Zinc fixation for flow cytometry analysis of intracellular and surface epitopes, DNA content, and cell proliferation.

Zinc salt-based fixation (ZBF) is a simple, cost-effective, and nonhazardous fixation method for cell suspensions that preserves all cellular structures and enables flow cytometric analysis of both surface and intracellular proteins, DNA content profiles, and pulse-labeling using the thymidine analog EdU in the same cell sample. ZBF performs equally well to formaldehyde in the preservation of surface epitope labeling and forward and side light scatter parameters, as measured by flow cytometry. DNA is maintained at high molecular weight, improving the quantification and allowing subsequent quantitative PCR analysis. Finally, ZBF treatment allows for long-term storage of labeled cells with little change in these parameters. Curr. Protoc. Cytom. 57:7.40.1-7.40.9. © 2011 by John Wiley & Sons, Inc. Keywords: DNA content; DNA synthesis; Click-iT assay; surface and intracellular markers