Bio-Synthesis provide phosphorothioate RNA oligonucleotide synthesis by substitute a sulfur atom for a non-bridging oxygen in the phosphate backbone of an oligonucleotide. While the natural phosphodiester bonds are highly susceptible to rapid degradation by cellular nucleases,  the modification of internucleotide linkage using phosphorothioate (PS) bond substitutes are substantially more stable towards hydrolysis by cellular degradation. This stabilization lead to enhanced biological activity. The phosphorothioate enhanced RNA oligomer have shown to inhibit RNase A, RNase T1 and calf serum nucleases. These properties allow the use of PS-RNA oligonucleotide to be use in the application where exposure to nucleases is inevitable in vivo or in vitro. Phosphorothioate (PS) bonds can be introduced between the last 3-5 nucleotides at the 5'- or 3'-end of the oligo to inhibit exonuclease degradation. Including phosphorothioate bonds throughout the entire oligo will help reduce attack by endonucleases as well. However, this type of modification have lesser affinity toward target sequence than the phosphodiester coutner part. T his can be minimized by the use of BNA and 2'-5' linked oligonucleotides. This modification can also be use to improve the stability of siRNA where at least one or two phosphorothioate linkages should be incorporated at 3' end of both sense and antisense strands. Phosphorothioate modified RNA are compatible with molecular biology experiment. It can also mimic standard RNA in side directed mutagenesis. RNA oligomer substitute with phsophorothioate can also be used for ribozyme study, aptamer selection.

Phosphorothioate RNA synthesized by Bio-Synthesis can be combined with other bases and/or sugar modified. These S-oigo  can be specified to have fully sulfur linkage substituted or a mixture of diester and thioate linkages as specified by customer. Contact us for phosphorothioate RNA synthesis.

Product Information


Product Name:

Phosphorothioate RNA Synthesis


Backbone Modificaiton, Antisense, Nuclease Resistance

Modification Code:

*rA, *rG, *rT, *rC


Bio-Synthesis Inc. Oligo Structure



Delivery Format:


Shipping Conditions:

Room Temperature

Storage Conditions:

-20°C To -70°C
Oligonucleotides are stable in solution at 4°C for up to 2 weeks. Properly reconstituted material stored at -20°C should be stable for at least 6 months. Dried DNA (when kept at -20°C) in a nuclease-free environment should be stable for years.