Modulating In Vitro Photodynamic Activities of Copper(II) Complexes

Abstract

The photodynamic activities of selected copper(II) complexes [Cu(L 1 )B]ClO 4 (1,2) and [Cu(L 2 )B]ClO 4 (3,4), where L 1 = 2-[(pyridin-2-yl)methyleneamino]phenol, L 2 = 2-[(pyridin-2yl)methyleneamino]benzenethiol and B are 1H-imidazo[4,5-f ]-[1,10]phenanthroline (L 3 ) and 1-(pyren-2-yl)-1H-imidazo[4,5-f ]-[1,10]phenanthroline (L 4 ), were studied in detail in a structureactivity relationship (SAR)-based approach to explore the role of S-coordination to Cu II in photodynamic therapy (PDT) to human cervical cancer (HeLa) cells. Although all of the complexes were toxic in the dark (IC 50 ≈ 10 μM), we observed enormous enhancement (about 10 fold) in the cytotoxicity of the complexes in visible light (400-700 nm, 10 J cm -2 ), resulting in IC 50 ≈ 1.0 μM. Intracellular reactive oxygen species (ROS) generated in the HeLa cells during photoactivation of the complexes was [a]

Phototherapeutic anticancer strategies with first-row transition metal complexes: a critical review

“…Roy and co-workers studied the role of S-coordination in Cu( ii ) complexes for PDT applications ( Cu-10 ). 127 They studied complexes coordinated to O or S, which were all toxic in the dark (IC 50 values of ∼10 μM, HeLa cells) but the cytotoxicity was significantly enhanced upon irradiation for all complexes (IC 50 values of ∼1 μM). S-Coordinated complexes possess low-lying and long-lived excited states, which favour ISC and hence singlet oxygen generation.…”

Photodynamic Therapy of Inorganic Complexes for the Treatment of Cancer†

“…However, they showed a high toxicity in visible light with IC 50 values of ~1.0 µ m due to 1 O 2 generation. Overall, the S‐coordination in modulating the in vitro photodynamic activity of the copper(II) complexes is crucial in designing copper‐based next‐generation PDT agents (77) (Fig. 7).…”

A fundamental role of the solvent polarity and remote substitution of the 2-(4-R-phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline framework in controlling the ground- and excited-state properties of Re(i) chromophores [ReCl(CO)3(R-C6H4-imphen)]

“…1–20 Possessing the 1,10-phenanthroline unit with strong abilities to bind transition metals, imidazo[4,5- f ][1,10]phenanthrolines have also become very popular ligands for controlling the photophysical and antiproliferative behaviour of transition metal complexes. They have been combined with numerous transition metal ions including Cu( i ), 21–25 Cu( ii ), 26–28 Ru( ii ), 29–40 and Ir( iii ). 41–46 The vast majority of these coordination compounds have potential uses in anticancer therapy, 26–28,31,34–37,39–46 bioimaging, 32,47 the conversion of solar energy, 22,29 organic light-emitting diodes, 21,23,48–50 photoredox catalysis, 38,51,52 and luminescence sensing.…”