I am working with disassociated cells taken from frozen tissue (-20 C) and need to stain their nucleus, but it is not working. I am unable to preserve fresh tissue in PFA or GLA before freezing it because I cannot introduce carbon contamination prior to their dissociation. Once they have been disassociated, it's fair game!

Is there a way for me to prepare the cells after freezing to allow the fluorochrome to penetrate the cell membrane (assuming that is the problem). Someone recommended doing an ethanol wash, but I don't have any experience with staining.

Thank you!