Publicaciones > Bosch et al

Org. Chem. Front. 2018 May 2; 5(12):1916-1927. doi: 10.1039/C8QO00236C

Dibenzopyridoimidazocinnolinium cations: a new family of light-up fluorescent DNA probes.

Pedro Bosch¹, David Sucunza¹, Francisco Mendicuti², Alberto Domingo³, Juan J Vaquero¹

1. Departamento de Quimica Organica y Quimica Inorganica, Instituto de Investigacion Quimica "Andres M. del Rio" (IQAR) , Universidad de Alcala , 28805 Alcala de Henares , Spain.  2. Departamento de Química Analítica, Química Física e Ingeniería Química, Universidad de Alcalá, Spain.  3. Departamento de Biología de Sistemas, Universidad de Alcalá, Spain.

Abstract

Steady-state and time-resolved fluorescence, circular dichroism and molecular modelling techniques have been applied to a new family of weakly fluorescent dibenzopyridoimidazocinnolinium derivatives whose fluorescence intensity increases significantly (larger than × 3.5) upon DNA addition. The synthesis of these azonia cations, which bind to DNA by intercalation, was carried out using a Westphal condensation and a Suzuki cross coupling reaction as key steps. A live-cell staining analysis by confocal microscopy imaging was also performed and showed the capacity of these new compounds for active uptake and accumulation by living cells, with complex patterns of intracellular distribution observed.

Publicaciones > Cañeque et al

Dyes & Pigments, 2017 Sep 1;144:17-31. doi: 10.1016/10.1016/j.dyepig.2017.05.005.

Azonia aromatic heterocycles as a new acceptor unit in D-π-A+ vs D-A+ nonlinear optical chromophores.

Tatiana Cañeque¹, Ana M. Cuadro¹, Raúl Custodio¹, Julio Alvarez-Builla¹, Belén Batanero¹, Pilar Gómez-Sal¹, Javier Pérez-Moreno², Koen Clays³, Obis Castaño⁴, José L. Andrés⁴, Thais Carmona⁴, Francisco Mendicuti⁴, Juan J Vaquero¹

1. Departamento de Química Orgánica y Química Inorgánica, Universidad de Alcalá, 28871, Alcalá de Henares, Madrid, Spain.  2. Department of Physics, Skidmore College, Saratoga Springs, NY, United States.  3. Department of Chemistry, University of Leuven, Celestijnenlaan 200 D, 3001, Leuven, Belgium.  4. Departamento de Química Analítica, Química Física e Ingeniería Química, Universidad de Alcalá, 28871, Alcalá de Henares, Madrid, Spain.

Abstract

A comparison of D-π-A+ and D-A+ cationic chromophores based on the quinolizinium system as new acceptor units is reported along with the results of studies into their linear and non-linear optical properties and electrochemical data. Experimental and theoretical data show that quinolizinium-based chromophores may provide a new generation of second-order non-linear materials with enhanced performance. The first hyperpolarizabilities were measured by Hyper-Rayleigh scattering experiments and the experimental data are supported by a theoretical analysis. In some chromophores the absence of a bridge (D-A+) between the donor and acceptor fragments enhances the NLO properties and the single crystal structure of such a material has been determined by X-ray diffraction.

Publicaciones > Bosch et al

Dyes & Pigments, 2017 Mar 1;138:135-146. doi: 10.1016/j.dyepig.2016.11.041.

Imidazopyridinium cations: A new family of azonia aromatic heterocycles with applications as DNA intercalators.

Pedro Bosch¹, Verónica García², Başak S.Bilen³, David Sucunza¹, Alberto Domingo², Francisco Mendicuti³, Juan J Vaquero¹

1. Departamento de Química Inorgánica y Química Orgánica, Química Física e Ingeniería Química, Universidad de Alcalá, 28871, Alcalá de Henares, Madrid, Spain.  2. Departamento de Biología de Sistemas, Química Física e Ingeniería Química, Universidad de Alcalá, 28871, Alcalá de Henares, Madrid, Spain.  3. Departamento de Química Analítica, Química Física e Ingeniería Química, Universidad de Alcalá, 28871, Alcalá de Henares, Madrid, Spain.

Abstract

Two novel imidazopyridinium cations formed by a hexacyclic azonia aromatic system have been synthesized. Spectrofluorimetric titrations, circular dichroism measurements, theoretical simulations and fluorescence-based thermal denaturation experiments on these materials have shown the interesting fluorescence properties and DNA-binding ability by intercalation, with a marked preference for AT-rich sequences. Compound 2 presents the highest fluorescence quantum yield (0.32 in 5% DMSO/water and 0.46 in MeOH) and affinity for DNA (binding constant of ∼4.5 × 105 M−1). Moreover, the potential of these compounds for cell staining has been investigated in living HeLa cells by confocal microscopy imaging. This analysis showed the remarkable capacity of both compounds for uptake and accumulation by living cells.

Publicaciones > Zacharioudakis et al

Biorg. Med. Chem. Lett., 2017 Jan 15;27(2):203-207. doi: 10.1016/j.bmcl.2016.11.074.

Quinolizinium as a new fluorescent lysosomotropic probe.

Emmanouil Zacharioudakis¹, Tatiana Cañeque¹, Raúl Custodio², Sebastian Müller¹, Ana M. Cuadro², Juan J Vaquero², Raphaël Rodriguez¹

1. Institut Curie, PSL Research University, Organic Synthesis and Cell Biology Group, 26 rue d’Ulm, 75248 Paris Cedex 05, France, CNRS UMR3666, 75005 Paris, France, INSERM U1143, 75005 Paris, France.  2. Departamento de Química Orgánica y Química Inorgánica, Universidad de Alcalá, 28871 Alcalá de Henares, Madrid, Spain.

Abstract

We have synthesized a collection of quinolizinium fluorescent dyes for the purpose of cell imaging. Preliminary biological studies in human U2OS osteosarcoma cancer cells have shown that different functional groups appended to the cationic quinolizinium scaffold efficiently modulate photophysical properties but also cellular distribution. While quinolizinium probes are known nuclear staining reagents, we have identified a particular quinolizinium derivative salt that targets the lysosomal compartment. This finding raises the question of predictability of specific organelle targeting from structural features of small molecules.

Publicaciones > Marcelo et al

The Journal of Physical Chemistry A. 2015 Aug 18; :2351-2362.

Nonlinear Emission of Quinolizinium Based Dyes With Application in Fluorescence Lifetime Imaging.

Gema Marcelo¹, Sandra Pinto¹, Tatiana Cañeque², Inês F. A. Mariz¹, Ana M. Cuadro², Juan J Vaquero², José M. G. Martinho¹, Ermelinda M. S. Maçôas¹

1. Centro de Química-Física Molecular (CQFM) and Institute of Nanoscience and Nanotechnology (IN), Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisboa, Portugal.  2. Departamento de Química Orgánica y Química Inorganica, Universidad de Alcalá, 28871, Alcalá de Henares, Madrid, Spain.

Abstract

Charged molecules based on the quinolizinum cation have potential applications as labels in fluorescence imaging in biological media under nonlinear excitation. A systematic study of the linear and nonlinear photophysics of derivatives of the quinolizinum cation substituted by either dimethylaniline or methoxyphenyl electron donors is performed. The effects of donor strength, conjugation length, and symmetry in the two-photon emission efficiency are analyzed in detail. The best performing nonlinear fluorophore, with two-photon absorption cross sections of 1140 GM and an emission quantum yield of 0.22, is characterized by a symmetric D-π-A+-π-D architecture based on the methoxyphenyl substituent. Application of this molecule as a fluorescent marker in optical microscopy of living cells revealed that, under favorable conditions, the fluorophore can be localized in the cytoplasmatic compartment of the cell, staining vesicular shape organelles. At higher dye concentrations and longer staining times, the fluorophore can also penetrate into the nucleus. The nonlinearly excited fluorescence lifetime imaging shows that the fluorophore lifetime is sensitive to its location in the different cell compartments. Using fluorescence lifetime microscopy, a multicolor map of the cell is drafted with a single dye.