Understanding Brij 35: A Deep Dive into Its Role as a Nonionic Surfactant
Understanding Brij 35: A Deep Dive into Its Role as a Nonionic Surfactant
Brij 35 (Brij™ L23 / Laureth-23):
Brij™ 35 (also sold as Brij™ L23); Laureth-23; polyoxyethylene (23) lauryl ether; tricosaethylene glycol monododecyl ether. CAS: 9002-92-0. It’s a nonionic ethoxylated fatty-alcohol surfactant derived from lauryl alcohol with an average of ~23 ethylene-oxide (EO) units (often abbreviated C12E23).
Composition note: as with all ethoxylates, “23” is an average; commercial grades are distributions around that mean.
Why it’s widely used. As a mild, high-HLB non-ionic, Brij 35 solubilizes membranes and hydrophobes while tending to preserve protein activity and showing low UV absorbance, which is handy when monitoring proteins spectroscopically.
Core physicochemical properties
Property | Value / Range | Notes / Context |
Chemical formula (avg.) | ~C58H118O24 | Polyoxyethylene (23) lauryl ether |
Molecular weight (avg.) | ~1199.6 g·mol⁻¹ | Distribution around 23 EO units |
Physical form | White waxy solid / viscous paste | Supplied also as 10–30% aqueous solution |
Melting range | ~36–45 °C | Solid at RT, liquefies upon mild heating |
Density | ~1.05 g·cm⁻³ | Bulk density |
Solubility | Fully miscible in water | Clear solutions at 10–30% |
HLB (Hydrophilic–Lipophilic Balance) | ~16.9 | Strongly hydrophilic; high HLB typical of O/W emulsifiers (suitable for oil-in-water emulsions) |
CMC (Critical Micelle Concentration) | ~0.09 mM (~0.011% w/v) at 25 °C | Forms micelles readily |
Aggregation number | ~40 (range 33–67, 10–70 °C) | Average molecules per micelle |
Micelle molecular weight | ~49 kDa | Derived from aggregation number |
Micelle hydrodynamic radius (Rh) | ~4–5 nm | Based on DLS and transport studies |
Cloud point | Concentration- and salt-dependent; >100 °C at ~30% w/v | Electrolytes depress cloud point; low concentration + high salt greatly lowers CP |
pH (100 g/L, 20 °C) | ~5.5–7.0 | Near-neutral aqueous solutions |
Flash point | ~149 °C (closed-cup) | Flammable classification threshold |
UV absorbance | Low absorbance in UV region | Facilitates UV-based protein detection |
Typical experimental use concentration | 0.01–1% | 0.01–0.1% for analytical/anti-fouling use; 0.05–1% for cell lysis/membrane solubilization |
Typical laboratory use & working ranges
Protein biochemistry / membrane solubilization: 0.05–1% (w/v or v/v) to lyse gently and extract membrane proteins while preserving complexes; favored when low absorbance in the UV is desired.
Assay workflows (ELISA/enzymes/spectroscopy): 0.01–0.1% can reduce nonspecific adsorption and turbidity; Brij 35 has been shown to stabilize catalase activity in micellar systems (illustrative of enzyme-friendly behavior).
Microemulsions / delivery systems: used as a non-ionic cosurfactant in transdermal microemulsions and related formulations.
Chromatography/HPLC: used as a surfactant additive and to limit hydrophobic sticking.
Electrokinetic methods: reduces electroosmotic effects in capillary electrophoresis/microfluidics (nonionic EOF suppression without introducing charge).
Pharma/cosmetics & industrial: recommended topical use ~0.5–5% in pharma/cosmetic emulsions. Widespread roles as wetting agent, detergent, and emulsifier in textiles/cleaners.
How Brij 35 compares (structure → behavior)
· High HLB, long EO head (≈23): favors oil-in-water emulsions, good wetting/solubilization of hydrophobes, and salt tolerance typical of non-ionics (uncharged headgroup). Expect lower denaturation than many ionic detergents.
· Low-to-moderate CMC (~0.09 mM):
Pros: robust micellization that resists dilution (less loss of solubilizing power during purifications).
Cons: harder to remove completely by dilution; consider adsorptive removal (e.g., hydrophobic resins) or size-exclusion rather than dialysis alone. (General practice note grounded in CMC magnitude.)
· Micelle metrics (Nagg ~40; Rh ~4–5 nm): consistent with compact, stable micelles suitable for gentle solubilization; Nagg and size rise with temperature, subtly increasing solubilization strength.
· Cloud point behavior: elevated CP at higher wt% and depressed by salts enables (or limits) temperature-triggered phase behavior; in practice, Brij 35 is often operated below CP to avoid phase separation.
Brij 35 carried by Aladdin
Aladdin catalog | Product name | Purity |
Brij® L23 solution | 30 % (w/v) in H2O | |
Decaethylene glycol monododecyl ether | nonionic surfactant | |
Brij® L23 | suitable for Stein-Moore chromatography | |
Brij®L23 concentrate | High-purity | |
Brij™ L23 | Proteomics grade | |
Polyethylene Glycol Monododecyl Ether | Hydroxyl Value 30-60 mgKOH/g | |
Brij™ L23 | 100% | |
Polyethylene Glycol Monododecyl Ether | for membrane research | |
Brij® L4 | average Mn ~362 | |
Brij® L4 | ≥99.5% |
Reference
1. Sigma-Aldrich / Merck. Brij® 35, polyoxyethylene (23) lauryl ether, CAS 9002-92-0 — Product Information. Provides identity, molecular weight distribution, form, solubility, and typical uses in biochemistry.
2. Thermo Scientific. Brij 35 Detergent Solution (30% aqueous) — Technical Data Sheet. Reports handling properties, density, stability, and common laboratory applications.
3. Rigaud, J. L., & Lévy, D. (2003). Reconstitution of membrane proteins into liposomes. Methods in Enzymology, 372, 65–86. Discusses Brij detergents including Brij 35 in reconstitution protocols.
4. Helenius, A., & Simons, K. (1975). Solubilization of membranes by detergents. Biochimica et Biophysica Acta (BBA) – Reviews on Biomembranes, 415(1), 29–79. Classic review, including Brij 35 among early non-ionic detergents for membrane solubilization.
5. Tanford, C. (1980). The Hydrophobic Effect: Formation of Micelles and Biological Membranes. 2nd edition. Wiley-Interscience. Includes data on polyoxyethylene alkyl ether detergents such as Brij 35, with aggregation number and micelle properties.
6. Seddon, A. M., Curnow, P., & Booth, P. J. (2004). Membrane proteins, lipids and detergents: not just a soap opera. Biochimica et Biophysica Acta (BBA) – Biomembranes, 1666(1–2), 105–117. Reviews properties of non-ionic detergents including Brij 35 in protein biochemistry.
7. Kumar, V. V. (1991). Micellar properties of nonionic surfactants: polyoxyethylene lauryl ethers (Brij series). Journal of Colloid and Interface Science, 143(2), 489–498. Provides experimental CMC values, aggregation numbers, and micelle size for Brij 35 and related surfactants.
8. López, O., Cócera, M., & de la Maza, A. (1995). Thermodynamics of micellization of Brij surfactants. Journal of Colloid and Interface Science, 172(2), 451–456. Reports micellization parameters including CMC and temperature dependence for Brij 35.
9. Oakes, J., & Dixon, S. (1992). Cloud points of nonionic surfactants: effects of additives. Colloids and Surfaces, 65(2–3), 175–183. Discusses cloud point behavior of Brij 35 and influence of salts/electrolytes.
10. Methods in Enzymology, Vol. 372 (2003). General detergent data tables summarizing Brij 35’s use in protein stabilization and enzyme assays.
Aladdin: https://www.aladdinsci.com/