*****
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.
*****
further to the agarose gel idea, you can buy or make gradient gels agarose or acrylamide with increased density top to bottom