Design and synthesis of new molecules based on indolium derivatives for two-photon absorption bioimaging applications

Bioimaging is the visualization of biological processes in real time, interfering as less as possible with these and using non-invasive methods. Among others, fluorescence methods have acquired a very important role in these purposes through the nature of the light. Bioimaging pretends to understand how our organism works identifing subcellular organelles, following cellular processes, quantifying ion or biological species and visualising interactions of molecules with their targets in living cells or tissues. In the last decades, two-photon (TP) microscopy is unseating classical one-photon (OP) microscopy due to its advantages, such as the use of lower energy excitation wavelengths or the possibility of focus in depth, among others. Nowadays, it is an interesting target design and develop of new probes for TP microscopy to biomaging. Fluorophores based on indolenines are a family of compounds with promising properties in this sense. In this work, we present the design, synthesis and characterization of new indolium derivatives with promising properties to be used in bioimaging applications in living cells with different purposes.Real Sociedad Española de Química, Jóvenes Invetigadores Químicos, Facultad de Ciencias Ambientales y Bioquímica (UCLM), Merck, Cortes de Castilla la Mancha, Reaxys (Elsevier), Diputación de Toledo, MestreLab Research, Sección Territorial de Castilla la Mancha (RSEQ), Grupo especializado en Nanociencia y Materiales Moleculares (RESEQ), Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

New molecules based indolium for two-photon absortion bioimaging applications

The development of organic materials with 2PA has attracted intensive attention in the past two decades. In two-photon bio-imaging applications the design of the chromophore requires to have a good cross-section and good biological compatibility which depends on the molecular volume and polarity. Fluorophores based on indolenines are one of these organic materials. These compounds and related are used in fluorescence microscopy as in super-resolution. The non-invasive nature of light allows imaging of biological specimens with minimal disruption, so you can see the dynamic processes that occur in living cells and tissues. In this work, we present the design, synthesis and characterization of new indolium derivatives. These compounds are easy to achieve with good yields and good photophysical properties. In addition, time-dependent density functional theory (TDDFT) has been carried out to investigate the energy level of the ground and excited state. Also, these molecules have been proved on cells.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Tuning pKa in new molecules based on indolines for two-photon absorption bioimaging applications

Fluorescence-based biosensors have become essential tools for modern biology, allowing real-time monitoring of biological processes within living cells. The differences between pH play a significant role in multiple biological process such as proliferation, apoptosis, endocytic process and defense. Therefore, intracellular fluorescent pH probes comprise one of the most widely used families of biosensors in microscopy. In this work, we present the design, synthesis and characterization of new one and two photon pH activatable fluorescent probes based on naphthalene-indoline derivatives with an off-on response to different pH environments. These compounds are easy to achieve with good yields and have good photophysical properties. Simple modifications in the structure of these compounds allow tuning their pKa easily and cover a width range of pH in their applications. The preliminary results obtained with these fluorescent probes indicate that they have promising properties to be use in bioimaging applications in living cells.Real Sociedad Española de Química y Grupo Especializado de Química Orgánica de la RSEQ•Universidade de Santiago de Compostela • CIQUS • Lilly • Mestrelab Research •Thieme •Scharlab • Acros • ABCR • AMSLab • GalChimia • Elsevier • The Journal of the American Chemical Society • ACS Omega • Organic Letters • The Journal of Organic Chemistry • Accounts of Chemical Research. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

New indolium fluorofores for two-photon absortion (2PA) bioimaging applications

The development of organic materials with 2PA has attracted intensive attention in the past two decades [1]. In two-photon bio-imaging applications the design of the chromophore requires to have a good cross-section (σ2PA) and good biological compatibility which depends on the molecular volume and polarity [2]. In this work, we present the design, synthesis and characterization of new indolium derivatives. These compounds are easy to achieve with good yields and good photophysical properties. In addition, time-dependent density functional theory (TDDFT) has been carried out to investigate the energy level of the ground and excited state. Their spectral properties and assays performed on cultured cells, demonstrate the potential of these compounds as fluorescent probes with application in two-photon bio-imaging.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Ministerio de Ciencia e Innovación-Spain (CTQ2013-41339-P and CTQ2015- 71896-REDT

Detecting hydroxyl radical with a new two-photon fluorescent probe in living cells

Reactive oxygen species (ROS) are known to be involved in the onset and development of multiple diseases, including cancer, cardiovascular diseases, neurodegenerative diseases and diabetes among others. Generation of ROS is a phenomenon that results from normal cell metabolism as well as from the response to certain pathologic stimuli like certain cytokines, xenobiotics and bacterial infection. These ROS are highly reactive, short-lived molecules that play critical roles in the living cell and it is well accepted that cellular oxidative stress results from the imbalance between generation and elimination of ROS in cells. In this work, we describe the design and synthesis of a two photon (TP) organelle-targeting activatable fluorescent probe. This probe is a naphthalene-indoline compound that targets specifically lysosomes, reaching these organelles in the fluorescence “off” state and minimizing background reactions. Upon arrival at the lysosomes, the probe is triggered and a fluorescence “on” signal is observed that can be combined with TP microscopy to image the lysosomal •OH in living cells.Real Sociedad Española de Química y Grupo Especializado de Química Orgánica de la RSEQ•Universidade de Santiago de Compostela • CIQUS • Lilly • Mestrelab Research •Thieme •Scharlab • Acros • ABCR • AMSLab • GalChimia • Elsevier • The Journal of the American Chemical Society • ACS Omega • Organic Letters • The Journal of Organic Chemistry • Accounts of Chemical Research. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Rapid amplitude-modulation of a diarylethene photoswitch: en route to contrast-enhanced fluorescence imaging

A water soluble diarylethene (DAE) derivative that displays exceptionally intense fluorescence from the colorless open form has been synthesized and characterized using UV/vis spectroscopy and fluorescence microscopy. We show that the bright emission from the open form can be rapidly switched using amplitude modulated red light, that is, by light at wavelengths longer than those absorbed by the fluorescent species. This is highly appealing in any context where undesired background fluorescence disturbs the measurement, e.g., the autofluorescence commonly observed in fluorescence microscopy. We show that this scheme is conveniently applicable using lock-in detection, and that robust amplitude modulation of the probe fluorescence is indeed possible also in cell studies using fluorescence microscopy

“Off-on” two-photon indolenine probes for pH bioimaging

Fluorescence-based biosensors have become an indispensable tool in modern biology. These molecules can be used to monitor processes inside living cells and in real-time. The control of the pH is crucial in multiple biological process such as proliferation, apoptosis and defense. Therefore, the use of such pH probes are widespread in fluorescence microscopy. Recently, we have described a biosensor with excellent photophysical and suitable two-photon absorption (TPA) properties. This sensor allows the detection of hydroxyl radicals inside lysosomes. Based on this scaffold, we have designed, synthesized and characterized a new TPA fluorescent probe with an “off-on” response to different pH environments. These naphthalene-indolenine derivatives have a high synthetic versatility through affordable and efficient synthesis. The preliminary results suggest that this sensor has promising properties for detecting pH changes inside living cells.Real Sociedad Española de Química. Universidad de Murcia. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Benzotriazole-based multidonor-acceptor systems as attractive two-photon absorption dye platforms

Pyrazine-decorated benzotriazole cores allow the orthogonal combination of two dipolar systems within a single molecule. A series of this type of derivatives was synthesized and their photophysical features were studied. The properties of these compounds showed remarkable differences in function depending on the substitution in the pyrazine ring of the benzotriazole core. Furthermore, the two-photon absorption property (2PA) was studied to determine the structure-properties relationship for the reported compounds. The best dye achieved a crosssection of 1532 GM, which was higher than values previously obtained for similar D-π-A-π-D benzotriazole derivatives. TD-DFT calculations, which supported the experimental observations, indicating the interaction between the two dipolar systems was responsible for enhancing the 2 PA properties and favoring bathochromic shifts.PCI2019-111825-2, PID2019-104293GB-I00, UMA18-FEDERJA-007, SBPLY/17/180501/000189, PID2020-119636GB-I00 , RED2018-102331-T, Universidad de Málaga / CBU

An outdoor test facility for the Cherenkov Telescope Array mirrors

The Cherenkov Telescopes Array (CTA) is planned to be an Observatory for very high energy γ-ray astronomy and will consist of several tens of telescopes which account for a reflective surface of more than 10000 m2 . The mirrors of these telescopes will be formed by a set of facets. Different technological solutions are under test inside the CTA Consortium. Most of them involve composite structures whose behavior under real observing conditions is not yet fully tested. An outdoor test facility has been built in one of the candidate sites for CTA, in Argentina (San Antonio de los Cobres [SAC], 3600m a.s.l) in order to monitor the optical and mechanical properties of these facets exposed to the local atmospheric conditions for a given period of time. In this work we present the preliminary results of the first Middle Size Telescope (MST) mirror-monitoring campaign, started in 2013.Fil: Medina, Maria Clementina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Garcia, Beatriz Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Tecnología en Detección y Astropartículas. Comisión Nacional de Energía Atómica. Instituto de Tecnología en Detección y Astropartículas. Universidad Nacional de San Martín. Instituto de Tecnología en Detección y Astropartículas; ArgentinaFil: Maya, J.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Tecnología en Detección y Astropartículas. Comisión Nacional de Energía Atómica. Instituto de Tecnología en Detección y Astropartículas. Universidad Nacional de San Martín. Instituto de Tecnología en Detección y Astropartículas; ArgentinaFil: Mancilla, A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Tecnología en Detección y Astropartículas. Comisión Nacional de Energía Atómica. Instituto de Tecnología en Detección y Astropartículas. Universidad Nacional de San Martín. Instituto de Tecnología en Detección y Astropartículas; ArgentinaFil: Larrarte, Juan Jose. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Rasztocky, Emiliano. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Benitez, Martin Ezequiel. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Dipold, J.. Instituto de Física de Sao Carlos; BrasilFil: Platino, Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Tecnología en Detección y Astropartículas. Comisión Nacional de Energía Atómica. Instituto de Tecnología en Detección y Astropartículas. Universidad Nacional de San Martín. Instituto de Tecnología en Detección y Astropartículas; ArgentinaFil: CTA Consortium. No especifíca;33rd International Cosmic Ray Conference (ICRC 2013): The Astroparticle Physics ConferenceRío de JaneiroBrasilCherenkov Telescope Array Consortiu

Toward Two-Photon Absorbing Dyes with Unusually Potentiated Nonlinear Fluorescence Response

The combination of two two-photon-induced processes in a F\uf6rster resonance energy transfer (FRET)-operated photochromic fluorene-dithienylethene dyad lays the foundation for the observation of a quartic dependence of the fluorescence signal on the excitation light intensity. While this photophysical behavior is predicted for a four-photon absorbing dye, the herein proposed approach opens the way to use two-photon absorbing dyes, reaching the same performance. Hence, the spatial resolution limit, being a critical parameter for applications in fluorescence imaging or data storage with common two-photon absorbing dyes, is dramatically improved