How the Dharmacon Edit-R Platform Improves CRISPR Knockout Workflows

Guide RNA quality and Cas9 delivery format are two of the most important variables in any CRISPR knockout experiment. Poor guide design can reduce knockout efficiency or introduce unwanted off-target effects, while the wrong Cas9 delivery strategy can add unnecessary complexity to an already sensitive workflow.

The Dharmacon™ Edit-R™ CRISPR-Cas9 platform, available in Australia and New Zealand through Millennium Science, is designed to support reliable functional knockout experiments across a range of cell models and delivery approaches.

Two significant updates make the platform especially relevant for researchers planning CRISPR knockout workflows in 2026: predesigned human guide RNAs have been realigned to the latest RefSeq database, and a new Cas9 Protein Hybrid NLS format is now available for DNA-free RNP editing.

Not all CRISPR guide RNAs are designed with the same experimental endpoint in mind. While some guide design approaches focus primarily on generating indels at the DNA level, many knockout experiments depend on achieving functional disruption at the protein level.

The Dharmacon Edit-R algorithm has been developed and empirically validated to prioritise guides that generate functional protein knockout. Each predesigned guide RNA is scored for two key factors:

• Functionality: the likelihood of producing protein-level knockout
• Specificity: the predicted risk of off-target editing

This gives researchers a practical way to balance knockout performance and specificity depending on their cell model, target gene and downstream assay.

The Edit-R platform supports several guide RNA formats, allowing researchers to choose a workflow that suits their experimental setup rather than forcing every project into the same delivery strategy.

Synthetic crRNA system

The synthetic crRNA workflow uses three core components:

• A source of Cas9 nuclease
• A gene-specific Edit-R crRNA
• The Edit-R tracrRNA scaffold

The tracrRNA complexes with the gene-specific crRNA to direct Cas9 to the target site. This cloning-free approach helps researchers move from design to editing quickly, without needing vector construction or sequencing confirmation before starting an experiment.

This format is well suited to researchers who want a flexible, modular workflow and the ability to pair synthetic guide RNAs with different Cas9 delivery options, including purified protein, mRNA or lentiviral Cas9 expression.

Synthetic sgRNA

For researchers who prefer a single-guide format, Edit-R synthetic sgRNA combines the crRNA and tracrRNA sequences into one molecule. This simplifies handling and reduces the number of components in the workflow while retaining compatibility with DNA-free Cas9 delivery strategies.

Synthetic sgRNA can be a useful option when workflow simplicity, transfection consistency and rapid experimental setup are priorities.

Lentiviral sgRNA vectors

For stable, long-term expression, particularly in difficult-to-transfect cells or for follow-up validation after pooled screening, Edit-R lentiviral sgRNA vectors provide a more durable delivery approach.

The Edit-R lentiviral sgRNA vector expresses the gene-specific crRNA and tracrRNA as a chimeric single guide RNA under the control of a human U6 promoter. A puromycin resistance marker, driven from the mouse CMV promoter, is co-expressed in the same vector. This allows researchers to select cells carrying the integrated sgRNA construct.

This format is especially useful for:

• Difficult-to-transfect cell types
• Stable knockout studies
• Follow-up validation from pooled CRISPR screens
• Experiments requiring longer-term guide RNA expression
• Workflows where antibiotic selection is useful for enriching edited populations

All-in-one lentiviral sgRNA

The all-in-one lentiviral sgRNA format takes the stable expression workflow one step further by combining Cas9 and sgRNA expression in a single vector. This reduces the number of transduction steps required and can simplify workflow optimisation, particularly where introducing separate Cas9 and guide RNA components would add time or variability.

For researchers working in challenging cell models, the all-in-one format may provide a more streamlined route to stable CRISPR knockout experiments.

In late 2025, all predesigned human Edit-R synthetic and lentiviral guide RNAs were realigned against the latest NCBI RefSeq database.

This update recalculates functionality and specificity scores using the current genomic reference. Any designs that no longer met the required scoring threshold were replaced with higher-scoring alternatives.

For most genes, previously used guides remain unchanged. Where a guide has been retired, the replacement reflects a stronger predicted balance of functionality and specificity based on updated genome annotations.

Researchers who have previously ordered Edit-R guide RNAs can check specific catalogue numbers through the Horizon Discovery website. This is useful if you are repeating an earlier experiment, comparing results across projects or planning follow-up work based on a previously ordered guide.

The new Edit-R Cas9 Protein Hybrid NLS is a purified Cas9 nuclease protein featuring an enhanced hybrid nuclear localisation signal composition. It is designed to improve nuclear delivery compared with traditional single-NLS formats.

The protein is optimised for co-electroporation or co-transfection with Edit-R synthetic guide RNAs to form ribonucleoprotein complexes, commonly referred to as RNPs. This enables a completely DNA-free CRISPR editing workflow.

DNA-free RNP editing can offer several practical advantages:

• No plasmid DNA is introduced into the system
• The risk of plasmid integration is avoided
• Promoter compatibility issues are removed
• Cas9 exposure is transient, helping to reduce off-target exposure
• The workflow can be useful for sensitive or clinically relevant cell models

Functional knockout has been demonstrated in primary human CD4+ T cells by nucleofection, and in U2OS cells using both nucleofection and lipid transfection.

The Edit-R Cas9 Protein Hybrid NLS is available in sizes from 50 µg to 5 × 500 µg, with bulk quantities available on request.

For molecular biology researchers, the value of these updates is not that CRISPR is new. It is that more current guide design and more flexible Cas9 delivery options can help improve the reliability of familiar workflows.

Edit-R reagents can support applications such as:

• Functional genomics studies
• Disease modelling
• Pathway analysis
• Target identification and validation
• Pooled screen follow-up
• Primary cell editing
• Cell and gene therapy research workflows

By choosing the appropriate guide RNA format and Cas9 delivery strategy, researchers can better tailor CRISPR knockout workflows to their cell type, experimental timeline and downstream readout.

Every predesigned Edit-R synthetic crRNA, sgRNA, lentiviral sgRNA and all-in-one lentiviral sgRNA is backed by an editing guarantee.

If a predesigned guide does not edit the target site when used as recommended, a replacement guide of the same format and quantity will be provided at no cost.

The latest Dharmacon Edit-R updates provide researchers with a more current and flexible platform for CRISPR knockout experiments.

• Edit-R guide RNAs are designed for functional protein knockout, not just indel generation
• Predesigned human guide RNAs were realigned to the latest RefSeq database in late 2025
• Multiple guide RNA formats support synthetic, lentiviral and all-in-one CRISPR workflows
• Lentiviral formats provide stable expression options for difficult-to-transfect cells and longer-term studies
• The new Cas9 Protein Hybrid NLS supports DNA-free RNP editing with enhanced nuclear delivery
• Edit-R predesigned guide RNAs are backed by an editing guarantee

Millennium Science supplies Revvity’s Dharmacon Edit-R CRISPR platform across Australia and New Zealand, supporting researchers with genome editing reagents, workflow selection and technical guidance.

Interested in learning more?

• Request pricing for Edit-R CRISPR reagents
• Discuss the best workflow for your cell model
• Explore DNA-free RNP editing strategies
• Speak with a CRISPR product specialist