15 results on '"Ng, D K"'
Search Results
2. Application of meso -CF 3 -Fluorophore BODIPY with Phenyl and Pyrazolyl Substituents for Lifetime Visualization of Lysosomes.
- Author
-
Trukhan, Irina S., Tomilin, Denis N., Dremina, Nataliya N., Sobenina, Lyubov N., Shurygin, Michael G., Petrushenko, Konstantin B., Petrushenko, Igor K., Trofimov, Boris A., and Shurygina, Irina A.
- Subjects
LYSOSOMES ,STAINS & staining (Microscopy) ,FLUORESCENT dyes ,LIGHT absorption ,EHRLICH ascites carcinoma ,POISONS ,VISUALIZATION - Abstract
A bright far-red emitting unsymmetrical meso-CF
3 -BODIPY fluorescent dye with phenyl and pyrazolyl substituents was synthesized by condensation of trifluoropyrrolylethanol with pyrazolyl-pyrrole, with subsequent oxidation and complexation of the formed dipyrromethane. This BODIPY dye exhibits optical absorption at λab ≈ 610–620 nm and emission at λem ≈ 640–650 nm. The BODIPY was studied on Ehrlich carcinoma cells as a lysosome-specific fluorescent dye that allows intravital staining of cell structures with subsequent real-time monitoring of changes occurring in the cells. It was also shown that the rate of uptake by cells, the rate of intracellular transport into lysosomes, and the rate of saturation of cells with the dye depend on its concentration in the culture medium. A concentration of 5 μM was chosen as the most suitable BODIPY concentration for fluorescent staining of living cell lysosomes, while a concentration of 100 μM was found to be toxic to Ehrlich carcinoma cells. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
3. Preparation and In Vitro Photodynamic Activity of Glucosylated Zinc(II) Phthalocyanines as Underlying Targeting Photosensitizers.
- Author
-
Jian-Yong Liu, Chen Wang, Chun-Hui Zhu, Zhi-Hong Zhang, and Jin-Ping Xue
- Abstract
Two novel glucosylated zinc(ІІ) phthalocyanines 7a–7b, as well as the acetyl-protected counterparts 6a–6b, have been synthesized by the Cu(I)-catalyzed 1,3-dipolar cycloaddition between the propargylated phthalocyanine and azide-substituted glucoses. All of these phthalocyanines were characterized with various spectroscopic methods and studied for their photo-physical, photo-chemical, and photo-biological properties. With glucose as the targeting unit, phthalocyanines 7a–7b exhibit a specific affinity to MCF-7 breast cancer cells over human embryonic lung fibroblast (HELF) cells, showing higher cellular uptake. Upon illumination, both photosensitizers show high cytotoxicity with IC
50 as low as 0.032 µM toward MCF-7 cells, which are attributed to their high cellular uptake and low aggregation tendency in the biological media, promoting the generation of intracellular reactive oxygen species (ROS). Confocal laser fluorescence microscopic studies have also revealed that they have high and selective affinities to the lysosomes, but not the mitochondria, of MCF-7 cells. The results show that these two glucosylated zinc(II) phthalocyanines are potential anticancer agents for targeting photodynamic therapy. [ABSTRACT FROM AUTHOR]- Published
- 2017
- Full Text
- View/download PDF
4. Glycosylated Metal Phthalocyanines.
- Author
-
Hanack, Michael
- Subjects
PHTHALOCYANINE synthesis ,GLYCOSYLATION ,ZINC phthalocyanine ,BENZENEDICARBONITRILE ,MACROCYCLIC compounds - Abstract
In the first part; the syntheses of mono-; di-; and tetra-glycosylated phthalonitriles is described; which are the most used starting materials for the preparation of the corresponding glycosylated metal (mostly zinc) phthalocyanines. In the second section; the preparation of symmetric and unsymmetric mono-; tetra-; and octa- glycosylated zinc phthalocyanines are reviewed; in which the sugar is attached to the phthalocyanine macrocycle; either anomerically or via another one of its OH-groups. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
5. Synthesis and Spectroscopic Evaluation of Two Novel Glycosylated Zinc(II)-Phthalocyanines.
- Author
-
Bächle, Felix, Hanack, Michael, and Ziegler, Thomas
- Subjects
PHTHALOCYANINE synthesis ,ULTRAVIOLET-visible spectroscopy ,EMISSION spectroscopy ,PHOTOSENSITIZERS ,GLYCOCONJUGATES - Abstract
In continuation of our work on glycoconjugated phthalocyanines, two new water soluble, non-ionic zinc(II) phthalocyanines have been prepared and fully characterized by means of 1H-NMR, 13C-NMR, MALDI-TOF, ESI-TOF, UV-Vis spectroscopy, emission spectroscopy and fluorescence lifetime measurements. The carbohydrate-containing phthalonitrile precursors were synthesized through a copper-catalyzed azide-alkyne cycloaddition (CuAAC). The 2-methoxyethoxymethyl protecting group (MEM) was used to protect the carbohydrate moieties. It resisted the harsh basic cyclotetramerization conditions and could be easily cleaved under mild acidic conditions. The glycoconjugated zinc(II) phthalocyanines described here have molar extinction coefficents εmax > 105 M
-1 cm-1 and absorption maxima λ > 680 nm, which make them attractive photosensitizers for photo-dynamic therapy. [ABSTRACT FROM AUTHOR]- Published
- 2015
- Full Text
- View/download PDF
6. Ring Opening Reactions through C-O Bond Cleavage Uniquely Adding Chemical Functionality to Boron Subphthalocyanine.
- Author
-
Bonnier, Catherine and Bender, Timothy P.
- Subjects
DIOXANE ,BUTYROLACTONES ,ALKYL bromides ,FLUORESCENCE yield ,CHEMICAL reactions - Abstract
We are reporting the unexpected reaction between bromo-boron subphthalocyanine (Br-BsubPc) and THF, 1,4-dioxane or ?-butyrolactone that results in the ring opening of the solvent and its addition into the BsubPc moiety. Under heating, the endocyclic C-O bond of the solvent is cleaved and the corresponding bromoalkoxy-BsubPc derivative is obtained. These novel alkoxy-BsubPc derivatives have remaining alkyl-bromides suitable for further functionalization. The alkoxy-BsubPcs maintain the characteristic strongly absorption in visible spectrum and their fluorescence quantum yields. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
7. Saccharide Substituted Zinc Phthalocyanines: Optical Properties, Interaction with Bovine Serum Albumin and Near Infrared Fluorescence Imaging for Sentinel Lymph Nodes.
- Author
-
Li Lu, Feng Lv, Bo Cao, Xujun He, and Tianjun Liu
- Subjects
ZINC phthalocyanine ,SERUM albumin ,LYMPH nodes ,SACCHARIDES ,BLOOD proteins ,LACTOSE ,PHTHALOCYANINES - Abstract
Saccharide-substituted zinc phthalocyanines, [2,9(10),16(17),23(24)-tetrakis((1- (β-D-glucose-2-yl)-1H-1,2,3-triazol-4-yl)methoxy)phthalocyaninato]zinc(II) and [2,9(10), 16(17),23(24)-tetrakis((1-(β-D-lactose-2-yl)-1H-1,2,3-triazol-4-yl)methoxy)phthalocyaninato] zinc(II), were evaluated as novel near infrared fluorescence agents. Their interaction with bovine serum albumin was investigated by fluorescence and circular dichroism spectroscopy and isothermal titration calorimetry. Near infrared imaging for sentinel lymph nodes in vivo was performed using nude mice as models. Results show that saccharide- substituted zinc phthalocyanines have favourable water solubility, good optical stability and high emission ability in the near infrared region. The interaction of lactose-substituted phthalocyanine with bovine serum albumin displays obvious differences to that of glucose- substituted phthalocyanine. Moreover, lactose-substituted phthalocyanine possesses obvious imaging effects for sentinel lymph nodes in vivo. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
8. Prospects for More Efficient Multi-Photon Absorption Photosensitizers Exhibiting Both Reactive Oxygen Species Generation and Luminescence.
- Author
-
Robbins, Emma, Leroy-Lhez, Stéphanie, Villandier, Nicolas, Samoć, Marek, and Matczyszyn, Katarzyna
- Subjects
MULTIPHOTON absorption ,REACTIVE oxygen species ,PHOTOSENSITIZERS ,LUMINESCENCE ,PHOTODYNAMIC therapy - Abstract
The use of two-photon absorption (TPA) for such applications as microscopy, imaging, and photodynamic therapy (PDT) offers several advantages over the usual one-photon excitation. This creates a need for photosensitizers that exhibit both strong two-photon absorption and the highly efficient generation of reactive oxygen species (ROS), as well as, ideally, bright luminescence. This review focuses on different strategies utilized to improve the TPA properties of various multi-photon absorbing species that have the required photophysical properties. Along with well-known families of photosensitizers, including porphyrins, we also describe other promising organic and organometallic structures and more complex systems involving organic and inorganic nanoparticles. We concentrate on the published studies that provide two-photon absorption cross-section values and the singlet oxygen (or other ROS) and luminescence quantum yields, which are crucial for potential use within PDT and diagnostics. We hope that this review will aid in the design and modification of novel TPA photosensitizers, which can help in exploiting the features of nonlinear absorption processes. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
9. Crystallographic and Spectroscopic Investigations on Oxidative Coordination in the Heteroleptic Mononuclear Complex of Cerium and Benzoxazine Dimer.
- Author
-
Wattanathana, Worawat, Suetrong, Natapol, Kongsamai, Peetikamol, Chansaenpak, Kantapat, Chuanopparat, Nutthawat, Hanlumyuang, Yuranan, Kanjanaboos, Pongsakorn, and Wannapaiboon, Suttipong
- Subjects
CERIUM ,X-ray powder diffraction ,BENZOXAZINES ,X-ray absorption ,CERIUM compounds ,CHEMICAL properties - Abstract
Among lanthanide-based compounds, cerium compounds exhibit a significant role in a variety of research fields due to their distinct tetravalency, high economic feasibility, and high stability of Ce(IV) complexes. Herein, a systematic investigation of crystallographic information, chemical properties, and mechanistic formation of the novel Ce(IV) complex synthesized from cerium(III) nitrate hexahydrate and 2,2′-(methylazanediyl)bis(methylene)bis(4-methylphenol) (MMD) ligand has been explored. According to the analysis of the crystallographic information, the obtained complex crystal consists of the Ce(IV) center coordinated with two nitrate ligands and two bidentate coordinated (N-protonated and O,O-deprotonated) MMD ligands. The fingerprint plots and the Hirshfeld surface analyses suggest that the C–H⋯O and C–H⋯π interactions significantly contribute to the crystal packing. The C–H⋯O and C–H⋯π contacts link the molecules into infinite molecular chains propagating along the [100] and [010] directions. Synchrotron powder X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) techniques have been employed to gain an understanding of the oxidative complexation of Ce(IV)-MMD complex in detail. This finding would provide the possibility to systematically control the synthetic parameters and wisely design the precursor components in order to achieve the desired properties of novel materials for specific applications. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
10. Unraveling the Photodynamic Activity of Cationic Benzoporphyrin-Based Photosensitizers against Bladder Cancer Cells.
- Author
-
Gomes, Ana T. P. C., Neves, M. Graça P. M. S., Fernandes, Rosa, Ribeiro, Carlos F., Cavaleiro, José A. S., and Moura, Nuno M. M.
- Subjects
BLADDER cancer ,CANCER cells ,PHOTOSENSITIZERS ,METALLOPORPHYRINS ,REACTIVE oxygen species ,CELL survival ,ZINC porphyrins - Abstract
In this study, we report the preparation of new mono-charged benzoporphyrin complexes by reaction of the appropriate neutral benzoporphyrin with (2,2′-bipyridine)dichloroplatinum(II) and of the analogs' derivatives synthesized through alkylation of the neutral scaffold with iodomethane. All derivatives were incorporated into polyvinylpyrrolidone (PVP) micelles. The ability of the resultant formulations to generate reactive oxygen species was evaluated, mainly the singlet oxygen formation. Then, the capability of the PVP formulations to act as photosensitizers against bladder cancer cells was assessed. Some of the studied formulations were the most active photosensitizers causing a decrease in HT-1376 cells' viability. This creates an avenue to further studies related to bladder cancer cells. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
11. Macrocyclic Receptors for Identification and Selective Binding of Substrates of Different Nature.
- Author
-
Mamardashvili, Galina, Mamardashvili, Nugzar, and Koifman, Oscar
- Subjects
MOLECULAR recognition ,MACROCYCLIC compounds ,PHENOMENOLOGICAL biology ,HYDROPHILIC interactions ,CHARGE transfer ,PHARMACODYNAMICS ,CATALYSIS - Abstract
Molecular recognition of host/guest molecules represents the basis of many biological processes and phenomena. Enzymatic catalysis and inhibition, immunological response, reproduction of genetic information, biological regulatory functions, the effects of drugs, and ion transfer—all these processes include the stage of structure recognition during complexation. The goal of this review is to solicit and publish the latest advances in the design and sensing and binding abilities of porphyrin-based heterotopic receptors with well-defined geometries, the recognition ability of which is realized due to ionic, H-bridge, charge transfer, hydrophobic, and hydrophilic interactions. The dissection of the considered low-energy processes at the molecular scale expands our capabilities in the development of effective systems for controlled recognition, selective delivery, and prolonged release of substrates of different natures (including drugs) to their sites of functioning. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
12. Mono-6-Substituted Cyclodextrins—Synthesis and Applications.
- Author
-
Kasal, Petr and Jindřich, Jindřich
- Subjects
CYCLODEXTRINS ,GLUCOSE - Abstract
Cyclodextrins are well known supramolecular hosts used in a wide range of applications. Monosubstitution of native cyclodextrins in the position C-6 of a glucose unit represents the simplest method how to achieve covalent binding of a well-defined host unit into the more complicated systems. These derivatives are relatively easy to prepare; that is why the number of publications describing their preparations exceeds 1400, and the reported synthetic methods are often very similar. Nevertheless, it might be very demanding to decide which of the published methods is the best one for the intended purpose. In the review, we aim to present only the most useful and well-described methods for preparing different types of mono-6-substituted derivatives. We also discuss the common problems encountered during their syntheses and suggest their optimal solutions. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
13. The TDDFT Excitation Energies of the BODIPYs; The DFT and TDDFT Challenge Continues.
- Author
-
Schlachter, Adrien, Fleury, Alexandre, Tanner, Kevin, Soldera, Armand, Habermeyer, Benoit, Guilard, Roger, Harvey, Pierre D., Wai-Yeung, Wong, and Ryota, Sakamoto
- Subjects
DENSITY functional theory ,INTRAMOLECULAR proton transfer reactions - Abstract
The derivatives of 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) are pivotal ingredients for a large number of functional, stimuli-responsive materials and therapeutic molecules based on their photophysical properties, and there is a urgent need to understand and predict their optical traits prior to investing a large amount of resources in preparing them. Density functional theory (DFT) and time-dependent DFT (TDDFT) computations were performed to calculate the excitation energies of the lowest-energy singlet excited state of a large series of common BODIPY derivatives employing various functional aiming at the best possible combination providing the least deviations from the experimental values. Using the common "fudge" correction, a series of combinations was investigated, and a methodology is proposed offering equal or better performances than what is reported in the literature. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
14. Azides and Porphyrinoids: Synthetic Approaches and Applications. Part 2—Azides, Phthalocyanines, Subphthalocyanines and Porphyrazines.
- Author
-
Araújo, Ana R. L., Tomé, Augusto C., Santos, Carla I. M., Faustino, Maria A. F., Neves, Maria G. P. M. S., Simões, Mário M. Q., Moura, Nuno M. M., Abu-Orabi, Sultan T., Cavaleiro, José A. S., and Banert, Klaus
- Subjects
PHTHALOCYANINES ,PORPHYRAZINES ,AZIDES ,METAL phthalocyanines ,ALKYNE derivatives ,GOLD nanoparticles - Abstract
The reaction between organic azides and alkyne derivatives via the Cu(I)-catalyzed azide–alkyne cycloaddition (CuAAC) is an efficient strategy to combine phthalocyanines and analogues with different materials. As examples of such materials, it can be considered the following ones: graphene oxide, carbon nanotubes, silica nanoparticles, gold nanoparticles, and quantum dots. This approach is also being relevant to conjugate phthalocyanines with carbohydrates and to obtain new sophisticated molecules; in such way, new systems with significant potential applications become available. This review highlights recent developments on the synthesis of phthalocyanine, subphthalocyanine, and porphyrazine derivatives where CuAAC reactions are the key synthetic step. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
15. Measuring Sulforaphane and Its Metabolites in Human Plasma: A High Throughput Method.
- Author
-
Langston-Cox, Annie, Anderson, Dovile, Creek, Darren J., Palmer, Kirsten, Wallace, Euan M., and Marshall, Sarah A.
- Subjects
LIQUID chromatography-mass spectrometry ,SULFORAPHANE ,METABOLITES ,BRASSICA ,CYSTEINE - Abstract
(1) Background: There is increasing understanding of the potential health benefits of cruciferous vegetables. In particular sulforaphane (SFN), found in broccoli, and its metabolites sulforaphane-glutathione (SFN-GSH), sulforaphane-cysteine (SFN-Cys), sulforaphane cysteine-glycine (SFN-CG) and sulforaphane-N-acetyl-cysteine (SFN-NAC) have potent antioxidant effects that may offer therapeutic value. Clinical investigation of sulforaphane as a therapeutic antioxidant requires a sensitive and high throughput process for quantification of sulforaphane and metabolites; (2) Methods: We collected plasma samples from healthy human volunteers before and for eight hours after consumption of a commercial broccoli extract supplement rich in sulforaphane. A rapid and sensitive method for quantification of sulforaphane and its metabolites in human plasma using Liquid Chromatography–Mass Spectrometry (LC–MS) has been developed; (3) Results: The LC–MS analytical method was validated at concentrations ranging between 3.9 nM and 1000 nM for SFN-GSH, SFN-CG, SFN-Cys and SFN-NAC and between 7.8 nM and 1000 nM in human plasma for SFN. The method displayed good accuracy (1.85%–14.8% bias) and reproducibility (below 9.53 %RSD) including low concentrations 3.9 nM and 7.8 nM. Four SFN metabolites quantitation was achieved using external standard calibration and in SFN quantitation, SFN-d
8 internal standardization was used. The reported method can accurately quantify sulforaphane and its metabolites at low concentrations in plasma; (4) Conclusions: We have established a time- and cost-efficient method of measuring sulforaphane and its metabolites in human plasma suitable for high throughput application to clinical trials. [ABSTRACT FROM AUTHOR]- Published
- 2020
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.