Custom siRNA Synthesis Overview
|Custom siRNA synthesis options
|Modified siRNA synthesis
|Multiple siRNA synthesis
|Custom SMARTpool design & synthesis
|siRNA Design Tools
Learn more about our proprietary siRNA modifications, dye labels, other chemical modifications, purification and processing options and in vivo RNAi by browsing the tabs at the top of this page.
Choose from a variety of custom options to meet your experimental needs
siRNA customization has never been easier. Numerous combinations of modifications, synthesis scales and purification options are available for convenient online ordering.
Consult the siRNA yield table for estimated yield information on unmodified siRNA at various synthesis scales.
Expert siRNA design assistance is available
If you are working in human, mouse or rat models, we may already have what you need as a pre-designed product: Search for your gene in the Search field found in the upper right corner.
Use the siDESIGN Center, a free online siRNA design tool, to design siRNAs targeting genes in non-standard species, particular splice variants or homologous regions across gene families or species.
Take advantage of our internal design experts and SMARTpool technology! Order a functionally guaranteed Custom SMARTpool for worry-free customization.
Our capabilities include a range of alternative siRNA designs to empower your RNAi research
If you can't find what you need or you require additional specifications not available through online order, please request a quote. Alternative siRNA designs that we support include:
- Longer duplexes (>23 nt)
- Mismatched strands
- Alternative bases or linkages
If you would like further assistance, please contact our experienced team of Technical Support Scientists at +1 800 235 9880 or firstname.lastname@example.org.
Dharmacon offers a broad portfolio of dye modifications for fluorescent labeling of your custom siRNA and RNA oligonucleotides.
- Include a fluorescent tag at the 3' or 5' positions on either strand of an siRNA
- Photostability of DyLight dyes from pH 4-9 frequently exceeds that of Cy dyes, with comparable spectra
- Synthesis of most dye-labeled siRNAs is scalable to gram quantities
Fluorescent dyes available online:
*Some 3' dye labels are only available upon request.
||λ max abs (nm)
||λ max em (nm)
||5' or 3'
|Fluorescein / 6-FAM
||Cy3, Alexa 546, Alexa 555
||Cy5, Alexa 647
||CY5.5, Alexa 680
Some of the dye options listed in the above tables will produce higher oligo yields than others. For assistance in choosing the most appropriate dye label for your application, please contact a Technical Support Scientist at +1 800 235 9880 or email@example.com. You can also request a quote online if you already know that an alternative dye will be required for your experiments.
Alexa Fluor® is a registered trademark of Invitrogen Corporation. All other trademarks are the property of GE Healthcare Limited and its subsidiaries.
Chemical modifications available for custom siRNA
In addition to fluorescent dyes, we offer a broad portfolio of other chemical modifications that can also be applied to both siRNA and single-stranded RNA.
For information on our specialized modification patterns for reducing off-targets, self-delivery and nuclease resistance, view the Proprietary siRNA tab.
siRNA can be modified at either end, on either strand. Multiple modifications are also available but availability may be dependent upon sequence or other factors. Please contact Technical Support for more information
The following standard chemical modifications are available for online order:
||idT (inverted deoxythymidine)
|N6 (amino, 6-carbon) linker
||ddC (terminal dideoxy-cytidine)
||N6 (amino, 6-carbon) linker
Standard modifications for single-stranded RNA can also be applied to siRNA by request. Please contact Technical Support to inquire about additional modifications or options for your siRNA, or request a quote now.
Purification & Processing
In vivo RNAi
Partner with the industry leader in RNAi technologies for the highest quality in vivo -ready RNAi reagents.
We want to ensure your in vivo experiments have the best chance of success. To assist you in your experimental planning, we offer the following options and guidance:
Assess your siRNA sequences in vitro
- We recommend identifying a highly functional siRNA design in vitro prior to initiating expensive experiments using animal models
- A predesigned Set of 4 siRNA reagents is ideal for testing multiple siRNA sequences
Consider a proprietary siRNA modification pattern for enhanced nuclease resistance
- siSTABLE modifications prevent degradation from exo-and endonucleases. siSTABLE is recommended when the siRNA will be exposed to a biological environment rich in nucleases, such as animal serum.
- Accell modifications incorporate delivery-enhancing properties in addition to stability enhancement. Accell is recommended when target cell or tissue types are not amenable to standard modes of delivery.
- See a list of recent publications using siSTABLE and Accell modified siRNA for in vivo experimentation.
ORDER custom siRNA with siSTABLE or Accell
Carefully calculate the total siRNA quantity required
- Consider the number of animals in each cohort, the number of treatments or doses that will be required, and the amount of siRNA required for each dose
- In vivo experiments typically require a large quantity of siRNA. Synthesis capabilities can accommodate up to 10 grams by request, or up to 100 mg available online
- Need help converting nmol to mg? Check our siRNA yield table.
Consider in vivo processing of your siRNA when toxicity to the animal is of concern
- A specialized post-synthesis siRNA processing procedure including counter-ion (Na+) exchange, sterile filtration, desalting, and endotoxin testing
- Available with or without HPLC purification. For more information, review our siRNA purification and processing options.
For more information on important considerations for in vivo experimentation see our Technical Note: "In vivo RNAi: Biodistribution, Delivery, and Applications"