Product Overview

Expert siRNA design provides guaranteed gene silencing from pre-designed genome-wide collections for human, mouse and rat targets.

Simply search for your gene of interest and choose from the available product formats and quantities.


  • We now offer a new 2 nmol size when purchasing pre-designed ON-TARGETplus or siGENOME siRNAs for human, mouse, or rat.
  • Guaranteed knockdown by SMARTpool and 3 of 4 individual siRNAs (see Product Formats tab.)
  • Rational strand bias approach to promote effective silencing and reduce sense strand off-targeting (see below).
  • Sequence information provided with siRNA purchase.

Design and modification strategies for optimal silencing

In addition to identifying potent siRNA designs with the SMARTselection algorithm, the creation of siGENOME siRNAs also involves:

  • Thermodynamic analysis to determine optimal antisense strand-loading characteristics for effective silencing.
  • BLAST analysis of both strands to alleviate cross-targeting.
  • To retain more high-scoring siRNA designs, the above analysis may trigger the selective use of a sense strand-blocking modification (ON-TARGET) to ensure only the appropriate strand enters RISC for effective target knockdown (supporting data tab).

Product Formats


  • A mixture of 4 siRNA provided as a single reagent; providing advantages in both potency and specificity. siGENOME and ON-TARGETplus are guaranteed to silence by 75% or better.

Set of 4:

  • A convenient option for purchasing aliquots of all 4 individual siRNAs targeting a single gene. Three of four siGENOME and ON-TARGETplus siRNAs are guaranteed to silence by 75% or better.

Set of 4 Upgrade:

  • Discounted price on the Set of 4 based on a concurrent or prior purchase of the SMARTpool reagent for the same gene.

Individual siRNAs:

  • Select 1, 2, 3 or 4 individual siRNAs per gene.

Our siRNA knockdown guarantee

siGENOME and ON-TARGETplus siRNA reagents (SMARTpool and three of four individual siRNAs) are guaranteed to silence target gene expression by at least 75% at the mRNA level when used under optimal delivery conditions (confirmed using validated positive control and measured at the mRNA level 24 to 48 hours after transfection using 100nM siRNA).

Note: Most siGENOME and ON-TARGETplus siRNA products are highly functional at 5 to 25nM working concentration.

Ordering Guidelines

Approximate # reactions (wells) at 25 nM siRNA concentration (assuming no loss from pipetting)

96-well plate
(100 uL total reaction volume)
24-well plate
(500 uL total reaction volume)
12-well plate
(1000 uL total reaction volume)
2 800 160 80
5 2000 400 200
10 4000 800 400
20 8000 1600 800

Product Line Selection

Which siRNA is right for you?

Dharmacon offers four complete pre-designed product lines across human, mouse and rat genomes. Use the table below to assist you in determining the right siRNA product line for your needs.

Cost-effective, efficient silencing High specificity for reduced off-targets + efficient silencing Highly specific knockdown of long noncoding RNA (lncRNA) Target silencing in difficult-to-transfect cells
siGENOME siRNA ON‑TARGETplus siRNA Lincode siRNA Accell siRNA
Pre-designed for Human, Mouse and Rat protein-coding genes + + +
Pre-designed for Human and Mouse long noncoding RNA (lncRNA) +
Recommended for transfectable mammalian cells in culture + + +
Recommended for neuronal, suspension, primary and other difficult-to-transfect cells +
Recommended transfection reagent DharmaFECT transfection reagent DharmaFECT transfection reagent DharmaFECT transfection reagent None required
Available as SMARTpool reagent + + + +
Available as four individual siRNAs + + + +
Guaranteed knockdown by SMARTpool and 3 of 4 siRNAs + +
Sense strand is modified to prevent interaction with RISC and favor antisense strand uptake Selective application when thermodynamic analysis indicates it necessary for favorable antisense RISC loading + + +
Antisense strand seed region is modified to destabilize off-target activity and enhance target specificity + +
Modifications to facilitate cellular uptake without separate transfection reagents +
Stabilizing modifications to prevent nuclease-mediated degradation +
Sequence information provided with purchase + + + +

Supporting Data

siGENOME SMARTpool reagents demonstrate potency at 5 nM working concentration


A comparison of target gene silencing at 5 and 100 nM concentration illustrates the high potency of siGENOME SMARTpool reagents. 5 or 100 nM siGENOME SMARTpool siRNA reagents targeting the indicated genes was transfected into HeLa cells (10K cells/well) using 0.1 ΜL/well DharmaFECT 1. The negative control (NTC pool) was siGENOME Non-Targeting Pool #2.

Unnecessary sense-strand inactivation can increase off-target activity

Unnecessary sense-strand inactivation

Unmodified and sense strand-inactivated siRNAs were used to target five genes. The unmodified siRNAs have natural guide-strand loading characteristics. In four cases off-targets were increased due to enhanced RISC loading of the antisense strand when the sense strand was modified. All siRNAs had comparable silencing potency.
Why not modify ALL siGENOME siRNAs to ensure proper strand loading? It has been demonstrated that forcing antisense (guide) strand entry into RISC may actually INCREASE off-targets due to increased loading of the guide strand and resulting off-target activity by its seed region. siGENOME siRNAs are designed with thermodynamic properties to naturally facilitate guide strand entry to RISC, which has been demonstrated to correlate with functionality. However, in cases where a high-scoring siGENOME siRNA does not possess ideal strand-loading characteristics, a sense (passenger) strand-inhibiting chemical modification (ON-TARGET) is utilized to promote guide strand entry.

Data shown represents genes down-regulated by twofold or more. HEK293 cells were transfected with 100 nM siRNA using 0.2 ΜL of DharmaFECT 1. Data was analyzed at 24 hours by genomewide microarray analysis (Agilent).