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Topic: Fluorophore

Related Topics

Fluorescence

Luminescence

Absorption

Phosphorescence

Phosphor

Transition

Stokes shift

	Olympus Microscopy Resource Center: Specialized Microscopy Techniques - Fluorescence - Basic Concepts in Fluorescence
		As new fluorophore molecules diffuse into the bleached region of the specimen (recovery), the fluorescence emission intensity is monitored to determine the lateral diffusion rates of the target fluorophore.
		The plane-polarized excitation light is absorbed maximally by fluorophores in the specimen (on the microscope slide) whose absorption dipole moments are oriented parallel to the plane of the excitation light.
		The fluorescence subsequently emitted by the fluorophore is measured in both parallel and perpendicular orientations with respect to the polarization plane of the excitation illumination.
	www.olympusmicro.com /primer/techniques/fluorescence/fluorescenceintro.html (8938 words)

	Fluorophore Characteristics: Making Intelligent Choices
		The fluorophore then emits light at a longer wavelength than that of the absorbed photon — this is simply because the energy of the emitted photon is lower than that of the absorbed photon, due to energy dissipation during the excited state lifetime.
		The molar extinction coefficient of the dye (and its conjugate).
		This is both due to the physical size of the fluorophore — which affects the physical size and shape of the conjugate — and to the ionic charge present on the dye — which affects mobility by altering the charge:base ratio of the resulting nucleic acid conjugate.
	www.promega.com /geneticidproc/ussymp8proc/21.html (2455 words)

	Olympus FluoView Resource Center: Fluorescent Protein Fluorophore Interactive Java Tutorials
		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.
		The principle fluorophore (often termed a chromophore) is a tripeptide consisting of the residues serine, tyrosine, and glycine at positions 65-67 in the sequence.
		This interactive tutorial explores the molecular re-arrangement that occurs during the maturation of the Kaede fluorescent protein fluorophore, which emits green fluorescence, as well as the mechanism of photoconversion that cleaves the peptide backbone to yield a red fluorescent optical highlighter.
	www.olympusconfocal.com /java/fpfluorophores/index.html (1186 words)

	Fluorophore - Wikipedia, the free encyclopedia
		A fluorophore, in analogy to a chromophore, is a component of a molecule which causes a molecule to be fluorescent.
		The amount and wavelength of the emitted energy depend on both the fluorophore and the chemical environment of the fluorophore.
		Fluorescein isothiocyanate is an example of a fluorophore which can be chemically attached to a different, non-fluorescent molecule to create a new and fluorescent molecule.
	en.wikipedia.org /wiki/Fluorophore (148 words)

	Quantitating fluorescence intensity from fluorophore: the definition of MESF assignment Journal of Research of the ...
		If we use the same fluorophore in the reference solution and the analyte then, to a good approximation, the molar extinction drops out from the comparison of fluorescence radiance and we are left with the comparison of fluorescence yield which is defined as the product of fluorophore concentration and the molecular quantum yield.
		In such cases the molar extinction and quantum yield of the fluorophore is the same for the analyte and the reference material and the fluorescence radiance from both is proportional to the relative number of fluorophores.
		In the case where one set of fluorophores is in solution and the other set of fluorophores is immobilized on a microbead, the quantum yields may be different for the two fluorophores and the equality of fluorescence radiance does not imply equal numbers of fluorophores.
	www.findarticles.com /p/articles/mi_m0IKZ/is_1_107/ai_86429869 (1067 words)

	Fluorescense Resonance Energy Transfer
		Sources of background noise, or cross-talk, occur because (1) the donor radiates slightly (but not optimally) at the acceptor's emission wavelength, and (2) the acceptor is excited somewhat by the donor's excitation wavelength.
		One is to express each fluorophore individually in the same conditions in vivo in which FRET will be performed, and measuring this cross-talking.
		If the fluorophores are over 200Ǻ apart while the proteins to which they are fused interact with each other, no signal will be observed.
	www.iscid.org /encyclopedia/Fluorescense_Resonance_Energy_Transfer (556 words)

	Olympus FluoView Resource Center: The GFP Fluorophore - Interactive Java Tutorial
		Perhaps the most important feature of all fluorescent proteins is that the fluorophore is fully encoded in the amino acid sequence, and is autocatalytically formed during maturation through a cyclization reaction between residues buried deep within the shielded environment of the barrel.
		During and after fluorophore maturation, the final structure and its intermediate states are stabilized by multiple interactions, including van der Waals and electrostatic forces, as well as hydrogen bonds, with neighboring amino acid residues and water molecules that are not illustrated in the tutorial.
		In this regard, the requirement for molecular oxygen as a fluorophore activation catalyst to form the extended aromatic system in fluorescent proteins is remarkable considering that oxygen must ultimately be excluded from regular interactions with the fluorophore to avoid collisional quenching of fluorescence.
	www.olympusconfocal.com /java/fpfluorophores/gfpfluorophore/index.html (969 words)

	FRET
		Regular (non-FRET) fluorescence occurs when a fluorescent molecule (fluorophore) absorbs electromagnetic energy of one wavelength (the excitation frequency) and re-emits that energy at a different wavelength (the emission frequency).
		Conceptually, one can imagine each fluorophore to have a two-peaked spectrum in which the first peak is the excitation peak, and the second is the emission peak.
		The physics of the FRET energy transfer between donor and acceptor (which is non-radiative) is such that the efficiency falls off with the sixth power of the distance between molecules.
	www.iscid.org /encyclopedia/FRET (556 words)

	Nikon MicroscopyU: Introduction to Fluorescent Proteins
		With the rapid evolution of fluorescent protein technology, the utility of this genetically encoded fluorophore for a wide spectrum of applications beyond the simple tracking of tagged biomolecules in living cells is now becoming fully appreciated.
		It is remarkable that the principle fluorophore is derived from a triplet of adjacent amino acids: the serine, tyrosine, and glycine residues at locations 65, 66, and 67 (referred to as Ser65, Tyr66, and Gly67; see Figure 2).
		Maturation of the wild-type fluorophore is quite efficient at 28 degrees, but increasing the temperature to 37 degrees substantially reduces overall maturation and results in decreased fluorescence.
	www.microscopyu.com /articles/livecellimaging/fpintro.html (6322 words)

	Invitrogen - Molecular Probes - Introduction to Fluorescence Techniques
		Fluorophores currently used as fluorescent probes offer sufficient permutations of wavelength range, Stokes shift and spectral bandwidth to meet requirements imposed by instrumentation (e.g., 488 nm excitation), while allowing flexibility in the design of multicolor labeling experiments (Figure 4).
		Self-quenching is the quenching of one fluorophore by another; it therefore tends to occur when high loading concentrations or labeling densities are used (Figure 1.54, Figure 1.76).
		Representative fluorophores include the aminonaphthalenes such as prodan, badan (Figure 2.28) and dansyl, which are effective probes of environmental polarity in, for example, a protein's interior.
	probes.invitrogen.com /handbook/sections/0001.html (4158 words)

	United States Patent: 5,784,157
		The stimulated fluorophore produces a resulting fluorescence which is demodulated to produce an electrical signal corresponding to the intensity modulation of the fluorescence.
		The fluorophore produces a responsive fluorescence which has an intensity also modulated in the time-domain corresponding to the modulation of the optical signal which is used to excite the fluorophore.
		In the case of four lasers (L.sub.k), the fluorophores are identified with label k=A, C, T, or G. In other words, L.sub.A is the output radiation of the laser "A", whose wavelength.lambda..sub.A is at the peak of the absorption spectrum of label A. The radiation L.sub.k is modulated at the radio frequency f.sub.k, viz.
	www.ece.sunysb.edu /~serge/pat27.html (7275 words)

	The Molecular Structure of Green Fluorescent Protein
		The fluorophore is highly protected, located on the central helix within a couple of Ångstroms of the geometric center of the cylinder.
		Mutations in regions of the sequence adjacent to the fluorophore, i.e.
		The fluorophore is defined as the 7 atoms of the phenol of Tyr
	www-bioc.rice.edu /Bioch/Phillips/Papers/gfpbio.html (4825 words)

	Automating Fluorescent Imaging Techniques- Developer Zone - National Instruments
		Most fluorophores are inert, but some change their fluorescence properties in response to the chemistry of the local environment.
		Or a fluorophore may be attached to a protein such as an antibody to select the target region within the cell.
		Fluorescence compounds or fluorophores are capable of absorbing light at one wavelength and emitting at a longer wavelength.
	zone.ni.com /devzone/cda/tut/p/id/3034 (2892 words)

	Cell Biology (Site not responding. Last check: 2007-11-02)
		Lastly, the fluorophore emits a photon of energy, and in doing so it generates fluorescence and return to its ground state (R0) and at the same time emits energy as a photon of light.
		In this technique the emission of one fluorophore is coupled to the excitation of another fluorophore resulting in direct energy transfer from the donor fluorophore to the acceptor flurorophore without the emission of a photon.
		In both techniques, the fluorophore of a particular region is made non-fluorescent by applying very high intensity illumination.
	www.stanford.edu /class/bio44/cellbio/cellbiotech.htm (1423 words)

	Multi-Photon Excitation Flourescence Microscopy
		This is equivalent to a single photon with an energy equal to the sum of the two that are absorbed.
		In this way, fluorophore excitation will only occur at the point of focus (where it is needed) thereby eliminating excitation of out-of-focus fluorophore and achieving optical sectioning.
		It is possible to select fluorophores such that multiple labeled samples by can be imaged by combination of 2- and 3 photon excitation, using a single IR excitation source.
	www.loci.wisc.edu /multiphoton/mp.html (731 words)

	Olympus Microscopy Resource Center: Fluorescence - Solvent Effects on Fluorescence Emission - Interactive Java Tutorial
		The tutorial initializes with a Jablonski energy diagram appearing in the left-hand portion of the window, and a hypothetical fluorophore bounded by a pair of solvent molecules positioned above a spectral plot of relative fluorescence absorption and emission intensity versus wavelength.
		Dipole moments for the fluorophore and solvent molecules are indicated by yellow arrows that are superimposed over the ellipsoidal molecules.
		As a result, there is a time delay between the excitation event and the re-ordering of solvent molecules around the solvated fluorophore (as illustrated in Figure 1), which generally has a much larger dipole moment in the excited state than in the ground state.
	www.olympusmicro.com /primer/java/jablonski/solventeffects/index.html (1045 words)

	Quantitating fluorescence intensity from fluorophore: assignment of MESF values Journal of Research of the National ... (Site not responding. Last check: 2007-11-02)
		The fluorometer is used to measure the fluorescence signal of a suspension of microspheres with immobilized fluorescein isothiocyanate (FITC).
		The calibration is used to obtain the concentration of soluble fluorophores which gives the same fluorescence signal as the microsphere suspension.
		The number concentration of microspheres is measured and the equality of fluorescence yields is used to obtain the number of soluble fluorescein moleculcs equivalent to a single microsphere.
	www.findarticles.com /p/articles/mi_m0IKZ/is_2_110/ai_n13820198 (850 words)

	The Scientist : When You Wish Upon A Star: Molecular Beacons: Real Time in a Twinkle (Site not responding. Last check: 2007-11-02)
		Molecular beacons are hairpin-shaped ("stem-and-loop") molecules with an internally quenched fluorophore.
		The fluorophore and quencher are moved away from each other, leading to the restoration of fluorescence.
		In molecular beacons, the fluorophore and the quencher are held so close together that direct transfer of energy is possible.
	www.the-scientist.com /article/display/18439 (1763 words)

	TauTec: Fluorescence Lifetime, Multifocal Multiphoton Microscopy and Spectroscopy
		In principle, straightforward fluorescence intensity imaging should report the distribution of a fluorophore, with the intensity being a function of the local fluorophore concentration.
		In practice the observed fluorescence intensity may originate from multiple fluorophores (with different quantum efficiencies), the quantum efficiency of an individual fluorophore population may change across a sample and the detected intensity may be modified by optical scattering and absorption in the sample.
		The radiative decay rate is essentially a function of the electronic energy level structure of the fluorophore molecule (although it does depend weakly on the local refractive index) while the non-radiative decay rate can be a sensitive function of the local fluorophore environment.
	www.tautec.com /25259/25352.html?sessionidkey=sessionidval (944 words)

	Metallic Nanoparticle as Fluorescence Enhancer for Lowering the Detection Limit of Fluorophore Mediated Immunosensor (Site not responding. Last check: 2007-11-02)
		Fluorophore mediated, fiber optic immunosensor has been recognized as a good tool for detecting various disease representative biomarkers in the bio-/physio- logical samples.
		The transferring of the lone pair electrons in the fluorophore normally used for self-quenching to the metallic nanoparticle was demonstrated to enhance the emission fluorescence.
		Organic solvents were also found to enhance the fluorescence in biosensing significantly, possibly by the shifting excitation/emission spectrums of the fluorophore, by shrinking fluorophore tagged proteins, or by their combination.
	aiche.confex.com /aiche/2005/techprogram/P3902.HTM (411 words)

	Spectral and Lifetime Imaging
		Perhaps the greatest power of collecting the entire spectrum is this allows fluorophore to be identified and separated computationally (by comparison to reference fluorophore spectra) in the presence of high levels of background.
		The excitation wavelength is chosen to primarily excite the cyan fluorophore.
		By the use of a gain-modulated detector, the phase shift and amplitude demodulation of the fluorescence signal is determined.
	www.loci.wisc.edu /optical/specdec.html (2380 words)

	Olympus FluoView Resource Center: Choosing Fluorophore Combinations in Confocal Microscopy - Interactive Java Tutorial
		This interactive tutorial is designed to explore the matching of dual fluorophores with efficient laser excitation lines, calculation of emission spectral overlap values, and determination of the approximate bleed-through level that can be expected as a function of the detection window wavelength profiles.
		The overlap region between the emission spectra of the two probes is indicated by a dark gray area where the overlap occurs, and the percentage is indicated in a yellow box positioned beneath the Spectral Profiles graph.
		The fluorophore spectra and laser line for each channel can be toggled on an off together using the Channel checkbox, and individual spectral profiles can also be similarly controlled with Ex and Em checkboxes.
	www.olympusconfocal.com /java/dualprobes/index.html (773 words)

	Imaging Research Inc.: Fluorescence Imaging
		Absorption of the photon causes an electron in the fluorophore to rise from its ground state to a higher energy level.
		A given fluorophore may emit at single or multiple wavelengths (creating an emission spectrum), as electrons drop from various orbitals to their ground states.
		In the simplest case (monochrome fluorescence imaging), a single fluorophore is used to mark a single molecular species.
	www.imagingresearch.com /applications/Fluorescence.asp (3004 words)

	Nikon MicroscopyU: Interactive Java Tutorials - Dual Band Excitation Fluorescence Filter Combinations
		Fluorophore absorption and emission spectral cross sections (the overlap region with filter transmission passbands) can be individually or collectively viewed by selecting the appropriate check box (Absorption or Emission) listed under the Spectral Cross Sections heading.
		Fluorophore absorption spectra are presented in the tutorial using a brown fill, while the corresponding emission spectra are represented with a gray fill.
		This is particularly important in sets designed for use with one fluorophore excited in the violet or ultraviolet spectral region, due to the high excitation efficiency of short wavelength radiation.
	www.microscopyu.com /tutorials/java/cubeprofiles/dual/index.html (1742 words)

	Synaptic Complex Formation of Two Retrovirus DNA Attachment Sites by Integrase: A Fluorescence Energy Transfer Study
		The degree of fluorophore labeling of DNA was determined on the basis of the ratio of attached fluorophore to DNA concentration.
		The increasing observed fluorescence emission intensity spectra of the acceptor fluorophore with increasing concentrations of IN strongly suggest that IN is capable of forming synaptic complexes wherein the excited donor fluorophore is transferring resonance energy to the acceptor fluorophore.
		Quenching of the donor fluorophore occurred in the broad low-wavelength region in comparison to the sensitized emission of the acceptor fluorophore.
	pubs.acs.org /cgi-bin/sample.cgi/bichaw/2005/44/i46/html/bi0508340.html (7480 words)

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