Hello Chit Care

You may freeze Alexa Fluor conjugated secondary antibodies at -20°C, but in aliquots for one time use just to avoid repeated freeze-thaw cycles. Many fluorochromes are fine when frozen and subsequently thawed including PE, most of the Alexa dyes, as well as FITC.

However, the dyes that don't fair too well when frozen are tandem dyes, such as PE-Cy7 and APC-Cy7, because freezing might result in denaturing of the donor fluorophores and thereby cause no or reduced staining. So, tandem dye antibody conjugates should never be frozen at -20°C. Also, fluorescent conjugates are susceptible to photobleaching. Hence, fluorochrome-conjugated antibodies should be stored protected from light in a darker coloured vial.

So, go ahead and freeze Alexa Fluor conjugated secondary antibodies at -20°C in aliquots for one time use only.

Best.

Hi Chit Care

It is recommended to store in Alexa Fluor at 4°C. We have stored the same for years.

Thanks,

Thermo Fisher technical support here. We've done storage stability testing and found that storage at 4C is stable for at least 6 months. But if you are storing for longer than that, you can make aliquots and store at -20C. Be careful not to repeatedly freeze/thaw, though, as it can degrade the antibody. The dye is stable, though.