A mitochondria-targeted green light-activatable binuclear ruthenium(ii) dithiocarbamate complex for synergistic type I/II photodynamic therapy

Abstract

We report the synthesis of a mitochondria-targeted binuclear ruthenium(II)-dithiocarbamate complex, [Ru(bpy)₂(S₂C(C₄H₈N₂)CS₂)Ru(bpy)₂](PF₆)₂ (Ru1), with a significant bathochromic absorbance shift when compared with the well-studied mononuclear [Ru(bpy)₃]Cl₂ complex. It demonstrates excellent singlet oxygen (¹O₂) and hydroxyl radical (˙OH) generation ability under green (518 nm)/red (637 nm) light, even at ultra-low power intensity (10 mW cm⁻²). It elicits potent photocytotoxicity against human lung cancer cells (A549) in vitro and in a 3D tumor spheroid model via type I/II photodynamic therapy.