*****
To join, leave or search the confocal microscopy listserv, go to:
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
Post images on http://www.imgur.com and include the link in your posting.
*****

I have a few questions regarding the use of gold nano particles as fiducial 
markers for STORM imaging that I was hoping the listserv community could help 
with: 

1) What is the mechanism by which they are visible under standard excitation 
wavelengths? It seems that they're based on surface plasmon resonance, and 
the amount of scatter across various wavelengths varies according to the 
properties of the particle. Is that correct?

2) If so, are there gold fiducials that anyone has used with success across 
multiple wavelengths? In other words, using a single fiducial that is visible 
across all channels. According to the OD curves, it seems that some are great in 
the red, but not so good in blue, etc. Or is this mitigated by the fact that even if 
there is a little bit of scatter, at the powers typically used for STORM it will be 
visible regardless?

3) Finally, does the size of the fiducial matter? Why would someone use 50 nm 
fiducials instead of 100 or 200 nm?

Any advice on all this would be appreciated.

Thanks,
Paul