[Zbrafish] Heat Morpholinos after frozen storage

Jon D.Moulton jmoulton at gene-tools.com
Thu May 11 12:48:47 EST 2006

Good day, I am Jon from Gene Tools.

Many investigators have experienced a decrease in Morpholino activity 
after freeze-thaw cycles.  This can be solved by heating the Morpholino 
solution to 65C for 10 minutes after thawing the oligo.

As Morpholino solutions freeze, the forming ice crystals can exclude the 
Morpholino oligo, causing its concentration in the bulk solution phase 
to increase and then the oligo to precipitate.  While most of the fluffy 
freeze-dried Morpholino oligos readily dissolve in water, the gummy 
deposits resulting from freezing an aqueous solution are harder to 
dissolve.  The heating step takes care of this.  We have checked this by 
spectrophotometry, testing absorbance of just-dissolved Morpholinos, 
testing the solution phase of recently-thawed aqueous solutions of 
Morpholinos and then testing again after heating.  We find that 
Morpholinos have the expected absorbance before freezing, the 
solution-phase absorbance decreases after freezing and thawing and then 
the absorbance recovers to its expected level after heating.


  - Jon

     Jon D. Moulton, Ph.D.
     Special Projects and Customer Support
     jmoulton at gene-tools.com
     (541) 929-7840 x1201

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