Photoluminescence Enhancement of CdSe Quantum Dots: A Case of Organogel–Nanoparticle Symbiosis

Highly fluorescent organogels (QD–organogel), prepared by combining a pseudopeptidic macrocycle and different types of CdSe quantum dots (QDs), have been characterized using a battery of optical and microscopic techniques. The results indicate that the presence of the QDs not only does not disrupt the supramolecular organization of the internal fibrillar network of the organogel to a significant extent, but it also decreases the critical concentration of gelator needed to form stable and thermoreversible organogels. Regarding the photophysical properties of the QDs, different trends were observed depending on the presence of a ZnS inorganic shell around the CdSe core. Thus, while the core–shell QDs preserve their photophysical properties in the organogel medium, a high to moderate increase of the fluorescence intensity (up to 528%) and the average lifetime (up to 1.7), respectively, was observed for the core QDs embedded in the organogel. The results are relevant for the development of luminescent organogels based on quantum dots, which have potential applications as advanced hybrid materials in different fields

Fluorescent macrocyclic probes with pendant functional groups as markers of acidic organelles within live cells

A new family of acidity sensitive fluorescent macrocycles has been synthesized and fully characterized. Their photophysical properties including emission quantum yield and fluorescence lifetime have been determined. The acid–base properties of the new molecules can be tuned by the incorporation of pendant functional groups. The nature of such functional groups (carboxylic acid or ester) influences dramatically the pKa of the probes, two compounds of which exhibit low values. Preliminary intracellular studies using confocal microscopy together with emission spectra of the probes from the cellular environment have shown that the synthesized fluorescent macrocycles mark the acidic organelles of RAW 264.7 macrophage cells

Photoluminescence enhancement of CdSe quantum dots: A case of organogel-nanoparticle symbiosis

Highly fluorescent organogels (QD-organogel), prepared by combining a pseudopeptidic macrocycle and different types of CdSe quantum dots (QDs), have been characterized using a battery of optical and microscopic techniques. The results indicate that the presence of the QDs not only does not disrupt the supramolecular organization of the internal fibrillar network of the organogel to a significant extent, but it also decreases the critical concentration of gelator needed to form stable and thermoreversible organogels. Regarding the photophysical properties of the QDs, different trends were observed depending on the presence of a ZnS inorganic shell around the CdSe core. Thus, while the core-shell QDs preserve their photophysical properties in the organogel medium, a high to moderate increase of the fluorescence intensity (up to 528%) and the average lifetime (up to 1.7), respectively, was observed for the core QDs embedded in the organogel. The results are relevant for the development of luminescent organogels based on quantum dots, which have potential applications as advanced hybrid materials in different fields. © 2012 American Chemical Society.Fil: Wadhavane, Prashant D.. Universitat Jaume I; EspañaFil: Galian, Raquel Eugenia. Universidad de Valencia; EspañaFil: Izquierdo, M. Angeles. Universitat Jaume I; EspañaFil: Aguilera Sigalat, Jordi. Universidad de Valencia; EspañaFil: Galindo, Francisco. Universitat Jaume I; EspañaFil: Schmidt, Luciana Carina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Valencia; EspañaFil: Burguete, M. Isabel. Universitat Jaume I; EspañaFil: Pérez Prieto, Julia. Universidad de Valencia; EspañaFil: Luis, Santiago V.. Universitat Jaume I; Españ