Cell biology / gene delivery · BEGINNER LESSON
Lipofection
Lipofection is a liposome-mediated transfection method that uses lipophilic, usually positively charged, reagents to help foreign nucleic acids enter cells. It measures how well DNA, RNA, or other oligonucleotides are delivered into cells and expressed or used there.
What lipofection is
Lipofection is a nonviral gene delivery method. In biology, transfection means introducing nucleic acids, such as DNA or RNA, into cells. Lipofection uses lipid-based reagents, often cationic lipids (positively charged lipids), to help these molecules cross the cell membrane. It is used for many constructs and oligonucleotides, and it can support both transient transfection, where the cargo works for a limited time, and stable transfection, where the cargo is maintained longer-term in cells. [Lipofection, lipoplex, and related nonviral vectors are described in the sources.]
[1] Transfection Techniques for Neuronal Cells - PMC [2] Lipofection-Mediated Introduction of CRISPR/Cas9 System into Porcine Oocytes and Embryos [3] Nonviral Vectors: We Have Come a Long Way
How it works
The main idea is charge-based binding and membrane interaction. Nucleic acids are negatively charged, while cationic lipids are positively charged, so they can form lipid–nucleic acid complexes called lipoplexes. These complexes can interact with the negatively charged plasma membrane. Some descriptions say the complex fuses with the membrane; others describe uptake by endocytosis, which means the cell brings material inside in a small membrane pocket. After uptake, the cargo must escape from the endosome, a membrane compartment inside the cell, and then reach the cytosol, the cell fluid outside organelles. One source also reports movement along actin filaments and microtubules, which are parts of the cell’s internal scaffold, leading to perinuclear accumulation near the nucleus. [0,1,2]
[1] Transfection Techniques for Neuronal Cells - PMC [2] Lipofection-Mediated Introduction of CRISPR/Cas9 System into Porcine Oocytes and Embryos [3] Nonviral Vectors: We Have Come a Long Way
What it is measured by
The practical measurement is transfection efficiency, meaning the fraction of cells that receive and use the nucleic acid cargo. The sources show that this can be very high in some cell lines, but much lower in post-mitotic neurons, which are mature neurons that no longer divide. Reported outcomes also include expression timing, reproducibility, cell viability, and any adverse effects on cell shape or survival. [0,1,2]
[1] Transfection Techniques for Neuronal Cells - PMC [2] Lipofection-Mediated Introduction of CRISPR/Cas9 System into Porcine Oocytes and Embryos [3] Nonviral Vectors: We Have Come a Long Way
Mechanisms and performance
Lipofection is usually simple, fast, and cost-effective, and it often needs little optimization. It can work well for many cell lines and can support RNA interference, or RNAi, where small RNA molecules reduce gene expression. Serum, a fluid component of growth media, can sometimes be present and may improve cell growth and reduce toxicity for some reagents. Performance depends strongly on cell type: cell lines may show high efficiency, while post-mitotic neurons often show much lower efficiency, though optimization can improve results. [0,1,2]
[1] Transfection Techniques for Neuronal Cells - PMC [2] Lipofection-Mediated Introduction of CRISPR/Cas9 System into Porcine Oocytes and Embryos [3] Nonviral Vectors: We Have Come a Long Way
Limitations
Lipofection is not equally effective in all cells. The sources report lower efficiency in post-mitotic neurons, possible toxicity, and effects on neuronal morphology or viability. In embryos, efficiency can also depend on developmental stage and timing, and one study found lower mutation efficiency than electroporation or microinjection for gene editing. More generally, nonviral vectors face barriers such as cellular uptake, endosomal escape, nuclear entry, and, for some uses, genome integration. [0,1,2]
[1] Transfection Techniques for Neuronal Cells - PMC [2] Lipofection-Mediated Introduction of CRISPR/Cas9 System into Porcine Oocytes and Embryos [3] Nonviral Vectors: We Have Come a Long Way
SEE THE IDEA
How lipofection delivers cargo into cells
Cationic lipids bind negatively charged DNA or RNA to form a lipoplex.
The complex interacts with the plasma membrane and enters by fusion or endocytosis.
The cargo must leave the endosome and move into the cytosol.
The nucleic acid can then be expressed or used, depending on the experiment.
Each step depends on the previous one; failure at uptake or endosomal escape lowers overall efficiency.
Lipofection is a stepwise delivery process, not a guarantee that cargo will reach its final site.
TRY IT YOURSELF
Test your understanding
Choose an answer, then check the explanation.
PUT IT TOGETHER
Match each concept to its meaning
Drag a label onto its description, or select a label and then select a description. This also works with a keyboard.
4 pairs to match
Sources and further reading
This general lesson was generated from public source material. It explains a concept; it does not interpret a private paper or provide medical advice.