I'm investigating the suitability of SU-8 for structures in an
experimental setup I'm working on, and I have a couple of concerns that
I'd like to look into.
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?
My other consideration is less significant--it's more about convenience
than compatibility. My target thickness of SU-8 will likely be between
0.5 and 1.0 microns. The lowest thickness listed in Microchem's SU-8
2-25 datasheet (and the SU-8 2000 2-15 datasheet) is 1.5 5m. Would it
be practical to achieve sub-micron thicknesses simply with higher spin
speeds, or would it be preferable to dilute the SU-8 2 formulation in
gamma-butyrolactone (or the SU-8 2002 formulation in cyclopentanone).
Does anyone have info on spin speed vs. thickness for dilutions of SU-8
2 (or 2002)?
Thanks,
-Cyrus