RESUMEN
Solid [CuI(piperazine)0.5]∞, characterized by a structure with an infinite double chain of CuI, presents an unexpected dual luminescence. The short copper-copper distances allow the existence of both cluster-centered and 1-D delocalized electronic transitions, as emerged from theoretical calculations. Beyond the more common cluster-centered emission a higher energy band, which differs in lifetime and in temperature dependence, is observed.
RESUMEN
A non-fluorescent naphthalene diimide (NDI) dimer, conjugating red and blue NDI dyes, becomes red/NIR emitting upon G-quadruplex binding. The fluorescence lifetime which is significantly different for the complexes, the G-quadruplex/dimer and the weakly emitting ds-DNA/dimer is the key feature for the development of new rationally engineered G-quadruplex sensors.
Asunto(s)
G-Cuádruplex , Imidas/química , Naftalenos/química , Colorantes/química , ADN/química , Dimerización , Fluorescencia , Espectrometría de FluorescenciaRESUMEN
Low aqueous solubility of porphyrin-based photosensitizers hampers their clinical use in photodynamic therapy because of complex delivery. In this study, we explore meso-tetra(m-hydroxyphenyl)-21,23H-porphyrin (mTHPP), a potent photosensitizer, covalently attached to ß-cyclodextrin (CD-mTHPP) with a focus on topical delivery and cellular uptake. The photophysical properties of CD-mTHPP were examined using steady-state fluorescence and lifetime measurements verifying increased aqueous solubility. Confocal and fluorescence lifetime imaging microscopy on human squamous carcinoma cells (A431) evidenced a cytoplasmic uptake of CD-mTHPP in predominantly monomeric form. CD-mTHPP was also delivered to human skin ex vivo and the skin penetration was assessed using two-photon fluorescence microscopy. The results indicated that CD-mTHPP exhibits improved skin distribution compared to mTHPP alone using aqueous vehicles. Thus the CD-mTHPP conjugate demonstrates improved biodistribution ex vivo compared to mTHPP and is a promising multimodal system for photodynamic therapy.
Asunto(s)
Fármacos Fotosensibilizantes/química , Fármacos Fotosensibilizantes/farmacocinética , Porfirinas/química , Porfirinas/farmacocinética , beta-Ciclodextrinas/química , beta-Ciclodextrinas/farmacocinética , Transporte Biológico Activo , Carcinoma de Células Escamosas/metabolismo , Línea Celular Tumoral , Femenino , Humanos , Técnicas In Vitro , Microscopía de Fluorescencia por Excitación Multifotónica , Procesos Fotoquímicos , Fotoquimioterapia , Piel/metabolismo , Solubilidad , Espectrometría de Fluorescencia , Espectrofotometría , AguaRESUMEN
A new class of calix[4]arene crown ethers with one or two bipyridines appended to the polyether ring (lariat calixcrowns) have been designed and synthesized; the luminescence properties of their Eu3+ and Tb3+ complexes have been studied in acetonitrile. In this solvent, long lifetimes for the metal emitting states and high metal-luminescence intensities obtained upon ligand excitation have been observed in both Eu3+ and Tb3+ complexes. The association constants in methanol have been determined for some of the complexes studied.