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Lecture

Fluorescence Spectroscopy: Principles and Applications

In course

CH-448: Photomedicine

The most important clinical diagnostic and therapeutic applications of light will be described. In addition, this course will address the principles governing the interactions between light and biological tissues, their optical properties and basic concept ...

Description

This lecture covers the principles and applications of fluorescence spectroscopy in photomedicine, including luminescence, quantum yield, lifetime, and biological fluorophores. It explains the Franck Condon principle, Jablonski diagram, and mirror image rule. The lecture also discusses the use of fluorochromes for oncologic applications and the detection of epithelial dysplasia in vivo.

Instructor

Georges Wagnières

Georges Wagnières received his diploma degree (MSc) in physics from the University of Lausanne, Switzerland, in 1986. He obtained his doctorate in science (PhD) in physics (Biomedical optics) from the Swiss Federal Institute of Technology at Lausanne (EPFL) in 1992 and did a postdoctoral work in the Wellman Laboratories of Photomedicine (Harvard Medical School), Boston, USA, from 1993 to 1994. He also obtained a Master degree in Management of Technology delivered by the Ecole des Hautes Etudes Commerciales (HEC) of Lausanne University and the EPFL in 2001. Georges Wagnières manages a research group active in the fields of: - Detection of early superficial cancers by fluorescence imaging. - Characterization of early superficial cancers by high magnification narrow band imaging. - In vivo and in vitro measurement of the vascular and tissular oxygen concentration by time-resolved luminescence spectroscopy and imaging. - Preclinical and clinical study of new photosensitizers for photodynamic therapy (PDT). - Treatment of neurodegenerative conditions (Alzheimer, Parkinson's diseases) by photobiomodulation. - Preclinical and clinical photodynamic therapy of inflammatory bowel diseases and atheroscerotic plaque. - Improvement of the selective vascular extravasation of chemotherapeutic agents by PDT. - Monitoring the light dosimetry during PDT by fluorescence spectroscopy and imaging. - Monitoring laser treatments of the retina by reflectance imaging. - Light dosimetry and tissue optical spectroscopy. - Radiometry. - Development of light delivery systems for biomedical applications. Georges Wagnières is also co-founder and was chairman of one spin-off companies: - Medlight SA, founded in July 1997, which develops, produces and commercializes light distributors for photodynamic therapy. Georges Wagnières has currently authored more than 235 papers (more than 150 in international journals with review board) and is inventor of 18 patents. He supervised 12 PhD students up to now, and currently teaches biomedical optics and photomedicine in master programs and doctoral schools. In addition, he gives the course entitled "Physique Générale I" to biology first year students registered to the Biology School of the Lausanne's University. MAIN PUBLICATIONS Please visit: https://www.epfl.ch/labs/lifmet/wagnieres/publications/

Official source

Ontological neighbourhood

Chemistry

Physical chemistry: Spectroscopy

Related concepts (32)

Fluorescence spectroscopy

Fluorescence spectroscopy (also known as fluorimetry or spectrofluorometry) is a type of electromagnetic spectroscopy that analyzes fluorescence from a sample. It involves using a beam of light, usually ultraviolet light, that excites the electrons in molecules of certain compounds and causes them to emit light; typically, but not necessarily, visible light. A complementary technique is absorption spectroscopy. In the special case of single molecule fluorescence spectroscopy, intensity fluctuations from the emitted light are measured from either single fluorophores, or pairs of fluorophores.

Fluorescence

Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, the emitted light has a longer wavelength, and therefore a lower photon energy, than the absorbed radiation. A perceptible example of fluorescence occurs when the absorbed radiation is in the ultraviolet region of the electromagnetic spectrum (invisible to the human eye), while the emitted light is in the visible region; this gives the fluorescent substance a distinct color that can only be seen when the substance has been exposed to UV light.

Spectroscopy

Spectroscopy is the field of study that measures and interprets the electromagnetic spectra that result from the interaction between electromagnetic radiation and matter as a function of the wavelength or frequency of the radiation. Matter waves and acoustic waves can also be considered forms of radiative energy, and recently gravitational waves have been associated with a spectral signature in the context of the Laser Interferometer Gravitational-Wave Observatory (LIGO).

Fluorescence microscope

A fluorescence microscope is an optical microscope that uses fluorescence instead of, or in addition to, scattering, reflection, and attenuation or absorption, to study the properties of organic or inorganic substances. "Fluorescence microscope" refers to any microscope that uses fluorescence to generate an image, whether it is a simple set up like an epifluorescence microscope or a more complicated design such as a confocal microscope, which uses optical sectioning to get better resolution of the fluorescence image.

Fluorophore

A fluorophore (or fluorochrome, similarly to a chromophore) is a fluorescent chemical compound that can re-emit light upon light excitation. Fluorophores typically contain several combined aromatic groups, or planar or cyclic molecules with several π bonds. Fluorophores are sometimes used alone, as a tracer in fluids, as a dye for staining of certain structures, as a substrate of enzymes, or as a probe or indicator (when its fluorescence is affected by environmental aspects such as polarity or ions).

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Fluorescence Lifetime in Photomedicine

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