New avenues in the design and potential application of metal complexes for photodynamic therapy

Abstract

Photodynamic therapy (PDT) requires a photosensitizing agent, which can undergo visible light activation, yielding reactive oxygen species and/or radical species. The key physical properties and desirable attributes of established PDT photosensitizer agents are discussed, together with a consideration of the role that photoactive metal coordination complexes may have in the future design of such agents. A number of classes of metal complex are included with a focus upon their ability to generate singlet oxygen, and prior indications of biological utility, compatibility and cytotoxicity through cellular imaging work and DNA binding behaviour.

Towards Water Soluble Mitochondria-Targeting Theranostic Osmium(II) Triazole-Based Complexes

“…Complexes of osmium(II) are also typically highly inert to ligand photosubstitution making them highly robust [34] (although the unprecedentedly facile ligand photoejection in the complex [Os(btz)3] 2+ was recently reported [35]). The intensity of phosphorescence is, however, sensitive to the presence of oxygen resulting in quenching through conversion of ground state 3 O2 to reactive 1 O2, thus enabling exploitation in photodynamic therapy (PDT) [36]. These combined properties thus present significant opportunities for the development of unique dual-mode theranostic agents.…”

Evaluation of Perylene Bisimide‐Based RuII and IrIII Complexes as Photosensitizers for Photodynamic Therapy

“…[42][43][44][45] Compared with the Ru complexes, less effective PDT agents based on Ir compounds have been reported so far, probably because of the difficulties in suppressing the competing electron-transfer processes. [46] Nevertheless, several Ir III compounds, most commonly bearing cyclometalated ligands, have recently been found to be promising PDT agents. [46][47][48][49][50][51][52] Figure 1.…”

“…[46] Nevertheless, several Ir III compounds, most commonly bearing cyclometalated ligands, have recently been found to be promising PDT agents. [46][47][48][49][50][51][52] Figure 1. Structures of TLD-1433, a PS in clinical trial as a PDT PS, and complexes 1 and 2 with their respective ligands L1 and L2 studied in this paper.…”

Optimierung photodynamischer Krebstherapien auf der Grundlage physikalisch‐chemischer Faktoren

“…[27] In jüngster Zeit haben viele Studien über die Entwicklung von effektiven Photosensibilisatoren mit einstellbarer Lçslichkeit, hoher 1 O 2 -Quantenausbeute und Gewebeansteuerung berichtet. Idealerweise muss ein Photosensibilisator,d er fürd ie PDT geeignet ist, eine abstimmbare Amphiphilie in biologischen Umgebungen vorweisen.…”