Dimethyldioctadecylammonium Chloride (D1821): FAQs & Guide

Dimethyldioctadecylammonium chloride(D1821) is a synthetic double-chain cationic quaternary ammonium lipid widely used in biomedical research as a key component of cationic liposomes and lipid-based gene delivery systems.

Chemical Name

Dimethyldioctadecylammonium chloride

Common Abbreviation

DODAC (or DDAC)

Charge Character

Permanently cationic at all physiological pH values

Hydrophobic Tails

Two C18 (octadecyl) alkyl chains

Primary Research Use

Cationic liposome formulation for nucleic acid delivery (DNA, RNA)

Aladdin SKU

D113403

What Is Dimethyldioctadecylammonium Chloride (D1821)?

Dimethyldioctadecylammonium chloride, commonly abbreviated DODAC, is a double-tailed cationic lipid belonging to the quaternary ammonium class of surfactants. Its molecular structure consists of a positively charged nitrogen head group bearing two methyl substituents and two long octadecyl (C18) hydrophobic chains. Because the positive charge on the nitrogen is permanent and does not depend on protonation, the compound retains its cationic character across the full physiological pH range.

In aqueous media, DODAC self-assembles into bilayer vesicles (liposomes) and other lamellar structures driven by the hydrophobic effect. The resulting cationic liposomes can electrostatically bind negatively charged nucleic acids such as plasmid DNA, siRNA, and mRNA, forming lipoplexes that facilitate cellular uptake. This property has made DODAC and related double-chain quaternary ammonium lipids standard tools in transfection research and, more broadly, in the formulation of lipid nanoparticle (LNP) delivery systems.

Key Physical and Chemical Properties

Dimethyldioctadecylammonium chloride is typically supplied as a white to off-white waxy solid or powder at room temperature. Its two C18 acyl chains give it a relatively high melting point compared with single-chain quaternary ammonium salts, and the compound is insoluble in neat water but dissolves or disperses readily in short-chain alcohols (e.g., ethanol) and chlorinated organic solvents (e.g., chloroform, dichloromethane). Homogeneous aqueous dispersions are best achieved by thin-film hydration or solvent-injection techniques commonly used in liposome preparation.

As a cationic surfactant, D1821 exhibits antimicrobial activity at higher concentrations due to membrane disruption—a property shared with other quaternary ammonium compounds. Researchers should account for this cytotoxicity when optimising lipoplex formulations; co-formulation with helper lipids such as DOPE or cholesterol is commonly used to balance transfection efficiency and cell viability.

Note: Specific values for molecular weight, melting point, and purity are listed on the Aladdin product page for SKU D113403. Please consult the product certificate of analysis (CoA) for lot-specific data.

Research Applications

The primary application of Dimethyldioctadecylammonium chloride in life-science research is the formulation of cationic liposomes and lipoplexes for in vitro and in vivo nucleic acid delivery. When hydrated and extruded or sonicated, DODAC forms unilamellar or multilamellar vesicles that complex with DNA or RNA payloads and mediate their intracellular delivery. Researchers frequently combine DODAC with neutral or fusogenic helper lipids to tune vesicle fusogenicity, endosomal escape efficiency, and cytotoxicity profile.

Beyond gene delivery, D1821 has been investigated as:

• An adjuvant carrier in vaccine formulations, exploiting its immunostimulatory properties when adsorbed onto antigen surfaces.
• A component of antibacterial coating formulations, leveraging its membrane-disrupting activity against Gram-positive and Gram-negative bacteria.
• A model double-chain surfactant for fundamental studies of self-assembly, phase behaviour, and colloidal stability of cationic bilayer membranes.

Always validate the suitability of D1821 formulations for your specific cell line or animal model, as cationic lipid toxicity and transfection efficiency are highly system-dependent.

Storage, Handling, and Safety

Storage: Store Dimethyldioctadecylammonium chloride in a tightly sealed container away from moisture, heat, and incompatible oxidising agents. Recommended storage is at room temperature (15–25 °C) or as specified on the product label and CoA. Stock solutions in organic solvents should be stored under inert atmosphere at −20 °C to prevent degradation. Consult the current Safety Data Sheet (SDS) for full storage requirements.

Handling precautions: As a cationic surfactant, D1821 is an irritant and potentially harmful if inhaled or absorbed through the skin. Handle in a well-ventilated area or fume hood. Wear appropriate personal protective equipment (PPE): nitrile gloves, safety glasses, and a lab coat. Avoid generating dust when weighing solid material.

Disposal: Do not discharge directly into drains or waterways. D1821 is toxic to aquatic organisms. Dispose of waste in accordance with local institutional and governmental regulations for quaternary ammonium surfactants.

First aid: In case of skin or eye contact, flush immediately with copious water and seek medical advice. Refer to the current SDS for full first-aid measures.

Ordering and Specifications for SKU D113403

Dimethyldioctadecylammonium chloride (D1821) is available from Aladdin Scientific under SKU D113403. For current pack sizes, pricing, purity grade, and availability, please visit the product listing on the Aladdin website or contact our customer service team.

When requesting a quotation or placing an order, provide the SKU number D113403 together with the required quantity and any special handling requirements (e.g., cold-chain shipping). Bulk quantities may be available upon request — please contact technical sales for custom packaging options.

A Certificate of Analysis (CoA) and Safety Data Sheet (SDS) are available for each lot and can be downloaded from the product page or requested from customer support. Review the CoA for lot-specific purity, appearance, and identity test results before use.

Frequently asked questions

What is the difference between Dimethyldioctadecylammonium chloride (DODAC) and DOTAP?

Both DODAC and DOTAP are permanently cationic double-chain lipids used in gene delivery, but they differ in their hydrophobic tails and ester linkages. DODAC has two saturated C18 alkyl (octadecyl) chains connected directly via N–C bonds, whereas DOTAP contains two oleoyl (C18:1) chains linked via ester bonds to the glycerol backbone. The ester linkages in DOTAP render it more biodegradable, while the fully saturated alkyl chains in DODAC generally result in a higher gel-to-liquid-crystalline phase transition temperature, affecting membrane fluidity and lipoplex properties.

How should I prepare a liposome formulation using D1821 (DODAC)?

A standard thin-film hydration method is commonly used: dissolve D1821 (and any helper lipids such as DOPE or cholesterol) in chloroform or ethanol at the desired molar ratio, evaporate the solvent under reduced pressure or a gentle nitrogen stream to form a thin lipid film, then hydrate the film with the appropriate aqueous buffer (e.g., HEPES or PBS) at a temperature above the phase transition temperature of the lipid mixture. Size the resulting multilamellar vesicles by sequential extrusion through polycarbonate membranes or by probe sonication to obtain the target particle size. For nucleic acid complexation, mix the cationic liposome suspension with the nucleic acid solution at the desired N/P (nitrogen-to-phosphate) ratio and allow self-assembly for 15–30 minutes at room temperature before use.

What helper lipids are typically co-formulated with D1821 to reduce cytotoxicity?

The most widely used helper lipids co-formulated with cationic lipids like D1821 are DOPE (1,2-dioleoyl-sn-glycero-3-phosphoethanolamine) and cholesterol. DOPE adopts an inverted hexagonal phase under physiological conditions and promotes membrane fusion and endosomal escape, thereby improving transfection efficiency while partially offsetting cytotoxicity through dilution of the cationic component. Cholesterol stabilises the lipid bilayer, reduces membrane permeability, and modulates particle rigidity. The optimal molar ratio of DODAC to helper lipid must be empirically determined for each cell type and nucleic acid payload.

Is Dimethyldioctadecylammonium chloride suitable for in vivo gene delivery experiments?

D1821-based cationic liposomes have been investigated in preclinical in vivo gene delivery studies, often formulated with helper lipids to improve tolerability. However, cationic lipids as a class can induce inflammatory responses and cytotoxicity in vivo, and DODAC is no exception. Careful optimisation of lipid composition, particle size, surface charge (zeta potential), and dose is essential before in vivo use. Researchers are advised to consult current literature, conduct preliminary toxicology assessments, and comply with all institutional animal care and use committee (IACUC) requirements.

How do I request a Certificate of Analysis (CoA) or Safety Data Sheet (SDS) for D113403?

The CoA and SDS for Dimethyldioctadecylammonium chloride (SKU D113403) can be downloaded directly from the product page on the Aladdin Scientific website by entering the lot number. If the document is not available online, please contact Aladdin customer service with the SKU (D113403) and your lot number, and the relevant documents will be provided promptly.

References

1. Bhattacharya S, Bajaj A. Advances in gene delivery through molecular design of cationic lipids. Chem Commun. 2009. Review of structure-activity relationships for double-chain cationic lipids including DODAC analogues.
2. Felgner PL et al. Lipofection: a highly efficient, lipid-mediated DNA-transfection procedure. Proc Natl Acad Sci USA. 1987;84:7413-7417. Seminal paper establishing cationic lipid-mediated transfection methodology.
3. Gregoriadis G (ed). Liposome Technology, 3rd ed. Informa Healthcare, 2006. Standard reference for liposome preparation methods including thin-film hydration and extrusion.

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.