RESUMEN
The fluorescence of sensors 1 and 6, which are designed in terms of photoinduced electron transfer (PET), is switched 'on' by factors of 15 and 6 with avidin in a rather selective manner. Sensors 3 and 7, simpler derivatives of 1, are switched 'on' by factors of 16 and 7.5 with bovine serum albumin, though at 30-fold higher concentrations.
Asunto(s)
Avidina/química , Colorantes Fluorescentes/química , Albúmina Sérica Bovina/química , Animales , Antracenos/química , Biotina/análogos & derivados , Biotina/química , Bovinos , Fluorescencia , Interacciones Hidrofóbicas e Hidrofílicas , LigandosRESUMEN
Herein we present a supramolecular (delayed luminescent) Eu(III)-based pH-responsive probe/sensor with the ability to detect the urease-mediated hydrolysis of urea in aqueous solution. A series of photophysical titrations show this Eu(III) chelate behaves as an "on-off" luminescent switching probe, with its luminescence being quenched upon urea being enzymatically converted into ammonia and carbon dioxide. Calculation of the rate constant (k) and activation energy (Ea) for this hydrolysis reaction are detailed; the results demonstrate a direct observation of enzymatic activity in solution by the sensor. The potential application of this probe in detecting the onset of catheter-associated urinary tract infections (CAUTIs) is also demonstrated by incorporating 1.Eu into water-permeable hydrogels that can be utilized as an alternative coating for catheters.
Asunto(s)
Compuestos Heterocíclicos/metabolismo , Hidrogeles/metabolismo , Elementos de la Serie de los Lantanoides/metabolismo , Polímeros/metabolismo , Ureasa/metabolismo , Infecciones Urinarias/diagnóstico , Ciclamas , Compuestos Heterocíclicos/química , Humanos , Hidrogeles/química , Concentración de Iones de Hidrógeno , Hidrólisis , Elementos de la Serie de los Lantanoides/química , Luminiscencia , Sondas Moleculares/química , Sondas Moleculares/metabolismo , Polímeros/química , Soluciones , Urea/química , Urea/metabolismo , Ureasa/química , Infecciones Urinarias/metabolismoRESUMEN
The synthesis of coordinatively unsaturated tetra-substituted 1,4,7,10-tetraazacyclododecane (cyclen) lanthanide complexes is described; these structures, possessing hydrophobic (C12-alkyl) tails and hydrophilic head groups, self-assemble into supramolecular micellar structures in aqueous solution, and hence can be utilised as novel contrast agents for MRI.
Asunto(s)
Medios de Contraste/química , Complejos de Coordinación/química , Elementos de la Serie de los Lantanoides/química , Mediciones Luminiscentes , Imagen por Resonancia Magnética , Micelas , Ciclamas , Europio/química , Gadolinio/química , Compuestos Heterocíclicos/química , Interacciones Hidrofóbicas e Hidrofílicas , Iones/químicaRESUMEN
The combination of lanthanides and nanoparticles to develop new hybrid nanomaterials has become a highly topical area of research in the field of sensing, biomedical imaging, drug delivery, etc. However, these novel nanomaterials have to be carefully designed to ensure that the unique properties conveyed by each component, i.e., lanthanide ions and nanoparticles, are maximized and not negatively affected by one another. In this Forum Article, the main advances in the design of lanthanide-based nanoparticles will be discussed, with the first part focusing on the design of gadolinium(III)-based nanoparticles and their use as magnetic resonance imaging agents. The second part will then describe the main and most recent designs of luminescent lanthanide-based nanoparticles and their applications as sensors or imaging agents, with a special emphasis on our contribution to this area.
