Tom, you might like to look at triplet probes such as eosin or erythrosin.  Eosin was used extensively in the 1980s for rotational diffusion measurements (keywords: transient dichroism) and can have lifetimes up to 2ms but is sensitive to quenching.  The eosin is introduced into proteins via the maleimide or isothiocyanate reactive groups, both from Invitrogen (no commercial interest).  Quenching was prevented by rigorous exclusion of oxygen, or it can also be a source of information about the accessibility of the eosin (exposed/buried).  Erythrosin was used for phosphorescence studies (check publications from Bill Sawyer at Melbourne University).  I have used both probes in widefield imaging, but not often by confocal as they have relatively low intensity and the long lifetime gave problems at normal scan rates.

If you need more information, contact me offline at my new address ([log in to unmask]).
Best wishes, Ian

Dr. I.E.G. Morrison, Biology Department, University of York, York UK.

-----Original Message-----
From: Confocal Microscopy List on behalf of Tom Lawson
Sent: Sat 18/04/2009 07:08
To: [log in to unmask]
Subject: Locate some easy-to-use long lifetime fluorphores?
 
Dear Confocalists,

I am trying to locate some commercial and easy-to-use long lifetime
fluorphores to time-gate autofluorescence. Ideally they would have to
last at least 1ms (which is a long time).

The research team I work with makes its own lanthanides organometallic
fluorophores Eu3+ and Tb3+ which last about 3ms. But I am anticipating
getting specimens from collaborators who may want to label the
specimens at their end and lanthanides are not easy to use.

I thought I might be able to find some organometallic transition
metal-ligand complexes such as ruthenium (Ru II), rhenium (Re I), or
osmium (Os II) (10 ns to 10 ?s) or some organic fluorophores such as
Pyrene (400ns) or Coronenes (200ns). But I have had no luck finding
any, they might not be easy to use and 400ns is cutting it a bit
short.

One suggestion I have had so far is quantum dots which I need to look
into. There maybe other options I am not aware of.

I would be grateful if you have any suggestions?

Regards,

--
Tom Lawson
[log in to unmask]
PhD Student,
Macquarie University
NSW, 2109
Australia