Question: Can alternative fixation buffers or fixation protocols be used for sample fixation with the Fixed RNA Profiling assay?
Answer: We have not tested the use of alternative fixation buffers or fixation protocols with the Fixed RNA Profiling (i.e. Single Cell Gene Expression Flex) assay, and thus cannot provide any specific recommendations.
Other fixation buffers containing formaldehyde at a final concentration of 4% may be compatible with the Fixed RNA Profiling assay but they are untested and unsupported. We advise performing a small pilot study before committing to large-scale experiments.
For additional guidance using formalin fixed tissues in the Fixed RNA Profiling assay, please see: Can I use formalin fixed tissue as input for the Gene Expression Flex assay?
If the formaldehyde validated in the 10x Demonstrated Protocol Fixation of Cells & Nuclei for Chromium Fixed RNA Profiling or Tissue Fixation & Dissociation for Chromium Fixed RNA Profiling is not available in your region, any Molecular Biology Grade stock solution of 37% formaldehyde that is ~10% methanol stabilized (with little to no precipitant) may be substituted.
Products: Fixed RNA Profiling Gene Expression, Single Cell Gene Expression Flex