RESUMEN
The development of the brightest luminescent europium(iii) complexes is traced, including analysis of the C3-symmetric core complex based on a functionalized triazacyclononane and identification of the most suitable strongly absorbing chromophore. Strategies for the synthesis of the complexes, including enantiopure analogues, are outlined and opportunities for applications in time-resolved microscopy and spectral imaging emphasised. Practicable examples are introduced, including selective organelle staining for cellular optical imaging at 65 nm resolution and the development of new bioassays using time-resolved FRET methods.
Asunto(s)
Bioensayo/métodos , Colorantes/síntesis química , Europio/química , Imagen Óptica/métodos , Compuestos Organometálicos/síntesis química , Animales , Técnicas de Química Sintética , Colorantes/química , Colorantes/metabolismo , Humanos , Compuestos Organometálicos/química , Compuestos Organometálicos/metabolismoRESUMEN
A circularly polarized luminescence (CPL) spectrometer has been built and used to study the binding interaction of lactate and four different proteins with racemic EuIII and TbIII complexes in aqueous solution. Lactate binding gives rise to strong induced CPL spectra, and the observed emission dissymmetry factors vary linearly with enantiomeric composition. Particularly strong induced TbIII CPL also characterizes the binding interaction of alpha-1-acid glycoprotein with a dissociation constant, Kd, of 2.5 µM.
RESUMEN
A series of five europium(III) complexes has been prepared from heptadentate N5O2 ligands that possess a brightness of more than 10 mM(-1) cm(-1) in water, following excitation over the range λ=330-355 nm. Binding of several oxy anions has been assessed by emission spectral titrimetric analysis, with the binding of simple carboxylates, lactate and citrate involving a common ligation mode following displacement of the coordinated water. Selectivity for bicarbonate allows the rapid determination of this anion in human serum, with K(d)=37 mM (295 K). The complexes are internalised quickly into mammalian cells and exhibit a mitochondrial localisation at early time points, migrating after a few hours to reveal a predominant lysosomal distribution. Herein, we report the synthesis and complexation behaviour of strongly emissive europium (III) complexes that bind oxy-anions in aqueous media with an affinity and selectivity profile that is distinctively different from previously studied systems.
Asunto(s)
Aniones/química , Compuestos Aza/química , Bicarbonatos/análisis , Bicarbonatos/química , Ácido Cítrico/química , Europio/análisis , Europio/química , Piperidinas/química , Suero/química , Humanos , Ligandos , Luminiscencia , Suero/metabolismoRESUMEN
A ratiometric Eu(III) complex has been developed that localises selectively within the endoplasmic reticulum of living cells. Careful calibration, using a time-gated spectral imaging microscope, allows the intensity ratio of emission bands and the variation of excited state lifetime to be used for pH determination, with a pKa of 7.15.
Asunto(s)
Retículo Endoplásmico/química , Europio/química , Animales , Concentración de Iones de Hidrógeno , Indicadores y Reactivos/química , Ratones , Células 3T3 NIHRESUMEN
The synthesis, structure and photophysical properties of a series of highly emissive europium complexes is reported. Certain complexes enter mammalian cells by macropinocytosis and stain the mitochondria selectively, allowing observation of the Eu emission in cellulo by time-gated spectral imaging.
Asunto(s)
Europio/análisis , Europio/química , Mitocondrias/química , Amilorida/farmacología , Androstadienos/farmacología , Animales , Ratones , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Modelos Moleculares , Estructura Molecular , Células 3T3 NIH , Compuestos Organometálicos/análisis , Compuestos Organometálicos/antagonistas & inhibidores , Compuestos Organometálicos/química , Temperatura , WortmaninaRESUMEN
Europium and terbium complexes of two structurally related ligands have been evaluated as optical probes to monitor changes in lysosomal pH; calibration using ionophores and fluorescent probes allows monitoring of the time dependence of lysosomal pH change, examining the green/red intensity ratio from internalised Tb-Eu complexes.
Asunto(s)
Colorantes Fluorescentes/química , Elementos de la Serie de los Lantanoides/química , Lisosomas/metabolismo , Animales , Células CHO , Línea Celular , Complejos de Coordinación/química , Cricetinae , Cricetulus , Europio/química , Células HeLa , Humanos , Concentración de Iones de Hidrógeno , Lisosomas/química , Células MCF-7 , Ratones , Células 3T3 NIH , Terbio/químicaRESUMEN
The synthesis of a novel Tb(III) luminescent probe for the detection of thiols is presented. The probe 1.Tb, possessing a maleimide moiety, as its sulfhydryl acceptor, was poorly emitting in aqueous pH 7 solution in the absence of a thiol. However, upon addition of thiols such as glutathione (GSH), large enhancements were observed, particularly within the physiological pH range. In contrast no enhancements were observed in the presence of the oxidized form of glutathione (GSSG), except in the presence of the enzyme glutathione reductase and NADPH which enabled 1.Tb to be used to observe the enzymatic reduction of GSSG to GSH in real time.