Ruthenium(II) polypyridyl complexes as mitochondria-targeted two-photon photodynamic anticancer agents

Synthesis and characterisation of phosphorescent rhenium(I) complexes of hydroxy- and methoxy-substituted imidazo[4,5- f ]-1,10-phenanthroline ligands

“…Corresponding emission lifetimes for these complexes lie in the range 149-166 ns, which are characteristic of neutral Re(I) based lumophores of this type, and again suggest that fluorescence from the ligand is quenched. 19 Taken together, and in comparison to related examples in the literature, the emission properties from this series of complexes can therefore be characterised as 3 MLCT in nature. Despite the variation noted in the 1 MLCT absorptions, the emission data suggests that the 3 MLCT energy is relatively insensitive to the variation of the substituents attached to the imidazole[4,5-f]-1,10-phenanthroline ligand.…”

“…This data is consistent with that obtained for related Re(I) complexes that incorporate the imidazo[4,5-f]-1,10-phenanthroline chromophore. 19 Across the series of complexes there was a subtle shift in the 1 MLCT absorption wavelengths (408-426 nm) for the isolated complexes with ortho methoxy-substitution of the S1 group leading to slightly higher 1 MLCT energies. In comparison, the 1 MLCT absorption (Re(5d)→π * ) for [ReCl(CO) 3 (phen)] has been reported at 383 nm, which is a higher energy absorption compared to the value of the complexes described herein, reflecting the increased conjugation across the imidazole[4,5-f]-1,10-phenanthroline core.…”

“…Related Ru(II) complexes have demonstrated mitochondrial targeting behaviour through cell imaging studies and have been postulated as anticancer agents. 19 The potential multidenticity of these ligands has also been exploited in the development of coordination polymers (including for the f-block) 20 In the context of Re(I), only a handful of reports exist on the coordination chemistry of imidazo [4,5-f The ligands (L1-L8) were synthesised according to an adaption of previously reported approaches (Scheme 2), allowing a range of aryl amine (S2-NH 2 ) and aldehyde (S1-CHO) reagents to be utilised in the procedure. The functionalised imidazo[4,5-f]-1,10-phenanthroline ligands possessed good solubility in a range of organic solvents (imparted by the different substituted aryl groups, S1 and S2) and were characterised using a range of standard spectroscopic and analytical techniques, confirming the proposed insensitive to coordination to Re(I).…”

Photo-induced cytotoxicity and anti-metastatic activity of ruthenium(ii)–polypyridyl complexes functionalized with tyrosine or tryptophan

“…After the successful entry of ruthenium-based drugs (NAMI-A and KP1019) into human clinical trials, there is a burgeoning interest in developing Ru(II)-based novel anticancer drugs with new and improved function. 8,9 The possibility of achieving high solubility by choosing appropriate counter anions or through appropriate functionalization of the coordinated ligands has led to the design of new Ru(II)-polypyridyl complexes for use of anti-cancer and antimetastatic drugs. 10,11 These complexes are attractive choices for use as photodynamic therapeutic reagents and they also possesses visible light excitation, reasonably long-lived triplet excited states, and higher stability towards photobleaching.…”

Getting It Right: 3D Cell Cultures for the Assessment of Photosensitizers for Photodynamic Therapy

“…These include the use of self-assembling peptides as a cellular scaffold to model drug and oxygen diffusion effects indicating that mass transfer is the main factor differentiating 2D and 3D responses [9]. 3D cultures can be used to evaluate the theranostics potential of new drugs [16] Other recent examples are the modeling of tumorstroma interactions [17], mixed neuron/cancer cell systems [11], the specific optimization of PDT drugs for hypoxic tumor environments [12], two-photon PDT studies [18], and a microfluidal breast cancer tissue model based on lab-on-a-chip technology [19], to name a few. Another noteworthy development is the use of optical coherence tomography for the visualization and study of 3D PDT models [20], which indicates the analytical and predictive power of contemporary imaging techniques in conjunction with modern tissue models.…”