Which buffer should you use to transport FACS-sorted cells for RNA analysis?

Protecting cells properly after collection or FACS sorting is crucial to the quality of subsequent RNA analyses. RNA is a molecule that is particularly susceptible to degradation, so the way the material is stored and transported can directly affect the quality of the resulting data.

Transporting cells in buffer

Cells intended for RNA isolation can be transported in standard buffers used during FACS sorting, optimised to maintain cell viability and stability. There is no need to use a single, strictly specified buffer.

The key requirements are that the buffer used:

• does not have an unusually high salt concentration,
• is as free from RNases as possible,
• does not contain components that can lead to RNA degradation,
• keeps the cellular material stable and in good condition during transport.

In most cases, we exchange the buffer during the initial stage of RNA isolation. Its exact composition should therefore not be an issue, provided it meets the requirements above.

Sample protection with Zymo DNA/RNA Shield

An alternative is to use Zymo DNA/RNA Shield. This reagent is fully accepted for protecting material intended for RNA analysis.

DNA/RNA Shield stabilises biological material and protects nucleic acids from degradation. It may be particularly useful when RNA isolation is not performed immediately after cell collection or when samples need to be transported. Its use may also offer advantages in terms of organisation and the cost of protecting each sample.

Always clearly indicate the use of DNA/RNA Shield or another buffer on the sample information form (SIF). This allows the RNA isolation procedure to be adapted accordingly.

Particular importance for low-input mRNA-seq

Protecting the material properly is particularly important for low-input mRNA-seq, an analysis performed using a very small number of cells or a small amount of RNA. In this case, even partial RNA degradation can significantly affect the ability to prepare a library, transcript representation and the quality of the resulting data.

For low-input samples, we recommend discussing the number of cells, buffer type, sample volume, transport time and planned storage conditions in advance.