D1163 Sigma

DOTAP methosulfate

Reagent for stable and transient DNA/RNA transfections

Synonym: N-(2,3-Dioleoyloxy-1-propyl)trimethylammonium methyl sulfate, Transfection reagent



Related Categories Cell Biology, Cell Signaling and Neuroscience, Cloning and Expression, Molecular Biology, Signal Transduction Research Tools,
grade   for molecular biology
form   liquid (MES buffered saline)
usage   sufficient for 40 transfections (10 cm dishes)
concentration   1 mg/mL
color   clear colorless
storage temp.   2-8°C


Frequently Asked Questions

Frequently Asked Questions are available for this Product.


Cationic liposome-forming compound for transfection of DNA, RNA and other negatively charged molecules into eukaryotic cells. Mixing DOTAP with DNA results in spontaneously formed stable complexes that can be directly added to cell culture medium. These complexes fuse with the cell membrane and release DNA into the cytoplasm. The cells are transfected efficiently without cytotoxic effects. Use approximately 5-10 μg DOTAP per μg DNA and approximately 10-20 μg DOTAP per mL cell culture medium. The optimal working concentration and transfection time depends in part on the cell line used, and the type of material (RNA, DNA, protein) loaded.

Suitable for transient and stable transfection of DNA into cultured mammalian cells. Use approximately 5-10 μg DOTAP per μg DNA and approximately 10-20 μg DOTAP per mL cell culture medium. Protocol optimization within these guidelines provides very efficient transfection. The following cells have been successfully transfected using the DOTAP method:

Embryonic Fibroblasts (rat)
Embryonic stem cells (mouse)
Fibroblasts (primary human)
Hepatocytes (primary rat)
Hippocampal neurons (mouse and rat)
Lymphocytes (human peripheral blood)
Macrophage (mouse)
Smooth Muscle (rat aortic)
Spleen (mouse)

Features and Benefits

• Up to 100x more efficient than calcium phosphate and DEAE transfection
• Lower toxicity than calcium phosphate and DEAE based transfection
• Compatible with both serum and serum-free transfection protocols
• Compatible with in-vivo transfection protocols


A stable complex is formed when DOTAP is mixed with DNA in the absence of serum. The complexes are stable and can be directly added to the cell culture medium, where they fuse with the cell membrane, releasing the DNA into the cytoplasm. Note: complex formation is inhibited by serum, but once stable complexes have formed, the presence of serum is without consequence.

General description

DOTAP or N-(2, 3-Dioleoyloxy-1-propyl) trimethylammonium methyl sulfate is a cationic liposome-forming compound for transfection of DNA, RNA and other negatively charged molecules into eukaryotic cells.

Price and Availability

All labs need water
Safety & Documentation

Safety Information

Personal Protective Equipment 
NONH for all modes of transport
WGK Germany 


Certificate of Analysis

Certificate of Origin

Frequently Asked Questions

Which document(s) contains shelf-life or expiration date information for a given product?
If available for a given product, the recommended re-test date or the expiration date can be found on the Certificate of Analysis. These documents are located on the product detail page under Useful Links & Tools. Click on the following link to search for a Certificate of Analysis. Please click the following link to see the details on our Product Dating Information.
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Transportation information can be found in Section 14 of the product's (M)SDS. To access the shipping information for this material, use the link on the product detail page for the product, or search here. 
My question is not addressed here, how can I contact Technical Service for assistance?
Use the option to the right to "Ask a Question" by email of a Technical Service Scientist.
Is low cell passage number an important consideration for transfection?
Yes, we recommend cells are at a low passage when being  used for any application, including transfection.  The reason why depends on what type of cells they are.   Primary cells will undergo a finite number of divisions, and as they get closer to senesence they divide more slowly - both affecting their ability to take up DNA (transient transfection), and minimizing their abillity to incorporate the DNA into the genome (stable selection). Cultured common cell lines are often immortalized, and generally continue to aquire mutations, leading to a heterogenous population that may perform differently from cells of lower passage number - leading to results that are not reproducible.
Is the size of the plasmid an important consideration for transfection?
The size of the plasmid should be considered when selecting a transfection reagent with the best efficiency.  In general, larger sized plasmids should easily transfect with readily available transfection reagents, as along as the plasmid DNA is of high purity.
Is optimizing the transfection protocol important?
For many common cell lines, transfection reagent efficiency is very high and the protocols will not require any optimization.  For hard-to-transfect cells or those ultimately expressing a toxic protein, the protocol should be optimized for best transfection efficiency.  Taking time to optimize will give you more transfected cells with each procedure, which can mean more protein expressed and results that are reproducible.
How do I choose a transfection reagent?
There are many guides that help you select a transfection reagent.  In general, consider: The type of cell(s) you will transfect The type of nucleic acid or protein you will introduce to the cell The composition of your cell culture medium The need for stable or transient transfection The equipment you have available The other factors important to you - cost, protocol flexibility, ease of use, etc.
What quality does the DNA need to be in order to use it for transfection?
The DNA needs to be good quality or it may cause the cells to lyse and/or they won't transfect efficiently.  Plasmid DNA prepared with a column-based DNA purification kit is suitable for transfections.  Sigma's GenElute™ Minprep, Midiprep and Maxiprep kits work well for DNA plasmid purification.  After preparing the DNA, confirm the OD A260:A280 ratio is greater than 1.6 for use in plasmid transfections.
What is transfection efficiency?
Transfection efficiency is a measure of how many cells take up the DNA during the transfection process.  Many transfection reagents can achieve a transfection efficiency of >90% in common cell lines.  Other cell lines are hard to transfect, and require special reagents and/or techniques to achieve even a small population of transfected cells.
How can I determine the efficiency of my transfection?
Calculating transfection efficiency is very useful when optimizing transfection protocols.  Transfection efficiency can be performed using a GFP-expressing plasmid.  After transfection, cells are stained with propidium iodide and counted.  The propidium iodide provides a count of the total cells in the population, and the GFP-expressing cells provide a count of the number of cells transfected.   The transfection efficiency (%) can then be calculated by: (# GFP-expressing cells / total cell #) * 100
How can I increase the efficiency of my transfection?
Transfection efficiency is affected by many different things, including plasmid size and purity, media components present, transfection reagent selected, amount of DNA and transfection reagent used, cell density, etc.  Optimizing the protocol with respect to these concerns will allow you to achieve a higher transfection efficiency.  For many cell lines and transfection reagents, optimized protocols are already available.
Can I transfect cells plated at low density?
For most transfections, cells should be >70% confluency the day of transfection, and growing in mid-log phase.  Some transfection reagents are now designed to work with cells at low density, when required.
Can antibiotics be present in the medium during transfection?
We recommend that no antibiotics are present during transfection.  The process of transfection can make the cells somewhat more porous to allow for efficient DNA entry.  During this time, antibiotics will also enter the cells more easily and the cells may show increased cell death.  Wait until about 24 hours after transfection to resume the use of preventative antibiotics and/or start the use of selective antibiotics.
What is the difference between stable and transient transfection?
When the DNA enters the nucleus of the cell, the plasmid is replicated by the cell machinery (transient transfection).  During this time, RNA is transcribed and protein translated until the plasmid DNA is lost after a few cell divisions.  This expression of the plasmid DNA, mRNA, and protein is transient (temporary). In some cases, the plasmid DNA is integrated into the host cell genome.  This is usually accompanied by forced expression using a selection antibiotic and sometimes a cloning step (to be sure all cells have the same integration site).  Once the DNA is stable, the cell line can be frozen and used to express protein for many years.  Clones may even be screened for those expressing the highest amount of protein.
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Protocols & Articles


Introduction to Transfection - Transfection Reagents

Transfection involves the introduction of DNA or RNA into eukaryotic cells and is used in research to study and modulate gene expression. Thus, transfection techniques serve as an analytical tool tha...
Keywords: Apoptosis, Biological techniques, Drug discovery, Gene expression, Genetic, Precipitation, Transfection, transformation

Transfection Best Practices

The work of scientific research is an art which requires good attention to detail.  The quality of transfection is highest when these commonly used best practices and notes on optimization are employ...
Keywords: Antibiotics, Apoptosis, Growth factors, Molecular biology, Purification, Transfection

Transfection Reagent Selection Guide

Choosing a transfection reagent is easier when you can rely on the work of researchers who have used it before you. During development of each reagent, good transfection efficiency was verified in a ...
Keywords: Transfection


Calcium Phosphate Transfection Kit Protocol

Calcium phosphate transfection is a commonly used method for the introduction of DNA into eukaryotic cells. This technique has been used to obtain both transient1 and stable2 transfections in a wide ...
Keywords: Antibiotics, Applications, Cell culture, Gene expression, Molecular biology, Transfection, Type

Escort™ III Transfection Reagent Protocol

Escort III is a liposome suspension composed of a polycationic lipid and a neutral, non-transfecting lipid compound.  Transfection using liposomes is a commonly used method for the introduction of DN...
Keywords: Cell culture, Transfection

Escort™ IV Transfection Reagent Protocol

Escort IV is a liposome suspension composed of a polycationic lipid and a neutral, non-transfecting lipid compound.  Transfection using liposomes is a commonly used method for the introduction of DNA...
Keywords: Cell culture, Transfection

Lipid Transfection Optimization Protocol

There are many steps of the lipid transfection protocol that can be optimized if the initial transfection attempt is not successful. You may boost transfection efficiency and/or lower toxicity by opt...
Keywords: Cell culture, Transfection

Peer-Reviewed Papers


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