Hexadecyltrimethylammonium bromide

Cetrimonium bromide Br; cetyltrimethylammonium bromide; hexadecyltrimethylammonium bromide; CTAB] is a quaternary ammonium surfactant. Cetrimonium bromide Br; cetyltrimethylammonium bromide; hexadecyltrimethylammonium bromide; CTAB] is a quaternary ammonium surfactant. It is one of the components of the topical antiseptic cetrimide. The cetrimonium (hexadecyltrimethylammonium) cation is an effective antiseptic agent against bacteria and fungi. It is also one of the main components of some buffers for the extraction of DNA. It has been widely used in synthesis of gold nanoparticles (e.g., spheres, rods, bipyramids), mesoporous silica nanoparticles (e.g., MCM-41), and hair conditioning products. The closely related compounds cetrimonium chloride and cetrimonium stearate are also used as topical antiseptics and may be found in many household products such as shampoos and cosmetics. CTAB, due to its relatively high cost, is typically only used in select cosmetics. As with most surfactants, CTAB forms micelles in aqueous solutions. At 303 K (30 °C) it forms micelles with aggregation number 75-120 (depending on method of determination; average ~95) and degree of ionization, α = 0.2–0.1 (fractional charge; from low to high concentration). The binding constant (K°) of Br− counterion to a CTA+ micelle at 303 K (30 °C) is ca. 400 M-1. This value is calculated from Br− and CTA+ ion selective electrode measurements and conductometry data by using literature data for micelle size (r = ~3 nm), extrapolated to the critical micelle concentration of 1 mM. However, K° varies with total surfactant concentration so it is extrapolated to the point at which micelle concentration is zero. Cell lysis is a convenient tool to isolate certain macromolecules that exist primarily inside of the cell. Cell membranes consist of hydrophilic and lipophilic endgroups. Therefore, detergents are often used to dissolve these membranes since they interact with both polar and nonpolar endgroups. CTAB has emerged as the preferred choice for biological use because it maintains the integrity of precipitated DNA during isolation. Cells typically have high concentrations of macromolecules, such as glycoproteins and polysaccharides, that co-precipitate with DNA during the extraction process, causing the extracted DNA to lose purity. The positive charge of the CTAB molecule allows it to denature these molecules that would interfere with this isolation. CTAB has been shown to have potential use as an apoptosis-promoting anticancer agent for head and neck cancer (HNC). In vitro, CTAB interacted additively with γ radiation and cisplatin, two standard HNC therapeutic agents. CTAB exhibited anticancer cytotoxicity against several HNC cell lines with minimal effects on normal fibroblasts, a selectivity that exploits cancer-specific metabolic aberrations. In vivo, CTAB ablated tumor-forming capacity of FaDu cells and delayed growth of established tumors. Thus, using this approach, CTAB was identified as a potential apoptogenic quaternary ammonium compound possessing in vitro and in vivo efficacy against HNC models. Glycoproteins form broad, fuzzy bands in SDS-PAGE (Laemmli-electrophoresis) because of their broad distribution of negative charges.Using positively charged detergents such as CTAB will avoid issues associated with glycoproteins. Proteins can be blotted from CTAB-gels in analogy to western blots ('eastern blot'), and Myelin-associated high hydrophobic protein can be analyzed using CTAB 2-DE. CTAB serves as an important surfactant in the DNA extraction buffer system to remove membrane lipids and promote cell lysis. Separation is also successful when the tissue contains high amounts of polysaccharides. CTAB binds to the polysaccharides when the salt concentration is high, thus removing polysaccharides from solution. A typical recipe can be to combine 100 mL of 1 M Tris HCl (pH 8.0), 280 mL 5 M NaCl, 40 mL of 0.5 M EDTA, and 20 g of CTAB then add double distilled water (ddH2O) to bring total volume to 1 L. Surfactants play a key role in nanoparticle synthesis by adsorbing to the surface of the forming nanoparticle and lowering its surface energy. Surfactants also help to prevent aggregation (e.g. via DLVO mechanisms). Gold (Au) nanoparticles are interesting to researchers because of their unique properties that can be used in applications such as catalysis, optics, electronics, sensing, and medicine. Control of nanoparticle size and shape is important in order to tune its properties. CTAB has been a widely used reagent to both impart stability to these nanoparticles as well as control their morphologies. CTAB may play a role in controlling nanoparticle size and shape by selectively or more strongly binding to various emerging crystal facets.