Storage FAQ for Antibodies and Proteins

The antibody I received was shipped at ambient temperature. Could this have damaged the antibody?

In many cases it is not necessary to keep the goods cooled during shipping. This is always true for lyophilized antibodies /proteins, but may also apply to proteins / antibodies sold in a liquid format. However, after you receive the goods you should observe the storage recommendations stipulated in the data sheet.

I forgot to put the lyophilized antibody I received in the fridge, what should I do?

Lyophilized antibodies / proteins are very stable and only become sensitive to storage conditions after dissolving. They can be stored unopened at ambient temperature for many days, but should be stored at 2-8 °C minimum. Long-term storage of unopened lyophilizates (years!) should be at a minimum of -20 °C.

How should I store the protein / antibody upon arrival?

You should always follow the recommendation in the datasheet. In general protein / antibody solutions should be stored at a minimum of 2-8 °C or -20 °C.

Why should I store my protein / antibody in aliquots?

Using aliquots help to avoid repeated freezing and thawing of your protein / antibody. It also helps you to avoid problems caused by contamination. After receiving your protein / antibody determine the optimal size of the aliquots according to your usage and aliquot the product accordingly. You should be careful to aliquot the protein / antibody under sterile conditions and only with sterile buffers / solutions. We strongly recommend to use only unopened / freshly autoclaved solutions and buffers as diluents.

Why should I avoid repeatedly freezing and thawing antibodies / proteins?

Repeated freezing and thawing of antibody / protein solutions should be avoided as this may result in degraded functionality. This may be caused by the formation of ice crystals and or the loss of functional protein due to agglutination etc.

If antibody/protein solutions stored at 2-8 °C are not used within a few weeks, they should be aliquoted for long-term storage and frozen at -20 °C or -80 °C.

Why do you recommend storing aliquots of protein / antibody in a minimum of 50µl  liquid?

Depending of the material of your storage container antibody / protein may bind to the surface of the vessel. The smaller the amount of protein / antibody the more material may be required to saturate the surface of the vessel. The material bound to the surface might not be recoverable.

This is why you should use low-protein binding microcentrifuge tubes and  aliquots should be at least 50µl in order to avoid loss by adsorbtion.

In addition, if you store small amounts of liquid at -20 °C or -80 °C for longer periods of time you may lose material by evaporation or sublimation even if you use seemingly air tight container.

For this purpose it can be helpful to pre-dilute the protein/antibody solution (e.g. 1:5 or 1:10 in PBS/5% BSA) for subsequent aliquotation.

How can I avoid thawing and refreezing my antibody / protein?

An alternative option is liquid storage of antibody/protein solutions in the presence of glycerol at -20 °C: For this purpose dilute the solution 1:1 with highly purified glycerol (ACS grade or better) as anti-freeze. The use of glycerol inhibits formation of damaging ice crystals by keeping the antibody / protein solution in a liquid state

IMPORTANT: Do I have to take special precautions if I add glycerol as an anti-freeze?

Using glycerol of lower purity or glycerol contaminated with bacteria can severely impair the function of antibody conjugates, especially HRPO conjugates. If you are unsure about the quality of your glycerol you should evaluate the suitability with a small aliquot, first!

Please note that the addition of glycerol reduces the amount of protein and salts (buffer) compared to the original concentration by half. Antibody / Protein dilution suggestions in your datasheet must be adapted accordingly.

Does glycerol also protect my antibody / protein when I store it at -80 °C?

No! The use of glycerol inhibits formation of damaging ice crystals by keeping the antibody / protein solution in a liquid state. This protection does not work at temperatures of -80 °C.

Do you recommend storage of antibodies / proteins in “frost free freezers”?

No! Frost free freezers use repeated freeze thaw cycles to reduce the internal build up of ice. Repeated freeze thaw cycles may damage your antibody / protein.

Do you have special recommendations for the storage of antibody conjugated to fluorophores?

Antibodies conjugated to fluorophores should be kept in lightproof containers in order to avoid loss of function.