT agents have several limitations, such as low water solubility, poor photostability, and limited selectivity towards cancer cells, aside from having very low two-photon cross-sections around 800 nm, which limits their potential use in TP-PDT. To tackle these drawbacks, three highly positively charged ruthenium(II) polypyridyl complexes were synthesized. These complexes selectively localize in the lysosomes, an ideal localization for PDT purposes. One of these complexes showed an impressive phototoxicity index upon irradiation at 800 nm in 3D HeLa multicellular tumor spheroids and thus holds great promise for applications in two-photon photodynamic therapy.

Targeting Nucleus DNA with a Cyclometalated Dipyridophenazineruthenium(II) Complex

Recently, coordinatively saturated and substitutionally inert Ru(II) complexes have been investigated as anticancer agents. Herein a cyclometalated Ru(II) complex, [Ru(bpy)(phpy)(dppz)](+), was found to be rapidly taken up by cancer cells, and nearly 90% of the complex accumulated in the nuclei of cancer cells after a 2 h incubation. The anticancer activity of this complex was screened against a panel of cancer cell lines. Remarkably, it exhibited IC50 values that were an order of magnitude lower than those of cisplatin. This complex also displayed potencies superior to those of cisplatin against 3D tumor spheroids. Further studies revealed that the high DNA binding affinity of [Ru(bpy)(phpy)(dppz)](+) resulted in effective disruption of the binding of transcription factor NF-κB to DNA sequences, thereby inhibiting cellular transcription and leading to irreversible cancer cell apoptosis. Our work provides new insights into understanding the biological interactions and anticancer molecular mechanisms of DNA-specific Ru(II) polypyridyl complexes.

DNA Condensation Induced by Ruthenium(II) Polypyridyl Complexes [Ru(bpy)2(PIPSH)]2+ and [Ru(bpy)2(PIPNH)]2+

Two novel DNA-intercalating ruthenium(II) complexes, [Ru(bpy)(2)(PIPSH)](2+) and [Ru(bpy)(2)(PIPNH)](2+), have been synthesized and characterized. Gel retardation assay, atomic force microscopy, and dynamic light scattering studies show that both complexes can induce the condensation of originally circular plasmid pBR322 DNA to particulate structures under neutral conditions.

Synthesis, characterization and biological evaluation of mixed-ligand ruthenium(II) complexes for photodynamic therapy

This study investigated the photodynamic therapy (PDT) and anticancer activity of mixed ligand Ru(ii) terpyridyl complexes (Ru1-Ru3). The photophysical and photochemical properties, hydrophobic properties, DNA binding and DNA transcription inhibition abilities, cell uptake efficiency, cellular localization and photo-cytotoxicity were investigated. Ru1-Ru3 exhibited red luminescence between 670-710 nm and functioned as photo-sensitizers (PSs) by generating both singlet oxygen and radical ions. Without light activation, Ru1-Ru3 were located at the cytoplasm and were nontoxic to cells. However, upon light activation, Ru1-Ru3 exhibited significant photocytotoxicity. After PDT treatment, mitochondria alteration and nuclear membrane disruption occurred, which resulted in relocalization of the complexes from the cytoplasm to the nucleus. Moreover, high cellular oxidative stress caused cell necrocytosis after PDT treatment.

A dendritic nano-sized hexanuclear ruthenium(II) complex as a one- and two-photon luminescent tracking non-viral gene vector

Fluorescent tracking gene delivery could provide us with a better understanding of the critical steps in the transfection process. However, for in vivo tracking applications, a small diameter (<10 nm) is one of the rigorous requirements for tracking vectors. Herein, we have demonstrated a new paradigm for two-photon tracking gene delivery based on a dendritic nano-sized hexanuclear ruthenium(II) polypyridyl complex. Because this metallodendrimer has a multivalent periphery, the complex, which is 6.1 nm, showed high stability and excellent dispersibility and could stepwise condense DNA in vitro. With the outstanding photochemical properties of Ru(II) polypyridyl, this complex could track gene delivery in vivo using one- and two-photon imaging.

Tetranuclear ruthenium(II) complexes with oligo-oxyethylene linkers as one- and two-photon luminescent tracking non-viral gene vectors

To prolong the observation time, increase the penetration depth and decrease self-absorption and phototoxicity, two-photon luminescent vectors have emerged as promising tools for tracking gene delivery in living cells. Herein, we report four new tetranuclear Ru(ii) complexes based on oligo-oxyethylene and polybenzimidazole as one- and two- photon luminescent tracking non-viral gene vectors. In such a molecular design, the oligo-oxyethylene, polybenzimidazole and Ru(ii) polypyridyl complexes were expected to render the vectors with increased cell permeability, biocompatibility, proton buffering capacity and one- and two-photon luminescence. Corresponding DNA interaction studies showed that the ability of the complexes to condense DNA decreased with increasing oligo-oxyethylene lengths. Additionally, all complexes protected DNA. The complexes were investigated as one- and two-photon tracking non-viral gene vectors in living cells and showed proper cellular uptake, good luciferase expression and low cytotoxicity.