We manufacture oligonucleotides on synthesizers (an automated reagent delivery machine) and/or manually, depending on the type and complexity of the oligo. Synthesis occurs 3’ to 5’, with the 3’ base anchored to a solid support within the synthesis column. The synthesis cycle involves five chemical reactions and repeats as it adds each base to the growing oligonucleotide chain. For further detail, refer to our article A Short History of Oligonucleotide Synthesis.