Oligo Synthesis

custom oligo and sirna synthesis

Highest Quality -- Custom Primers and Probes 

excellent prices negotiated for our clients
Most regular primers (<50 nucleotides) only need simple desalting.
Cost-effective modified oligos and labels.

Other Synthesis Products

  • Longmers with good yield out to 200 nucleotides. RNA and siRNA custom synthesis is available.
  • Gene Fragments custom synthesis of 125-500 base-paired dsDNA, sequence verified.
    • Uses include: pPCR positive control, cloning cassette, custom gene construction.
  • qPCR assays, pre-designed or custom; for intercalating dye assays or Taqman® style assays.

ASR and GMP Oligos are also available (description).



NCBI publishes an excellent introduction to RNA interference.

Protocol for forming duplex: annealing single-stranded oligos.

RNA RNA and mixed RNA/DNA and other unusual nucleic acid molecules can be made.

Did you know?

  • Synthetic oligos are single stranded with hydroxyl groups (not phosphates) at both termini. This means you must phosphorylate, either off or on the synthesizer, if you wish to use in a ligation reaction.
  • To form a duplex with the complement: simply add equi-molar amounts to the your buffered solution, heat to well over the Tm, then allow to slowly cool to room temperature on the bench. Store cold.

As of Jan, 2012, we have negotiated improved pricing for oligos.

Simply choose the outside synthesis service provider on the work-request form on-line ordering The oligos will be delivered to OHSU and we will contact you for either pickup or delivery to your lab. We can help with design and troubleshooting.

Oligo Calculations

Given Ext. coef in nmole/OD (Ex) and A260 of  oligo (OD).
Note: the A260 is measured for 1 mL of oligo. This is the OD value of the dried down oligo that you receive.
  1. Calculate the amount in nanomoles of dried down oligo:  nmole = OD x Ex
  2. Figure out the volume (X) needed to make a specific concentration, e.g. 100 µM (note µM is µmoles/L which is equal to nmole/mL)
    nmole/X = 100µM
    X = nmole/100 = mL water or buffer
Note X is in mL so multiply by 1000 to get µL of buffer for you stock of oligo.

Example: if the A260 of the dried down oligo is 18, this is the ODs. If the Ex(260) is 4.01 nmol/OD then
Amount of oligo (in nanomoles) = 18*4.01 = 72.18 nmole
For 100µM solution, dissolve oligo in 72.18/100 = 0.7218 mL = 721.8 µL for a stock solution at 100 µM ( = 100 nmole/mL = 100 pmole/µL)