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Frequently asked questions

Our Scientific Applications Support team has assembled a list of frequently asked questions to help you find answers quickly. Filter using one or more categories to focus on specific topics, or use the search bar to perform a text search.

What reagents will I need in addition to the Alt-R® RNAs for a CRISPR-Cas9 genome editing experiment?

Ribonucleoprotein (RNP) components

The Alt-R® CRISPR-Cas9 System includes a target-specific CRISPR-Cas9 crRNA and a universal CRISPR-Cas9 tracrRNA, both of which are required for genome editing using the Alt-R CRISPR-Cas9 System protocol. Nuclease-Free Duplex Buffer, which is used to complex the crRNA and the tracrRNA, is included with the Alt-R tracrRNA. You will also need an S. pyogenes Cas9 endonuclease:

  • Alt-R S.p. Cas9 Nuclease 3NLS, recommended for most experiments
  • Alt-R S.p. HiFi Cas9 Nuclease 3NLS, for reduced off-target effects
  • Alt-R S.p. Cas9 D10A or H840A Nickase 3NLS, for increased specificity and reduced off-target effects
  • S.p. Cas9 Expression Plasmid.


Supply your own transfection reagents to effectively deliver CRISPR reagents into your cells. We recommend delivery of an RNP for best results. The CRISPR-Cas9 System is compatible with transfection (lipid-mediated or electroporation) and microinjection.

Additional reagents

We also highly recommend the use of control crRNAs, which can be ordered as part of the Alt-R CRISPR-Cas9 Control Kits or individually.

The Alt-R Cas9 Electroporation Enhancer, which is a non-targeting carrier DNA, can increase the efficiency of electroporation. The fluorescently labeled Alt-R CRISPR-Cas9 tracrRNA – ATTO™ 550, which functions like the unlabeled Alt-R CRISPR-Cas9 tracrRNA, can be used to monitor transfection efficiency, study cellular localization, or enrich for CRISPR-edited cells.

If you are interested in additional options for genome editing, we also offer reagents to perform CRISPR-Cpf1 genome editing.

*RUO—For research use only. Not for use in diagnostic procedures. Unless otherwise agreed to in writing, IDT does not intend for these products to be used in clinical applications and does not warrant their fitness or suitability for any clinical diagnostic use. Purchaser is solely responsible for all decisions regarding the use of these products and any associated regulatory or legal obligations.