Figure 3. Preservation strategies.

Cells or tissue can often be preserved prior to a single cell experiment to allow for samples to be acquired at different times or locations and then processed synchronously. Either fully dissociated cell suspensions or partially intact, minced tissue can be frozen in liquid nitrogen and stored for weeks or months prior to thawing. If minced tissue pieces were frozen initially, single cell suspensions can be prepared after thawing by standard dissociation protocols used for fresh tissue. Alternatively, cells can be chemically preserved with a variety of fixatives that have been demonstrated to be compatible with many single-cell workflows, such as paraformaldehyde (PFA), glyoxal, or methanol (MeOH). Protocols to reconstitute the fixed single cells prior to sequencing vary depending on the fixative and the chemistry of the single-cell application.