Frequently Asked Questions - Drying Antibodies and Proteins

Can the drying method cause variability in my assay?

High background can be caused by the drying technique: It is very important that the antibodies do not dry to the surface of the substrate before StabilCoat or StabilGuard Stabilizer is added as it will cause a loss of activity.  After incubation and aspiration of StabilCoat or StabilGuard, the antibodies should be completely dried.  The faster the drying time, the better.  We recommend using a humidity-controlled (less than 15% humidity) incubator for 4 to 24 hours, or drying the antibodies in a dry vacuum oven for 4 hours at 30°C.  If an incubator or vacuum oven is not available, the antibodies can be dried in a sealed, desiccated container, such as an airtight plastic container, jar, or plastic bag containing calcium sulfate or silica gel dessicant for 2 to 24 hours.  It is also important to store the dried proteins in airtight containers with desiccant to prevent moisture from getting into the product. Anything that reduces the drying time can greatly improve the stability and activity of the antigen.  Studies were conducted that compared drying times and humidity levels and results demonstrated these to be the two most critical factors in maintaining antibody stability. Extended drying times at higher humidity levels can result in a significant loss of coated antibody activity.

What percentage of humidity is optimal for drying microtiter plates?

We recommend drying at 20% humidity or less for the best stability.  Drying at room temperature is acceptable, although this may increase drying time and result in a slight loss of activity unless the humidity is below 20%.  The faster the plates are dried, the better the retained activity will be.  We recommend using an airtight container filled with desiccant for plate drying.  Once dried, the plates should be sealed and stored in an air tight container with desiccant.

Can StabilZyme products be used for dried assay components?

No.  All of the StabilZyme products are designed to stabilize biologically active components in solution.

Can you recommend a stabilizer for lyophilized material?

We recommend using the StabilCoat Immunoassay Stabilizer for this purpose.  The customer should NOT use the StabilGuard Biomolecule Stabilizer--some of the components in the product may result in a “gelling” or “gooey” substance when the lyophilized material is thawed.

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