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Nikon MicroscopyU: Introduction to Fluorescence Microscopy The technique of fluorescence microscopy has become an essential tool in biology and the biomedical sciences, as well as in materials science due to attributes that are not readily available in other contrast modes with traditional optical microscopy. The widespread growth in the utilization of fluorescence microscopy is closely linked to the development of new synthetic and naturally occurring fluorophores with known intensity profiles of excitation and emission, along with well-understood biological targets. Fluorescence vertical illuminators are designed with the purpose of controlling the excitation light through the application of readily interchangeable filter (neutral density and interference excitation balancers) insertions into the light path on the way toward the specimen, and again in the path between the specimen and the observation tubes or camera detector system. www.microscopyu.com /articles/fluorescence/fluorescenceintro.html   (5489 words)

Olympus Microscopy Resource Center: Specialized Microscopy Techniques - Fluorescence Microscopy Fluorescence is the property of some atoms and molecules to absorb light at a particular wavelength and to subsequently emit light of longer wavelength after a brief interval, termed the fluorescence lifetime. Fluorescence and Differential Interference Contrast Combination Microscopy - Fluorescence microscopy can also be combined with contrast enhancing techniques such as differential interference contrast (DIC) illumination to minimize the effects of photobleaching by locating a specific area of interest in a specimen using DIC then, without relocating the specimen, switching the microscope to fluorescence mode. Fluorescence Microscopy of Cells in Culture - Serious attempts at the culture of whole tissues and isolated cells were first undertaken in the early 1900s as a technique for investigating the behavior of animal cells in an isolated and highly controlled environment. www.olympusmicro.com /primer/techniques/fluorescence/fluorhome.html   (2351 words)

Nikon MicroscopyU: Fluorescence Microscopy TIRF Microscopy: Introduction and Applications - Various mechanisms are often employed in fluorescence microscopy applications to restrict the excitation and detection of fluorophores to a thin region of the specimen. The fluorescence illumination reveals which organisms are producing the fluorescent protein and the stereoscopic vision coupled to a large field of view and ample working distance enables observers to conduct experiments with forceps, pipettes, or micromanipulators. Typically, the fluorescence illuminator consists of a xenon or mercury arc lamp contained in an external lamphouse that is attached to the microscope via an intermediate tube (or vertical illuminator) positioned between the microscope zoom body and observation tubes. www.microscopyu.com /articles/fluorescence/index.html   (1980 words)

Olympus FluoView Resource Center: Fluorescence Lifetime Imaging Multi-color staining with fluorescent dyes is actively used for observing the distribution of biological materials (such as proteins, lipids, nucleic acids, and ions) in the field of tissue and cell research. In addition to multi-color staining, fluorescence lifetime imaging can also be utilized to visualize the factors that affect the fluorescence lifetime properties of the dye molecule, that is, the state of the environment around the molecule. Conventional fluorescence microscopy makes use of the color properties of fluorescent dyes, that is, identification is based on differences in fluorescence spectral characteristics between dyes. www.olympusfluoview.com /applications/flimintro.html   (951 words)

Fluorescence Microscopy by Benjamin D. Williams Fluorescence is a term used to signify a compounds ability to absorb light at one wavelength and emit light of a longer wavelength. Fluorescent microscopy is used primarily by scientists or clinicians to detect and localize minute amounts of a substance in tissues, where the fluorescence is observed as luminosity against a fl background. The fluorescence emission that is emitted from these fluorochromes is the range of.000001 seconds to.000000001seconds.Once the fluorochrome is attached to the sample, the objective lens of the microscope must perform two objectives (Howard,1994). www.samford.edu /~gekeller/williams.html   (1433 words)

Olympus Microscopy Resource Center Fluorescent Protein Fluorophore Maturation Mechanisms - Autocatalytic formation of the fluorophore (also referred to as a chromophore) within the shielded environment of the polypeptide backbone during fluorescent protein maturation follows a surprisingly unified mechanism, especially considering the diverse natural origins of these useful biological probes. The spectral properties of fluorescent proteins are dependent upon the structure of the fluorophore as well as the localized interactions of amino acid residues in the immediate vicinity, and in some cases, residues far removed from the fluorophore. Matching Fluorescence Filter Blocks with Fluorescent Probes - The essential feature of any fluorescence microscope is to provide a mechanism for excitation of the specimen with selectively filtered illumination followed by isolation of the much weaker fluorescence emission using a second filter to enable image formation on a dark background with maximum sensitivity. www.olympusmicro.com   (2715 words)

Invitrogen - Molecular Probes - Introduction to Fluorescence Techniques The emission intensity is proportional to the amplitude of the fluorescence excitation spectrum at the excitation wavelength (Figure 2). Fluorescence intensity is quantitatively dependent on the same parameters as absorbance — defined by the Beer–Lambert law as the product of the molar extinction coefficient, optical path length and solute concentration — as well as on the fluorescence quantum yield of the dye and the excitation source intensity and fluorescence collection efficiency of the instrument. Fluorescence detection sensitivity is severely compromised by background signals, which may originate from endogenous sample constituents (referred to as autofluorescence) or from unbound or nonspecifically bound probes (referred to as reagent background). probes.invitrogen.com /handbook/sections/0001.html   (4158 words)

Two-Photon Microscopy Fluorescence microscopy ased on three- or more-photon absorption using the Ti:Sapphire laser for excitation would excite far-UV absorbing fluorophores that are not very well characterised and rarely used. The fluorescence originates from a Calmodulin(CaM)-EGFP fusion protein, which binds to Myosin Light Chain Kinase (at the cell membrane) and to CaM-Kinase II (in the meiotic spindle poles) during cell division. Fluorescence lifetime imaging is valuable especially for intracellular measurements, where the absolute number of fluorophores, either membrane permeable organic fluorophores or autofluorescent proteins (e.g. www.fz-juelich.de /ibi/ibi-1/Two-Photon_Microscopy   (904 words)

Tutorial - Fluorescent Microscope Optics: C&L Instruments, Inc. A fluorescent microscope also produces a magnified image of the sample, but the image is based on the second light source -- the light emanating from the fluorescent species -- rather than from the light originally used to illuminate, and excite, the sample. In order to excite fluorescent species in a sample, the optics of a fluorescent microscope must focus the illumination (excitation) light on the sample to a greater extent than is achieved using the simple condenser lens system found in the illumination light path of a conventional microscope. In a fluorescence microscope, a dichroic mirror is used to separate the excitation and emission light paths. www.fluorescence.com /tutorial/fm-optic.htm   (1202 words)

Encyclopedia of Laser Physics and Technology - fluorescence microscopy Fluorescence microscopy is a technique to generate microscopic images of samples (often biological materials) using fluorescence, which is usually excited with a sharply focused diffraction-limited laser beam. The fluorescence microscope is usually operated with a computer (a PC or a laptop), which controls the scan, records the fluorescence intensities, and finally generates and stores the obtained images. In the simplest form of fluorescence microscopy, the laser is operated continuously, and its wavelength is chosen to be in an absorbing spectral region of the fluorescent molecules, which can therefore be excited with single-photon absorption. www.rp-photonics.com /fluorescence_microscopy.html   (729 words)

Fluorescence Microscopy With the recent development of fluorescent probes and new high-resolution microscopes, biological imaging has entered a new era and is presently having a profound impact on the way research is being conducted in the life sciences. Fluorescence microscopy was invented almost a century ago, when microscopists were experimenting with ultraviolet light to achieve higher resolutions. But it was not until the 1940s that fluorescence microscopy became popular, when Coons and Kaplan introduced a technique to label antibodies with a fluorescent dye to study antibody-antigen interactions, profoundly changing the field of immunohistochemistry. bigwww.epfl.ch /publications/vonesch0601.html   (709 words)

Fluorescence Microscopy To understand how fluorescence microscopy works and why it has become so important to modern biology, one must understand what the term fluorescence means. In microscopy, fluorescence is used as a means of preparing specific biological probes. Fluorescence of a substance is seen when the molecule is exposed to a specific wavelength of light (excitation wavelength or spectrum) and the light it emits (the emission wavelength or spectrum) is always of a higher wavelength. www.gonda.ucla.edu /bri_core/fluoresc.htm   (565 words)

FRAEN - Fluorescence Microscopy Fraen Corporation Srl develops integrated optical solutions for fluorescence microscopy consisting of a unique, proprietary illumination system with high power solid-state (LED) sources which replaces the mercury and xenon arc-lamps found in traditional epifluorescence microscopy. Bright field microscopy is not affected since the halogen white light function remains intact, which means that transmitted light observation is possible without major changes in the optical configuration. LED fluorescence is available as add-on kit for existing microscopes or as a complete ready-to-use instrument. www.fraensrl.com /flmicro.html   (152 words)

Cell Biology: Microscopy, Kent State University - Fluorescence Microscopy   (Site not responding. Last check: 2007-11-02) Fluorescence microscopy is used to detect structures, molecules or proteins within the cell. In fluorescence microscopy, a cell is stained with a dye and the dye is illuminated with filtered light at the absorbing wavelength; the light emitted from the dye is viewed through a filter that allows only the emitted wavelength to be seen. Among the common fluorescence dyes are fluorescein, which emits green light when exited with blue light and rhodamine, which emits a deep red fluorescence when excited by green-yellow light. dept.kent.edu /projects/cell/FLUORO.HTM   (1613 words)

Microscopy - Wikipedia, the free encyclopedia Microscopy is any technique for producing visible images of structures or details too small to otherwise be seen by the human eye, using a microscope or other magnification tool. Most fluorescence microscopes are operated in the Epi-illumination mode (illumination and detection from one side of the sample) to further decrease the amount of excitation light entering the detector. Fluorescence microscopy is extremely powerful due to its ability to show specifically labelled structures within a complex environment but also because of its inherent ability to provide three dimensional information of biological structures. en.wikipedia.org /wiki/Microscopy   (4205 words)

Pharmaceutical Microscopy glossary Microscopy of specimens stained with fluorescent dye (usually fluorescein isothiocyanate) or of naturally fluorescent materials, which emit light when exposed to ultraviolet or blue light. Microscopy in which the object is examined directly by an electron beam scanning the specimen point- by- point, giving the surface image a three- dimensional quality. Since the vertical resolution of the surface plasmons extends from subnanometer to hundreds of nanometers, surface plasmon microscopy is potentially useful for the study of cell membranes, and transport and trafficking processes involving the membrane, as well as for studies of cell- nanofabricated surface interactions. www.genomicglossaries.com /content/Microscopy.asp   (2773 words)

Simultaneous Atomic Force and Fluorescence Microscopy Using the MFP-3DTM AFM From Asylum Research Fluorescence microscopy is typically used to detect specific molecules. Another limitation of this microscopy is that the molecule must be bound to the fluorochrome, which in turn, can alter the state of the molecule. Some common methods of increasing the efficiency of fluorescent emissions cannot be used in the MFP-3D because it would prevent the AFM probe from coming into contact with the sample — for example, using a hydrophobic medium and replacing water with glycerol, or adding antioxidants, to increase the efficiency of the fluorescence. www.azonano.com /Details.asp?ArticleID=1663   (1688 words)

Botany online: Microscopy - Fluorescence Microscopy Fluorescence microscopy is based on the fact that some molecules emit part of the light absorbed by them as longer waves. A well-known example is the red fluorescence of chlorophyll. Since roughly twenty years fluorescence microscopy is flowering again, on one hand, because the range of fluorochromes became much broader and on the other hand, because completely new approaches like indirect fluorescence could be used successfully. www.biologie.uni-hamburg.de /b-online/e03/03b.htm   (406 words)

Welcome to the Fluorescence Foundation The use and application of fluorescence techniques is increasing daily both in the academia and in industry. The course is designed for students who utilize fluorescence instrumentation and techniques, as well as for researchers and industrial scientists who intend to deepen their knowledge of fluorescence techniques. The theoretical lectures delivered by key scientists in the field are complemented by the direct utilization of steady state and lifetime fluorescence instrumentation provided by leading companies. www.fluorescence-foundation.org   (144 words)

Optical Microscopy Facility The deconvolution system (Inovision) is able to collect the three most common fluorescence emission wavelengths (red, green, and blue) with a minimum of complexity. Fluorescence microscopy is a quantitative technique when used with the proper controls. Other fluorescent molecules will then re-fill the bleached area; a time-lapse movie can show which pools of fluorescent molecules diffuse or can be transported into that area. cpmcnet.columbia.edu /dept/gsas/anatomy/Files/results.htm   (2264 words)

Olympus FluoView Resource Center: Confocal versus Widefield Fluorescence Microscopy - Interactive Java Tutorial Confocal microscopy offers several distinct advantages over traditional widefield fluorescence microscopy, including the ability to control depth of field, elimination or reduction of background information away from the focal plane (that leads to image degradation), and the capability to collect serial optical sections from thick specimens. The basic key to the confocal approach is the use of spatial filtering techniques to eliminate out-of-focus light or glare in specimens whose thickness exceeds the dimensions of the focal plane. Confocal microscopy provides only a marginal improvement in both axial (z; along the optical axis) and lateral (x and y; in the specimen plane) optical resolution, but is able to exclude secondary fluorescence in areas removed from the focal plane from resulting images. www.olympusconfocal.com /java/confocalvswidefield/index.html   (469 words)

Liquid Domains in Vesicles Investigated by NMR and Fluorescence Microscopy Biophysical Journal - Find Articles A transition at T^sub low^ is also evident in fluorescence microscopy measurements of the surface area fraction of ordered phase in giant unilamellar vesicles. Using fluorescence microscopy, two of us (S.L.V. and S.L.K.) have observed coexisting liquid phases in GUVs containing ternary mixtures of cholesterol, saturated lipids, and unsaturated lipids (Veatch and Keller, 2002, 2003a,b). We verify the existence of a liquid-ordered phase, quantify the lipid composition of coexisting phases, and estimate tie-lines in the DOPC/DPPC/Chol miscibility phase diagram. www.findarticles.com /p/articles/mi_qa3938/is_200405/ai_n9457360   (782 words)

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