Phototoxicity of cyclometallated Ir(III) complexes bearing a thio-bis-benzimidazole ligand, and its monodentate analogue, as potential PDT photosensitisers in cancer cell killing

Martínez-Alonso, M. orcid.org/0000-0002-0931-5274, Jones, C.G. orcid.org/0000-0003-2958-8322, Shipp, J.D. orcid.org/0000-0002-0452-8895 et al. (3 more authors) (2024) Phototoxicity of cyclometallated Ir(III) complexes bearing a thio-bis-benzimidazole ligand, and its monodentate analogue, as potential PDT photosensitisers in cancer cell killing. JBIC Journal of Biological Inorganic Chemistry, 29 (1). pp. 113-125. ISSN 0949-8257

Abstract

Two novel cyclometallated iridium(III) complexes have been prepared with one bidentate or two monodentate imidazole-based ligands, 1 and 2, respectively. The complexes showed intense emission with long lifetimes of the excited state. Femtosecond transient absorption experiments established the nature of the lowest excited state as 3IL state. Singlet oxygen generation with good yields (40% for 1 and 82% for 2) was established by detecting 1O2 directly, through its emission at 1270 nm. Photostability studies were also performed to assess the viability of the complexes as photosensitizers (PS) for photodynamic therapy (PDT). Complex 1 was selected as a good candidate to investigate light-activated killing of cells, whilst complex 2 was found to be toxic in the dark and unstable under light. Complex 1 demonstrated high phototoxicity indexes (PI) in the visible region, PI > 250 after irradiation at 405 nm and PI > 150 at 455 nm, in EJ bladder cancer cells.

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Item Type:	Article
Authors/Creators:	Martínez-Alonso, M. https://orcid.org/0000-0002-0931-5274 Jones, C.G. https://orcid.org/0000-0003-2958-8322 Shipp, J.D. https://orcid.org/0000-0002-0452-8895 Chekulaev, D. Bryant, H.E. https://orcid.org/0000-0003-2720-7020 Weinstein, J.A. https://orcid.org/0000-0001-6883-072X
Copyright, Publisher and Additional Information:	© The Author(s) 2024. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
Keywords:	Anticancer drugs; Iridium; PDT; Phototoxicity
Dates:	Published: February 2024 Published (online): 6 January 2024 Accepted: 18 October 2023
Institution:	The University of Sheffield
Academic Units:	The University of Sheffield > Faculty of Science (Sheffield) > Department of Chemistry (Sheffield) The University of Sheffield > Faculty of Medicine, Dentistry and Health (Sheffield) > School of Medicine and Population Health
Funding Information:	Funder Grant number MEDICAL RESEARCH COUNCIL MR/K015753/1
Depositing User:	Symplectic Sheffield
Date Deposited:	09 Feb 2024 10:57
Last Modified:	15 Apr 2024 10:32
Status:	Published
Publisher:	Springer Science and Business Media LLC
Refereed:	Yes
Identification Number:	10.1007/s00775-023-02031-z
Related URLs:	PubMed URL
Open Archives Initiative ID (OAI ID):	oai:eprints.whiterose.ac.uk:208823

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Phototoxicity of cyclometallated Ir(III) complexes bearing a thio-bis-benzimidazole ligand, and its monodentate analogue, as potential PDT photosensitisers in cancer cell killing

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