[Histonet] Processing 3-dimensional cell cultures into paraffin

[Monfils, Paul]

I have processed and embedded cells grown in/on agar, or post-embedded in agar or agarose, many times.  It really isn't much different from processing and embedding tissue. You can trim the agar blocks to appropriate size with a scalpel (if necessary) either before or after fixation (if you trim them before fixation, do it while they are cold, so the agar is firm), and place them in a cassette just like a piece of tissue. Put them on the processor as usual, processing times the same as you would use for tissues of equivalent size, and embed as usual. One difference in sectioning however.  Don't place the blocks in water after facing them off.  The agar absorbs too much water and becomes soft.  The blocks should be cut cold, but not moistened.  Either place them on a cold plate without water, or put them in the refrigerator after facing, and take them out one at a time as you section them.