Ethylhexadecyldimethylammonium Bromide Research Articles

Ethylhexadecyldimethylammonium bromide, a quaternary ammonium compound, controls inflammatory response through NRF2 pathway in a human immortalized keratinocyte cell line.

Many everyday products contain quaternary ammonium compounds (QAC) and some of them are known to be skin irritants such as benzalkonium chloride. Others, such as didecyldimethylammonium chloride, have been shown to cause allergic contact dermatitis. Ethylhexadecyldimethylammonium bromide (EHD) is a QAC for which sensitization potential is not clearly known. Therefore, we have studied its mechanism in human keratinocytes (KC), the main cells of the epidermis. We used the well-described human KC cell line KERTr exposed to EHD, cinnamaldehyde (CinA), a well-known skin sensitizer, and a mixture of both. Since chemical sensitizers are known to activate the transcription factor nuclear factor (erythroid-derived 2)-like 2 (NRF2), leading to cellular detoxification and suppressed proinflammatory cytokines, protein or mRNA expression of NRF2 pathway-related enzymes and pro-inflammatory cytokines were investigated by Western blot and RT-qPCR. The activity of the NRF2 pathway on inflammation was studied by RT-qPCR in NRF2-invalidated KERTr cells. We showed that EHD cannot induce the NRF2 pathway, unlike contact sensitizers like CinA. EHD triggers an inflammatory response by inducing the mRNA expression of pro-inflammatory cytokines such as IL-1β or IL-6. Moreover, mixing EHD and CinA inhibits the effect of CinA on NRF2 expression and mitigates the inflammatory response induced by EHD alone. EHD treatment of KERTr cells in which NRF2 has been invalidated showed an exacerbation of the inflammatory response at the transcriptional level. Hence, EHD may elicit an inflammatory response in KC via the NF-κB pathway, which could lead to irritation when applied to the skin. This inflammation is negatively controlled by the basal activity of the NRF2 pathway.

Disinfectant and antimicrobial susceptibility studies of the foodborne pathogen Campylobacter jejuni isolated from the litter of broiler chicken houses

Foodborne illness is an ongoing problem worldwide and is caused by bacteria that invade the food chain from the farm, slaughter house, restaurant or grocery, or in the home and can be controlled by strategies using biocides (antiseptics and disinfectants). Susceptibility profiles were determined for 96 Campylobacter jejuni strains obtained in 2011–2012 from broiler chicken house environments to antimicrobials and disinfectants as per the methods of the Clinical and Laboratory Standards Institute and TREK Diagnostics using CAMPY AST Campylobacter plates. Low prevalence of antimicrobial resistance was observed in C. jejuni strains to tetracycline (TET; 21.9%), ciprofloxacin (CIP; 13.5%), and nalidixic acid (NAL; 12.5%). The resistance profiles had a maximum of 3 antimicrobials, CIP-NAL-TET, with TET being the main profile observed. No cross-resistance was observed between antimicrobials and disinfectants. The C. jejuni strains (99%) were resistant to triclosan, 32% were resistant to chlorhexidine, and they all were susceptible to benzalkonium chloride. The strains had low-level minimum inhibitory concentrations (MICs) to the disinfectants P-128, Food Service Sanitizer, F-25 Sanitizer, Final Step 512 Sanitizer, OdoBan, dioctyldimethylammmonium chloride, didecyldimethylammonium chloride (C10AC), benzyldimethyldodecylammonium chloride (C12BAC), and benzyldimethyltetradecylammonium chloride (C14BAC). Intermediate MICs against DC&R, cetylpyridinium bromide hydrate, hexadecylpyridinium chloride, ethylhexadecyldimethylammonium bromide, and hexadecyltrimethylammonium bromide with elevated intermediate MICs against Tek-Trol, benzyldimethylhexadecylammonium chloride, tris(hydroxylmethyl)nitromethane (THN), and formaldehyde. The highest MIC were obtained for povidone-iodine. The components THN and the benzylammonium chlorides C12BAC and C14BAC were responsible for the inhibition by DC&R. The components C10AC and C12BAC may act synergistically causing inhibition of C. jejuni by the disinfectant P-128. The formaldehyde component in DC&R was not effective against C. jejuni compared with the ammonium chloride components. Its use in disinfectants may result in additional unnecessary chemicals in the environment. Didecyldimethylammonium chloride is the most effective ammonium chloride component against C. jejuni.

The effect of cationic surfactants on improving natural clinoptilolite for the flotation of cesium

Flotation using cationic surfactants has been investigated as a rapid separation technique to dewater clinoptilolite ion exchange resins, for the decontamination of radioactive cesium ions (Cs+) from nuclear waste effluent. Initial kinetic and equilibrium adsorption studies of cesium, suggested the large surface area to volume ratio of the fine zeolite contributed to fast adsorption kinetics and high capacities (qc = 158.3 mg/g). Adsorption of ethylhexadecyldimethylammonium bromide (EHDa-Br) and cetylpyridinium chloride (CPC) surfactant collectors onto both clean and 5 ppm Cs+ contaminated clinoptilolite was then measured, where distribution coefficients (Kd) as high as 10,000 mL/g were evident with moderate concentrations CPC. Measurements of particle sizes confirmed that adsorption of surfactant monolayers did not lead to significant aggregation of the clinoptilolite, while < 8% of the 5 ppm contaminated cesium was remobilised. Importantly for flotation, both the recovery efficiency and dewatering ratios were measured across various surfactant concentrations. Optimum conditions were found with 0.5 mM of CPC and addition of 30 μL of MIBC frother, giving a recovery of ∼90% and a water reduction ratio > 4, highlighting the great viability of flotation to separate and concentrate the contaminated powder in the froth phase.

Selective separation of cesium contaminated clays from pristine clays by flotation

The ongoing boom of industrialization is conflicted by concerns regarding increased levels of environmental contamination, in particular the uncontrolled release of heavy metal ions and radionuclides into soils and groundwater systems. The extent of contamination can be substantial, hence ways to remediate and reduce the volume of waste for further treatment and ultimate disposal are highly desired. In the current study, flotation has been considered as an engineering solution to rapidly separate cesium contaminated clays from low-level contaminated and pristine clays. Cesium (Cs+) sorption by montmorillonite clay particles was considered over a range of ionic concentrations (0.01–500 mM), showing a multistage sorption isotherm that can be interpreted using a two-site model, which considers both interlayer ion-exchange and specific ion sorption on the clay basal planes at higher cesium concentrations. Assessment by X-ray photoelectron spectroscopy (XPS) and zeta potential confirmed the increased surface contamination with increasing Cs+ concentration, with the surface enrichment sufficiently altering the surface chemistry of the contaminated clays for them to favourably interact with the flotation collector, ethylhexadecyldimethyl-ammonium-bromide (EDAB). Within a critical concentration range of EDAB, the cesium contaminated clays were separated from pristine clays using flotation, with recovery efficiencies of ∼75% for the contaminated clays, compared to <25% for the pristine clays. When contaminated and pristine clays were blended, separation by flotation once again demonstrated excellent selectivity for the contaminated clays. The current study highlights the potential for flotation to rapidly treat contaminated clay rich soils and significantly reduce the volume of contaminated solids for further treatment or ultimate disposal.

Removal of Cd(II) and Hg(II) from effluents by ionic solid impregnated chitosan

Ethylhexadecyldimethyl ammonium bromide impregnated chitosan (EHDAIC) was prepared to remove cadmium and mercury from synthetic effluent. The adsorbent was characterized by FTIR, XRD, SEM, EDX and TGA-DTA. Adsorption studies were carried out under different conditions of pH, adsorbent dose, temperature, and contact time. The results showed that the adsorption capacity of EHDAIC is a function of the solution pH and the optimum pH for these metal ions was found to be 3.0. The equilibrium data has been described using Langmuir and Freundlich isotherm models. The maximum adsorption capacity of 341.30mg/g was observed for Cd(II) and 43.43mg/g for Hg(II) in accordance with Langmuir adsorption isotherm in the form of their chloro complexes. The kinetic data fitted well with pseudo-second-order model, and equilibrium data was found to follow Freundlich isotherm model. The calculated thermodynamic parameters showed that the adsorption process was feasible, exothermic and spontaneous. Effect of common excipient ions was studied. Also the material was tested for large sample volumes using column extraction process. The adsorbent material could be regenerated for repetitive applications.

Investigation on interaction of DNA and several cationic surfactants with different head groups by spectroscopy, gel electrophoresis and viscosity technologies

In this study, the interaction between DNA and several cationic surfactants with different head groups such as ethyl hexadecyl dimethyl ammonium bromide (EHDAB), hexadecyl dimethyl benzyl ammonium chloride (HDBAC), and cetyl pyridinium bromide (CPB) were investigated by UV–vis absorption, fluorescence and circular dichroism (CD) spectroscopy, gel electrophoresis, and viscosity technologies. The results show that these cationic surfactants can interact with DNA and major binding modes are electrostatic and hydrophobic. Also, CPB and HDBAC molecules interact with DNA by partial intercalation, and CPB has slightly stronger intercalation than HDBAC, while EHDAB interacts with DNA by non-intercalation. The different head groups of the surfactant molecules can influence the interaction strength. CPB has the stronger interaction with DNA than the others. Moreover, surfactant concentration, the ratio of DNA and fluorescence probe, ionic strength can influence the interaction. The surfactants may interact with DNA by the competition reactions with BR for DNA-BR. The increase of ionic strength may favor the surface binding between DNA and surfactants to some extent. This work provides deep mechanistic insight on the toxicity of cationic surfactants with different head groups to DNA molecules.

Application of micellar enhanced ultrafiltration for the removal of sunset yellow dye from aqueous media

ABSTRACTIn this article, we report the removal of a reactive dye, viz. sunset yellow, from the aqueous solution using micellar media of two cationic surfactants, viz. cetyltrimethylammonium bromide and ethyl hexadecyldimethyl ammonium bromide (. The values of rejection coefficient (R%) and permeate flux (J) have been calculated using membranes with different pore sizes, viz. 10,000 (10k) molecular weight cutoff (MWCO) and 30,000 (30k) MWCO at 1.5 bar transmembrane pressure. The membrane of 30k MWCO was found to be more suitable in order to retain the dye molecules incorporated in the micelles.

Physicochemical investigation of sulfonamide-derived compounds interacting with conventional cationic surfactants in aqueous media

ABSTRACTThe sulfonamide core in compounds is effective synthons, which offer exciting perspectives in chemotherapeutic and pharmacological research. In this study, we investigated the molecular interaction of potent sulfonamide derivatives (SDs), 2-benzenesulfonamido-3-methylbutyric acid (BSB) and tetraaquabis{3-methyl-2-[(phenylsulfonyl)amino]butanoate}copper(II) (Cu-BSB), with cationic surfactants, cetyltrimethyl ammonium bromide (CTAB) and ethylhexadecyl dimethyl ammonium bromide (EHDAB), using UV-visible spectroscopy and steady-state fluorescence measurements. Various mathematical models were applied to quantify the effect of cationic surfactants on physicochemical characteristics of BSB and Cu-BSB. These interactions were confirmed by estimating the partition coefficient (Kx), binding capacities (Kb), Stern-Volmer quenching constant (Ksv), and related Gibbs free energies (ΔGb). The in-depth mechanism revealed that the binding mode in SD–surfactants combinational system is spontaneous and quenching exists in static mode initiated by ground-state complex formation. We believe that the true knowledge of host–guest interaction mechanisms concerning model membrane with entrapped moiety can help in better understanding of molecular recognition in related phospholipid membrane models.

Experimental study of nanoparticle-surfactant-stabilized CO2 foam: Stability and mobility control

CO2 injection has proved to be the most common and efficient enhanced oil recovery techniques which leads to more residual oil recovery. Unfavorable sweep efficiency which results in fingering propagation and causes early gas breakthrough is the most challenging issue of gas flooding process. The aim of this work is to study foam stability and analyze the mobility of CO2 foam stabilized by mixture of raw silica nanoparticles and ethyl hexadecyl dimethyl ammonium bromide (cationic surfactant). The result is obtained through both dynamic and static techniques using a new adsorption index.NPS-stabilized foams are generated using Ross-Miles method. A novel index for the adsorption of surfactant molecules on the nanoparticles is proposed using electrical conductivity measurement. Analyzing the foam decay behavior based on this adsorption index, it is found that the foam life can be divided into two general regions. First, low adsorption region that the foam stability is initially dominated by surfactant concentration and after a while it is controlled by nanoparticles. Second, high adsorption region, that the foam stability, is mostly affected by both nanoparticles and surfactant concentrations as well.The pressure behavior and morphology of the foam are investigated using dynamic characterization apparatus. By using a capillary viscometer in this apparatus, foam apparent viscosity is measured for different phase ratios, and nanoparticle and surfactant concentrations. It is observed that NPS solutions produce uniformly smaller foams with higher apparent viscosity compared to those with surfactant solutions. The results reveal that in different surfactant concentrations, the apparent viscosity of NPS-stabilized foam experiences a maximum value of 6.03cp which is about 9 times larger than that of CO2/water dispersion flood. This maximum is coincided with the maximum adsorption index and the maximum hydrophobicity.

Removal of malachite green dye from aqueous solutions using organically modified hydroxyapatite

The removal of malachite green dye (MG) from aqueous solution was studied using organically modified hydroxyapatite. Hydroxyapatite (HAP) was organically modified with different concentrations of the organic surfactant ethylhexadecyldimethyl ammonium bromide (EHDAB). The modified apatite was characterized using FTIR, XRD and SEM. The modified apatite was studied for removal of MG from aqueous solution and the experimental parameters were studied. The effect of contact time, adsorbent dose, dye concentration and temperature was studied. The equilibrium uptake was increased with increasing the initial dye concentration in solution. The experimental isotherm data were analyzed using Langmuir adsorption isotherm model. The adsorbed amount of MG onto the modified apatite was found to increase with increasing the adsorbent concentration. The maximum monolayer adsorption capacity was found to be 188.18mg/g at 30°C.

Ion flotation for removal of Ni(II) and Zn(II) ions from wastewaters

Ion flotation was applied to Ni(II) and Zn(II) cation removal from low concentration synthetic wastewaters. Ethylhexadecyldimethylammonium bromide (EHDABr) and sodium dodecyl sulfate (SDS) were used as collectors and Dowfroth250 and methyl isobutyl carbonyl (MIBC) as frothers. The effective parameters were investigated by the experimental design performed by DX7 software. In this regard, a two-level factorial method was used, and sixteen experiments including 6-level variables were designed. In the first step, the tests were conducted in a Hallimond tube. It was concluded from test results that the optimum conditions for the removal of Ni(II) and Zn(II) ions by initial concentrations of 10ppm were: pH=3, SDS=300ppm, Dowfroth250=90ppm and air flow rate=1.8ml/min. In the second step, optimal results from the first step were evaluated in a mechanical flotation cell. In optimal conditions, the recovery of Ni(II) and Zn(II) ions were 88% and 92%, respectively at 60min. This study showed that the use of ion flotation is a very effective method for Ni(II) and Zn(II) ion removal from industrial wastewaters. The flotation time in achieving an optimum recovery of Zn(II) ions is shorter than that for Ni(II) ions.

Application of Micellar-Enhanced Ultrafiltration for the Removal of Reactive Blue 19 from Aqueous Media

The present study reports the surfactant-based separation of a reactive dye (reactive blue 19 (RB-19), from aqueous solution containing two cationic surfactants (cetyltrimethylammonium bromide (CTAB) and ethyl hexadecyldimethyl ammonium bromide (EHAB)). Three membranes of different pore size (5000, 10,000, and 30,000 molecular weight cutoff (MWCO)) were used for the determination of rejection coefficient and permeate flux of the solution at 1.5 bar transmembrane pressure (TMP). The membrane of 10,000 MWCO was found to be the most suitable in regard to retaining the dye molecules incorporated in the micelles.

Effect of molecular structures of Gemini and polymerizable emulsifiers on cationic emulsion copolymerization of styrene and butyl acrylate

In order to understand the effect of molecular structures of emulsifiers on the cationic emulsion copolymerization of styrene (St) and butyl acrylate (BA) in details, hexadecyl trimethyl ammonium bromide (CTAB), methacryloxy ethyl hexadecyl dimethyl ammonium bromide (DMHB), ethanediyl bis(hexadecyl dimethyl ammonium bromide) (G16-2-16), and maleic acid diethyl bis(hexadecyl dimethyl ammonium bromide) (P16-8-16) were used as emulsifiers. TEM photos, instantaneous conversions, and colloidal features, such as the particle size, surface charge density, and glass transition temperature (Tg), were measured. Compared with polymerizable emulsifiers (DMHB and P16-8-16), non-polymerizable emulsifiers (CTAB and G16-2-16) produced more uniform nanospheres. In the reactions with polymerizable emulsifiers, higher reaction rates, lower surface charge densities, and lower Tg were observed. Compared with the single-chain emulsifiers, the double-chain emulsifiers resulted in lower reaction rates, bigger particle sizes, better monodispersities, and higher surface charge densities.

Photophysical Investigations of Carmoisine Interacting with Conventional Cationic Surfactants Under Different pH Conditions

The present study describes the extent of interactions of an efficient food dye, Carmoisine (CAR), with conventional cationic surfactants, hexadecyltrimethylammonium bromide, and ethylhexadecyldimethylammonium bromide (EHDAB). The study was carried out by quantifying the spectral changes of CAR as a function of premicellar to postmicellar surfactant concentrations at various pH conditions. The quantification of CAR molecules entrapped by cationic micellar systems has been estimated with the help of mathematical models. Binding parameters of each surfactant were calculated using differential spectroscopic method. The enhanced solubilization of dye by switching the pH was observed. In support of the electrostatic forces, the larger and more hydrophobic head group favors the promising solubilization of CAR in the outer region of the micellar interior. These findings extend the proficiency of dye molecule as a reporter for sensing electrostatic environment in lipidic membranes and related organized assemblies.

Influence of Adding Surfactants to an Analyte Solution on Separation Performance in Open-tubular Capillary Chromatography Based on the Tube Radial Distribution of Ternary Mixed Carrier Solvents

Abstract An open-tubular capillary chromatography system has been developed using a ternary mixed solvent mixture, i.e., water–hydrophilic/hydrophobic organic solvent mixture as a carrier solution. In this study, the influence of adding surfactants to an analyte solution on separation performance was examined in a chromatographic system using a fused-silica capillary tube (75 µm inner diameter and 100 cm effective length) and a ternary mixture of water–acetonitrile–ethyl acetate (3:8:4 volume ratio) carrier solution. Sodium dodecyl sulfate (anionic), ethylhexadecyldimethylammonium bromide (cationic), and Triton X-100 (nonionic) were used as surfactants. Model analytes, 1-naphthol and 2,6-naphthalenedisulfonic acid, were separated in this order by adding the anionic and nonionic surfactants. These surfactants in the analyte solution greatly improved the separation performance (theoretical plate numbers for 2,6-naphthalenedisulfonic acid; &amp;gt;10000) compared with the same separation performed in the absence of surfactants. On the other hand, the analytes were not separated at all using a cationic surfactant.

Ordered gold nanoparticle arrays as surface-enhanced Raman spectroscopy substrates for label-free detection of nitroexplosives

Nitroexplosives, such as 2,4,6-trinitrotoluene (TNT) which is a leading example of nitroaromatic explosives, are causing wide concern. Motivated by the urgent demand for trace analysis of explosives, novel surface-enhanced Raman spectroscopy substrates based upon highly ordered Au nanoparticles have been fabricated by a simple droplet evaporation method. It is noteworthy that an ethylhexadecyldimethyl ammonium bromide bilayer surrounding each individual nanoparticle not only is responsible for these periodic gap structures, but also tends to promote the adsorption of TNT on the composite NPs, thus resulting in a considerable increase of Raman signal. These desirable features endow the resulting SERS substrates with excellent enhancement ability and allow for a label-free detection of common plastic explosive materials even with a concentration as low as 10 −9 M.

Study on Associative Polymerizable Inverse Microemulsion

In an effort to determine the suitable polymerizable inverse microemulsion region in pseudoternary phase diagram (PPD), the pseudoternary system of Span80‐Tween80/isopar M/aqueous solution of acrylamide and 2‐(methacryloyloxyl) ethyl hexadecyl dimethyl ammonium bromide (DM16) was investigated at 40°C. The PPD was obtained by a combination method of turbidimetry and conductivity (CMTC). The reliability of the PPD line was checked by investigating the state of selected experimental points near the boundary line using the Pulsed Near Infrared Light Scattering (PNILS) and centrifugation. Based on the achieved PPD, a series of hydrophobically associating polyacrylamide (HAPAM) microlatex were successfully prepared by choosing the right formulation. It shows that CMTC could be used as a good method in ascertaining a polymerizable inverse microemulsion region, from which optimized HAPAM can be prepared. The factors governing the area of the polymerizable inverse microemulsion region were also discussed.

Modified Carbon Paste Sensor for Cetyltrimethylammonium Ion Based on Its Ion-associate with Tetrachloropalladate(II)

A comparative study was made between developed chemically modified carbon paste electrodes and PVC membrane electrodes for the cationic surfactant cetyltrimethylammonium bromide (CTAB). The carbon paste electrode modified with cetyltrimethylammonium-tetrachloropalladate(II) (CTA-TClP) provides a more sensitive and stable device than that shown by electrodes with an inner reference solution. The best performance was obtained by an electrode based on the paste containing 3.6 wt% CTA-TCIP, 1.8 wt% ethylhexadecyldimethylammonium bromide, 37.6 wt% graphite and 57 wt% tricresyl phosphate. The sensor exhibited a Nernstian response for CTAB over a wide concentration range of 3.5 x 10(-7) to 1.0 x 10(-3) M with a detection limit of 2.0 x 10(-7) M between pH 2.7 and 8.2 with a fast response time of <or=15 s. The electrode showed excellent selectivity for CTAB over a large number of ions. Interferences caused by common cationic surfactants have been investigated in simulated mixtures containing high concentration levels of interfering surfactants, and the sensor was found to be tolerant against these compounds.

Thermal properties and adhesiveness of soy protein modified with cationic detergent

AbstractThis research studied the effects of cationic detergents on the adhesiveness and thermal properties of soy protein isolate (SPI). Three cationic detergents, hexadecyltrimethyl ammonium bromide, ethylhexadecyldimethyl ammonium bromide (EDAB), and benzyldimethylhexadecyl ammonium chloride, each at concentrations of 1.3, 2.6, 5.2, and 7.8 mM, were used to modify SPI. The effect of pH at selected EDAB concentrations was also studied. Results showed that both detergent concentration and pH had significant effects on the adhesiveness of modified SPI. SPI modified with detergent at a concentration of 2.6 mM yielded the greatest dry tensile strength and water resistance, which indicated that a moderate protein denaturation might be favorable to the adhesion of SPI. Both modified and unmodified SPI showed greater adhesive strength at their optimal pH values. Modified SPI showed greatest adhesive strength at pH 7, whereas unmodified SPI showed greatest adhesive strength at pH 4.5; the tensile strength of modified SPI was greater than that of unmodified SPI. The protein‐denaturation temperature and the enthalpy of modified SPI adhesives were also analyzed by using DSC. Denaturation of the native structure of SPI increased as detergent concentration increased.

Staining of intracellular deposits of uranium in cultured murine macrophages

In our studies of the health effects of internalized depleted uranium, we developed a simple and rapid light microscopic method to stain specifically intracellular uranium deposits. Using J774 cells, a mouse macrophage line, treated with uranyl nitrate and the pyridylazo dye 2-(5-bromo-2- pyridylazo)-5-diethylaminophenol, uranium uptake by the cells was followed. Specificity of the stain for uranium was accomplished by using masking agents to prevent the interaction of the stain with other metals. Prestaining wash consisting of a mixture of sodium citrate and ethylenediaminetetraacetic acid eliminated staining of metals other than uranium. The staining solution consisted of the pyridylazo dye in borate buffer along with a quaternary ammonium salt, ethylhexadecyldimethylammonium bromide, and the aforementioned sodium citrate/ethylene-diaminetetraacetic acid mixture. The buffer was essential for maintaining the pH within the optimum range of 8 to 12, and the quaternary ammonium salt prevented precipitation of the dye. Staining was conducted at room temperature and was complete in 30 min. Staining intensity correlated with both uranyl nitrate concentration and incubation time. Our method provides a simple procedure for detecting intracellular uranium deposits in macrophages.