Easily prepared ruthenium-complex nanomicelle probes for two-photon quantitative imaging of oxygen in aqueous media

Khan, Aamir A.; Fullerton‐Shirey, Susan K.; Howard, Scott S.

doi:10.1039/c4ra11229f

Cited by 24 publications

(11 citation statements)

References 53 publications

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“…Overall, the photophysical evaluation indicated that the encapsulation of the Ru II polypyridine complex did not influence its excited state behavior. This finding is in agreement with the recently reported encapsulation of [Ru(4,7‐diphenyl‐1,10‐phenanthroline) 3 ] 2+ with the same polymer as well as the encapsulation [Ru(2,2'‐bipyridine) 2 (dipyrido[3,2‐a:2',3'‐ c ]phenazine‐7‐hydroxymethyl)] 2+ with a polylactide polymer …”

Section: Resultssupporting

confidence: 93%

“…As no significant changed were observed within 48 h (Figure S9–S20), the stability of the particles is confirmed. These findings are in agreement with stability studies of particles formed by the encapsulation of [Ru(4,7‐diphenyl‐1,10‐phenanthroline) 3 ] 2+ with the same polymer carrier …”

Section: Resultsmentioning

confidence: 99%

“…The generated micelles were shown to have a decreased toxicity profile while having an increased selectivity towards cancer cells in comparison to non‐cancerous cells . The group of Howard et al has reported the encapsulation of [Ru(4,7‐diphenyl‐1,10‐phenanthroline) 3 ] 2+ with Poloxamer‐407/Pluronic F‐127 as a two‐photon excited oxygen imaging agent in aqueous solution . Lemercier et al encapsulated [Ru(1,10‐phenanthroline) 3 ] 2+ derivatives as PDT PSs with poly( d , l ‐lactide‐ co ‐glycolide) and Poloxamer 188/Pluronic F‐68.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis, Characterization, and Biological Evaluation of the Polymeric Encapsulation of a Ruthenium(II) Polypyridine Complex with Pluronic F‐127/Poloxamer‐407 for Photodynamic Therapy Applications

2020

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The therapy of cancer remains a major challenge for modern medicine. Complementary to classical treatments, the use of photodynamic therapy (PDT) has received increasing attention over the last decades. Among the classes of PDT photosensitizers (PSs) investigated, RuII polypyridine complexes are currently considered as a valuable option. To improve the water solubility of these lipophilic compounds and generate a drug delivery system, these complexes can be encapsulated with polymers. Herein, the physical encapsulation of the photoactive [Ru((E,E')‐4,4'‐bis[p‐methoxystyryl]‐2,2'‐bipyridine)3][PF6]2 complex with the polymer Pluronic F‐127/Poloxamer‐407 is presented. The resulting spherical particles were found to have a toxic effect in the micromolar range in human cervical carcinoma cells upon light irradiation (500 nm).

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Section: Resultssupporting

confidence: 93%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Synthesis, Characterization, and Biological Evaluation of the Polymeric Encapsulation of a Ruthenium(II) Polypyridine Complex with Pluronic F‐127/Poloxamer‐407 for Photodynamic Therapy Applications

2020

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“…The gas permeability and the photophysics of the polymeric matrices seem to be the principal properties to control for the efficient design of these delivery systems. A bioprobe for high-resolution two-photon quantitative imaging of oxygen in aqueous media was obtained by encapsulating the commercial hydrophobic phosphorescent dye [Ru(4,7-diphenyl-1,10phenanthroline) 3 ] 2+ in the core of Pluronic ® F-127 nanomicelles using hydrophobic interactions 130 . Based on the 'collisional quenching' process, the collision between O 2 and an excited luminophore provides a non-radiative pathway for highly electronically excited species to relax, decreasing its phosphorescence intensity and lifetime 131 .…”

Section: [H2] Biodegradable Polymersmentioning

confidence: 99%

Polymer encapsulation of ruthenium complexes for biological and medicinal applications

et al. 2019

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Some Ru complexes have extremely promising anticancer or antibacterial properties, but their poor H 2 O solubility and/or low stability of many Ru complexes in aqueous solution under physiological conditions and/or metabolic/biodistribution profile prevent their therapeutic use. To overcome these drawbacks, various strategies have been developed to improve the delivery of these compounds to their target tissues. The first strategy is based on physical encapsulation of Ru complexes in carriers, such as polymeric micelles, microparticles, nanoparticles and polymer-lipid hybrids, which enabled the delivery and controlled release of the active Ru drug candidate. The second strategy involves covalent conjugation of the ruthenium complex to a polymer to give a prodrug that can be converted to the active drug at a more controllable rate. In this Review, we provide an overview of recent developments in polymer encapsulation of Ru complexes for biological and medicinalapplications, and place particular Here, the presence of Ru centre enable 3D geometries not available with organic chemistry. For example, the Ru(II) complex DW1 and its enantiomer DW2 mimic the shape of the alkaloid staurospaurine, and complexes thus also exhibit impressive kinase inhibition activity (targeting glycogen synthase kinase 3 (GSK3) signalling) and cytotoxicity in human melanoma cancer cells 38. The biological properties of Ru complexes-such as bioactivity, cellular uptake and intracellular distribution-depend, among others, on chemical properties such as electronegativity, chemical hardness, stereochemistry and net charge of the Ru centre. Ru drug candidates often feature strongly bound ligands, such as amine, phosphine, π-bound arenes and cyclopentadienyl derivatives. These are complemented by weakly bound ligands such as Cl − or RCO 2 − , which can be displaced by chelators or simply when an excess of competitive ligands is present. As is the case for reduced Pt derivatives, the lower-valent Ru(II) and Ru(III) complexes have favourable ligand exchange kinetics with O-donor and N-donor ligands. Ru complexes have several other advantages for biological and medicinal applications, including their usual low (or zero) toxicity to healthy tissues and their distinct mode of action. Indeed, they operate through different pathways to most Pt-based drugs, which typically only interact with DNA (BOX 1). Ru(II) and Ru(III) complexes have similar ligand exchange kinetics to the Pt(II) complexes used as antineoplastic drugs 39. For small ligands such as H 2 O, the ligand exchange rate on the Ru centre is on the order of hours, which is similar to the timescale of cell division in many cell types 40. Furthermore, Ru can bind biomolecules responsible for Fe solubilization and transport in plasma, including serum transferrin and albumin. Rapidly dividing cells, such as cancer cells, require more Fe, which leads to an upregulation of the number of transferrin receptors at the cell surface 41. Consequently, Ru complexes have been proposed to preferentially targ...

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“…TPEF emission for Hb has been observed elsewhere [13][14][15] and is used here for the direct visualization and stimulation of SCD Hb fiber formation. Studying SCD sickling kinetics by fluorescence microscopy is particularly interesting because simultaneous measurements of various environmental factors, such as dissolved oxygen [16], pH, concentration of labeled treatment molecules or temperature, could be acquired alongside those of HbS, therefore, enabling a systematic approach of screening interventions which removes some of the inherent ambiguity of the clinical environment. In order for intrinsic emission of sickled HbS to be utilized in such a fashion, the TPEF spectra of sickled HbS is characterized and presented.…”

Section: Introductionmentioning

confidence: 99%

Photophysical characterization of sickle cell disease hemoglobin by multi-photon microscopy

Vigil¹,

Howard²

2015

Biomed. Opt. Express

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The photophysical properties of human sickle cell disease (SCD) Hemoglobin (Hb) is characterized by multi-photon microscopy (MPM). The intrinsic two-photon excited fluorescence (TPEF) signal associated with extracted hemoglobin was investigated and the solidified SCD variant (HbS) was found to demonstrate broad emission peaking around 510 nm when excited at 800 nm. MPM is used to dynamically induce and image HbS gelling by photolysis of deoxygenated HbS. For comparison, photolysis conditions were applied to a healthy variant of human hemoglobin (HbA) and found to remain in solution not forming fibers. The use of this signal to study the mechanism of HbS polymerization associated with the sickling of SCD erythrocytes is discussed.

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Easily prepared ruthenium-complex nanomicelle probes for two-photon quantitative imaging of oxygen in aqueous media

Abstract: Easily prepared, biocompatible, and oxygen-sensitive optical probes with a large two-photon cross-section: towards inexpensive quantitative oxygen imaging in vivo.

Cited by 24 publications

References 53 publications

Synthesis, Characterization, and Biological Evaluation of the Polymeric Encapsulation of a Ruthenium(II) Polypyridine Complex with Pluronic F‐127/Poloxamer‐407 for Photodynamic Therapy Applications

Synthesis, Characterization, and Biological Evaluation of the Polymeric Encapsulation of a Ruthenium(II) Polypyridine Complex with Pluronic F‐127/Poloxamer‐407 for Photodynamic Therapy Applications

Polymer encapsulation of ruthenium complexes for biological and medicinal applications

Photophysical characterization of sickle cell disease hemoglobin by multi-photon microscopy

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