Presence Of Triton X-100 Research Articles

The role of Triton X-100 as a surfactant on the CdO nanostructures grown by the SILAR method

Abstract In this work, the effect of surfactant Triton X-100 (TX-100) on structural, morphological and optical properties of nanostructured CdO films has been researched. Four series of nanostructured CdO films with TX-100 concentrations of 0.25–1.0 M% of the growth solution were prepared by the Successive Ionic Layer Adsorption and Reaction (SILAR) technique on glass substrates and were characterized by scanning electron microscopy, surface roughness, X-Ray diffraction and UV–Vis. Spectroscopy. Scanning electron microscopy exhibited that the particle thickness increased with increasing TX-100 content. Surface roughness (Ra) measurement exhibited that Ra value accordingly decreases in the presence of TX-100. From the X-Ray diffraction patterns it was calculated that the crystallite size of the films increased parallel to the particle size with increasing TX-100 content. UV results presented that the optical bandgap values of the film can be adjusted with TX-100 content where optical bandgap decreased with increasing TX-100 content in the growth bath. The results show that the amount of TX-100 in the growth bath played a significant mission in adjusting the main physical properties of the nanostructured CdO film.

Membrane fouling and wetting in membrane distillation and their mitigation by novel membranes with special wettability

Membrane distillation (MD) has been identified as a promising technology to desalinate the hypersaline wastewaters from fracking and other industries. However, conventional hydrophobic MD membranes are highly susceptible to fouling and/or wetting by the hydrophobic and/or amphiphilic constituents in these wastewaters of complex compositions. This study systematically investigates the impact of the surface wetting properties on the membrane wetting and/or fouling behaviors in MD. Specifically, we compare the wetting and fouling resistance of three types of membranes of different wetting properties, including hydrophobic and omniphobic membranes as well as composite membranes with a hydrophobic substrate and a superhydrophilic top surface. We challenged the MD membranes with hypersaline feed solutions that contained a relatively high concentration of crude oil with and without added synthetic surfactants, Triton X-100. We found that the composite membranes with superhydrophilic top surface were robustly resistant to oil fouling in the absence of Triton X-100, but were subject to pore wetting in the presence of Triton X-100. On the other hand, the omniphobic membranes were easily fouled by oil-in-water emulsion without Triton X-100, but successfully sustained stable MD performance with Triton X-100 stabilized oil-in-water emulsion as the feed solution. In contrast, the conventional hydrophobic membranes failed readily regardless whether Triton X-100 was present, although via different mechanisms. These findings are corroborated by contact angle measures as well as oil-probe force spectroscopy. This study provides a holistic picture regarding how a hydrophobic membrane fails in MD and how we can leverage membranes with special wettability to prevent membrane failure in MD operations.

Effect of mesoporous g-C3N4 substrate on catalytic oxidation of CO over Co3O4

Mesoporous graphitic carbon nitride (mpg-CN) was synthesized using Triton X-100, a surfactant containing a hydrophilic polyethylene oxide group and a tert-octyl-phenyl hydrophobic moiety, as a soft template. The obtained mpg-CN was used as a support for Co3O4, and this supported catalyst was used for CO oxidation. The effects of the amount of Triton X-100, weight ratio of Co3O4 to mpg-CN and calcination temperature on the catalytic performances for CO oxidation of Co3O4/mpg-CN composites were systematically studied. It was found that the presence of Triton X-100 not only retarded the polymerization of dicyandiamide, but also affected the microstructure of Co3O4. Bubbles formed because of the hydrophobic group of the surfactant Triton X-100 can be act as a soft template for the synthesis of mesoporous g-C3N4. The enhanced catalytic activity of Co3O4/mpg-CN was attributed to a synergistic effect, enlarged BET surface areas, increased Co3+ and lattice oxygen contents, and the porous structure of mpg-CN support. The high stability of 12.5% Co3O4/mpg-CN(1.0) makes it a promising catalyst for practical applications.

Biomembrane solubilization mechanism by Triton X-100: a computational study of the three stage model.

The solubilization mechanism of lipid membranes in the presence of Triton X-100 (TX-100) is investigated at molecular resolution using molecular dynamics (MD) simulations. Thanks to the large time and length scales accessible by the hybrid particle-field formulation of the models employed here, the complex process of membrane solubilization has been studied, with the goal of verifying the three stage model reported in the literature. DPPC lipid bilayers and vesicles have been studied at different concentrations of the TX-100 detergent employing coarse grained (CG) models. Systems up to ∼600.000 beads, corresponding to more than 2 millions heavy atoms, have been simulated. Moreover, in order to clarify several experimental pieces of evidence, both slow and fast detergent partition scenarios have been investigated. Flat and curved (vesicles) lipid bilayer surfaces, interacting with TX-100, have been considered to study the curvature effects on the detergent partition rate in the membrane. Shape and conformational changes of mixed DPPC/TX-100 vesicles, as a function of TX-100 content, have also been studied. In particular, high curvature surfaces, corresponding to a higher local TX-100 content, promote a membrane rupture. In flat lipid surfaces, on the time scale simulated the detergent partition is almost absent, following a different pathway of the solubilization membrane mechanism.

Determination of Nickel (II) by Spectrophotometry in Micellar Media

A spectrophotometry method for the determination of nickel (II) with nicotinohydroxamic acid (NHA) in the presence of Triton X-100 was studied at pH 9.0 using phosphate-borax buffer medium. Molar absorptivity of the sensitized complex was 1.37 × 104 L mol-1 cm-1 at 530 nm and adhered to Beer’s law in the concentration range 0.43-8.56 μg mL-1 of nickel (II). The molar composition of the sensitized complex was 1:2 (nickel-NHA). The possible interfering effects of various ions were studied. The method was used for the determination of nickel in tap water and alloy samples.

Catalytic Conversion of Lipophilic Substrates by Phase constrained Enzymes in the Aqueous or in the Membrane Phase.

Both soluble and membrane-bound enzymes can catalyze the conversion of lipophilic substrates. The precise substrate access path, with regard to phase, has however, until now relied on conjecture from enzyme structural data only (certainly giving credible and valuable hypotheses). Alternative methods have been missing. To obtain the first experimental evidence directly determining the access paths (of lipophilic substrates) to phase constrained enzymes we here describe the application of a BODIPY-derived substrate (PS1). Using this tool, which is not accessible to cytosolic enzymes in the presence of detergent and, by contrast, not accessible to membrane embedded enzymes in the absence of detergent, we demonstrate that cytosolic and microsomal glutathione transferases (GSTs), both catalyzing the activation of PS1, do so only within their respective phases. This approach can serve as a guideline to experimentally validate substrate access paths, a fundamental property of phase restricted enzymes. Examples of other enzyme classes with members in both phases are xenobiotic-metabolizing sulphotransferases/UDP-glucuronosyl transferases or epoxide hydrolases. Since specific GSTs have been suggested to contribute to tumor drug resistance, PS1 can also be utilized as a tool to discriminate between phase constrained members of these enzymes by analyzing samples in the absence and presence of Triton X-100.

Membrane permeabilization induced by Triton X-100: The role of membrane phase state and edge tension

Detergents are widely used to solubilize and separate biomembrane components. It is therefore relevant to study and understand the mechanistic details underlying detergent-lipid interactions using biomimetic systems. Here, we have investigated in detail the process of membrane permeabilization and the nature of pores induced by sub-solubilizing concentrations of the detergent Triton X-100 (TX-100) in bilayers composed of palmitoyl oleoyl phosphatidylcholine (POPC), sphingomyelin (SM) and binary mixtures of these phospholipids with 30 mol% cholesterol (chol). A fluorescence quenching assay was used to evaluate the permeability of large unilamellar vesicles (LUVs) in the presence of increasing concentrations of TX-100. Confocal microscopy was employed to visualize and quantify the permeability of giant unilamellar vesicles (GUVs) to two fluorescent dyes of different sizes in the presence of TX-100. Both methods showed that POPC, POPC/chol and SM membranes become fully permeable at a specific TX-100 concentration, followed by complete (POPC and SM) and partial (POPC/chol) solubilization at a higher detergent concentration. The confocal microscopy experiments revealed that opening of pores occurs as a well-defined event and that for POPC and POPC/chol the pores were initially selective to the small probe and then grew and allowed passage of the larger dye as well. On the other hand, the insoluble SM/chol membranes exhibited only a mild TX-100-induced permeabilization. The membrane edge tension of the liquid phases was measured from the closure rate of macropores induced by electric pulses in GUVs. Membrane edge tension was shown to be sensitive to membrane composition and to decrease in the presence of TX-100. We propose that extensive permeabilization occurs below a critical membrane edge tension, which is eventually reached in the partially and fully soluble compositions, but not in the insoluble mixture.

A mobile phone-based analyzer for quantitative determination of urinary albumin using self-calibration approach

This work demonstrates use of a smart mobile phone installed with an Android application, termed ‘Albumin smart test’, as an analyzer for quantitative determination of urinary albumin. The reaction between albumin and tetrabromophenolphthalein ethyl ester (TBPE) in the presence of Triton X-100 was employed for detection principle.The mobile phone was exploited with the sample cassette and the test paper. One sample cassette composes of two holders for accommodation of control and test samples. The test paper was designed in order to contain standard colorimetric strip and space for situating the sample cassette. Optical images of the strip and the samples were simultaneously captured in a single shot by a digital camera of the mobile phone and were digitally processed by the developed application for quantification of the albumin concentration based on self-calibration approach. With the advantage of self-calibration, the albumin test by our mobile phone can be performed in ambient light without using any extra module integrated with lighting control device. The other advantages are portability, ease of implementation and rapid analysis (3min) with high precision (RSD≤2.5%) and high accuracy (Recovery=98.7%±1.6). The mobile device was successfully applied to diagnosis of microalbuminuria.

The cooperative effect of reduced graphene oxide and Triton X-114 on the electromembrane microextraction efficiency of Pramipexole as a model analyte in urine samples

A new design of electromembrane microextraction coupled with high-performance liquid chromatography was developed for the determination of Pramipexole as a model analyte in urine samples. The presence of reduced graphene oxide in the membrane and Triton X-114 in the donor phase augments the extraction efficiency of Pramipexole by the proposed method. Dispersed reduced graphene oxide in the organic solvent was held in the pores of the fiber wall by capillary forces and sonication. It is possible that the immobilized reduced graphene oxide acts as a sorbent, affording an additional pathway for analyte transportation. Besides, the presence of Triton X-114 in the donor phase promotes effective migration of ionic analytes across the membrane. The parameters influencing the extraction procedure, such as type and concentration of surfactant, type of organic solvent, amount of reduced graphene oxide, sonication time, applied voltage, extraction time, ionic strength, pH of the donor and acceptor solutions, and stirring rate were optimized. The linear working ranges of the method for preconcentration- determination of Pramipexole in water and urine samples were found to be 0.13–1000 and 0.47–1000ngmL−1 with corresponding detection limits of 0.04 and 0.14ngmL−1, respectively. The proposed method allows achieving enrichment factors of 301 and 265 for preconcentration of the analyte in water and urine samples, respectively. The method was successfully applied for the determination of Pramipexole in the urine samples.

Toward Active and Durable ORR/Oer Bifunctional Non-PGM Electrocatalysts: Surfactant-Assisted Electrodeposition of Mn Oxides

Development of novel bifunctional electrocatalysts with high electrocatalytic activity and durability for both oxygen reduction and evolution reactions (ORR and OER) is of outmost importance to grasp the full potential of the regenerative H2-O2 fuel cells and rechargeable metal-air batteries (e.g., Zn-air, Al-air, Mg-air, Li-air) as reliable and efficient energy conversion/storage systems. Manganese oxides have been on the spotlight as an attractive catalyst material due to cost competitiveness, environmental friendliness, natural abundance as well as excellent reactivity for ORR and to some extent for OER (1, 2). The physicochemical and electrochemical properties of MnOx are highly dependent on its morphology and crystallographic nature (3). The aim of this work is to provide a systematic study on finding an active nanostructured manganese oxide for both ORR and OER via anodic electrodeposition method. A comprehensive study has been performed to investigate the main and interaction effects of key electrodeposition factors that significantly influence the electrosynthesis of manganese oxides, i.e. Mn2+ concentration (C), applied anodic potential (E), temperature (T), surfactant type and concentration (S), on the bifunctional activity of MnOx using a two-level half-fraction factorial design. Sodium dodecyl sulfate (SDS) as anioinc, hexadecyl-trimethyl-ammonium bromide (CTAB) as cataionic and Triton X-100 as non-ionic surfactants were used in this study to electro-synthesize the nanostructured MnOx. Surface characterization methods including XPS and SEM have been employed to analyze morphology and Mn valance of the synthesized electrocatalysts. Fig. 1 shows the surface plots of three different responses studied here for the electrodeposited manganese oxides in presence of Triton X-100, correlating them to the most important factors and two-factor interactions based on the Pareto plots of estimates. In this case, high surfactant concentration together with low applied anodic potential is believed to bring the best ORR/OER bifunctional performances for the electrodeposited Mn oxides (Fig. 1A and 1B). Mn concentration was found to be an insignificant player. Temperature, on the other hand, is believed to have different effect depending on its value with high temperatures providing low ORR/OER potential window while low temperatures lead to high ORR/OER mass activities (Fig. 1). Triton X-100 samples provide best performing nano-sized structures with promising ORR and OER performances comparing to both noble metals and other non-precious metals, i.e. between 50 to 150 mV lower ORR overpotential (at -2 mA cm-2) comparing to CoMn2O4 and Core-Corona Structured Bifunctional Catalyst (CCBC) and min. 100 mV lower OER overpotential (at 2 mA cm-2) comparing to Ir, Ru and IrO2 (1, 2). Galvanostatic polarizations at 5 mA cm-2 showed low OER potentials of 490 mV (at t=2 hrs), about 40 mV lower than commercial MnOx, and degradation rate of 43 mV h-1, about 10 mV h-1 lower than its commercial counterpart. The surface modifications of MnOx via surfactant-assisted electrodeposition can help destabilizing the HOO(ads) and HO(ads) intermediates, breaking away from the linear scaling relationship between their binding energies as a major contributor to the ORR and OER overpotentials, enhancing the ORR and OER electrocatalytic activity of electrodeposited manganese oxides. The formation of hydrogen-bonded complexes, i.e. HO(ads)…H-OH, with specially configured water molecules called “activated water” (4), can further enhance the ORR activity of the catalysts, depending on the surface coverage of OH(ads) which is needed to provide sites for formation of HO(ads)…H-OH complexes.

Purification and characterisation of a salt-stable protease from the halophilic archaeon Halogranum rubrum.

Because proteases play an important role in the fermentation of fish sauce, the purification and characterisation of an extracellular protease from the halophilic archaeon Halogranum rubrum was investigated. The molecular mass of the protease was estimated to be approximately 47 kDa based on sodium dodecyl sulfate-polyacrylamide gel electropheresis (SDS-PAGE) and native-PAGE analysis. The optimum conditions for catalytic activity were pH 8.0 and 50°C. The protease showed alkaline stability (pH 7.0-10.0). The protease also exhibited novel catalytic ability over a broad range of salinity (NaCl 0-3 mol L-1 ). Calcium ion enhanced the proteolytic activity of the enzyme. The Km and Vmax values of the purified protease for casein were calculated to be 4.89 mg mL-1 and 1111.11 U mL-1 , respectively. The protease was strongly inhibited by ethylenediamine tetraacetic acid (EDTA) and phenylmethanesulfonyl fluoride (PMSF). Meanwhile, the protease was stable in the presence of Triton X-100, isopropanol, ethanol or dithio-bis-nitrobenzoic (DTNB), but was inhibited by sodium dodecyl sulfate (SDS), dimethyl sulfoxide (DMSO) or methanol. MALDI -TOF/TOF MS analysis revealed that the protease shared some functional traits with protease produced by Halogranum salarium. Furthermore, it exhibited high hydrolytic activity on silver carp myosin protein. The protease is an alkaline and salt-tolerant enzyme that hydrolyses silver carp myosin with high efficiency. These excellent characteristics make this protease an attractive candidate for industrial use in low-salt fish sauce fermentation. © 2016 Society of Chemical Industry.

A mechanism of basal spacing reduction in sodium smectitic clay materials in contact with DNAPL wastes

There has been concern regarding the possible attack of clays in aquitards, slurry walls and landfill liners by dense nonaqueous phase liquid (DNAPL) wastes, resulting in cracking. Despite the fact that a reduction in basal spacing in sodium smectitic clay materials has been linked to cracking, no plausible mechanism by which this reduction occurs in contact with waste DNAPLs has been formulated. To elucidate a mechanism, screening studies were conducted that showed that the combination of an anionic surfactant (AOT), a nonionic surfactant (TritonX-100) and a chlorinated solvent, tetrachloroethylene (PCE), could replicate the basal spacing reduction and cracking behavior of water-saturated bentonite caused by two waste DNAPLs obtained from the field. FTIR measurements of this system showed a displacement of the HOH bending band of water symptomatic of desiccation. Sorption measurements showed that the uptake of AOT by bentonite increased eight fold in the presence of TritonX-100 and PCE. The evidence presented here supports a mechanism of syneresis, involving the extraction of water from the interlayer space of the clay through the synergistic sorption of a nonionic and anionic surfactant mixture. It is speculated that the solvation of water in reverse micellar aggregates is the process driving the syneresis.

SPECTROPHOTOMETRIC DETERMINATION OF TITANIUM (IV) IN STEEL, PAINT AND A COSMETIC CREAM USING TANNIC ACID IN MICELLAR MEDIUM

A highly simple, rapid and sensitive spectrophotometric procedure is described for micro-amounts determination of titanium (IV) using tannic acid (tannin) as a new reagent in presence of Triton X-100 (micellar medium). Titanium (IV) reacted with tannic acid in slightly acidic medium at pH=6 using citrate buffer solution to form a 1:2 red coloured stable complex with maximum absorption at 436 nm. The complex is instantaneously formed and remain stable over 2 hr. Beer's law is obeyed in the range of 2-26 μg Ti ml-1 with molar absorptivity to be 3.66 × 104 L mol-1 cm-1. The proposed method is successfully applied for titanium determination in steel, paint and pharmaceutical samples.

Real-Time Monitoring of Superoxide Anion Radical Generation in THP-1 Cells Using Iron-Porphyrin Modified Carbon Electrode

Background: Immune cells such as monocytes and neutrophils responds to external stimuli and during the invasion by foreign body undergoes phagocytosis during which reactive oxygen species (ROS) such as superoxide anion radical (O2 •−), hydrogen peroxide (H2O2) and hydroxyl radical (•OH) are produced. The ROS generated in animal cells can then lead to oxidative degradation of biomolecules comprising of lipids, proteins and nucleic acid influencing the structural organization and metabolic functions within the cells. Reactive oxygen species are known to be involved in several diseases and ailments when either generated in excess or if the balance between the scavenging activities mediated by antioxidants and its production is disturbed. Therefore, specific and sensitive ROS detection methods is required for precise evaluation and monitoring of oxidative stress which can be employed in immune function evaluation and disease detection. The aim of the current study is to introduce our newly developed iron-porphyrin based modified carbon electrode as novel detection sensor with high specificity and sensitivity for detection of O2 •−in animal cells. Methods: The detection of O2 •− is based on amperometry comprising of counter electrode and working electrodes. The counter electrode is a platinum plate (2.5×2.5mm) while the working electrodes (φ1mm) was an iron-porphyrin modified carbon electrode. Ag/AgCl was used as a reference electrode.The oxidation current of O2 •− was measured at +0.5V veresus Ag/AgCl in phosphate buffer solution of containing 11.4mM glucose and THP-1(human monocytic cell line). The iron-porphyrin modified carbon electrode acts as O2 •−detection sensor (scheme 1). The iron-porphyrin modified carbon electrode is prepared by the electropolymerization of 1-methylimidazole-coordinated iron meso-tetra (3-thienyl) porphyrin ([Fe(im)2(ttp)]Br). For the basics characterization of iron porphyrin modified carbon electrode, differential pulse voltammogram for the electropolymerized [Fe(im)2(ttp)]Br complex was recorded in an aqueous electrolyte solution containing phosphate buffer at pH 7.2 at a scan rate of 50 mV/sec using a high performance potentiostat HZ-7000 (Hokuto denko Co., Ltd., Japan). Results and Discussion The O2 •− generation was measured in THP-1 cells under the effect of differentiation inducer phorbol 12-myristate 13-acetate (PMA) in the absence and presence of exogenous addition 0.01 wt% Triton X at 25°C at a cell density of 3.0 × 106 cells/well. Triton X is known to permeabilize the membranes of living cells. The results obtained showed no considerable changes in oxidation currents for O2 •− under the effect of inducer (PMA). However, the addition of Triton-X showed a fast increase in oxidation current for O2 •− by approximately 2 nA followed by a gradual drop which continued for a time span of more than 3 hours. To confirm the production of O2 •−, the effect of superoxide dismutase (SOD) on oxidation current in PMA induced THP-1 cells was tested. The addition of 0.01 wt% Triton X100 in presence of SOD showed small change in oxidation currents for O2 •−. Conclusion The newly developed iron-porphyrin modified carbon electrode is claimed to be a useful tool for real-time monitoring and precise detection of O2 •− in animal cells. It can claimed to bear potential for its wide application in biomedical research and clinical trials with high specificity and sensitivity. Figure 1

Surfactant-Assisted Electrodeposition of Mn Oxides As Promising ORR/Oer Bifunctional Non-PGM Electrocatalysts: Factorial Design Study of the Electrodeposition Parameters

Development of novel bifunctional electrocatalysts with high electrocatalytic activity and durability for both oxygen reduction and evolution reactions (ORR and OER) is of outmost importance to grasp the full potential of the regenerative H2-O2 fuel cells and metal-air batteries (e.g., Zn-air, Al-air, Mg-air, Li-air) as beneficial energy conversion and storage devices. Manganese oxides have been on the spotlight as an attractive catalyst material due to cost-competitiveness, environmentally friendliness, natural abundance as well as excellent reactivity for ORR and to some extent for OER (1, 2). The physicochemical and electrochemical properties of MnOx are highly dependent on its morphology and crystallographic nature (3). The aim of this work is to provide a systematic study on finding an active nanostructured manganese oxide for both ORR and OER via anodic electrodeposition method. A comprehensive study have been performed to investigate the main and interaction effects of key electrodeposition factors that significantly influence the electrosynthesis of manganese oxides, i.e. Mn2+ concentration (C), applied anodic potential (E), temperature (T), surfactant type and concentration (S), on the bifunctional activity of MnOx using a two-level half-fraction factorial design. Sodium dodecyl sulfate (SDS) as anioinc, hexadecyl-trimethyl-ammonium bromide (CTAB) as cataionic and Triton X-100 as non-ionic surfactants were used in this study to electro-synthesize the nanostructured MnOx. Surface characterization methods including XPS and SEM has been employed to analyze morphology and Mn valance of the synthesized electrocatalysts. Fig. 1 shows the surface plots of three different responses studied here for the electrodeposited manganese oxides in presence of Triton X-100, correlating them to the most important factors and two-factor interactions based on the Pareto plots of estimates. The highest ORR mass activity can be achieved at high surfactant concentration and low temperature (Fig. 1-A). Moreover, low applied anodic potential was found to further improve the ORR mass activity of the electrodeposited samples. The same trend was observed for highest OER mass activity as it appeared at low applied anodic potential, high surfactant concentration and low temperature (Fig. 1-B). The lowest ORR/OER potential window of below 600 mV can be obtained at high surfactant concentration, low applied anodic potential but high temperature (Fig. 1-C). The temperature seems to be a defining factor for the bifunctional characteristics of electrodeposited manganese oxides with high temperatures providing low ORR/OER potential window while low temperatures lead to high ORR/OER electrocatalytic activities.

A Surfactant-Induced Functional Modulation of a Global Virulence Regulator from Staphylococcus aureus

Triton X-100 (TX-100), a useful non-ionic surfactant, reduced the methicillin resistance in Staphylococcus aureus significantly. Many S. aureus proteins were expressed in the presence of TX-100. SarA, one of the TX-100-induced proteins, acts as a global virulence regulator in S. aureus. To understand the effects of TX-100 on the structure, and function of SarA, a recombinant S. aureus SarA (rSarA) and its derivative (C9W) have been investigated in the presence of varying concentrations of this surfactant using various probes. Our data have revealed that both rSarA and C9W bind to the cognate DNA with nearly similar affinity in the absence of TX-100. Interestingly, their DNA binding activities have been significantly increased in the presence of pre-micellar concentration of TX-100. The increase of TX-100 concentrations to micellar or post-micellar concentration did not greatly enhance their activities further. TX-100 molecules have altered the secondary and tertiary structures of both proteins to some extents. Size of the rSarA-TX-100 complex appears to be intermediate to those of rSarA and TX-100. Additional analyses show a relatively moderate interaction between C9W and TX-100. Binding of TX-100 to C9W has, however, occurred by a cooperative pathway particularly at micellar and higher concentrations of this surfactant. Taken together, TX-100-induced structural alteration of rSarA and C9W might be responsible for their increased DNA binding activity. As TX-100 has stabilized the somewhat weaker SarA-DNA complex effectively, it could be used to study its structure in the future.

Study of laccase activity and stability in the presence of ionic and non-ionic surfactants and the bioconversion of indole in laccase-TX-100 system

The aim of this study was to characterize the stability and activity of laccase from Trametes versicolor in the presence of three different surfactants, namely sodium di-2-ethylhexylsulfosuccinate (AOT), Triton X-100 (TX-100), and cetyltrimethylammonium bromide (CTAB). The kinetic parameters (such as Km, kcat, kcat/Km ratio), optimal pH and temperature and the thermostability of the enzyme at different temperatures were determined and compared in the absence and presence of the three surfactants. Results revealed that the catalytic activity of the enzyme was greatly improved in the presence of low concentrations of AOT, whereas the activity declined in the presence of TX-100 and CTAB inactivated it almost completely. Results also depicted that, in general, the presence of the surfactants affected the enzyme optimum pH and temperature. In terms of stability, TX-100-induced stabilization and AOT and CTAB-mediated destabilization of the enzyme were observed. Laccase-mediated bioconversion of indole to 2,2-bis(3′-indolyl)-indoxyl in the presence of TX-100 as the effective stabilizing surfactant and TEMPO as the enzyme mediator was also investigated.

Suppression of interfering ions by using ionic liquid and micelle moieties in spectrofluorimetric analysis of manganese

Eosin-Y exhibits high affinity and emission based spectral response to most of the major ions in water samples. In the present study we performed selective spectrofluorimetric analysis of manganese with eosin-Y in the presence of potential interferents. We employed green chemistry reagents, ionic liquids (ILs) and two different micelles, to suppress the effect of conventional cations and anions on the response of eosin-Y. The experimental data revealed that different test moieties caused enhanced analytical response to Mn$^{2+}$. The highest analytical signal of eosin-Y was obtained in the presence of Triton X-100 at a concentration of 2.0 $\times $ 10$^{-3}$ mol L$^{-1}$. Presence of the green chemistry reagents ILs enhanced the limit of quantification for Mn$^{2+}$ 10-fold with respect to the IL-free moieties. The interfering effects of the metal ions of Ca$^{2+}$, Cu$^{2+}$, Hg$^{+}$, Hg$^{2+}$, As$^{5+}$, Li$^{+}$, Al$^{3+}$, Cr$^{3+}$, Co$^{2+}$, Ni$^{2+}$,$^{}$ and the anionic groups were completely suppressed in the presence of the ILs and micelles. Additionally, the tolerance limit of Na$^{+}$ and Zn$^{2+}$ ions increased 6-fold in the presence of IL and sodium dodecyl sulfate. The presented method did not use any harmful conventional solvents and was employed successfully for the detection of Mn$^{2+}$ ions in real water samples.

Enhanced photocatalytic degradation of norfloxacin in aqueous Bi2WO6 dispersions containing nonionic surfactant under visible light irradiation

Photocatalytic degradation is an alternative method to remove pharmaceutical compounds in water, however it is hard to achieve efficient rate because of the poor solubility of pharmaceutical compounds in water. This study investigated the photodegradation of norfloxacin in a nonionic surfactant Triton-X100 (TX100)/Bi2WO6 dispersion under visible light irradiation (400–750nm). It was found that the degradation of poorly soluble NOF can be strongly enhanced with the addition of TX100. TX100 was adsorbed strongly on Bi2WO6 surface and accelerated NOF photodegradation at the critical micelle concentration (CMC=0.25mM). Higher TX100 concentration (>0.25mM) lowered the degradation rate. In the presence of TX100, the degradation rate reached the maximum value when the pH value was 8.06. FTIR analyses demonstrated that the adsorbed NOF on the catalyst was completely degraded after 2h irradiation. According to the intermediates identified by HPLC/MS/MS, three possible degradation pathways were proposed to include addition of hydroxyl radical to quinolone ring, elimination of piperazynilic ring in fluoroquinolone molecules, and replacement of F atoms on the aromatic ring by hydroxyl radicals.

Evaluation of Triton X-100 Effect on Coagulation Tests

CONTEXT:Triton X-100 is a non-ionic surfactant that has been proposed as a virus inactivator in a laboratory setting for it causes cell lysis through lipid membrane disruption without denaturing proteins. Very few studies have tried to evaluate its effect on laboratory tests, especially on coagulation tests that require a phospholipid subtract.METHOD:Plasma samples were collected. Triton X-100 was spiked at a concentration of 0,25% and specimens were incubated for an hour. We performed international normalized ratio (INR), activated partial thromboplastin time (aPTT), thrombin time (TT), fibrinogen dosing and D-Dimer dosing, comparing the standard plasma with the triton X-100 exposed plasma. We also dosed coagulation factors, and performed dilution and lupus anticoagulant studies. Finally, we compared prothrombin time and aPTT using reagents from various manufacturers.RESULTS:We observed an important difference for the INR and the aPTT with addition of triton x-100. A slight decrease of an average of 6.6 to 16.4% was also found in factor assays. Differences in the INR and the aPTT were dependent respectively on the ISI and the phospholipids content of the reagent.CONCLUSION:The addition of triton x-100 significantly modifies INR and aPTT results with every reagent tested. The impact on TT and fibrinogen is not clinically relevant, and the D- Dimer dosage is not affected. The slight decrease in all coagulation factors does not explain those results. The interference could result from an interaction with phospholipids, calcium or some enzymatic reactions caused by the presence of triton x-100 in the analyzed specimen.TableTestMeanMeanMean of differencep-value (paired t-test)without Tritonwith TritonINR1,592,8768,80%p<0,001aPTT31,59 sec61,80 sec86,10%p<0,001TT16,82 sec17,42 sec3,50%p<0,001Fibrinogen3,27 g/L3,21 g/L-0,70%p=0,001D-Dimer2897 mcg/L2905 mcg/L4,30%p=0,697 DisclosuresNo relevant conflicts of interest to declare.