RNA interference (RNAi) is the best way to effectively knock down gene expression to study protein function in a wide range of cell types. Traditional RNAi methods for gene knockdown in mammalian cells involved the use of synthetic RNA duplexes consisting of two unmodified 21-mer oligonucleotides annealed together to form short/small interfering RNAs (siRNAs). Silencer® Select siRNA and Stealth RNAi™ siRNA improve upon these traditional duplexes by using proprietary chemical modifications to ensure better RNAi results.

For Research Use Only. Not for use in diagnostic procedures.

Finding the Right Ambion siRNA  

Search the more than 200,000 Ambion® siRNAs using our siRNA Selection Tool.

Which siRNA is right for you?

Cost-effective siRNA Good knock-down, low off-target Highest knock-down, lowest off-target
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  Silencer® siRNA
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Stealth RNAi™ siRNA
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Silencer® Select siRNA
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Potency 100 nM recommended conc. 20 nM recommended conc. 5 nM recommended conc.
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2 of 3 siRNA guaranteed 2 of 3 siRNA guaranteed 2 of 2 siRNA guaranteed
Target specificity Moderate High Highest
Innate immune response Low Minimized through chemical modifications Minimized through chemical modifications
Molecular format Unmodified 21-bp duplex with overhangs Modified 25-bp duplex with no overhangs LNA modified 21-bp duplex with overhangs
Coverage Coding RNA Coding RNA Coding & non-coding RNA
Target species Human, mouse, rat
(Other species: use custom tool)
Human, mouse, rat
(Other species: use custom tool)
Human, mouse, rat
(Other species: use custom tool)
Custom tool Custom Silencer® siRNA Custom Stealth RNAi™ siRNA Custom Silencer® Select siRNA
Cat. No.
AM16708: Silencer® Pre-designed siIRNA 5 nmol 1299003: RNA-Stealth Oligos Tube Set 4392420: Silencer® Select Pre-Designed siRNA 5 nmol

siRNA selection tool

siRNA videos

Meet the Inventor: Silencer® Select siRNA technology

Meet the inventor: Susan Magdaleno discusses Silencer® Select siRNA technology


Dr. Gavin Robertson describes how Silencer® Select siRNA technology is advancing melanoma research.


Additional siRNA ordering tools


If you have any questions on products or ordering, please contact us at RNAiresearcher@lifetech.com