Can I order duplexed Ultramer® Oligonucleotides?
We unfortunately do not offer duplexed Ultramer Oligonucleotides. However, we do provide gBlocks Gene Fragments, which are sequence-verified, dsDNA fragments up to 750 bp. Alternatively, you can order single-stranded Ultramer Oligonucleotides and anneal them using the following Annealing Protocol: Dissolve the oligos at high concentration—as high as 500 µM if possible, although as low as 100 µM will work; i.e., 1-10 OD260 units / 100 µL—in STE Buffer (10 mM Tris pH 8.0, 50 mM NaCl, 1 mM EDTA) or Nuclease-free Duplex Buffer (30 mM Hepes pH 7.5, 100 mM KAc) (available from IDT). The presence of some salt is necessary for the oligos to hybridize. Then mix the two oligos in equimolar concentrations, heat to 94° C, and allow the solution to cool slowly to room temperature. For sequences with significant hairpin potential, a more gradual cooling step is beneficial; this is easily done by placing the oligos in a water bath or heating block and unplugging the machine. The resulting product will be a stable, double-stranded construct.