Increasing the π-Expansive Ligands in Ruthenium(II) Polypyridyl Complexes: Synthesis, Characterization, and...

Area of Science:

• Materials Science
• Chemistry
• Biomedical Engineering

Background:

• Chemotherapies lack selectivity, damaging healthy cells alongside cancerous ones.
• Photodynamic therapy (PDT) offers spatiotemporal control for treating diseases like cancer.
• Ruthenium(II) polypyridyl compounds are emerging as effective photosensitizers for PDT.

Purpose of the Study:

• To synthesize and evaluate four novel Ruthenium(II) polypyridyl compounds as photosensitizers for PDT.
• To investigate the photocytotoxic properties and cellular mechanisms of these Ru(II) complexes.
• To explore their potential as targeted cancer therapeutics.

Main Methods:

• Synthesis of four Ru(II) polypyridyl compounds with improved yields.
• Solid-state structure determination of key compounds.
• DNA interaction studies using a Ru(II) complex model.
• Evaluation of singlet oxygen quantum yields.
• Photocytotoxicity assays against two cancer cell lines.
• Confocal microscopy for cellular localization studies.
• Mitochondrial respiration impairment assays.

Main Results:

• Novel Ru(II) complexes synthesized with enhanced yields.
• [Ru(DIP)phen]Cl and [Ru(dppz)phen](PF) solid-state structures obtained.
• A Ru(II) model compound stabilized duplex DNA sequences.
• Most derivatives exhibited high singlet oxygen quantum yields.
• Significant photocytotoxicity against cancer cells (IC50: 0.06-7 μM).
• [Ru(DIP)phen]Cl and [Ru(DIP)TAP]Cl localized in mitochondria.
• [Ru(dppn)phen](PF) impaired mitochondrial respiration post-irradiation.

Conclusions:

• The synthesized Ru(II) polypyridyl compounds are potent PDT agents.
• Specific compounds show preferential mitochondrial accumulation or induce mitochondrial dysfunction.
• [Ru(dppn)phen](PF) demonstrates significant potential due to high efficacy and mechanism of action.
• These findings support the development of Ru(II) complexes for targeted photodynamic cancer therapy.