Question: Is it possible to freeze nuclei prior to Single Cell 3'?
Answer: We haven't tested isolating nuclei and freezing them prior to running Single Cell 3' and therefore can't provide specific guidance. In general, we do not recommend freezing a nuclei suspension as the freezing and thawing process may compromise the nuclear membrane leading to a loss of single-nuclei behavior.
If you choose to do this, however, we would recommend freezing the nuclei in an appropriate freezing medium. An example of a protocol can be found here: http://collaslab.org/wp-content/uploads/2011/07/Isolation_somatic_cell_nuclei.pdf.
At least one million nuclei should be frozen to ensure a sufficient number will be recovered post-thaw. It is expected that you will lose almost half from the freeze-thaw and during the wash and centrifugation steps.
After thawing, the quality of the nuclei should be examined under a microscope and the nuclear membrane should appear intact. The nuclei can be counted using Trypan blue staining with an automated cell counter or hemocytometer. Note, the nuclei should stain as “dead" (blue staining when using Trypan blue).
Products: Single Cell 3'