Octahedral Molybdenum Cluster Complexes with Optimized Properties for Photodynamic Applications

Abstract

Two new octahedral molybdenum cluster complexes act as an efficient singlet oxygen supplier in the context of the photodynamic therapy of cancer cells under blue-light irradiation. These complexes integrate the {Mo6I8}4+ core with 4′-carboxybenzo-15-crown-5 or cholate apical ligands and were characterized by 1H NMR, HR ESI-MS, and CHN elemental analysis. Both complexes display high quantum yields of luminescence and singlet oxygen formation in aqueous media associated with a suitable stability against hydrolysis. They are internalized into lysosomes of HeLa cells with no dark toxicity at pharmacologically relevant concentrations and have a strong phototoxic effect under blue-light irradiation, even in the presence of fetal bovine serum. The last feature is essential for further translation to in vivo experiments. Overall, these complexes are attractive molecular photosensitizers toward photodynamic applications.

Molybdenum cluster loaded PLGA nanoparticles as efficient tools against epithelial ovarian cancer

“…The results showed that non-activated TMB, CMB and CMIF loaded nanoparticles were not toxic up to 15 µM (figure 4). These results were in adequation with the toxicity of the previously reported Mo 6 complexes (Kirakci et al, 2020). The cellular viability obtained for all nonactivated CNPs decreased with increasing cluster concentrations (for example, with CMIF loaded nanoparticles with a P/C ratio of 2.5, the cellular viability decreased from 98% to 2% when concentration was increaded from 0.5 to 50 µM).…”

Avenue to X-ray-induced photodynamic therapy of prostatic carcinoma with octahedral molybdenum cluster nanoparticles

“…Thus, 1NPs displayed phototoxicity which is among the highest ever reported for Mo 6 -based photosensitizing systems in the presence of foetal bovine serum (FBS), comparable to the phototoxicity of [Mo 6 I 8 L 6 ] 2− cluster complexes bearing crown-ether carboxylate or cholate apical ligands (1.4 and 1.5 μM, respectively). 14 Only a mitochondrion-targeting Mo 6 complex with a net positive charge displayed higher phototoxicity with an IC 50 of 100 nM, but in this case, high phototoxicity was associated with substantial dark toxicity characterized by an IC 50 of 5 μM. 13 Here, the therapeutic window of 1NPs is wider with more than 200 times higher phototoxicity over dark toxicity.…”

“…4A and B), resembling the previously described uptake of Mo 6 cluster complexes. 11,14 Spinning disc confocal microscopy showed binding of 1NPs to cultured cells with a portion of the material localized in cell vesicles (Fig. 4C).…”

“…11 Several photosensitizing systems based on Mo 6 cluster complexes have recently been reported to have relevant properties for blue-light PDT in vitro, allowing the isolation of the key parameters for efficient therapeutic effects that can be transposed to X-PDT. [11][12][13][14][15][16][17][18] Among all the tested complexes, the [Mo 6 I 8 (OPOPh 2 ) 6 ] 2À complex displayed the most relevant properties with low dark toxicity, high phototoxic effect, and stable biological activity over a long time-period. In parallel, we validated the concept of X-PDT for these complexes in vitro using nanoparticles of the cluster compound (Bu 4 N) 2 [Mo 6 I 8 (OCOCF 3 ) 6 ] prepared by the solvent displacement method.…”

Mesoporous organosilica nanoparticles: Degradation strategies and application in tumor therapy

“…[7][8][9][10] To date, a variety of materials (liposomes, polymers, gold, Fe 3 O 4 , mesoporous silica, upconversion nanoparticles, and metal-organic frameworks) [11][12][13][14][15] have been developed to construct nanocarriers for delivering various therapeutic agents like antitumor drugs, inhibitors, proteins, nucleic acids, and even probes in tumor therapy. [16][17][18] Among them, mesoporous silica nanoparticles (MSNs) have achieved increasing attention in biomedicine for tumor therapy due to their biocompatibility, mesoporous structure with large specific surface area and pore volume, and easy surface functionalization, which facilitate to deliver guest cargos. 19,20 For example, Rao et al proposed to construct a MSNs-based nanoplatform as a reactive oxygen species (ROS)-responsive magnetic resonance (MR) imaging-guided photodynamic chemotherapeutic agent (DOX-R-MSN).…”