Activation of a Photodissociative Ruthenium Complex by Triplet–Triplet Annihilation Upconversion in Liposomes

Askes, Sven H. C.; Bahreman, Azadeh; Bonnet, Sylvestre

doi:10.1002/anie.201309389

Cited by 184 publications

(184 citation statements)

References 33 publications

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“…Although our group previously demonstrated that blue-light sensitive Ru polypyridyl complex could be effectively activated by a red-to-blue TTA-UC in liposomes (Figure 1b), this demonstration was performed under argon, which is not relevant for clinical applications [26,27]. In the first part of this article, we report that it is possible to solve this issue by using the antioxidant strategy mentioned above.…”

Section: Introductionmentioning

confidence: 85%

“…TTA-UC has been demonstrated in various organic, inorganic, and/or supramolecular materials [15,[18][19][20][21][22], as well as in nano-or micro-sized particles [23][24][25]. For biological applications, i.e., for drug delivery and activation [26,27] or bio-imaging [13,[28][29][30][31][32][33], one of the main problems of TTA-UC is its sensitivity to molecular oxygen, which readily quenches the triplet state chromophores involved in the TTA-UC mechanism.…”

Section: Introductionmentioning

confidence: 99%

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Red Light Activation of Ru(II) Polypyridyl Prodrugs via Triplet-Triplet Annihilation Upconversion: Feasibility in Air and through Meat

et al. 2016

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Triplet-triplet annihilation upconversion (TTA-UC) is a promising photophysical tool to shift the activation wavelength of photopharmacological compounds to the red or near-infrared wavelength domain, in which light penetrates human tissue optimally. However, TTA-UC is sensitive to dioxygen, which quenches the triplet states needed for upconversion. Here, we demonstrate not only that the sensitivity of TTA-UC liposomes to dioxygen can be circumvented by adding antioxidants, but also that this strategy is compatible with the activation of ruthenium-based chemotherapeutic compounds. First, red-to-blue upconverting liposomes were functionalized with a blue-light sensitive, membrane-anchored ruthenium polypyridyl complex, and put in solution in presence of a cocktail of antioxidants composed of ascorbic acid and glutathione. Upon red light irradiation with a medical grade 630 nm PDT laser, enough blue light was produced by TTA-UC liposomes under air to efficiently trigger full activation of the Ru-based prodrug. Then, the blue light generated by TTA-UC liposomes under red light irradiation (630 nm, 0.57 W/cm 2 ) through different thicknesses of pork or chicken meat was measured, showing that TTA-UC still occurred even beyond 10 mm of biological tissue. Overall, the rate of activation of the ruthenium compound in TTA-UC liposomes using either blue or red light (1.6 W/cm 2 ) through 7 mm of pork fillet were found comparable, but the blue light caused significant tissue damage, whereas red light did not. Finally, full activation of the ruthenium prodrug in TTA-UC liposomes was obtained under red light irradiation through 7 mm of pork fillet, thereby underlining the in vivo applicability of the activation-by-upconversion strategy.

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Section: Introductionmentioning

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Red Light Activation of Ru(II) Polypyridyl Prodrugs via Triplet-Triplet Annihilation Upconversion: Feasibility in Air and through Meat

et al. 2016

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“…32 Because the emission intensity from quenched samples was low (<1%), we adopted a procedure described by Askes et al 33 In this procedure, absorption/scatter at the excitation wavelength and emission from the sample/reference were acquired under the same instrument settings (λ ex = 400 nm; 5 nm excitation slit; 0.3 nm emission slit; scan 390−410 nm for scatter/absorption; scan 500−850 nm for emission). However, the absorption/ scatter scans were measured with a neutral density filter, with known absorption (OD = 3; 0.1% transmittance), placed between the integrating sphere and the monochromator/ detector.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Modulating Electron Transfer Dynamics at Dye–Semiconductor Interfaces via Self-Assembled Bilayers

2015

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Forward and back electron transfer at dye−semiconductor interfaces are pivotal events in dye-sensitized solar cells and dye-sensitized photoelectrosynthesis cells. Here we introduce self-assembled bilayers as a strategy for manipulating electron transfer dynamics at these interfaces. The bilayer films are achieved by stepwise layering of bridging molecules, linking ions, and dye molecules on the metal oxide surface. The formation of the proposed architecture is supported by ATR-IR and UV−vis spectroscopy. By using time-resolved emission and transient absorption, we establish that the films exhibit an exponential decrease in electron transfer rate with increasing bridge length. The findings indicate that self-assembled bilayers offer a simple, straightforward, and modular method for manipulating electron transfer dynamics at dye−semiconductor interfaces. ■ INTRODUCTIONElectron transfer from a photoexcited chromophore to a semiconducting metal oxide surface is a critical event in dyesensitized solar cells and dye-sensitized photoelectrosynthesis cells. 1−3 Considerable efforts have been dedicated to manipulate electron transfer rates at these interfaces by reducing the electronic coupling between the dye and semiconductor which in turn slows the electron transfer rates. 4−8 Spatial separation of the dye and semiconductor is arguably the most common method of reducing electronic coupling and is achieved by two primary strategies: (1) atomic layer deposition (ALD) and (2) synthetic modification of the dye.ALD of "insulating" layers between the dye and semiconductor effectively increases their separation and is effective in manipulating electron transfer rates. 9−11 However, this method requires dedicated, high vacuum instrumentation that is less than ideal for large scale production of dye-sensitized devices.The second strategy involves covalently modifying the dye molecules with rigid bridging moieties terminated in a surfacebinding group. 12−15 Despite their elegant design, many of these elongated bridge-dyes lie down on the surface, negating the desired effect. Recently, Meyer and co-workers demonstrated thatwith at least some bridge-dyesincreasing bridge lengths can be effective in slowing electron transfer rates. 16 However, the covalent interaction between the dye and bridge influences the electrochemical and photophysical properties of the dye, making it difficult to differentiate the distance dependence from other variables. 8 Additionally, the multistep synthesis required for bridge-dye molecules limits the generalizability of these systems.In this report, we introduce an alternative strategy, selfassembled bilayers, as a means of controlling the distance between dye and the metal oxide surface. This approach, based on the work of Mallouk and Haga, 17,18 provides a simple and modular method for the self-assembly of bilayer structures on metal oxide surfaces via metal ion linkages. This stepwise assembly method has been successfully implemented with chromophore−catalyst and chromophore−chromophore assemblie...

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“…17,18 Typically, complexes are designed incorporating sterically encumbered ligands that weaken metal-ligand bonds and thus stabilise 3 MC states with respect to the 3 MLCT states when compared to complexes where such encumbrance is absent. This thereby increases the thermal accessibility of 3 MC states from photoexcited 3 MLCT states [19][20][21][22][23][24][25] (the terms stabilisation and destabilisation here refer to changes in the energies of these 3 MLCT and 3 MC states with respect to each other and the ground state when comparing complexes, for example, with the archetypical [Ru(bpy) 3 ] 2+ .…”

Section: Introductionmentioning

confidence: 99%

Photochemistry of [Ru(pytz)(btz)₂]²⁺ and Characterization of a κ¹-btz Ligand-Loss Intermediate

et al. 2016

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We report the synthesis, characterisation and photochemical reactivity of the triazolecontaining complex [Ru(pytz)(btz) 2 ] 2+ (1, pytz = 1-benzyl-4-(pyrid-2-yl)-1,2,3-triazole, btz = 1,1'-dibenzyl-4,4'-bi-1,2,3-triazolyl). The UV-visible absorption spectrum of 1 exhibits pytz- and that the T 1 state from a single point triplet state calculation at the S 0 geometry suggests 3 MC character. Optimisation of the T 1 state of the complex starting from the ground state geometry leads to elongation of the two Ru-N(btz) bonds cis to the pytz ligand to 2.539 and 2.544 Å leading to a psuedo 4-coordinate 3 MC state rather than the 3 MLCT state. The work therefore provides additional insights into the photophysical and photochemical properties of ruthenium triazole-containing complexes and their excited state dynamics.2

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Activation of a Photodissociative Ruthenium Complex by Triplet–Triplet Annihilation Upconversion in Liposomes

Cited by 184 publications

References 33 publications

Red Light Activation of Ru(II) Polypyridyl Prodrugs via Triplet-Triplet Annihilation Upconversion: Feasibility in Air and through Meat

Red Light Activation of Ru(II) Polypyridyl Prodrugs via Triplet-Triplet Annihilation Upconversion: Feasibility in Air and through Meat

Modulating Electron Transfer Dynamics at Dye–Semiconductor Interfaces via Self-Assembled Bilayers

Photochemistry of [Ru(pytz)(btz)₂]²⁺ and Characterization of a κ¹-btz Ligand-Loss Intermediate

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Activation of a Photodissociative Ruthenium Complex by Triplet–Triplet Annihilation Upconversion in Liposomes

Cited by 184 publications

References 33 publications

Red Light Activation of Ru(II) Polypyridyl Prodrugs via Triplet-Triplet Annihilation Upconversion: Feasibility in Air and through Meat

Red Light Activation of Ru(II) Polypyridyl Prodrugs via Triplet-Triplet Annihilation Upconversion: Feasibility in Air and through Meat

Modulating Electron Transfer Dynamics at Dye–Semiconductor Interfaces via Self-Assembled Bilayers

Photochemistry of [Ru(pytz)(btz)2]2+ and Characterization of a κ1-btz Ligand-Loss Intermediate

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Photochemistry of [Ru(pytz)(btz)₂]²⁺ and Characterization of a κ¹-btz Ligand-Loss Intermediate