Primary Cell Transfection
Primary Cell Transfection Reagents
Primary cells present physical and logistical barriers to transfection in addition to their innate immune sensing machinery. Compared to HEK293/HEK293T or CHO cell transfection, primary cells are indeed more challenging to transfect with plasmid DNA, sgRNA, siRNA, and large nucleic acids. However as we will explain these challenges, our Avalanche proprietary formulation for primary cell transfection, minimizes these challenges to increase overall transfection efficiency for gene delivery.
Explore our 33 different formulations for primary cells including formulations for specific organ systems, epithelial, endothelial, and many more applications. Avalanche® Transfection Reagents For Primary Cells – Filter by cell type, organ source, and species (see below table).
The Challenges of Primary Cell Transfection - Why Primary Cells Are Harder to Transfect Than Immortalized Lines
Immune Sensing:
The core challenge is that primary cells are biologically aware in ways that immortalized cells are not. They have intact innate immune sensing machinery, particularly the cGAS-STING pathway, RIG-I/MDA5 helicases, and TLR signaling, which detects foreign nucleic acids and triggers inflammatory responses, cell death, or both.
Cell Cycle Status:
Many primary cells are post-mitotic or quiescent. Plasmid DNA cannot exploit mitosis to enter the nucleus. Dividing lines like HEK293 or CHO benefit enormously from nuclear envelope breakdown during division.
Membrane Composition:
Primary cells often have stiffer, more complex membranes with different lipid ratios, reducing the efficiency of some lipid-based transfection reagents.
Sensitivity and Lifespan:
Primary cells are fragile and require a sensitive transfection process. Electroporation voltages, cationic lipid toxicity, and osmotic stress that immortalized cells shrug off can push primary cells into apoptosis.
Passage Tolerance:
Primary cells can only be cultured for a limited number of passages, giving you fewer opportunities to optimize conditions.
Transfection Efficiency By Cargo Type
Plasmid DNA:
Plasmid DNA is the hardest cargo to deliver because it’s large, often 4 kb or more, negatively charged throughout, and must reach the nucleus, not just the cytoplasm.
sgRNA and siRNA:
siRNA and sgRNA are smaller nucleic acids and only need cytoplasmic or nuclear access (respectively). sgRNA and siRNA molecules can be modified (2′-O-methyl, phosphorothioate backbones) to evade innate immune sensing.
CRISPR Payloads:
Delivering Cas9-sgRNA as a ribonucleoprotein molecule is often far more efficient in primary cells than plasmid delivery because RNPs bypass transcription, are transient (reducing off-target risk), and are less immunostimulatory than DNA. Explore our Avalanche®-CRISPR Transfection Reagent.
Transfection Efficiency By Species
Mouse primary cells are generally more tolerant of transfection stress than human primary cells. For example, mouse T cells tend to survive electroporation better than human T cells and can be activated and expanded more easily. Rat primary cells, particularly neurons and hepatocytes, are widely used in research partly because they culture robustly. Human primary cells are the most clinically relevant but often the most sensitive and complex. The innate immune response thresholds differ subtly across species (mouse cells tend to have a slightly higher tolerance for dsRNA intermediates before triggering interferon responses compared to human cells) though this is highly cell-type dependent.
Learn More About Avalanche® Transfection Reagents for Primary Cell Transfection
Our proprietary formulation of lipids and polymers ensures the highest possible transfection efficiencies and viabilities for primary cells. No other transfection reagents can match the efficiency, convenience, and individualized formulation for specific primary cells than Avalanche®. Browse our formulations by cell type, species, and tissue source below.
If you and your team have technical questions about our transfection reagents, need advice on optimizing your workflow, have a question about our transfection protocols (all available on each product page), or want a product recommendation, contact our team anytime.
Interested in a sample of our proprietary transfection reagent? Request a sample!