How stable is my antisense/PTO once I have resuspended it?

To gain a maximum shelf life for oligonucleotides, samples should generally be stored dehydrated at ≤ –15 °C in absence of light. Under the mentioned conditions, samples are stable for at least 6 months. In case of a longer storage period, oligos should be pretested for molecular integrity prior to experimental use. If stored frozen at –20 °C or –70 °C, it will remain stable for several months. Repeated freeze-thaw cycles should be avoided, as this will denature the dsDNA. Moreover, the oligo stability in solution depends on the pH. Dissolving an oligo into acidic solutions may result in its degradation. Therefore, avoid the use of non-sterile distilled water as a diluent, since solution pH may be as low as 4–5.
In addition to what above advised, we recommend that you minimize the exposure of modified antisense/PTOs– especially if fluorescently labelled - to light, to avoid any bleaching effect.

Moreover, we recommend storing dye-labelled antisense/PTOs highly concentrated and not in working dilutions, if you are not planning to use it within 24 hours. The higher the dilution factor, the faster the fluorescent activity fades away. Therefore, try to store highly concentrated aliquots frozen, thaw them only once, dilute them just before you use the probe and store the aliquots at 4 °C in the dark.