https://hdl.handle.net/10259/3591 2026-04-17T17:33:38Z https://hdl.handle.net/10259/11326 A Novel Near‐IR Absorbing Ruthenium(II) Complex as Photosensitizer for Photodynamic Therapy and its Cetuximab Bioconjugates Martínez Alonso, Marta; Gandioso, Albert; Thibaudeau, Chloé; Qin, Xue; Arnoux, Philippe; Demeubayeva, Nurikamal; Guérineau, Vincent; Frochot, Céline; Jung, Alain C.; Gaiddon, Christian; Gasser, Gilles A novel Ru(II) cyclometalated photosensitizer (PS), Ru-NH2, for photodynamic therapy (PDT) of formula [Ru(appy)(bphen)2]PF6 (where appy=4-amino-2-phenylpyridine and bphen=bathophenanthroline) and its cetuximab (CTX) bioconjugates, Ru-Mal-CTX and Ru-BAA-CTX (where Mal=maleimide and BAA=benzoylacrylic acid) were synthesised and characterised. The photophysical properties of Ru-NH2 revealed absorption maxima around 580 nm with an absorption up to 725 nm. The generation of singlet oxygen (1O2) upon light irradiation was confirmed with a 1O2 quantum yield of 0.19 in acetonitrile. Preliminary in vitro experiments revealed the Ru-NH2 was nontoxic in the dark in CT-26 and SQ20B cell lines but showed outstanding phototoxicity when irradiated, reaching interesting phototoxicity indexes (PI) >370 at 670 nm, and >150 at 740 nm for CT-26 cells and >50 with NIR light in SQ20B cells. The antibody CTX was successfully attached to the complexes in view of the selective delivery of the PS to cancer cells. Up to four ruthenium fragments were anchored to the antibody (Ab), as confirmed by MALDI-TOF mass spectrometry. Nonetheless, the bioconjugates were not as photoactive as the Ru-NH2 complex. 2023-08-01T00:00:00Z https://hdl.handle.net/10259/11325 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, Marta; Jones, Callum G.; Shipp, James D.; Chekulaev, Dimitri; Bryant, Helen E.; Weinstein, Julia A. 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. 2024-02-01T00:00:00Z https://hdl.handle.net/10259/11324 Photostable Iridium(III) Cyclometallated Complex is an Efficient Photosensitizer for Killing Multiple Cancer Cell Lines and 3D Models under Low Doses of Visible Light Jones, Callum G.; Martínez Alonso, Marta; Gagg, Hannah; Kirby, Liam; Weinstein, Julia A.; Bryant, Helen E. Photodynamic therapy delivers more targeted cell killing than classical chemotherapy. It uses light-absorbing compounds, photosensitizers (PSs), to generate lethal reactive oxygen species (ROS) at sites of localized irradiation. Transition metal complexes are attractive PSs due to their photostability, visible-light absorption, and high ROS yields. Here, we introduce a low-molecular weight, photostable iridium complex, [Ir(thpy)2(benz)]Cl, 1, that localizes to the Golgi apparatus, mitochondria, and endoplasmic reticulum, absorbs visible light, phosphoresces strongly, generates 1O2 with 43% yield, and undergoes cellular elimination after 24 h. 1 shows low dark toxicity and under remarkably low doses (3 min, 20–30 mJ s–1 cm–2) of 405 or 455 nm light, it causes killing of bladder (EJ), malignant melanoma (A375), and oropharyngeal (OPSCC72) cancer cells, with high phototoxic indices > 100–378. 1 is also an efficient PS in 3D melanoma spheroids, with repeated short-time irradiation causing cumulative killing. 2024-09-01T00:00:00Z https://hdl.handle.net/10259/9276 Silver hexacyanoferrate (II) nanocrystals as a new material to improve Raman scattering enhancement during silver surface oxidation Hernández Muñoz, Sheila; Cheuquepan Valenzuela, William; Pérez Estébanez, Martín; Heras Vidaurre, Aránzazu; Colina Santamaría, Álvaro Raman spectroscopy is a powerful analysis technique that shows its full potential when a high amplification of the Raman signal is achieved. In this sense, Surface-Enhanced Raman scattering (SERS) has been the most widely used phenomenon for analysis. SERS provides the amplification of the Raman intensity due to the interaction of molecules with a plasmonic nanostructured surface. The enhancement of the Raman signal can be also obtained during the electrochemical oxidation of a metal electrode; this phenomenon was denoted as Electrochemical-Surface Oxidation Enhanced Raman Scattering (EC-SOERS) and yields a good Raman signal enhancement with high reproducibility. Until now, only chloride and bromide have been employed in EC-SOERS, using a silver electrode to generate silver chloride and silver bromide nanocrystals. In this work, a new EC-SOERS substrate based on the electrogeneration of silver hexacyanoferrate (II) nanocrystals is presented which provides a very sensitive Raman response. The electrogeneration of this new material can be easily followed using spectroelectrochemistry since the characteristic Raman bands of the nanocrystals lie outside of the fingerprint region used for the analysis where the detection of most of the target molecules is performed. Indigo Carmine has been selected as target molecule, obtaining a very good response at nanomolar level under Raman resonance and non-resonance conditions. 2023-10-10T00:00:00Z