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John Oreopoulos John Oreopoulos
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Who sells Congo red?

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

I'm having trouble locating a commercial vendor that sells Congo red dye. Is there another name for this dye and can anyone direct me to a site that sells Congo red? And can someone out there show me an absorption and emission spectrum of this dye?

Thanks!


John Oreopoulos, BSc,

PhD Candidate

University of Toronto

Institute For Biomaterials and Biomedical Engineering

Centre For Studies in Molecular Imaging


Tel: W:416-946-5022



Howard Berg Howard Berg
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Re: Who sells Congo red?

Search the CONFOCAL archive at http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal We got ours from Fluka, cat no. 60910.

Cheers,

Howard

On Dec 6, 2007, at 11:24 AM, John Oreopoulos wrote:

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

I'm having trouble locating a commercial vendor that sells Congo red dye. Is there another name for this dye and can anyone direct me to a site that sells Congo red? And can someone out there show me an absorption and emission spectrum of this dye?

Thanks!


John Oreopoulos, BSc,
PhD Candidate
University of Toronto
Institute For Biomaterials and Biomedical Engineering
Centre For Studies in Molecular Imaging

Tel: W:416-946-5022



R. Howard Berg, Ph.D.
Director, Integrated Microscopy Facility
Danforth Plant Science Center
975 N. Warson Rd.
St. Louis, MO 63132

ph 314-587-1261    fx 314-587-1361   cell 314-378-2409
visit this educational resource: http://www.danforthcenter.org/Cells/






Tobias Baskin Tobias Baskin
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Re: Who sells Congo red?

In reply to this post by John Oreopoulos
Search the CONFOCAL archive at http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal Re: Who sells Congo red?
John,
        Polysciences.  http://www.polysciences.com/shop/

        Tobias


At 12:24 PM -0500 12/6/07, John Oreopoulos wrote:
Search the CONFOCAL archive at http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal Hi,

I'm having trouble locating a commercial vendor that sells Congo red dye. Is there another name for this dye and can anyone direct me to a site that sells Congo red? And can someone out there show me an absorption and emission spectrum of this dye?

Thanks!


John Oreopoulos, BSc,
PhD Candidate
University of Toronto
Institute For Biomaterials and Biomedical Engineering
Centre For Studies in Molecular Imaging

Tel: W:416-946-5022


-- 
      _      ____          __   ____   
     /  \   /          / \    /   \ \        Tobias I. Baskin
    /   /  /          /   \   \      \         Biology Department
   /_ /   __      /__ \   \       \__    611 N. Pleasant St.
  /      /          /       \   \       \        University of Massachusetts
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/      / ___   /           \   \__/  \ ____
http://www.bio.umass.edu/biology/baskin/
Voice: 413 - 545 - 1533 Fax: 413 - 545 - 3243
Julio Vazquez Julio Vazquez
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Re: Who sells Congo red?

In reply to this post by John Oreopoulos
Search the CONFOCAL archive at http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal -


here are some references:




last reference lists the product as purchased from SIGMA  (C-6277)


You will get more info if you Google "congo red"

--
Julio Vazquez
Fred Hutchinson Cancer Research Center
Seattle, WA 98109-1024





On Dec 6, 2007, at 9:24 AM, John Oreopoulos wrote:

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

I'm having trouble locating a commercial vendor that sells Congo red dye. Is there another name for this dye and can anyone direct me to a site that sells Congo red? And can someone out there show me an absorption and emission spectrum of this dye?

Thanks!


John Oreopoulos, BSc,
PhD Candidate
University of Toronto
Institute For Biomaterials and Biomedical Engineering
Centre For Studies in Molecular Imaging

Tel: W:416-946-5022



James Pawley James Pawley
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Re: super resolution - Zeiss enters the boat

In reply to this post by Martin Wessendorf
Search the CONFOCAL archive at http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal Hi all,

While there are definitely dye-choice/bleaching/cytotoxicity/ problems with STED, I don't think that it is quite as bad as Martin calculates. This is because the various damage mechanisms are all proportional to the time that the dye is in the singlet-excited state. And, as the STEp pulse follows the excitation pulse by a few ps, each molecule that is quenched by this pulse is only excited for a few ps, not for the few ns that characterize its normal fluorescence lifetime.

Of the other hand, most STED is done with pulsed beams and, as this means that dye molecules are neither excited or being stimulated at least 90% of the time, the signal level is lower and one must operate 10x closer to the singlet-state saturation. This will probably lead to more "1+1 photon" damage and enhanced bleaching.

In addition, as has been pointed out before, unless the dyes molecules are concentrated into very small nm-scale structures (i.e., a ribosome or a centriole), having a smaller effective excitation volume means that fewer dyes molecules will be located in each volume and this will either reduce signal or require increased pixel-dwell time.

STED is a very clever technique, however, I think that over the long run, its widespread application will be determined in competition with  correlated LM/EM microscopy.

One really has to compare the utility of one STED vs. about 4-5 standard confocals.

Happy Holidays!

Jim P.

On Dec 6, 2007, at 10:51 AM, Martin Wessendorf wrote:

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Hey, Chris--

Chris Wood wrote:

And it seems to me that STED will be suitable for live cells sooner than the PALM-STORM techniques.

Interesting question.  Someone pointed out to me off-list that with STED, the fluorophore gets taken up to the excited state many more times (--presumably 25x for a 5x increase in resolution) than with conventional multiphoton microscopy for each photon of actual fluorescence.  However, for each time it's in the excited state, it has the same probability of bad photochemistry occuring--e.g., transition to the triplet state and/or phototoxicity.  In this example, you'd expect 25x more phototoxicity with STED than with multiphoton in order to obtain the same image.  Thus there may be inherent limitations with STED with regards to live-cell imaging.

That being said, it'd appear that the weakness is relative: if you can create a fluorophore that has a lower probability of engaging in bad photochemistry, live-cell might be doable.  So it strikes me that (in agreement with what other people have already pointed out) we'll probably need new, better fluorophores to do live-cell imaging with STED.

Martin Wessendorf
--
Martin Wessendorf, Ph.D.                   office: (612) 626-0145
Assoc Prof, Dept Neuroscience                 lab: (612) 624-2991
University of Minnesota             Preferred FAX: (612) 624-8118
6-145 Jackson Hall, 321 Church St. SE    Dept Fax: (612) 626-5009
Minneapolis, MN  55455             E-mail: martinw[at]med.umn.edu

Prof. James B. Pawley,                                          Ph.  608-263-3147  
Room 223, Zoology Research Building,            FAX  608-265-5315
1117 Johnson Ave., Madison, WI, 53706           [hidden email] 
3D Microscopy of Living Cells Course, June 14-26, 2008, UBC, Vancouver Canada
Info: http://www.3dcourse.ubc.ca/                         Applications due by March 15, 2008
"If it ain't diffraction, it must be statistics." Anon.

Mark Cannell Mark Cannell
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Re: super resolution - Zeiss enters the boat

In reply to this post by Martin Wessendorf
Search the CONFOCAL archive at
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Hi Martin

Perhaps you could expand on this, I'd have thought that  if the  
fluorophore is depleted by stimulated emission with I/Isat > 1 it is  
in the excited state for very much less time.

Cheers Mark

On 7/12/2007, at 5:51 AM, Martin Wessendorf wrote:

>
>
> Interesting question.  Someone pointed out to me off-list that with  
> STED, the fluorophore gets taken up to the excited state many more  
> times (--presumably 25x for a 5x increase in resolution) than with  
> conventional multiphoton microscopy for each photon of actual  
> fluorescence.  However, for each time it's in the excited state, it  
> has the same probability of bad photochemistry occuring--e.g.,  
> transition to the triplet state and/or phototoxicity.  In this  
> example, you'd expect 25x more phototoxicity with STED than with  
> multiphoton in order to obtain the same image.  Thus there may be  
> inherent limitations with STED with regards to live-cell imaging.
>
>
Martin Wessendorf Martin Wessendorf
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Re: super resolution - Zeiss enters the boat

Search the CONFOCAL archive at
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Hey, Mark--

Mark Cannell wrote:

> Perhaps you could expand on this, I'd have thought that  if the
> fluorophore is depleted by stimulated emission with I/Isat > 1 it is in
> the excited state for very much less time.

I think that you and Jim Pawley make the same point--correctly, as
nearly as my feeble quantum mechanics can apprehend!

As Jim and others have pointed out, the dwell time per unit area will be
increased, and that will tend to increase both photobleaching and
phototoxicity.  But no, it appears that the increased cycling of the
fluorophore shouldn't be much of an issue.

Martin
--
Martin Wessendorf, Ph.D.                   office: (612) 626-0145
Assoc Prof, Dept Neuroscience                 lab: (612) 624-2991
University of Minnesota             Preferred FAX: (612) 624-8118
6-145 Jackson Hall, 321 Church St. SE    Dept Fax: (612) 626-5009
Minneapolis, MN  55455             E-mail: martinw[at]med.umn.edu
George McNamara George McNamara
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Re: Who sells Congo red?

In reply to this post by John Oreopoulos
Search the CONFOCAL archive at http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal Hi John,


http://www.usca.edu/chemistry/spectra/ has the UV-VIS (absorption spectrum) for Congo Red and the other dyes in Jack Goldsmith's web site is in the no longer supported Thermo Galactic ".p7b" file format. All Jack's spectra data are in our standard format in one of our PubSpectra Excel files in
http://home.earthlink.net/~gfpology/McNamara_Boswell_Spectra_ Dyes_FPs .zip
(the one with Goldsmith in the name).

Absorption spectra page 220 of Green 1990 Sigma-Aldrich Handbook of Dyes and Indicators, on page 490 of Gurr 1971 Synthetic Dyes in Biology and Medicine, and W.E. Klunk 1999 Analytical Biochemistry 266: 66-76. Emission spectrum is in fig 2 of A. Elhaddaoui 1995 Biospectroscopy 1: 351-356. Spectra may differ in solution and bound to amyloid, etc.

George
p.s. another link for histology stains is http://stainsfile.info/StainsFile/dyes/22120.htm


At 12:24 PM 12/6/2007, you wrote:
Search the CONFOCAL archive at http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal Hi,

I'm having trouble locating a commercial vendor that sells Congo red dye. Is there another name for this dye and can anyone direct me to a site that sells Congo red? And can someone out there show me an absorption and emission spectrum of this dye?

Thanks!


John Oreopoulos, BSc,

PhD Candidate

University of Toronto

Institute For Biomaterials and Biomedical Engineering

Centre For Studies in Molecular Imaging


Tel: W:416-946-5022




 

George McNamara, Ph.D.
University of Miami, Miller School of Medicine
Image Core
Miami, FL 33010
[hidden email]
[hidden email]
305-243-8436 office
http://home.earthlink.net/~pubspectra/
http://home.earthlink.net/~geomcnamara/
http://www.sylvester.org/health_pro/shared_resources/index.asp (see Analytical Imaging Core Facility)


ae275 ae275
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Re: super resolution - Zeiss enters the boat

In reply to this post by Michael Weber-4
Search the CONFOCAL archive at
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Hi,
   from the department of Stefan Hell this problem has been tackled from
many point of view. First of all, the repeteation rate can be optimized in
order to minimize photobleaching (see D-Rex [PMID: 17179937] illumination
and STED [I think PMID: 17307826 is the correct one]) and a generalization
of STED (RESOLFT - [PMID: 16314572]) was proposed that makes use of lower
intensities at the sample. On regard of photobleaching alone, they are
trying to develop better fluorophores. The last example is PMID: 18058955.

STORM/PALM/PALMIRA may become faster then currently is, but these
techniques will be always limited by the necessity of sequential imaging of
each single fluorophore. I am looking forward for fluorophores optimized
for these kind of techniques and I am quite sure that other
optimization/innovations are possible...

Cheers,

--
Dr. Alessandro Esposito
Laser Analytics Group - Department of Chemical Engineering
University Cambridge
E.mail:  [hidden email]
CV:      http://home.quantitative-microscopy.org
Web:     http://www.wikiscope.org
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