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Alt-R™ CRISPR gRNA Libraries

For researchers looking for better flexibility and higher performance CRISPR screening libraries, IDT’s custom synthetic gRNA libraries offer a highly customizable option, strong CRISPR expertise and support, and an optimized RNA synthesis process.

Custom libraries for better CRISPR screening.


Alt-R Custom CRISPR gRNA Libraries

Custom arrayed synthetic guide RNA libraries are a great way to accomplish CRISPR knockout screens. They accelerate your research by avoiding the cloning and sequencing associated with lentiviral screens while also integrating into existing automation workflows. IDT has experience designing and manufacturing arrayed panels of gRNAs in a range of sizes, from a few guides to thousands or more. Our high-capacity manufacturing systems offers delivery of your custom CRISPR panel starting at as fast as five business days.

  • Highly customizable CRISPR libraries: Different gRNA formats (2-part or sgRNA), plate type, custom formulations, and lab automation platforms, to suit a variety of project needs
  • Reliable, consistent solution offered by a global leader in RNA synthesis and innovation
  • Adaptable for alternative CRISPR systems such as Cas12a, Cas13, and prime editing
  • Enhanced nuclease resistance for maximal editing in Cas nuclease-expressing cells or via ribonucleoprotein (RNP) delivery

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Product details

Alt-R Custom CRISPR gRNA libraries are available for all CRISPR nucleases, including Cas9, Cas12a, Cas13, prime editing enzymes, and other alternative systems. These libraries were developed to address the need for better CRISPR screening solutions. They are chemically modified guide RNAs synthesized on IDT’s proprietary, high-fidelity RNA manufacturing platform to provide high quality, reliable gRNA libraries with fast delivery.

DesignPredesigned, custom, user-provided
CRISPR systemsCas9, Cas12a, Cas13, prime editing, and other alternative systems
Guaranteed yield0.5 nmol, 2 nmol, 5 nmol, and custom normalized deliverables
Cas9 gRNA formats2-part crRNA:tracrRNA complex and sgRNA
Custom lengths supported30–150 nt
Chemical modifications2’-O-methyl RNA, PS linkages, end-blocking Alt-R modifications
Plate types96- & 384-well PCR, Deep-well, V-bottom, Echo, custom options available
Formulation optionsMulti-guide per well; pooled by gene
Arrayed (single gRNA/well)
Custom formulations upon request
QCIndividual ESI/MS
Supporting reagents & functional analysis pipeline (optional)WT Cas9, HiFi Cas9, Cas12a. and Cas12a Ultra
Glycerol-free options available in tubes or plates (ideal for robotics)
Electroporation Enhancers
rhAmpSeq™ CRISPR Analysis System (NGS-based on-/off-target editing analysis)

Alt-R CRISPR Enzymes

Our Alt-R CRISPR enzymes are available in a variety of formats, with stock sizing available up to 50 mg. Larger formats and lot matching are also available for all products upon request.

Cas proteinAvailable versionsKey features
S.p. Cas9 Nuclease V3Wild-type, 50% Glycerol
Wild-type, Glycerol-free
High Fidelity (HiFi)
Wild-type Fluorescent-fusion
Targeting GC-rich regions
Low viscosity for high-throughput applications
Reduced off-target activity*
Fluorescent label for enrichment (GFP or RFP)
A.s. Cas12a (Cpf1) V3Wild-type
Targeting AT-rich regions
Increased on-target activity*
L.b. Cas12a (Cpf1) UltraIncreased on-target activity and low-temperature tolerance*

* when compared to corresponding Wild-type controls

Product data

Alt-R guide RNA libraries and CRISPR products offer an efficient solution for creating knockout libraries

We investigated the efficiency of inducing non-homologous DNA end joining (NHEJ) by designing 3 sgRNAs per gene (N=95 genes) via an internal pipeline and using IDT’s Alt-R Cas9 nuclease S.p. Cas9 WT V3, electroporation enhancer, and rhAmpSeq™ CRISPR analysis system. The combined use of the Alt-R guides and additional CRISPR products provided an effective, high-throughput editing solution with >90% NHEJ editing in 99% of targeted genes (Figure 1).

Figure 1. A 3-guide-per-gene library design resulted in >90% NHEJ editing in almost all (90/91) targeted amplicons.
95 genes of interest were fed into an internal design pipeline to generate 3 guide RNA designs per gene, all located within a 500 base span. Once target sites were identified, singleplex genotyping assays for each gene were selected using the rhAmpSeq Design Tool. K562 cells were transfected with 3 sgRNAs complexed to Alt-R S.p. Cas9 WT Nuclease V3 per well (final concentration = 1 µM per guide). rhAmpSeq CRISPR Library preparation and subsequent sequencing on the Illumina MiSeq platform was then performed. IDT’s rhAmpSeq Analysis Tool revealed a high level of NHEJ-type editing events (dark blue) in nearly all amplified regions (N = 91 amplicons with sequencing reads >500).

Alt-R CRISPR-Cas9 sgRNAs provide effective editing in Jurkat cells

To highlight the editing efficiency of sgRNAs, we designed sgRNAs targeting 255 sites across the human genome and delivered them to Jurkat cells (a human T-lymphocyte-derived cancer cell line) along with Alt-R S.p. WT Cas9 Nuclease V3. The result of this experiment shows that Alt-R CRISPR-Cas9 sgRNAs provide high levels of editing.

Figure 2. High levels of editing with Alt-R CRISPR-Cas9 sgRNAs.
Ribonucleoprotein (RNP) complexes were formed with Alt-R S.p. WT Cas9 Nuclease V3, combined with Alt-R Cas9 sgRNAs synthesized for 255 randomly selected Cas9 guide RNA sites across the human genome. RNP complexes (4 μM) were delivered into Jurkat cells via a Nucleofector™ system (Lonza) in the presence of Alt-R Electroporation Enhancer. Genome editing efficiencies were determined by target amplification followed by next generation sequencing (NGS) on an Illumina™ instrument.

Frequently asked questions