Adding to what Jeff Zahn wrote, it's better to stay away from the blue
and UV when doing any fluorescence microscopy on SU-8. Cross-linked SU-8
has an absorption coefficient of 1000/m at about 600nm and goes up to
almost ten times that at 400nm.

If you have access to a source for two-photon excitation of your
fluorophore (like a Ti:sapphire laser) and are examining the proteins by
confocal microscopy, the rhodamine dyes  work really well. I have good
success with imaging Rhodamine B by 1- and 2-photon excitation in SU-8.
I haven't had a problem with autofluorescence of the material either.

Good luck,

Chris

On Tuesday, August 13, 2002, at 05:20  am, Cyrus Wilson wrote:

> I'm most worried about fluorescence behavior of SU-8.  I'd like to be
> able to use fluorescence microscopy to visualize fluorescently-labeled
> protein bundles suspended on SU-8 pillars (fabricated on a glass cover
> slip).  I have flexibility in my choice of fluorophores, so it would
> seem wise to avoid those with excitation frequencies in the UV range
> that SU-8 absorbs.  But I'm concerned about slight absorption and
> emission of wavelengths above 400nm that aren't a problem for most uses
> but could get in my way.  Is anyone aware of info on absorption and
> emission spectra of SU-8 after it is baked & developed?
--
Christopher F. Blanford
Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR, UK
Phone: (44)/(0)-1865-282603; Fax: (44)/(0)-1865-272690
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