Oligo will be shipped in lyophilized format. We recommend dissolving the stock oligo in concentrated form in TE (10mM Tris pH 8.0, 1 mM EDTA). Alternatively, sterile dH2O can be used. DNA kept frozen in a nuclease-free environment should be stable for years. We find it convenient to initially make a freezer stock (which should be thawed relatively infrequently) at 100uM concentration. To resuspend an oligo at 100uM concentration, add the volume of TE (in uL) equal to ten times the number of nanomoles of DNA present in the tube (as noted on the spec sheet provided with the oligo) will produce a stock solution at this concentration.