Fluorescéine

Résumé

La fluorescéine (C20H12O5 ou 3H-xanthène-3-one), dont le sel de sodium se nomme uranine (C20H10Na2O5), est un composé organique dont la structure comporte deux molécules de phénol liées à un cycle pyrane lui-même connecté en position ortho à un acide benzoïque. Cette substance acide dérivée du xanthène se caractérise par une fluorescence intense d'où elle tire son nom. Tandis que la fluorescéine solide est une poudre brun rougeâtre, les solutions aqueuses sont rouges lorsqu'elles sont vues par transparence mais réfléchissent la lumière blanche dans une teinte vert « fluo ». Synthèse chimique vignette|gauche|400px|Synthèse chimique de la fluorescéine à partir de résorcine et d'anhydride phtalique. Cette substance a été découverte et synthétisée par Adolf von Baeyer en 1871. Von Baeyer nommera sa découverte « de » (« résorcinphtaléine ») puisque synthétisée à partir de résorcine et d'anhydride phtalique. Le nom « fluorescéine » daterait, lui, de 1878. Usages

Source officielle

https://fr.wikipedia.org/wiki/Fluoresc%C3%A9ine

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Cours associés (2)

Introduction to geometrical and wave optics for understanding the principles of optical microscopes, their advantages and limitations. Describing the basic microscopy components and the commonly used biomicrocopy methods such as widefield and fluorescence.

Chemical biology is a key discipline in biomedical research for drug discovery, synthetic biology and protein functional annotation. We will give a broad perspective of the field ranging from seminal classical experiments to state-of-the-art approaches to dissect and perturb biological systems.

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Characterization of monomeric and gemini cationic amphiphilic molecules by fluorescence intensity and anisotropy

Kuppuswamy Kalyanasundaram

Pyrene fluorescence intensity and conductivity measurements were used to determine the cmc of two monomeric surfactants namely, dodecyltrimethylammonium bromide and cetyltrimethylammonium bromide as well as two gemini surfactants, 16-3-16 2Br and 16-4-16 2Br of the alkanediyl-alpha,omega-bis(alkyldimethyl ammonium bromide) type. Cmc measurements were confirmed using fluorescence anisotropy measurements employing fluorescein as probe. Anisotropy-concentration plots showed sigmoidal behaviour and the obtained values for cmc were in good agreement with those determined using conductivity and pyrene fluorescence intensity. Also, the anisotropy of both fluorescein and another fluorescent probe. perylene, were used to provide information on the micellar structure. (C) 2008 Elsevier Ltd. All rights reserved.

Elsevier2009

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Characterization of monomeric and gemini cationic amphiphilic molecules by fluorescence intensity and anisotropy

Kuppuswamy Kalyanasundaram, Guido Viscardi

2009

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An endoscopic fluorescence imaging system for simultaneous visual examination and photodetection of cancers

André Studzinski, Hubert van den Bergh, Georges Wagnières

We describe the design and performance tested during six years of clinical trials of a fluorescence endoscope for the detection and delineation of cancers in several hollow organs. The apparatus is based on the imaging of the laser-induced fluorescence that differs between a tumor and its surrounding normal tissue. The tests are carried out in the upper aerodigestive tract, the tracheobronchial tree, the esophagus, and the colon. In the three former cases an exogenous dye is used (Photofrin II), whereas in the latter case fluorescein molecules conjugated with monoclonal antibodies directed against carcinoembryonic antigen are injected. The decrease of native tissue autofluorescence observed in early cancers is also used for detecting lesions in the tracheobronchial tree. The fluorescence contrast between the tumor and surrounding normal tissue is enhanced by real time image processing. This is done by simultaneously recording the fluorescenceimage in two spectral domains, after which these two images are digitized and manipulated with a mathematical operator (look-up table) at video frequency. Moreover, the device that is described below allows for an immediate observation of the endoscopic area under white light illumination during fluorescence detection in order to localize the origin of the “positive” fluorescence signals. Typical results obtained in the tracheobronchial tree and in the colon are presented and the sources of false positives and false negatives are evaluated in terms of the fluorescent dye, tissue optical properties, and illumination optics.

1997

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