Accell siRNA

Accell siRNA

Product Overview

Accell siRNA achieves what no other product can claim: delivery into difficult-to-transfect cells without additional reagents, virus, or instruments. Achieve gene silencing in cells that had been beyond the reach of conventional RNAi methods due to toxicity from transfection reagents, electroporation, or undesirable viral responses.


  • Novel, patented siRNA modifications facilitate passive uptake, protection against nuclease degradation, specificity, and knockdown efficiency
  • Accell self-delivering siRNA enters cells without the need for transfection reagents, viral vector transduction, or instruments (nucleofection or electroporation)
  • Low toxicity enables extended-duration silencing from multiple doses – up to 30 days!
  • View published references that demonstrate proven performance in difficult-to-transfect cell types
    • Immunological cells – Jurkat cells, primary T cells, lymphocytes, mononuclear cells (PBMC), macrophages
    • Neuronal cells – primary neurons, glioma cells, organotypic brain slices
    • Primary cells – fibroblasts, cardiomyocytes, β-islet cells
    • In vivo models – brain delivery, dermal (skin) delivery, periodontal model

Experimental considerations

This breakthrough in siRNA delivery requires no transfection reagent, but has some unique application requirements.

  • Accell siRNA works at a higher concentration than conventional siRNA; recommended 1µM working concentration.
  • Delivery may be inhibited by the presence of BSA in serum. Optimization studies with serum-free media formulations (Accell Delivery Media) or < 2.5% serum in standard media is recommended.
  • Full-serum media can be added back after 48 hours of incubation, optimal mRNA silencing is typically achieved by 72 hours, or up to 96 hours for protein knockdown.

Product Formats


  • A mixture of 4 siRNA provided as a single reagent; providing advantages in both potency and specificity.

Set of 4:

  • A convenient option for purchasing aliquots of all 4 individual siRNAs targeting a single gene.

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.

Ordering Guidelines

Approximate # reactions (wells) at 1 µM 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 20 4 2
5 50 10 5
10 100 20 10
20 200 40 20

Due to the unique nature of Accell siRNA delivery, it requires a higher working concentration than conventional siRNAs. This table provides the approximate number of reactions (wells) at recommended 1μM Accell siRNA working concentration in different plate formats (assuming no loss from pipetting).

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
predesigned for Human, Mouse and Rat protein-coding genes + + +
predesigned 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

View the published references citing successful Accell siRNA application

Cell types demonstrating effective silencing with Accell siRNA

cell table accell

Internal validation and peer-reviewed publications report numerous successes with difficult-to-transfect cell types.

The Accell siRNA application protocol simplifies targeted gene knockdown

accell protocol

(A) Combine Accell siRNA with Accell delivery media (or other low- or no-serum media) (B) Add Accell delivery mix directly to cells and incubate for 72 hours.

Accell siRNA delivery and gene silencing in cardiomyocytes

sirna accell nrvm

Neonatal rat ventricular myocytes were incubated with 1 μM Accell Green (A; Cat# D-001950-01) or Red (B; Cat# D-001960-01) Non-targeting siRNA for 72 hours in Accell delivery media (Cat# B-005000). Nuclei were stained with DAPI (blue). Labeled control uptake showed diffuse cytoplasmic localization in nearly all cells. The bar graph indicates the level of gene silencing achieved with Accell GAPD Control siRNA (Cat# D-001930-03) and Pool (Cat# D-001930-30) control reagents when used with neonatal rat ventricular myocyte (NRVM) media or Accell delivery media. Myocytes were prepared as described in Maass AH & Buvoli M. Cardiomyocyte preparation, culture, and gene transfer. Methods in Molecular Biology 2007;366: 321-30. mRNA expression was determined by QuantiGene branched DNA assay (Panomics).

Accell siRNA Resources