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23 results on '"Mariano, L"'

5. Triarylmethane Fluorophores Resistant to Oxidative Photobluing

Author

Gražvydas Lukinavičius, Alexey N. Butkevich, Stefan W. Hell, and Mariano L. Bossi

Subjects
Fluorescence-lifetime imaging microscopy, Fluorophore, Spectral stability, STED microscopy, Context (language use), General Chemistry, 010402 general chemistry, Photochemistry, 01 natural sciences, Biochemistry, Photobleaching, Fluorescence, Catalysis, Article, 0104 chemical sciences, Rhodamine, chemistry.chemical_compound, Colloid and Surface Chemistry, chemistry
Abstract

Spectral stability of small-molecule fluorescent probes is required for correct interpretation and reproducibility of multicolor fluorescence imaging data, in particular under high (de)excitation light intensities of super-resolution imaging or in single-molecule applications. We propose a synthetic approach to a series of spectrally stable rhodamine fluorophores based on sequential Ru- and Cu-catalyzed transformations, evaluate their stability against photobleaching and photoconversion in the context of other fluorophores using chemometric analysis, and demonstrate chemical reactivity of fluorophore photoproducts. The substitution patterns providing the photoconversion-resistant triarylmethane fluorophores have been identified, and the applicability of nonbluing labels in live-cell STED nanoscopy is demonstrated.

Published
2018

6. Photoisomerization of azobenzenes and spirocompounds in nematic and in twisted nematic liquid crystals

Author

Bossi, Mariano L., Murgida, Daniel H., and Aramendia, Pedro F.

Subjects
Azo compounds -- Chemical properties, Azo compounds -- Optical properties, Benzene -- Chemical properties, Benzene -- Optical properties, Twisted nematic liquid crystal displays -- Research, Isomerization -- Analysis, Chemicals, plastics and rubber industries
Abstract

The nematic and twisted nematic liquid crystals mixed with azobenzene (AB), spirooxazine (SO) and spiropyran (SP) are investigated by using spectroscopic methods, including birefringence and polarized transmission, to monitor the amplitude of the changes upon phototransformation as well as the dark kinetics. The results have shown SP to be an interesting photochemical probe as it has orientation photochromism and is able to adequately sense the orientation dependent polarity of this anisotropic medium.

Published
2006

9. Correction to 'Triarylmethane Fluorophores Resistant to Oxidative Photobluing'

Author

Mariano L. Bossi, Gražvydas Lukinavičius, Alexey N. Butkevich, and Stefan W. Hell

Subjects
Colloid and Surface Chemistry, Chemistry, General Chemistry, Computational biology, Oxidative phosphorylation, Biochemistry, Catalysis, Addition/Correction
Abstract

Spectral stability of small-molecule fluorescent probes is required for correct interpretation and reproducibility of multicolor fluorescence imaging data, in particular under high (de)excitation light intensities of super-resolution imaging or in single-molecule applications. We propose a synthetic approach to a series of spectrally stable rhodamine fluorophores based on sequential Ru- and Cu-catalyzed transformations, evaluate their stability against photobleaching and photoconversion in the context of other fluorophores using chemometric analysis, and demonstrate chemical reactivity of fluorophore photoproducts. The substitution patterns providing the photoconversion-resistant triarylmethane fluorophores have been identified, and the applicability of nonbluing labels in live-cell STED nanoscopy is demonstrated.

Published
2019

10. A Photochromic Bioconjugate with Photoactivatable Fluorescence for Superresolution Imaging

Author

Subramani Swaminathan, Beatriz Araoz, Mariano L. Bossi, Shiori Yamazaki, Mercedes M. A. Mazza, Jaume Garcia-Amorós, Françisco M. Raymo, M. Julia Roberti, Janet Cusido, Ek Raj Thapaliya, Sherif Shaban Ragab, and Amy M. Scott

Subjects
Fluorophore, 02 engineering and technology, 010402 general chemistry, Photochemistry, 01 natural sciences, Photochromism, chemistry.chemical_compound, Stimulated emission, Fluorescence Nanoscopy, Physical and Theoretical Chemistry, Bioconjugation, Otras Ciencias Químicas, Ciencias Químicas, food and beverages, Chromophore, 021001 nanoscience & nanotechnology, STED, GSDIM, Fluorescence, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Bioconjugates, General Energy, chemistry, Excited state, Superresolution Microscopy, 0210 nano-technology, CIENCIAS NATURALES Y EXACTAS, Conjugate
Abstract

A coumarin fluorophore and an oxazine photochrome can be integrated within the same molecular skeleton and connected covalently to a secondary antibody. Illumination of the antibody-dyad conjugate at an appropriate activation wavelength opens the oxazine ring reversibly and shifts bathochromically the ground-state absorption of the coumarin component. Selective excitation of the photochemical product then produces significant fluorescence and allows the detection of activated bioconjugates at the single-molecule level. Such fluorescence activation events can be exploited to resolve temporally individual emitters and reconstruct images of immunolabeled cells with subdiffraction resolution. Relying on a similar conjugation protocol, a model compound, incorporating the same chromophore of the photochemical product, can also be connected covalently to a secondary antibody. Stimulated emission can be exploited to deplete the excited state of the bioconjugated chromophores and switch their fluorescence off. These operating principles for fluorescence switching also permit the imaging of immunolabeled cells with subdiffraction resolution. Thus, these photoswitchable molecules, in combination with the labeling ability of antibodies, can evolve into valuable probes for bioimaging with superresolution. Fil: Cusido, Janet. University of Miami; Estados Unidos Fil: Ragab, Sherif Shaban. University of Miami; Estados Unidos. National Research Centre; Estados Unidos Fil: Thapaliya, Ek Raj. University of Miami; Estados Unidos Fil: Swaminathan, Subramani. University of Miami; Estados Unidos Fil: Garcia-Amorós, Jaume. University of Miami; Estados Unidos Fil: Roberti, Maria Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina Fil: Araoz, Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina Fil: Mazza, Mercedes M. A.. University of Miami; Estados Unidos Fil: Yamazaki, Shiori. University of Miami; Estados Unidos Fil: Scott, Amy M.. University of Miami; Estados Unidos Fil: Raymo, Françisco M.. University of Miami; Estados Unidos Fil: Bossi, Mariano Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina

Published
2016
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12. Mapping the fluorescence performance of a photochromic-fluorescent system coupled with gold nanoparticles at the single molecule-single particle level

Author

Beatriz Araoz, Maria Julia Roberti, Mariano L. Bossi, Sabrina Simoncelli, and Pedro F Aramendía

Subjects
Indoles, Analytical chemistry, Metal Nanoparticles, INGENIERÍAS Y TECNOLOGÍAS, photobleaching, Photochemistry, Biochemistry, Catalysis, Fluorescence, Photochromism, Colloid and Surface Chemistry, Microscopy, Fluorescence microscope, Molecule, Benzopyrans, Fluorescent Dyes, Nanotecnología, Chemistry, fluorescence enhancement, General Chemistry, Nitro Compounds, Nano-materiales, Photobleaching, spiropyran-merocyanine, Microscopy, Fluorescence, Colloidal gold, gold nanoparticles, Particle, Gold
Abstract

Single-molecule (SM) fluorescence microscopy was used to investigate the photochromic fluorescent system spiropyran-merocyanine (SP - MC) interacting with gold nanoparticles (AuNPs). We observe a significant increase in the brightness of the emissive MC form, in the duration of its ON time, and in the total number of emitted photons. The spatial distribution of SMs with improved photophysical performance was obtained with 40 nm precision relative to the nearest AuNP. We demonstrate that even photochromic systems with poor photochemical performance for SM can become suitable for long time monitoring and high performance microscopy by interaction with metallic NP. Fil: Simoncelli, Sabrina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina Fil: Roberti, Maria Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina Fil: Araoz, Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de Los Materiales, Medioambiente y Energía; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina Fil: Bossi, Mariano Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de Los Materiales, Medioambiente y Energía; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina Fil: Aramendia, Pedro Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Published
2014
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15. Photoactivatable Fluorophores for Super-Resolution Imaging Based on Oxazine Auxochromes

Author

Ibrahim Yildiz, Françisco M. Raymo, Erhan Deniz, Janet Cusido, Massimiliano Tomasulo, Salvatore Sortino, Mariano L. Bossi, and Marco Petriella

Subjects
Fluorophore, Photochemistry, Auxochrome, Otras Ciencias Químicas, Ciencias Químicas, Nuclear magnetic resonance spectroscopy, Fluorene, Photoswitching, Fluorescence, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, chemistry.chemical_compound, General Energy, Nanoscopy, chemistry, Pyrene, Physical and Theoretical Chemistry, Cyanine, Acetonitrile, CIENCIAS NATURALES Y EXACTAS
Abstract

We synthesized five fluorophore-photochrome dyads designed to switch reversibly between nonfluorescent and fluorescent isomers under optical control. These compounds pair an oxazine photochrome to a biphenyl, fluorene, pyrene, coumarin, or cyanine fluorophore in their molecular skeleton and can be prepared in a single step from known precursors in yields ranging from 30 to 63%. Nuclear magnetic resonance spectroscopy indicates that the oxazine ring of these compounds opens and closes spontaneously on a millisecond time scale in acetonitrile at ambient temperature. Under these conditions, the fraction of ring-open isomer at equilibrium is negligible in all instances with the exception of the cyanine derivative, which instead is almost exclusively in this form. Absorption and emission spectroscopies demonstrate, however, that the fraction of ring-open isomer is sensitive to solvent polarity and increases with a transition from acetonitrile to methanol. Alternatively, the ring-open isomer can be populated photochemically or trapped with the addition of acid. In both instances, the characteristic absorption and emission bands of the 3H-indolium chromophores, embedded within the ring-open species, can clearly be observed in the visible region. In the case of the coumarin derivative, the brightness of this chromophoric fragment is sufficiently high to permit the imaging of individual molecules with excellent signal-to-noise ratios. In fact, the fluorescence of single fluorophore-photochrome dyads can be activated under the influence of ultraviolet inputs and the resulting species can be localized with nanoscale precision under visible illumination. Indeed, subdiffraction images of polymer nanoparticles, doped with this particular dyad, can be reconstructed with nanoscale resolution. Thus, our operating principles for fluorescence switching at the single-molecule level can offer the opportunity to overcome diffraction and, eventually, lead to the development of an entire family of probes for super-resolution fluorescence imaging. © 2012 American Chemical Society. Fil: Deniz, Erhan. University of Miami; Estados Unidos Fil: Tomasulo, Massimiliano. University of Miami; Estados Unidos Fil: Cusido, Janet. University of Miami; Estados Unidos Fil: Yildiz, Ibrahim. University of Miami; Estados Unidos Fil: Petriella, Marco. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina Fil: Bossi, Mariano Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina Fil: Sortino, Salvatore. University of Catania; Italia Fil: Raymo, Françisco M.. University of Miami; Estados Unidos

Published
2012
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18. Influence of Monolayer State on Spectroscopy and Photoisomerization of an Amphiphilic Styryl-Pyridinium Dye on a Solid Substrate.

Author

Mariano L. Bossi, Andrey A. Turshatov, Sergei Yu. Zaitsev, Michael V. Alfimov, Dietmar Möbius, and Stefan W. Hell

Subjects
*MONOMOLECULAR films, *SPECTRUM analysis, *PHOTOISOMERIZATION, *PHOTOCHROMIC materials
Abstract

The spectroscopy and photochromic properties of transferred monolayers of the amphiphilic styryl-pyridinium dye 4-(3‘,4‘-dimethoxystyryl)-N-octadecylpyridinium perchlorate (DMPOP) were studied at different conditions during their transfer. The emission maxima of the monolayers transferred from the air−water interface in the liquid-expanded phase are strongly dependent on the surface pressure applied during the transfer process, even at values when the area per molecule is 2−3 times larger than the area occupied by a chromophore. In monolayers transferred from the liquid-condensed phase, the presence of a different kind of aggregates was observed. The fluorescence emission properties of the monolayers can be reversibly modulated by photoinduced E−Zisomerization. A blue shift up to 72 nm in the emission maximum, depending on the transfer conditions of the films, can be obtained by irradiation with blue light, and partially recovered (a red shift of up to 26 nm) with UV radiation. The rate at which the first process (E→Z) takes place is drastically reduced in monolayers transferred from the liquid-condensed phase as compared to those transferred from the liquid-expanded one. However, the rate of the reverse reaction (Z→E) is not significantly altered. These properties make DMPOP a promising material for the preparation of Langmuir−Blodgett films, whose properties can be effectively controlled by the transfer conditions and subsequently optically modulated, for potential applications as photonics devices for data storage. [ABSTRACT FROM AUTHOR]

Published
2007
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19. Photoisomerization of Azobenzenes and Spirocompounds in Nematic and in Twisted Nematic Liquid Crystals.

Author

Mariano L. Bossi, Daniel H. Murgida, and Pedro F. Aramendía

Subjects
*LIGHT sources, *LIQUID crystals, *SPECTRUM analysis, *ETHANES
Abstract

Samples of a nematic mixture of ZLI1132 and of a twisted nematic mixture composed of ZLI1132 and chiral inductor S811, including 1%−10% (w/w) 4-N,N-dimethylaminoazobenzene (DAB), (4‘-nitro)-4-N,N-dimethylaminoazobenzene (NDAB), spiropyran (SP), or spirooxazine (SO) were irradiated to produce the photochromic transformation of the dopant. The changes in the system were monitored by time-resolved transmission spectroscopy, time-resolved birefringence, or polarized Raman scattering. The medium sensitivity of the kinetics and spectroscopy of some of the probes was used to derive information on polarity of the medium. In the systems studied, apart from the changes in absorption spectrum, great changes in birefringence can be photoinduced and the order of the nematic phase can be changed in either direction, depending on the dopant. The open form of SP can discriminate orientation polarity. Although the polarity parallel to the mesogenic director is similar to that for acetone, the perpendicular orientation has a polarity similar to acetonitrile. In agreement with this observation, the kinetics of the Z → E isomerization of NDAB, oriented parallel to the mesogenic director, also experiences a polarity similar to that for acetone. The decay rate constant of the open form of SP displays a linear relationship between its Arrhenius parameters, which is universal in a great variety of homogeneous solvents, solvent mixtures, and liquid crystals, therefore validating the hypothesis that the same type of transformation is observed in all these cases, namely, the decay of the open form monomer. The dopants used have been proven to be adequate probes of bulklike properties in locally heterogeneous systems as liquid crystals. [ABSTRACT FROM AUTHOR]

Published
2006
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22. Fluorescent Photoswitchable Diarylethenes for Biolabeling and Single-Molecule Localization Microscopies with Optical Superresolution.

Author

Roubinet B, Weber M, Shojaei H, Bates M, Bossi ML, Belov VN, Irie M, and Hell SW

Abstract

A modular assembly of water-soluble diarylethenes (DAEs), applicable as biomarkers for optical nanoscopy, is reported. Reversibly photoswitchable 1,2-bis(2-alkyl-6-phenyl-1-benzothiophene-1,1-dioxide-3-yl)perfluorocyclopentenes possessing a fluorescent "closed" form were decorated with one or two methoxy group(s) attached to the para-position(s) of phenyl ring(s) and two, four, or eight carboxylic acid groups. Antibody conjugates of these DAEs feature low aggregation, efficient photoswitching in aqueous buffers, specific staining of cellular structures, and photophysical properties (high emission efficiencies and low cycloreversion quantum yields) enabling their application in superresolution microscopy. Images of tubulin, vimentin, and nuclear pore complexes are presented. The superresolution images can also be acquired by using solely 488 nm light without additional photoactivation with UV light. These DAEs exhibit reversible photoswitching without requiring any additives to the imaging media and open new paths toward the modular design of fluorescent dyes for bioimaging with optical superresolution.

Published
2017
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23. Molecular organization of an amphiphilic styryl pyridinium dye in monolayers at the air/water interface in the presence of various anions.

Author

Turshatov AA, Möbius D, Bossi ML, Hell SW, Vedernikov AI, Lobova NA, Gromov SP, Alfimov MV, and Zaitsev SY

Subjects
Anions chemistry, Coloring Agents chemistry, Membranes, Artificial, Pyridinium Compounds chemistry
Abstract

Amphiphilic 4-(3',4'-dimethoxystyryl)-N-octadecylpyridinium perchlorate and bromide form stable monolayers at the air/water interface. Small differences in the surface pressure-area and surface potential-area isotherms depending on the anion indicate interactions between the chromophore and the anions on the pure water subphase. The monolayer behavior is considerably modified on 10 mM aqueous solutions of KI, KClO4, KCl, and KF as revealed by isotherm measurements, reflection spectroscopy, and Brewster angle microscopy. The phase transition observed in the isotherms is shifted to higher surface pressure because of variation of the salt according to the Hofmeister series. Upon monolayer compression, the chromophores are increasingly tilted, and a shift of the band to longer wavelengths is attributed to the environment becoming less polar. However, in the case of KCl at small areas per molecule, relaxation is observed at constant area with the appearance of a new band shifted to shorter wavelengths. This band is assigned to small associates of about four chromophores (H aggregates). In the case of KI, a new band shifted to longer wavelengths is found. Theoretical calculations did not yield a transition in the observed range, even for large aggregates (J aggregates). Therefore, other interactions may be responsible for the appearance of this band.

Published
2006
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