Quantum yield

[Henriette Madsen]

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Hi all,

I am a new member of the confocal list, and I have a question regarding
quantum yield.

Does some kind of list exist with quantum yield of different probes, or
what is the easiest way to find out which probes are the brightest and
most stable ones. They all say they are “the best and brightest”.

Kind regards
Henriette

[Martin Wessendorf]

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Henriette Madsen wrote:

> I am a new member of the confocal list, and I have a question regarding
> quantum yield.
>
> Does some kind of list exist with quantum yield of different probes, or
> what is the easiest way to find out which probes are the brightest and
> most stable ones. They all say they are “the best and brightest”.

Molecular Probes sometimes includes qualitative info on quantum yields.
  However, quantum yield is sensitive to environment.  The concentration
of fluorophore (and the fluorophore-to-protein ratio of a conjugate such
as a labeled antibody), the solvent surrounding the fluorophore, the
solvent's viscosity, the presence or absence of agents affecting
photobleaching, etc. can all affect the probability that a photon will
be emitted from an excited molecule.  Thus the quantum yield can be
different depending upon the conditions.

My own thought would just to try different labels and see what works
best for your system.

Good luck!

Martin Wessendorf
--
Martin Wessendorf, Ph.D.                   office: [phone]
Assoc Prof, Dept Neuroscience                 lab: [phone]
University of Minnesota             Preferred FAX: [phone]
6-145 Jackson Hall, 321 Church St. SE    Dept Fax: [phone]
Minneapolis, MN  55455             E-mail: martinw[at]med.umn.edu

[mmodel]

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Hi Henriette: You can find this, and many other useful things, in
Chapter 16 of Handbook of Biological Confocal Microscopy, 3rd ed.

Mike Model

-----Original Message-----
From: Confocal Microscopy List [mailto:[hidden email]] On
Behalf Of Henriette Madsen
Sent: Thursday, August 16, 2007 7:27 AM
To: [hidden email]
Subject: Quantum yield

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http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal

Hi all,

I am a new member of the confocal list, and I have a question regarding
quantum yield.

Does some kind of list exist with quantum yield of different probes, or
what is the easiest way to find out which probes are the brightest and
most stable ones. They all say they are "the best and brightest".

Kind regards
Henriette

[Boswell, Carl A - (cboswell)]

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http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal

Henriette,
This site has whatever quantum yield information is available on a large
list of fluorochromes.  http://www.mcb.arizona.edu/ipc/fret/  In addition,
one may calculate a relative output of a dye passing through selected
filters and dichroics.
Cheers
Carl

Carl A. Boswell, Ph.D.
Molecular and Cellular Biology
University of Arizona
520-954-7053
FAX [phone]
----- Original Message -----
From: "Henriette Madsen" <[hidden email]>
To: <[hidden email]>
Sent: Thursday, August 16, 2007 4:27 AM
Subject: Quantum yield


Search the CONFOCAL archive at
http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal

Hi all,

I am a new member of the confocal list, and I have a question regarding
quantum yield.

Does some kind of list exist with quantum yield of different probes, or
what is the easiest way to find out which probes are the brightest and
most stable ones. They all say they are “the best and brightest”.

Kind regards
Henriette

[George McNamara]

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Hi Henriette,


Sort on the QY column of http://home.earthlink.net/~fluorescentdyes/McNamara2007FluorophoresTable.xls    
Best way to get the file is to go to
http://home.earthlink.net/~pubspectra/
scroll down to
McNamara 2007 Fluorophore Data Tables 
right click, and download to your computer.

If you just need one QY, go to the graphing website Carl set up http://www.mcb.arizona.edu/ipc/fret/index.html, select the dye, and click the notes icon (to the right of the dye dropdown after you've selected a dye). All the dyes on Carl's site are in the index file at
McNamara_Boswell_000_2006_Index _Dyes_FPs_Filters_Lamps_Other_Spectra.xls  
(column P of the McNamara Boswell Spectra Dyes worksheet - the Excel file opens to the lamp worksheet).


As pointed out by Martin, what you get in your experiment may not be the maximum possible QY. A trivial reason is that the solvent you are using may not be the solvent used in the measurement. For example, putting a lot of dyes on a protein can result in self-quenching, for examples DQ-collagen or Ralph Weissleder's many Cy5-protease substrates, or overloaded antibodies. for the same reason, fluorescent protein multimers (i.e. 5xGFP) are usually no brighter than monomers or dimers.



best wishes,


George
p.s. some listserv readers may find of interest:

McNamara G, Boswell C (2007) A Thousand Proteins of Light:  15 Years of Advances in Fluorescent Proteins. Modern Research and Educational Topics in Microscopy (volume 3), in press. http://www.formatex.org/microscopy3/     
you can try right clicking these two links in your email:  Word Doc Draft   Data
or go to http://home.earthlink.net/~pubspectra and download from there. Again, best to save to your computer rather than opening in a web browser.


At 07:27 AM 8/16/2007, you wrote:

Search the CONFOCAL archive at
http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal

Hi all,

I am a new member of the confocal list, and I have a question regarding
quantum yield.

Does some kind of list exist with quantum yield of different probes, or
what is the easiest way to find out which probes are the brightest and
most stable ones. They all say they are “the best and brightest”.

Kind regards
Henriette

 

George McNamara, Ph.D.
University of Miami, Miller School of Medicine
Image Core
Miami, FL 33010
[hidden email]
[hidden email]
305-243-8436 office