Name: Polyoxyethylene (40) stearate
Brand: Molecular Depot
SKU: B2018231
Price: 695.00 USD
Availability: InStock

<h2>What are research detergents and surfactants?</h2>
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Research detergents and surfactants are amphipathic molecules with hydrophilic head groups and hydrophobic tail chains that disrupt hydrophobic interactions in biological membranes or protein assemblies when present above their critical micelle concentration (CMC). The three major classes used in research are ionic detergents, where the head group carries a net charge (SDS is anionic, CTAB is cationic), which are more disruptive and typically denaturing; non-ionic detergents, where the head group is uncharged (Triton X-100, Tween 20, NP-40), which are milder and often non-denaturing; and zwitterionic detergents, which carry both positive and negative charges (CHAPS, CHAPSO), which are generally the mildest for preserving protein-protein interactions.
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<h2 dir="ltr">What you will find:</h2>
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SDS Lysis Concentrates: High-purity 20% Sodium Dodecyl Sulfate solutions optimized for rapid cellular denaturing and rigid protein unfolding.
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Pre-Mixed Electrophoresis Running Packs: Standardized 10X Tris-Glycine-SDS running buffer systems calibrated for high-resolution polyacrylamide gel separation.
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Non-Ionic Membrane Solubilizers: Gentle biological detergents engineered to extract hydrophobic membrane proteins without disrupting native structural activity.
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Zwitterionic Lysis Reagents: Advanced structural surfactants designed to maintain delicate molecular charge balances during complex protein-protein interaction studies.
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<h2>How to choose research detergents</h2>
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Use SDS for denaturing applications and SDS-PAGE sample preparation
Sodium dodecyl sulfate (SDS) is an anionic detergent that denatures proteins by disrupting non-covalent interactions and coats proteins in a uniform negative charge, enabling size-based separation by SDS-PAGE. At 0.1% in PAGE running buffer and 2&ndash;5% in sample loading buffer, it is the standard reagent for denaturing electrophoresis, but it is not compatible with applications requiring native protein structure.
Use Triton X-100 or NP-40 for non-denaturing cell lysis
Triton X-100 and NP-40 are non-ionic detergents commonly used for non-denaturing cell lysis buffers, solubilizing membrane lipids to release intracellular protein complexes while generally maintaining protein-protein interactions and protein structure better than ionic detergents.
Use Tween 20 in immunoassay blocking and washing
Tween 20 (polysorbate 20) is a mild non-ionic detergent used at 0.05&ndash;0.1% in TBST or PBST wash buffers to reduce non-specific antibody binding during western blotting and ELISA, and in blocking buffers alongside BSA or non-fat dry milk to reduce background signal.
Choose CHAPS or CHAPSO for the mildest membrane protein solubilization
CHAPS and CHAPSO are zwitterionic detergents derived from bile acids with minimal effects on protein charge and generally the mildest impact on protein structure and function, making them preferable when preserving membrane protein native function or protein-protein interactions is critical, such as for structural studies or functional assays.
Work above the CMC but use the minimum effective concentration
Detergents must be used above their critical micelle concentration to solubilize membranes or proteins, but excess detergent beyond the minimum needed can interfere with downstream assays, reduce protein recovery, and complicate detergent removal by dialysis or gel filtration. Using the minimum effective detergent concentration is good practice.
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<h2>Specifications context</h2>
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The critical micelle concentration (CMC) of a detergent is the threshold above which individual molecules assemble into micelles and the detergent effectively solubilizes membrane lipids. SDS has a CMC of approximately 0.24% in water, Triton X-100 approximately 0.015%, and CHAPS approximately 0.49%, so these detergents require different minimum concentrations for effective lysis. As of 2026, LDAO and digitonin continue to be used for specific membrane protein structural biology where CHAPS alone is insufficient, while traditional nonionic detergents remain dominant for routine lysis and immunoassay applications.
<a href="https://mbpinc.net/contact-us" title="Contact the helpful team at MB">Contact the helpful team at M</a><a href="https://mbpinc.net/contact-us">BP</a> today to request a quote for your specific research requirements.

Detergents & Surfactants

Molecular Depot

Key Specifications

Polyoxyethylene (40) stearate

Polyoxyethylene (40) stearate, catalog B2018231, is a non-ionic surfactant (also known as PEG-40 stearate), with typical uses including emulsifier and solubilizer in formulation research. Available from MBP, a registered vendor at leading US research institutions.