Long term preservation and high transfection efficacy of siRNA is achieved by use of SAINT-RED.
Reproducibility and the introduction of an (internal) standard is difficult when using siRNA to
knock-down gene-expression. If the experiment does have a time-spanning period
(several transfections in days/months), and contains different subsets of data to be generated,
it is even more complex. The siRNA could become inactive even if you aliquot the solution and
store at -20°C

The solution to this problem would be to make a standard siRNA dilution which can be used directly
in the transfection experiment and can be stored at 4°C degrees over such a longer period without
affecting the knock-down efficiency of the siRNA molecule.

A series of tests have shown that SAINT-RED can act as a preservative for siRNA preparations.

Two solutions of duplexed siRNA (20nM) were prepared. The siRNA against a housekeeping gene
was diluted in the standard siRNA buffer (pink bars) or in SAINT-RED (Blue bars).
Standard solution were stored at 4°C.

Transfections of 3T3 cells were performed on the same day (day zero) and the next day (day 1),
the second day(day 2), in between time points (data not shown) and after 5 and 9 months.
Enzyme activity of the expressed housekeeping gene was measured 48 hours after transfection.

The results clearly show that the siRNA complexed with SAINT-RED remains as effective as the
complex prepared at day zero over a period of 5 months or even more.
Thus, it is possible to prepare one single transfection batch, and use this as a stock solution,
improving experiment-to-experiment reproducibility.