I have not had much experience with animal cells, but I have done some labelling of fungal spores.  The spores pick up the dye, and when they germinate, the mycelia are fluorescent for a few mm until the dye is diluted out as the cells divide.  The viability of the fungus seems unaffected, so incubation of sperm in a similar manner should probably work.  I have used both  Cell Tracker Blue CMAC and Cell Tracker Green CMFDA from molecular probes.  The Blue fluoresces in UV, which will probably not make the sperm very happy, but the Green might meet your applications (around the same range as fluorescein).

good luck
shea



Dr. S. Shea Miller
Agriculture and Agri-Food Canada
Eastern Cereal and Oilseed Research Centre
2068 K.W. Neatby Bldg
Central Experimental Farm
Ottawa, Ontario
Canada   K1A 0C6
email:  [log in to unmask]
phone:  613-759-1760
fax:  613-759-1701
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