The basic principle of DNA synthesis

The chemical DNA synthesis is based on the solid-phase synthesis strategy and phosphoramidite chemistry. Different from the biological DNA synthesis, the material in chemical DNA synthesis is DMT (4, 4-dimethoxytrityl) and phosphoramidite modified deoxyriboxyside, as shown in Figure 1. The DNA synthesis is carried out on the solid support(we can offer various of Oligo Synthesis Column), i.e. CPG (controlled pore glass) and PS (polystyrene), and the whole synthesis is performed on a DNA/RNA synthesizer, which is our main equipment, has different model such as: HY Single Channel Synthesizer, HY-12, HY-192 and etc, the synthesis direction is from 3' to 5', and a nucleotide is introduced to the solid support via one synthesis cycle. A typically synthesis cycle contains four steps, Deprotection, Coupling, Capping and Oxidation (Figure 2). The Deprotection is set to remove the DMT group on the solid support or the 5' hydroxyl group on the previous nucleoside, the 3% trichloroacetic acid in dichloromethane is used as the deprotection reagent. Then the phosphoramidite modified deoxyriboxyside was allowed to exposure hydroxyl group with the assistance of activator, i.e. 5-ethylthiotetrazole or 4, 5-dicyanoimidazole, forming the phosphitetriester (III), and realized the Coupling step. A Capping step is carried out to block the unreacted hydroxyl group during coupling step, to minimize the formation of undesired defect sequences. Finally, the unstable phosphitetriester (III) is oxidized to chemical stable phosphortriester (V) with iodine as oxidant in the present of pyridine.

The synthesized DNA could be cleavage from the solid support by aminolysis, the 2-cyanoethyl protected group on the phosphortriester and the amide on the nucleobase is cleavaged at the same time, the Synthesis Plates and Synthesis Columns in racks are placed directly in the reaction chamber of the Deprotection Equipment. Crude DNA could be prepared by HPLC, electrophoresis and OPC on demand, we can also provide you the Purification Equipment for Post-processing.