Biological stability and activity of siRNA in ionic liquids.

We report substantially enhanced biological stability of siRNA in a hydrated ionic liquid (IL) based on buffered choline dihydrogen phosphate (CDP). The results show that hydrated CDP IL substantially prolongs the shelf-life of siRNA for up to three months in the presence of RNase A. Remarkably, siRNA stored in the IL remained active and eGFP siRNA exhibited clear gene knockdown effects in eGFP-expressing HeLa cells.