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Sample records for micelle concentration cmc

  1. Modeling of the Critical Micelle Concentration (CMC) of Nonionic Surfactants with an Extended Group-Contribution Method

    DEFF Research Database (Denmark)

    Mattei, Michele; Kontogeorgis, Georgios; Gani, Rafiqul

    2013-01-01

    , those compounds that exhibit larger correlation errors (based only on first- and second-order groups) are assigned to more detailed molecular descriptions, so that better correlations of critical micelle concentrations are obtained. The group parameter estimation has been performed using a data set......A group-contribution (GC) property prediction model for estimating the critical micelle concentration (CMC) of nonionic surfactants in water at 25 °C is presented. The model is based on the Marrero and Gani GC method. A systematic analysis of the model performance against experimental data...... concentration, and in particular, the quantitative structure−property relationship models, the developed GC model provides an accurate correlation and allows for an easier and faster application in computer-aided molecular design techniques facilitating chemical process and product design....

  2. Critical micelle concentration values for different surfactants measured with solid-phase microextraction fibers

    NARCIS (Netherlands)

    Haftka, Joris J H; Scherpenisse, Peter; Oetter, G??nter; Hodges, Geoff; Eadsforth, Charles V.; Kotthoff, Matthias; Hermens, Joop L M

    The amphiphilic nature of surfactants drives the formation of micelles at the critical micelle concentration (CMC). Solid-phase microextraction (SPME) fibres were used in the present study to measure CMC values of twelve nonionic, anionic, cationic and zwitterionic surfactants. The SPME derived CMC

  3. The Critical Micelle Concentration of Asphaltenes as Measured by Calorimetry

    DEFF Research Database (Denmark)

    Andersen, Simon Ivar; Christensen, S. D.

    2000-01-01

    Micellization of asphaltenes in solution has been investigated using a micro calorimetric titration procedure (Andersen, S. I.; Birdi, K. S. J Colloid Interface Sci. 1991, 142, 497). The method uses the analysis of heat of dissociation and dilution of asphaltene micelles when a pure solvent (or...... solvent mixture) is titrated with a solution of asphaltene in the same solvent. The asphaltene concentration of the injected solution is at a level above the critical micelle concentration (CMC). In the present paper the procedure is applied in investigation of asphaltenes as well as subfractions...

  4. A nonparametric approach to calculate critical micelle concentrations: the local polynomial regression method

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Fontan, J.L.; Costa, J.; Ruso, J.M.; Prieto, G. [Dept. of Applied Physics, Univ. of Santiago de Compostela, Santiago de Compostela (Spain); Sarmiento, F. [Dept. of Mathematics, Faculty of Informatics, Univ. of A Coruna, A Coruna (Spain)

    2004-02-01

    The application of a statistical method, the local polynomial regression method, (LPRM), based on a nonparametric estimation of the regression function to determine the critical micelle concentration (cmc) is presented. The method is extremely flexible because it does not impose any parametric model on the subjacent structure of the data but rather allows the data to speak for themselves. Good concordance of cmc values with those obtained by other methods was found for systems in which the variation of a measured physical property with concentration showed an abrupt change. When this variation was slow, discrepancies between the values obtained by LPRM and others methods were found. (orig.)

  5. Structural study of concentrated micelle-solutions of sodium octanoate by light scattering

    International Nuclear Information System (INIS)

    Hayoun, Marc

    1982-05-01

    Structural investigation of sodium octanoate (CH 3 -(CH 2 ) 6 -COONa) by light scattering has been made to study properties of concentrated aqueous micelle-solutions. From static light scattering data, the micellar weight and shape have been determined. The monomer aggregation number and the apparent micellar charge have been confirmed. Quasi-elastic light scattering, has been used to measure the effective diffusion coefficient as a function of the volume fraction. Extrapolation to the c.m.c. give the hydrodynamic radius of the micelles. At low micelle-concentration, strong exchange reaction between monomers and micelles affects the Brownian motion and resulting is an increase in the diffusion coefficient. The experimental data show a strong hydrodynamic contribution to S(q) (factor structure) and D(q) (effective diffusion coefficient) arising from hard spheres interactions with a large repulsive potential. (author) [fr

  6. Lowering of the critical concentration for micelle formation in aqueous soap solutions by action of truly dissolved hydrocarbon at various temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Markina, Z.N.; Kostova, N.Z.; Rebinder, P.A.

    1970-03-01

    The effect of dissolved hydrocarbons (octane, benzene, and ethylbenzene) on critical micelle concentration of aqueous solutions of sodium salts of fatty acids from caproate to sodium myristate at various temperatures was studied. Experimental results showed that formation of micelles is promoted by presence of hydrocarbons dissolved in the water phase. Such solutions have below normal critical micelle concentration. The change in critical micelle concentration decreases with increase in length of hydrocarbon chain in the soap molecule and with decrease of hydrocarbon solubility in pure water. The nature of the hydrocarbon also affects the forms and dimension of the micelle. Aromatic hydrocarbons increase micelle volume and greatly decrease C.M.C., while aliphatic hydrocarbons decrease C.M.C. slightly. (12 refs.)

  7. Critical micelle concentration of surfactants in aqueous buffered and unbuffered systems

    International Nuclear Information System (INIS)

    Fuguet, Elisabet; Rafols, Clara; Roses, Marti; Bosch, Elisabeth

    2005-01-01

    Critical micelle concentration (CMC) of sodium dodecyl sulphate (SDS), lithium perfluorooctanesulfonate (LPFOS), hexadecyltrimethylammonium bromide (HTAB), tetradecyltrimethylammonium bromide (TTAB), and sodium cholate (SC), surfactants commonly used as pseudostationary phases in micellar electrokinetic chromatography (MEKC), have been determined by means of three different methods: MEKC, spectrophotometry, and conductometry. Determinations have been performed in water, and also in different concentrations of phosphate buffer at pH 7.0. CMC values ranging from 8.08 (water) to 1.99 (50 mM phosphate buffer) mM for SDS, from 7.16 (water) to 2,81 (30 mM phosphate buffer) mM for LPFOS, from 3.77 (water) to 1.93 (20 mM phosphate buffer) mM for TTAB, from 0.91 (water) to ∼0.34 (20 mM phosphate buffer) for HTAB, and around 13 mM (20 mM phosphate buffer) for SC, are obtained. The effect of the electrolyte concentration on the CMC, as well as the linear relationship between the electrolyte counter-ion concentration and the CMC are discussed. This linear relationship provides an easy way for users to estimate the CMC of a MEKC system, at a given electrolyte concentration. A comparison between experimental methods, as well as a discussion about the suitability of a given method for the determination of the CMC for a given surfactant system is also provided

  8. Preparation of Polymeric Micelles for Use as Carriers of ...

    African Journals Online (AJOL)

    Erah

    Tropical Journal of Pharmaceutical Research, December 2007; 6 (4): 815-824 ... by the tuberculostatic; by Sudan III solubility tests, to estimate the critical micelle concentration (CMC); ... Furthermore, the micelles were stable in vitro, exhibiting a low level of CMC and stronger anti- ... that take the form of micelles 5, 6, 7, 8.

  9. Determination of critical micelle concentration of cetyltrimethylammonium bromide: Different procedures for analysis of experimental data

    Directory of Open Access Journals (Sweden)

    Goronja Jelena M.

    2016-01-01

    Full Text Available Conductivity of two micellar systems was measured in order to determine critical micelle concentration (CMC of cetyltrimethylammonium bromide (CTAB. Those systems were: CTin water and CTin binary mixture acetonitrile (ACN-water. Conductivity (κ-concentration (c data were treated by four different methods: conventional method, differential methods (first and second derivative and method of integration (methods A-D, respectively. As CTin water micellar system shows a sharp transition between premicellar and postmicellar part of the κ/c curve, any of the applied methods gives reliable CMC values and there is no statistically significant difference between them. However, for CTin ACN-water mixture micellar system the integration method for CMC determination is recommended due to a weak curvature of κ/c plot.

  10. Determination of the critical micelle concentration in simulations of surfactant systems.

    Science.gov (United States)

    Santos, Andrew P; Panagiotopoulos, Athanassios Z

    2016-01-28

    Alternative methods for determining the critical micelle concentration (cmc) are investigated using canonical and grand canonical Monte Carlo simulations of a lattice surfactant model. A common measure of the cmc is the "free" (unassociated) surfactant concentration in the presence of micellar aggregates. Many prior simulations of micellizing systems have observed a decrease in the free surfactant concentration with overall surfactant loading for both ionic and nonionic surfactants, contrary to theoretical expectations from mass-action models of aggregation. In the present study, we investigate a simple lattice nonionic surfactant model in implicit solvent, for which highly reproducible simulations are possible in both the canonical (NVT) and grand canonical (μVT) ensembles. We confirm the previously observed decrease of free surfactant concentration at higher overall loadings and propose an algorithm for the precise calculation of the excluded volume and effective concentration of unassociated surfactant molecules in the accessible volume of the solution. We find that the cmc can be obtained by correcting the free surfactant concentration for volume exclusion effects resulting from the presence of micellar aggregates. We also develop an improved method for determination of the cmc based on the maximum in curvature for the osmotic pressure curve determined from μVT simulations. Excellent agreement in cmc and other micellar properties between NVT and μVT simulations of different system sizes is observed. The methodological developments in this work are broadly applicable to simulations of aggregating systems using any type of surfactant model (atomistic/coarse grained) or solvent description (explicit/implicit).

  11. Determination of the Critical Micelle Concentration of Neutral and Ionic Surfactants with Fluorometry, Conductometry, and Surface Tension-A Method Comparison.

    Science.gov (United States)

    Scholz, Norman; Behnke, Thomas; Resch-Genger, Ute

    2018-01-01

    Micelles are of increasing importance as versatile carriers for hydrophobic substances and nanoprobes for a wide range of pharmaceutical, diagnostic, medical, and therapeutic applications. A key parameter indicating the formation and stability of micelles is the critical micelle concentration (CMC). In this respect, we determined the CMC of common anionic, cationic, and non-ionic surfactants fluorometrically using different fluorescent probes and fluorescence parameters for signal detection and compared the results with conductometric and surface tension measurements. Based upon these results, requirements, advantages, and pitfalls of each method are discussed. Our study underlines the versatility of fluorometric methods that do not impose specific requirements on surfactants and are especially suited for the quantification of very low CMC values. Conductivity and surface tension measurements yield smaller uncertainties particularly for high CMC values, yet are more time- and substance consuming and not suitable for every surfactant.

  12. The critical micelle concentration of lecithin in bulk oils and medium chain triacylglycerol is influenced by moisture content and total polar materials.

    Science.gov (United States)

    Kim, JiSu; Kim, Mi-Ja; Lee, JaeHwan

    2018-09-30

    Effects of different moisture contents and oxidised compounds on the critical micelle concentration (CMC) of lecithin were determined in bulk oils and in medium-chain triacylglycerols (MCT). CMC of lecithin in MCT was significantly higher than that in other vegetable oils including olive, soybean, corn, and rapeseed oils (p < 0.05). Presence of moisture significantly affected the CMC of lecithin in MCT (p < 0.05). CMC of lecithin was high when the moisture content was below 900 ppm, whereas at a moisture content of 1000 ppm, CMC of lecithin decreased significantly (p < 0.05), and then started to increase. Addition of total polar materials (TPM), which are oxidation products, at 3 and 5% concentrations, decreased CMC of lecithin significantly (p < 0.05) in MCT, compared to when 0, 1, and 1.5% of TPM was added to MCT. As the degree of oxidation increased in corn oil, CMC of lecithin gradually decreased. Additionally, under different moisture contents, corn oils showed a similar pattern of CMC of lecithin in MCT, whereas oxidised corn oil had a little lower CMC of lecithin than unoxidised corn oil. The results clearly showed that the concentration of lecithin for the formation of micelles is greatly influenced by the presence of oxidation products and the moisture content in bulk oils. Copyright © 2018 Elsevier Ltd. All rights reserved.

  13. The Role of Decorated SDS Micelles in Sub-CMC Protein Denaturation and Association

    DEFF Research Database (Denmark)

    Andersen, Kell; Oliveira, Cristiano Luis Pinto De; Larsen, Kim Lambertsen

    2009-01-01

    structures. SAXS data show that, at this stage, a decorated micelle links two ACBP molecules together, leaving about half of the polypeptide chain as a disordered region protruding into the solvent. Further titration with SDS leads to the additional uptake of 26 SDS molecules, which, according to SAXS, forms...

  14. Determination of the critical micelle concentration in simulations of surfactant systems

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Andrew P.; Panagiotopoulos, Athanassios Z., E-mail: azp@princeton.edu [Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544 (United States)

    2016-01-28

    Alternative methods for determining the critical micelle concentration (cmc) are investigated using canonical and grand canonical Monte Carlo simulations of a lattice surfactant model. A common measure of the cmc is the “free” (unassociated) surfactant concentration in the presence of micellar aggregates. Many prior simulations of micellizing systems have observed a decrease in the free surfactant concentration with overall surfactant loading for both ionic and nonionic surfactants, contrary to theoretical expectations from mass-action models of aggregation. In the present study, we investigate a simple lattice nonionic surfactant model in implicit solvent, for which highly reproducible simulations are possible in both the canonical (NVT) and grand canonical (μVT) ensembles. We confirm the previously observed decrease of free surfactant concentration at higher overall loadings and propose an algorithm for the precise calculation of the excluded volume and effective concentration of unassociated surfactant molecules in the accessible volume of the solution. We find that the cmc can be obtained by correcting the free surfactant concentration for volume exclusion effects resulting from the presence of micellar aggregates. We also develop an improved method for determination of the cmc based on the maximum in curvature for the osmotic pressure curve determined from μVT simulations. Excellent agreement in cmc and other micellar properties between NVT and μVT simulations of different system sizes is observed. The methodological developments in this work are broadly applicable to simulations of aggregating systems using any type of surfactant model (atomistic/coarse grained) or solvent description (explicit/implicit)

  15. Determination of the critical micelle concentration in simulations of surfactant systems

    International Nuclear Information System (INIS)

    Santos, Andrew P.; Panagiotopoulos, Athanassios Z.

    2016-01-01

    Alternative methods for determining the critical micelle concentration (cmc) are investigated using canonical and grand canonical Monte Carlo simulations of a lattice surfactant model. A common measure of the cmc is the “free” (unassociated) surfactant concentration in the presence of micellar aggregates. Many prior simulations of micellizing systems have observed a decrease in the free surfactant concentration with overall surfactant loading for both ionic and nonionic surfactants, contrary to theoretical expectations from mass-action models of aggregation. In the present study, we investigate a simple lattice nonionic surfactant model in implicit solvent, for which highly reproducible simulations are possible in both the canonical (NVT) and grand canonical (μVT) ensembles. We confirm the previously observed decrease of free surfactant concentration at higher overall loadings and propose an algorithm for the precise calculation of the excluded volume and effective concentration of unassociated surfactant molecules in the accessible volume of the solution. We find that the cmc can be obtained by correcting the free surfactant concentration for volume exclusion effects resulting from the presence of micellar aggregates. We also develop an improved method for determination of the cmc based on the maximum in curvature for the osmotic pressure curve determined from μVT simulations. Excellent agreement in cmc and other micellar properties between NVT and μVT simulations of different system sizes is observed. The methodological developments in this work are broadly applicable to simulations of aggregating systems using any type of surfactant model (atomistic/coarse grained) or solvent description (explicit/implicit)

  16. QUANTITATIVE ANALYSIS OF RELATIONSHIP STRUCTURE AND ANIONIC SURFACTANT MICELLE CONCENTRATION CRITIC WITH SEMIEMPIRIS AM1

    Directory of Open Access Journals (Sweden)

    Eva Vaulina Yulistia Delsy

    2017-05-01

    Full Text Available This research determines the mathematical equation which calculate the Concentration Micelle Critic theoretical anionic surfactant. The research was conducted the depiction of each surfactant anionic three-dimensional compound models, followed by optimizing the model structure anionic surfactant by using AM1 calculation method. Furthermore the calculation of descriptors (QSPR method, then it was analyzed statistically using Multiple Linear Regression (MLR. The results of statistical calculations showed that to calculate the theoretical CMC anionic surfactant can use the QSPR equation: log CMC = 4.157+0.118qC1+7.698qC2+0.425α–0.010µ-0.129RD–0.138 log P+0.021BM–0.034Avdw, n = 100 ; r = 0.927 ; r2 = 0.860 ; SE = 0.352 ; F= 30.888 ; PRESS = 23.506

  17. Micelle formation of nonionic surfactants in a room temperature ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate: surfactant chain length dependence of the critical micelle concentration.

    Science.gov (United States)

    Inoue, Tohru; Yamakawa, Haruka

    2011-04-15

    Micellization behavior was investigated for polyoxyethylene-type nonionic surfactants with varying chain length (C(n)E(m)) in a room temperature ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF(4)). Critical micelle concentration (cmc) was determined from the variation of (1)H NMR chemical shift with the surfactant concentration. The logarithmic value of cmc decreased linearly with the number of carbon atoms in the surfactant hydrocarbon chain, similarly to the case observed in aqueous surfactant solutions. However, the slope of the straight line is much smaller in bmimBF(4) than in aqueous solution. Thermodynamic parameters for micelle formation estimated from the temperature dependence of cmc showed that the micellization in bmimBF(4) is an entropy-driven process around room temperature. This behavior is also similar to the case in aqueous solution. However, the magnitude of the entropic contribution to the overall micellization free energy in bmimBF(4) is much smaller compared with that in aqueous solution. These results suggest that the micellization in bmimBF(4) proceeds through a mechanism similar to the hydrophobic interaction in aqueous surfactant solutions, although the solvophobic effect in bmimBF(4) is much weaker than the hydrophobic effect. Copyright © 2011 Elsevier Inc. All rights reserved.

  18. Preparation of Polymeric Micelles for use as Carriers of ...

    African Journals Online (AJOL)

    These micelles were characterized by dynamic light scattering, to measure the micelle diameter; by acid-base titration, to determine the percentage of carboxylic groups occupied by the tuberculostatic; by Sudan III solubility tests, to estimate the critical micelle concentration (CMC); and visual control and spectrophotometric ...

  19. Indication of critical micelle concentration of nonionic surfactants with large emission change using water-soluble conjugated polymer as molecular light switch

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Lilin, E-mail: sunlilin126@126.com [Anhui Key Laboratory of Chemo-Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000 (China); Hao, Dan; Zhang, Ping; Qian, Zhangsheng; Shen, Weili [Anhui Key Laboratory of Chemo-Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000 (China); Shao, Taili [Anhui Key Laboratory of Chemo-Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000 (China); Department of Pharmacy, Wannan Medical College, Wuhu 241000 (China); Zhu, Changqing, E-mail: zhucq@mail.ahnu.edu.cn [Anhui Key Laboratory of Chemo-Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000 (China)

    2013-02-15

    A new near-infrared water-soluble conjugated polymer, i.e. poly [2,5-di (propyloxysulfonate)-1,4-phenylene-ethynylene-9,10-anthrylene] (PPEASO3) was synthesized to investigate its interaction with surfactants. It was found that PPEASO3 has only a weak fluorescence emission at about 670 nm due to its self-aggregation in water and in aqueous solution containing a low concentration of nonionic surfactants, i.e. below their critical micelle concentration (CMC). However, a dramatic fluorescence enhancement with a large emission blue-shift (>40 nm) was found once the concentration of nonionic surfactants reached the CMC (especially for Triton X-100). An orange fluorescence could be observed even with naked-eyes under UV-lamp, which gave a direct indication for the micelle forming process and provided a simple method for the CMC determination of the nonionic surfactants. The CMC values determined by this method were in good agreement with those obtained by other techniques. The dramatic emission change observed could be ascribed to the intensive hydrophobic interaction between PPEASO3 and surfactants micelle, which greatly disrupts the aggregation of the polymer and increase the fluorescence efficiency of PPEASO3. Highlights: Black-Right-Pointing-Pointer Investigated the interaction of a new water-soluble conjugated polymer with surfactants. Black-Right-Pointing-Pointer The dramatic fluorescence enhancement and emission blue-shift were observed at the CMC. Black-Right-Pointing-Pointer The obvious emission color change could be observed with naked-eyes under UV-lamp. Black-Right-Pointing-Pointer Gave a direct indication for the micelle forming process. Black-Right-Pointing-Pointer Provided a simple method for the CMC determination of the nonionic surfactants.

  20. Wheat germ cell-free expression: Two detergents with a low critical micelle concentration allow for production of soluble HCV membrane proteins.

    Science.gov (United States)

    Fogeron, Marie-Laure; Badillo, Aurélie; Jirasko, Vlastimil; Gouttenoire, Jérôme; Paul, David; Lancien, Loick; Moradpour, Darius; Bartenschlager, Ralf; Meier, Beat H; Penin, François; Böckmann, Anja

    2015-01-01

    Membrane proteins are notoriously difficult to express in a soluble form. Here, we use wheat germ cell-free expression in the presence of various detergents to produce the non-structural membrane proteins 2, 4B and 5A of the hepatitis C virus (HCV). We show that lauryl maltose neopentyl glycol (MNG-3) and dodecyl octaethylene glycol ether (C12E8) detergents can yield essentially soluble membrane proteins at detergent concentrations that do not inhibit the cell-free reaction. This finding can be explained by the low critical micelle concentration (CMC) of these detergents, which keeps the monomer concentrations low while at the same time providing the necessary excess of detergent concentration above CMC required for full target protein solubilization. We estimate that a tenfold excess of detergent micelles with respect to the protein concentration is sufficient for solubilization, a number that we propose as a guideline for detergent screening assays. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Estimation of AOT and SDS CMC in a methanol using conductometry, viscometry and pyrene fluorescence spectroscopy methods

    Science.gov (United States)

    Mitsionis, Anastasios I.; Vaimakis, Tiverios C.

    2012-09-01

    Critical micelle concentration (CMC) of two anionic surfactants in methanol was estimated using conductometry, viscometry and pyrene fluorescence spectroscopy methods. The surfactants used, were sodium bis(2-ethylhexyl) sulfosuccinate (Aerosol-OT, AOT) and sodium dodecyl sulfate (SDS) dispersed in pure methanol. The CMC determination was evaluated in room temperature. The results have shown nearly similar concentrations.

  2. Determination of the aggregation number for micelles by isothermal titration calorimetry

    DEFF Research Database (Denmark)

    Olesen, Niels Erik; Holm, Rene; Westh, Peter

    2014-01-01

    Isothermal titration calorimetry (ITC) has previously been applied to estimate the aggregation number (n), Gibbs free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) of micellization. However, some difficulties of micelle characterization by ITC still remain; most micelles have aggregation numbers...... insight into optimal design of titration protocols for micelle characterization. By applying the new method, the aggregation number of sodium dodecyl sulphate and glycochenodeoxycholate was determined at concentrations around their critical micelle concentration (CMC)...

  3. Calculations of critical micelle concentration by dissipative particle dynamics simulations: the role of chain rigidity.

    Science.gov (United States)

    Lee, Ming-Tsung; Vishnyakov, Aleksey; Neimark, Alexander V

    2013-09-05

    Micelle formation in surfactant solutions is a self-assembly process governed by complex interplay of solvent-mediated interactions between hydrophilic and hydrophobic groups, which are commonly called heads and tails. However, the head-tail repulsion is not the only factor affecting the micelle formation. For the first time, we present a systematic study of the effect of chain rigidity on critical micelle concentration and micelle size, which is performed with the dissipative particle dynamics simulation method. Rigidity of the coarse-grained surfactant molecule was controlled by the harmonic bonds set between the second-neighbor beads. Compared to flexible molecules with the nearest-neighbor bonds being the only type of bonded interactions, rigid molecules exhibited a lower critical micelle concentration and formed larger and better-defined micelles. By varying the strength of head-tail repulsion and the chain rigidity, we constructed two-dimensional diagrams presenting how the critical micelle concentration and aggregation number depend on these parameters. We found that the solutions of flexible and rigid molecules that exhibited approximately the same critical micelle concentration could differ substantially in the micelle size and shape depending on the chain rigidity. With the increase of surfactant concentration, primary micelles of more rigid molecules were found less keen to agglomeration and formation of nonspherical aggregates characteristic of flexible molecules.

  4. Effects of gamma radiation on phase behaviour and critical micelle concentration of Triton X-100 aqueous solutions

    International Nuclear Information System (INIS)

    Valdes Diaz, G.; Rodriguez-Calvo, S.; Perez-Gramatges, A.; Rapado-Paneque, M.; Fernandez-Lima, F. A.; Ponciano, C. R.; Silveira, E. F. . E-mail. apgram@instec.cu

    2007-01-01

    Ionising radiation used for sterilisation can have an effect on the physico-chemical properties of pharmaceutically relevant excipient systems, affecting therefore the stability of the formulation. The effect of gamma irradiation on the phase behaviour (cloud point - CP) and critical micelle concentration (CMC) of aqueous solutions of Triton X-100, used as a model nonionic surfactant, is investigated in this paper. Micellar solutions irradiated with ?-rays in a dose range between 0 and 70 kGy, including the sterilisation range of pharmaceutical preparations, were analysed using mass spectrometry. Results show a slight shift in molecular mass distribution of ethoxylated surfactant, which indicates degradation of polyethoxylated chains by water radical attacks. This fact, combined with the formation of cross-linked species, is considered to be responsible for the decrease observed in CP and CMC values of micellar solutions at all absorbed doses. There is no spectroscopic evidence of radiation damage to aromatic ring or hydrocarbon tail of surfactant. Models based on Flory-Huggins theory were employed to estimate CP from changes in mass distribution and to obtain cross-linking fractions. (Author)

  5. Effect of calcium chelators on physical changes in casein micelles in concentrated micellar casein solutions

    NARCIS (Netherlands)

    Kort, de E.J.P.; Minor, M.; Snoeren, T.H.M.; Hooijdonk, van A.C.M.; Linden, van der E.

    2011-01-01

    The effect of calcium chelators on physical changes of casein micelles in concentrated micellar casein solutions was investigated by measuring calcium-ion activity, viscosity and turbidity, and performing ultracentrifugation. The highest viscosities were measured on addition of sodium

  6. Effect of Urea on the Thermodynamics of Hexadecyltrimethylammonium Bromide Micelle Formation in Aqueous Solutions

    Science.gov (United States)

    Velikov, A. A.

    2018-02-01

    The effect of urea on the thermodynamics of hexadecyltrimethylammonium bromide (CTAB) micelle formation in aqueous urea solutions was studied by isothermal titration microcalorimetry. The thermodynamic functions of Δ H, Δ G, and Δ S of CTAB micelle formation were calculated. The critical micelle concentrations (CMC) were determined. The addition of urea to the solution decreased the micelle formation entropy. This was attributed to the "lowering" of the structural temperature of the solution, which led to an increased number of hydrogen bonds and structure formation of water.

  7. The optimization of CMC concentration as graphite binder on the anode of LiFePO4 battery

    Science.gov (United States)

    Hidayat, S.; Cahyono, T.; Mindara, J. Y.; Riveli, N.; Alamsyah, W.; Rahayu, I.

    2017-05-01

    Recently, the most dominating power supply on the mobile electronics market are rechargeable Lithium-ion batteries. This is because of a higher energy density and a longer lifetime compared to similar rechargeable battery systems. Graphite is commonly used as anode material in the Lithium-ion batteries, because of its excellent electrochemical characteristics and low cost fabrication. In this paper, we reported the optimization of the concentration of the CMC (carboxymethyl cellulose), that acts as the binder for graphite anode. Based on our experimental results, the best composition of graphite : C : CMC is 90 : 8 : 2 in weight %. Anode with such composition has, based on SEM measurement, a relatively good surface morphology, while it also has relatively high conductivity, about 2.68 S/cm. The result of cyclic voltammogram with a scan rate of 10 mV/s in the voltage range of 0 to 1 Volt, shows the peak of reduction voltage at 0.85 Volts and the peak voltage of oxidation is at -1.5 Volt. The performance of the battery system with LiFePO4 set as the cathode, shows that the working voltage is about 2.67 Volts at 1 mA current-loading, with the efficiency around 47%.

  8. Stereocomplex-Reinforced PEGylated Polylactide Micelle for Optimized Drug Delivery

    Directory of Open Access Journals (Sweden)

    Chunsheng Feng

    2016-04-01

    Full Text Available The instability of PEGylated polylactide micelles is a challenge for drug delivery. Stereocomplex interaction between racemic polylactide chains with different configurations provides an effective strategy to enhance the stability of micelles as the nanocarriers of drugs. In this work, a stereocomplex micelle (SCM self-assembled from the amphiphilic triblock copolymers comprising poly(ethylene glycol (PEG, and dextrorotatory and levorotatory polylactides (PDLA and PLLA was applied for efficient drug delivery. The spherical SCM showed the smallest scale and the lowest critical micelle concentration (CMC than the micelles with single components attributed to the stereocomplex interaction between PDLA and PLLA. 10-Hydroxycamptothecin (HCPT as a model antitumor drug was loaded into micelles. Compared with the loading micelles from individual PDLA and PLLA, the HCPT-loaded SCM exhibited the highest drug loading efficiency (DLE and the slowest drug release in phosphate-buffered saline (PBS at pH 7.4, indicating its enhanced stability in circulation. More fascinatingly, the laden SCM was demonstrated to have the highest cellular uptake of HCPT and suppress malignant cells most effectively in comparison to the HCPT-loaded micelles from single copolymer. In summary, the stereocomplex-enhanced PLA–PEG–PLA micelle may be promising for optimized drug delivery in the clinic.

  9. Micelles As Delivery System for Cancer Treatment.

    Science.gov (United States)

    Keskin, Dilek; Tezcaner, Aysen

    2017-01-01

    Micelles are nanoparticles formed by the self-assembly of amphiphilic block copolymers in certain solvents above concentrations called critical micelle concentration (CMC). Micelles are used in different fields like food, cosmetics, medicine, etc. These nanosized delivery systems are under spotlight in the recent years with new achievements in terms of their in vivo stability, ability to protect entrapped drug, release kinetics, ease of cellular penetration and thereby increased therapeutic efficacy. Drug loaded micelles can be prepared by dialysis, oil-in-water method, solid dispersion, freezing, spray drying, etc. The aim of this review is to give an overview of the research on micelles (in vitro, in vivo and clinical) as delivery system for cancer treatment. Passive targeting is one route for accumulation of nanosized micellar drug formulations. Many research groups from both academia and industry focus on developing new strategies for improving the therapeutic efficacy of micellar systems (active targeting to the tumor site, designing multidrug delivery systems for overcoming multidrug resistance or micelles formed by prodrug conjugates, etc). There is only one micellar drug formulation in South Korea that has reached clinical practice. However, there are many untargeted anticancer drug loaded micellar formulations in clinical trials, which have potential for use in clinics. Many more products are expected to be on the market in the near future. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  10. Pyrene absorption can be a convenient method for probing critical micellar concentration (cmc) and indexing micellar polarity.

    Science.gov (United States)

    Basu Ray, Gargi; Chakraborty, Indranil; Moulik, Satya P

    2006-02-01

    The critical micellar concentration (cmc) of both ionic and non-ionic surfactants can be conveniently determined from the measurements of UV absorption of pyrene in surfactant solution. The results on a number of surfactants have agreed with that realized from pyrene fluorescence measurements as well as that obtained following conductometric, tensiometric and calorimetric methods. The absorbance vs [surfactant] profiles for all the major UV spectral peaks of pyrene have been found to be sigmoidal in nature which were analyzed according to Sigmoidal-Boltzmann equation (SBE) to evaluate the cmcs of the studied surfactants. The difference between the initial and the final asymptotes (a(i) and a(f), respectively) of the sigmoidal profile, Delta a = (a(f)-a(i)) and the slope of the sigmoid, S(sig) have been observed to depend on the type of the surfactant. The Delta a has shown a linear correlation with the ratio of the fluorescence intensities of the first and the third vibronic peaks, I1/I3 of pyrene which is considered as a measure of the environmental polarity (herein micellar interior) of the probe (pyrene). Thus, Delta a values have the prospect for use as another index for the estimation of polarity of micellar interior.

  11. Self-Assembly of Calix[4]arene-Based Amphiphiles Bearing Polyethylene Glycols: Another Example of "Platonic Micelles".

    Science.gov (United States)

    Yoshida, Kenta; Fujii, Shota; Takahashi, Rintaro; Matsumoto, Sakiko; Sakurai, Kazuo

    2017-09-12

    The aggregation number of classical micelles exhibits a certain distribution, which is a recognizable feature of conventional micelles. However, we recently identified perfectly monodisperse calix[4]arene-based micelles whose aggregation numbers agree with the vertex numbers of regular polyhedra, that is, Platonic solids, and thus they are named "Platonic micelles". Regarding our hypothesis of the formation mechanism of Platonic micelles, both repulsive interactions including steric hindrance and electrostatic repulsions among the headgroups are important for determining their aggregation number; however, neither of these is necessarily needed to consider. In this study, we employed polyethylene glycols (PEGs) as the nonionic headgroup of calix[4]arene-based amphiphiles to study the effects of only repulsive interactions caused by steric hindrance on the formation of Platonic micelles. The amphiphiles containing relatively low-molecular-weight PEGs (550 or 1000 g mol -1 ) form dodecamer or octamer micelles, respectively, with no variation in the aggregation number. However, relatively high-molecular-weight PEGs (2000 g mol -1 ) produce polydispersed micelles with a range of aggregation number. PEG 2000 exhibits a greater affinity for water than PEG 550 and 1000, resulting in fewer hydrophobic interactions in micelle formation, as indicated by the drastic increase of the critical micelle concentration (CMC) value in the PEG 2000 system. The instability of the structure of PEG 2k CaL5 micelles might contribute to the higher mobility of PEG in the micellar shell, resulting in a non-Platonic aggregation number with polydispersity.

  12. Effect of Molecular Weight and Molar Ratio of Dextran on Self-Assembly of Dextran Stearate Polymeric Micelles as Nanocarriers for Etoposide

    Directory of Open Access Journals (Sweden)

    Jaleh Varshosaz

    2012-01-01

    Full Text Available Amphiphilic polymer surfactants are composed of hydrophilic and hydrophobic polymers and are widely used in targeted drug delivery. The purpose of this study was the evaluation of the effect of molecular weight and molar ratio of dextran on physicochemical properties of dextran stearate polymeric micelles. Dextran stearate was synthesized by acylation of dextran with stearoyl chloride. Etoposide loaded polymeric micelles were prepared by dialysis method. The resulting micelles were evaluated for particle size, zeta potential, critical micelle concentration (CMC, drug loading capacity, and release efficiency. Cytotoxicity and cellular uptake of micelles were studied in CT-26 colorectal carcinoma cell line. Molecular weight and molar ratio of dextran-stearate were impressive on zeta potential, CMC, drug loading capacity, and release efficiency. Unlike polymer molecular weight, molar ratio of stearate had a significant effect on cytotoxicity and particle size of etoposide loaded micelles. Although molecular weight of dextran had no significant effect on cytotoxicity of micelles on CT-26 cells, it had drastic attributes for stability of polymeric micelles. Consequently, both variables of molecular weight of dextran and molar ratio of stearate should be taken into account to have a stable and effective micelle of dextran-stearate.

  13. Titration calorimetry of surfactant–drug interactions: Micelle formation and saturation studies

    International Nuclear Information System (INIS)

    Waters, Laura J.; Hussain, Talib; Parkes, Gareth M.B.

    2012-01-01

    Highlights: ► Isothermal titration calorimetry can be used to monitor the saturation of micelles with pharmaceutical compounds. ► The number of drug molecules per micelle varies depending on the drug used and the temperature of the calorimeter. ► The change in enthalpy for the saturation of micelles with drugs can be endothermic or exothermic. ► The critical micellar concentration of an anionic surfactant (SDS) does not appear to vary in the presence of drugs. - Abstract: Isothermal titration calorimetry (ITC) was employed to monitor the addition of five model drugs to anionic surfactant based micelles, composed of sodium dodecyl sulfate (SDS), through to the point at which they were saturated with drug. Analysis of the resultant data using this newly developed method has confirmed the suitability of the technique to acquire such data with saturation limits established in all cases. Values for the point at which saturation occurred ranged from 17 molecules of theophylline per micelle at T = 298 K up to 63 molecules of caffeine per micelle at 310 K. Micellar systems can be disrupted by the presence of additional chemicals, such as the drugs used in this study, therefore a separate investigation was undertaken to determine the critical micellar concentration (CMC) for SDS in the presence of each drug at T = 298 K and 310 K using ITC. In the majority of cases, there was no appreciable alteration to the CMC of SDS with drug present.

  14. Determination of micelle formation of ketorolac tromethamine in aqueous media by acoustic measurements

    International Nuclear Information System (INIS)

    Savaroglu, Gokhan; Genc, Lütfi

    2013-01-01

    Graphical abstract: Value of critical micelle concentration (CMC) were detected by speed of sound and determined by an analytical method based on the Phillips definition of the CMC. Highlights: ► The aim of this study was to investigate the aggregation behaviour of KT. ► Influence of KT concentration and temperature upon volumetric properties was studied. ► CMC of KT aqueous solution was determined by using speeds of sound measurements. - Abstract: Density and speed of sound of ketorolac tromethamine in aqueous solutions have been measured as a function of concentration at atmospheric pressure and in the temperature range from 293.15 to 313.15 K. Apparent molar volumes, apparent isentropic compressibility and isentropic compressibility values have also been calculated from the experimental density and speed of sound data. Partial molar volume and partial molar isentropic compressibility are obtained from fitting procedures the data on apparent molar volume, V φ , and apparent isentropic compressibility, K φ(S) . Partial molar volume, V φ 0 , and partial molar isentropic compressibility, k φ(S) 0 , are informative thermodynamic characteristics that reflect solute hydration. The critical micelle concentration (CMC) was determined from speed of sound data by an analytical method based on the Phillips definition of the CMC. Using these results, it was possible to establish the solvent–drug interactions.

  15. Light-responsive micelles of spiropyran initiated hyperbranched polyglycerol for smart drug delivery.

    Science.gov (United States)

    Son, Suhyun; Shin, Eeseul; Kim, Byeong-Su

    2014-02-10

    Light-responsive polymeric micelles have emerged as site-specific and time-controlled systems for advanced drug delivery. Spiropyran (SP), a well-known photochromic molecule, was used to initiate the ring-opening multibranching polymerization of glycidol to afford a series of hyperbranched polyglycerols (SP-hb-PG). The micelle assembly and disassembly were induced by an external light source owing to the reversible photoisomerization of hydrophobic SP to hydrophilic merocyanine (MC). Transmission electron microscopy, atomic force microscopy, UV/vis spectroscopy, and dynamic light scattering demonstrated the successful assembly and disassembly of SP-hb-PG micelles. In addition, the critical micelle concentration (CMC) was determined through the fluorescence analysis of pyrene to confirm the amphiphilicity of respective SP-hb-PGn (n = 15, 29, and 36) micelles, with CMC values ranging from 13 to 20 mg/L, which is correlated to the length of the polar polyglycerol backbone. Moreover, the superior biocompatibility of the prepared SP-hb-PG was evaluated using WI-38 cells and HeLa cells, suggesting the prospective applicability of the micelles in smart drug delivery systems.

  16. Reduction-sensitive micelles self-assembled from amphiphilic chondroitin sulfate A-deoxycholic acid conjugate for triggered release of doxorubicin.

    Science.gov (United States)

    Liu, Hongxia; Wu, Shuqin; Yu, Jingmou; Fan, Dun; Ren, Jin; Zhang, Lei; Zhao, Jianguo

    2017-06-01

    Reduction-sensitive chondroitin sulfate A (CSA)-based micelles were developed. CSA was conjugated with deoxycholic acid (DOCA) via a disulfide linkage. The bioreducible conjugate (CSA-ss-DOCA) can form self-assembled micelles in aqueous medium. The critical micelle concentration (CMC) of CSA-ss-DOCA conjugate is 0.047mg/mL, and its mean diameter is 387nm. The anticancer drug doxorubicin (DOX) was chosen as a model drug, and was effectively encapsulated into the micelles with high loading efficiency. Reduction-sensitive micelles and reduction-insensitive control micelles displayed similar DOX release behavior in phosphate buffered saline (PBS, pH7.4). Notably, DOX release from the reduction-sensitive micelles in vitro was accelerated in the presence of 20mM glutathione-containing PBS environment. Moreover, DOX-loaded CSA-ss-DOCA (CSA-ss-DOCA/DOX) micelles exhibited intracellular reduction-responsive characteristics in human gastric cancer HGC-27 cells determined by confocal laser scanning microscopy (CLSM). Furthermore, CSA-ss-DOCA/DOX micelles demonstrated higher antitumor efficacy than reduction-insensitive control micelles in HGC-27 cells. These results suggested that reduction-sensitive CSA-ss-DOCA micelles had the potential as intracellular targeted carriers of anticancer drugs. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Reverse micelles in organic solvents: a medium for the biotechnological use of extreme halophilic enzymes at low salt concentration

    Directory of Open Access Journals (Sweden)

    Frutos C. Marhuenda-Egea

    2002-01-01

    Full Text Available Alkaline p-nitrophenylphosphate phosphatase (pNPPase from the halophilic archaeobacterium Halobacterium salinarum (previously halobium was solubilized at low salt concentration in reverse micelles of hexadecyltrimethylammoniumbromide in cyclohexane with 1-butanol as cosurfactant. The enzyme maintained its catalytic properties under these conditions. The thermodynamic “solvation–stabilization hypothesis” has been used to explain the bell-shaped dependence of pNPPase activity on the water content of reverse micelles, in terms of protein–solvent interactions. According to this model, the stability of the folded protein depends on a network of hydrated ions associated with acidic residues at the protein surface. At low salt concentration and low water content (the ratio of water concentration to surfactant concentration; w0, the network of hydrated ions within the reverse micelles may involve the cationic heads of the surfactant. The bell-shaped profile of the relationship between enzyme activity and w0 varied depending on the concentrations of NaCl and Mn2+.

  18. Thermodynamic analysis of unimer-micelle and sphere-to-rod micellar transitions of aqueous solutions of sodium dodecylbenzenesulfonate

    International Nuclear Information System (INIS)

    Valente, Artur J.M.; López Cascales, J.J.; Fernández Romero, Antonio J.

    2014-01-01

    Highlights: • Unimer-micelle and sphere-to-rod micellar transitions were observed to sodium dodecylbenzenesulfonate in aqueous solutions. • Two micellar transitions were seen by electrical conductivity and surface tension. • An anomalous ΔS 0 and ΔH 0 increase with T was found for the second critical transition. • More stable aggregates are evidenced for spherical micelles than for the other shapes. - Abstract: Temperature dependence of specific conductivity of sodium dodecylbenzenesulfonate (NaDBS) aqueous solutions was analyzed. Two breaks on the plot appeared for all temperature, which suggest two micellar transitions. This has been corroborated by surface tension measurements. The first transition concentration occurs at the critical micelle concentration (CMC), whilst the second critical concentration (so-called transition micellar concentration, TMC) is due to a sphere-to-rod micelles transition. The dependence of CMC and TMC on the temperature allows the computation of the corresponding thermodynamic functions: Gibbs free energy, enthalpy and entropy changes. For the CMC, enthalpy and entropy increments were found that decrease with the temperature values. However, an anomalous behavior was obtained for the TMC, where both ΔS 0 and ΔH 0 values raised with the temperature increase. However, for both transitions, an (enthalpy + entropy) compensation is observed. These results will be compared with similar systems reported in the literature

  19. Détermination de la concentration micellaire

    African Journals Online (AJOL)

    SARAH

    30 nov. 2014 ... ABSTRACT. Objective: This study aims to determine some characteristic quantities of traditional soaps prepared in. Benin in aqueous solution. Methods and Results: The critical micelle concentration (CMC) and the Krafft point of traditional soaps were determined by the conductivity method. The results of ...

  20. Mixed micelles of sodium cholate and sodium dodecylsulphate 1:1 binary mixture at different temperatures--experimental and theoretical investigations.

    Directory of Open Access Journals (Sweden)

    Balázs Jójárt

    Full Text Available Micellisation process for sodium dodecyl sulphate and sodium cholate in 1∶1 molar ratio was investigated in a combined approach, including several experimental methods and coarse grained molecular dynamics simulation. The critical micelle concentration (cmc of mixed micelle was determined by spectrofluorimetric and surface tension measurements in the temperature range of 0-50°C and the values obtained agreed with each other within the statistical error of the measurements. In range of 0-25°C the cmc values obtained are temperature independent while cmc values were increased at higher temperature, which can be explained by the intensive motion of the monomers due to increased temperature. The evidence of existing synergistic effect among different constituent units of the micelle is indicated clearly by the interaction parameter (β1,2 calculated from cmc values according to Rubingh. As the results of the conductivity measurements showed the negative surface charges of the SDS-NaCA micelle are not neutralized by counterions. Applying a 10 µs long coarse-grained molecular dynamics simulation for system including 30-30 SDS and CA (with appropriate number of Na+ cations and water molecules we obtained semi-quantitative agreement with the experimental results. Spontaneous aggregation of the surfactant molecules was obtained and the key steps of the micelle formation are identified: First a stable SDS core was formed and thereafter due to the entering CA molecules the size of the micelle increased and the SDS content decreased. In addition the size distribution and composition as well as the shape and structure of micelles are also discussed.

  1. Assessment of Palmitoyl and Sulphate Conjugated Glycol Chitosan for Development of Polymeric Micelles

    Directory of Open Access Journals (Sweden)

    Ikram Ullah Khan

    2013-06-01

    Full Text Available Introduction: Amphiphilic copolymers are capable of forming core shell-like structures at the critical micellar concentration (CMC; hence, they can serve as drug carriers. Thus, in the present work, polymeric micelles based on novel chitosan derivative were synthesized. Methods: Block copolymer of palmitoyl glycol chitosan sulfate (PGCS was prepared by grafting palmitoyl and sulfate groups serving as hydrophobic and hydrophilic fractions, respectively. Then, fourier transform infrared spectra (FTIR and spectral changes in iodine/iodide mixture were carried out. Results: FTIR studies confirmed the formation of palmitoyl glycol chitosan sulfate (PGCS and spectral changes in iodine/iodide mixture indicated CMC which lies in the range of 0.003-0.2 mg/ml. Conclusion: Therefore, our study indicated that polymeric micelles based on palmitoyl glycol chitosan sulphate could be used as a prospective carrier for water insoluble drugs.

  2. Lipoamino acid-based micelles as promising delivery vehicles for monomeric amphotericin B.

    Science.gov (United States)

    Serafim, Cláudia; Ferreira, Inês; Rijo, Patrícia; Pinheiro, Lídia; Faustino, Célia; Calado, António; Garcia-Rio, Luis

    2016-01-30

    Lipoamino acid-based micelles have been developed as delivery vehicles for the hydrophobic drug amphotericin B (AmB). The micellar solubilisation of AmB by a gemini lipoamino acid (LAA) derived from cysteine and its equimolar mixtures with the bile salts sodium cholate (NaC) and sodium deoxycholate (NaDC), as well as the aggregation sate of the drug in the micellar systems, was studied under biomimetic conditions (phosphate buffered-saline, pH 7.4) using UV-vis spectroscopy. Pure surfactant systems and equimolar mixtures were characterized by tensiometry and important parameters were determined, such as critical micelle concentration (CMC), surface tension at the CMCCMC), maximum surface excess concentration (Γmax), and minimum area occupied per molecule at the water/air interface (Amin). Rheological behaviour from viscosity measurements at different shear rates was also addressed. Solubilisation capacity was quantified in terms of molar solubilisation ratio (χ), micelle-water partition coefficient (KM) and Gibbs energy of solubilisation (ΔGs°). Formulations of AmB in micellar media were compared in terms of drug loading, encapsulation efficiency, aggregation state of AmB and in vitro antifungal activity against Candida albicans. The LAA-containing micellar systems solubilise AmB in its monomeric and less toxic form and exhibit in vitro antifungal activity comparable to that of the commercial formulation Fungizone. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Critical micelle concentrations of allelopathic substances produced by Nannochloris oculata which affect a red tide organism, Gymnodinium breve.

    Science.gov (United States)

    Pérez, E; Martin, D F

    2001-01-01

    Laboratory cultures of the green algae Nannochloris oculata and Nannochloris eucaryotum are known to cause lysis of Gymnodinium breve, which is Florida's red tide organism. Two cytolytic agents were previously identified as methyl palmitate and methyl stearate. In this study, the critical micelle concentrations of these substances were determined by ultraviolet light and turbidimetric methods to be 3.5 +/- 0.3 ppm (methyl stearate) and 4.3 +/- 0.6 (methyl palmitate). There were no significant differences in results obtained using the two methods.

  4. The structure of normal ionic micelles by interpretation of small-angle neutron scattering data from selectively labeled (2H, 19F) surfactant solutions

    International Nuclear Information System (INIS)

    Berr, S.S.

    1986-12-01

    We have determined the structure of micelles formed in water by several classes of ionic surfactants under a variety of experimental conditions using small-angle neutron scattering (SANS) techniques. Contrast between the micelles and the solvent was achieved through either selective deuteration or fluorination of the surfactant, or through the use of D 2 O. Interpretation of SANS data was facilitated by the use of Hayter, Penfold, and Hansen's rescaled Mean Spherical Approximation theory to calculate the scattering due to interparticle interactions. We have devised a number of micelle models, both spherical and ellipsoidal, to account for the scattering due to single micelles. It was found that changing the solvent from H 2 O to D 2 O results in the formation of larger micelles due to changes in the solvent-surfactant hydrocarbon interactions. This solvent isotope effect increased as the length of the alkyl chain increased. The fractional micellar charge did not change with respect to isotopic composition of solvent. We found that alkyltrimethylammonium bromide surfactants form drier micelles than do the sodium alkyl sulfate surfactants of equal chain length. Also, all micelles studied were found to be dry near the critical micelle concentration (cmc) and to become increasingly wetter as the concentration increased. The increase in aggregation number with respect to the square root of surfactant concentration was found to be linear for all systems studied. 80 figs

  5. (CMC)/gum arabic

    Indian Academy of Sciences (India)

    Administrator

    material, which is widely used as food additives, washes, paste, etc. It is an anionic and ... This was ascribed to the good interaction between cassava starch and CMC ... drugs and also release the heavy metals to improve the agricultural soil.

  6. Temperature Effect on Micelle Formation: Molecular Thermodynamic Model Revisited.

    Science.gov (United States)

    Khoshnood, Atefeh; Lukanov, Boris; Firoozabadi, Abbas

    2016-03-08

    Temperature affects the aggregation of macromolecules such as surfactants, polymers, and proteins in aqueous solutions. The effect on the critical micelle concentration (CMC) is often nonmonotonic. In this work, the effect of temperature on the micellization of ionic and nonionic surfactants in aqueous solutions is studied using a molecular thermodynamic model. Previous studies based on this technique have predicted monotonic behavior for ionic surfactants. Our investigation shows that the choice of tail transfer energy to describe the hydrophobic effect between the surfactant tails and the polar solvent molecules plays a key role in the predicted CMC. We modify the tail transfer energy by taking into account the effect of the surfactant head on the neighboring methylene group. The modification improves the description of the CMC and the predicted micellar size for aqueous solutions of sodium n-alkyl sulfate, dodecyl trimethylammonium bromide (DTAB), and n-alkyl polyoxyethylene. The new tail transfer energy describes the nonmonotonic behavior of CMC versus temperature. In the DTAB-water system, we redefine the head size by including the methylene group, next to the nitrogen, in the head. The change in the head size along with our modified tail transfer energy improves the CMC and aggregation size prediction significantly. Tail transfer is a dominant energy contribution in micellar and microemulsion systems. It also promotes the adsorption of surfactants at fluid-fluid interfaces and affects the formation of adsorbed layer at fluid-solid interfaces. Our proposed modifications have direct applications in the thermodynamic modeling of the effect of temperature on molecular aggregation, both in the bulk and at the interfaces.

  7. Synthesis and characterization of novel P(HEMA-LA-MADQUAT) micelles for co-delivery of methotrexate and Chrysin in combination cancer chemotherapy.

    Science.gov (United States)

    Davaran, Soodabeh; Fazeli, Hamed; Ghamkhari, Aliyeh; Rahimi, Fariborz; Molavi, Ommoleila; Anzabi, Maryam; Salehi, Roya

    2018-08-01

    A Novel poly [2-hydroxyethyl methacrylate-Lactide-dimethylaminoethyl methacrylate quaternary ammonium alkyl halide] [P(HEMA-LA-MADQUAT)] copolymer was synthesized through combination of ring opening polymerization (ROP) and 'free' radical initiated polymerization methods. This newly developed copolymer was fully characterized by FT-IR, 1 HNMR and 13 CNMR spectroscopy. Micellization of the copolymer was performed by dialysis membrane method and obtained micelles were characterized by FESEM, dynamic light scattering (DLS), zeta potential (ξ), and critical micelle concentration (CMC) measurements. This copolymer was developed with the aim of co-delivering two different anticancer drugs: methotrexate (MTX) and chrysin. In vitro cytotoxicity effect of MTX@Chrysin-loaded P(HEMA-LA-MADQUAT) was also studied through assessing the survival rate of breast cancer cell line (MCF-7) and DAPI staining assays. Cationic micelle (and surface charge of + 7.6) with spherical morphology and an average diameter of 55 nm and CMC of 0.023 gL -1 was successfully obtained. Micelles showed the drug loaded capacity around 87.6 and 86.5% for MTX and Chrysin, respectively. The cytotoxicity assay of a drug-free nanocarrier on MCF-7 cell lines indicated that this developed micelles were suitable nanocarriers for anticancer drugs. Furthermore, the MTX@Chrysin-loaded micelle had more efficient anticancer performance than free dual anticancer drugs (MTX @ chrysin), confirmed by MTT assay and DAPI stainingmethods. Therefore, we envision that this recently developed novel micelle can enhance the efficacy of chemotherapeutic agents, MTX and Chrysin, combination chemotherapy and has the potential to be used as an anticancer drug delivery system for in vivo studies. Therefore, this recently developed novel micelle can enhance the efficacy of chemotherapeutic agents, MTX and Chrysin, combination chemotherapy and has the potential to be used as an anticancer drug delivery system for in vivo studies.

  8. Micelle assisted thin-film solid phase microextraction: a new approach for determination of quaternary ammonium compounds in environmental samples.

    Science.gov (United States)

    Boyacı, Ezel; Pawliszyn, Janusz

    2014-09-16

    Determination of quaternary ammonium compounds (QACs) often is considered to be a challenging undertaking owing to secondary interactions of the analytes' permanently charged quaternary ammonium head or hydrophobic tail with the utilized labware. Here, for the first time, a micelle assisted thin-film solid phase microextraction (TF-SPME) using a zwitterionic detergent 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS) as a matrix modifier is introduced as a novel approach for in-laboratory sample preparation of the challenging compounds. The proposed micelle assisted TF-SPME method offers suppression/enhancement free electrospray ionization of analytes in mass spectrometric detection, minimal interaction of the micelles with the TF-SPME coating, and chromatographic stationary phase and analysis free of secondary interactions. Moreover, it was found that the matrix modifier has multiple functions; when its concentration is found below the critical micelle concentration (CMC), the matrix modifier primarily acts as a surface deactivator; above its CMC, it acts as a stabilizer for QACs. Additionally, shorter equilibrium extraction times in the presence of the modifier demonstrated that micelles also assist in the transfer of analytes from the bulk of the sample to the surface of the coating. The developed micelle assisted TF-SPME protocol using the 96-blade system requires only 30 min of extraction and 15 min of desorption. Together with a conditioning step (15 min), the entire method is 60 min; considering the advantage of using the 96-blade system, if all the blades in the brush are used, the sample preparation time per sample is 0.63 min. Moreover, the recoveries for all analytes with the developed method were found to range within 80.2-97.3%; as such, this method can be considered an open bed solid phase extraction. The proposed method was successfully validated using real samples.

  9. Importance of critical micellar concentration for the prediction of solubility enhancement in biorelevant media.

    Science.gov (United States)

    Ottaviani, G; Wendelspiess, S; Alvarez-Sánchez, R

    2015-04-06

    This study evaluated if the intrinsic surface properties of compounds are related to the solubility enhancement (SE) typically observed in biorelevant media like fasted state simulated intestinal fluids (FaSSIF). The solubility of 51 chemically diverse compounds was measured in FaSSIF and in phosphate buffer and the surface activity parameters were determined. This study showed that the compound critical micellar concentration parameter (CMC) correlates strongly with the solubility enhancement (SE) observed in FaSSIF compared to phosphate buffer. Thus, the intrinsic capacity of molecules to form micelles is also a determinant for each compound's affinity to the micelles of biorelevant surfactants. CMC correlated better with SE than lipophilicity (logD), especially over the logD range typically covered by drugs (2 < logD < 4). CMC can become useful to guide drug discovery scientists to better diagnose, improve, and predict solubility in biorelevant media, thereby enhancing oral bioavailability of drug candidates.

  10. Multiseed liposomal drug delivery system using micelle gradient as driving force to improve amphiphilic drug retention and its anti-tumor efficacy.

    Science.gov (United States)

    Zhang, Wenli; Li, Caibin; Jin, Ya; Liu, Xinyue; Wang, Zhiyu; Shaw, John P; Baguley, Bruce C; Wu, Zimei; Liu, Jianping

    2018-11-01

    To improve drug retention in carriers for amphiphilic asulacrine (ASL), a novel active loading method using micelle gradient was developed to fabricate the ASL-loaded multiseed liposomes (ASL-ML). The empty ML were prepared by hydrating a thin film with empty micelles. Then the micelles in liposomal compartment acting as 'micelle pool' drove the drug to be loaded after the outer micelles were removed. Some reasoning studies including critical micelle concentration (CMC) determination, influencing factors tests on entrapment efficiency (EE), structure visualization, and drug release were carried out to explore the mechanism of active loading, ASL location, and the structure of ASL-ML. Comparisons were made between pre-loading and active loading method. Finally, the extended drug retention capacity of ML was evaluated through pharmacokinetic, drug tissue irritancy, and in vivo anti-tumor activity studies. Comprehensive results from fluorescent and transmission electron microscope (TEM) observation, encapsulation efficiency (EE) comparison, and release studies demonstrated the formation of ML-shell structure for ASL-ML without inter-carrier fusion. The location of drug mainly in inner micelles as well as the superiority of post-loading to the pre-loading method , in which drug in micelles shifted onto the bilayer membrane was an additional positive of this delivery system. It was observed that the drug amphiphilicity and interaction of micelles with drug were the two prerequisites for this active loading method. The extended retention capacity of ML has been verified through the prolonged half-life, reduced paw-lick responses in rats, and enhanced tumor inhibition in model mice. In conclusion, ASL-ML prepared by active loading method can effectively load drug into micelles with expected structure and improve drug retention.

  11. Interactions of short chain phenylalkanoic acids within ionic surfactant micelles in aqueous media

    Directory of Open Access Journals (Sweden)

    Naeem Kashif

    2012-01-01

    Full Text Available % SDS KR nema Solubilization and interactions of phenylalkanoic acids induced by cationic surfactant, cetyltrimethylammonium bromide (CTAB and an anionic surfactant, sodium dodecyl sulfate (SDS was investigated spectrophotometrically at 25.0°C. The UV spectra of the additives (acids were measured with and without surfactant above and below critical micelle concentration (cmc of the surfactant. The presence of alkyl chain in phenylalkanoic acids is responsible for hydrophobic interaction resulting in shift of the spectra towards longer wavelength (red shift. The value of partition coefficient (Kx between the bulk water and surfactant micelles and in turn standard free energy change of solubilization (ΔGpº were also estimated by measuring the differential absorbance (ΔA of the additives in micellar solutions.

  12. Environmentally safe separation and pre-concentration of rhodium and ruthenium from spent nuclear fuel using mixed-micelle cloud point extraction and determination by ICP-MS

    International Nuclear Information System (INIS)

    Ranjit, M.; Meeravali, N.N.; Kumar, S.J.

    2010-01-01

    Full text: Recently, spend nuclear fuel waste of thermal and fast reactors are emerging as an alternative valuable resource for Rh, Ru and Pd. In addition, its presence causes the difficulty in the vitrification process. Hence, its safe extraction from these wastes has to be carried out by using the environmental friendly extraction procedure. In this study, we have reported the simple mixed-micelle cloud point extraction (MM-CPE) procedure for separation as well as pre-concentration of Rh, Ru and Pd. This MM-CPE is carried out preliminarily from aqueous chloride medium with Aliquat-336/Triton X-114 mixed-micelles in the absence and presence of tin(II) chloride. In presence of chloride medium alone, only Pd get extracted quantitatively, while extraction of Rh and Ru are negligible. In presence of tin chloride, the extraction of Rh and Ru increases and becomes quantitative, without affecting the extraction of Pd. The MM-CPE conditions are optimized under influence of variables such as HCI, Aliquat-336, Triton X-114 and tin chloride concentrations and incubation time and temperature. Under the optimized conditions, the accuracy of the procedure is verified by using recovery study carried out from real water samples. This work is under progress to apply real nuclear fuel waste samples

  13. Fluorescent, thermo-responsive biotin-P(NIPAAm-co-NDAPM)- b-PCL micelles for cell-tracking and drug delivery

    International Nuclear Information System (INIS)

    Li Yongyong; Zhang Xianzheng; Cheng Han; Zhu Jingling; Li Unnam; Cheng Sixue; Zhuo Renxi

    2007-01-01

    An amphiphilic, biotinylated poly(N-isopropylacrylamide-co-N-(3-dimethylamino propyl)methacrylamide)-block- poly(ε-caprolactone) (biotin-P(NIPAAm-co-NDAPM)- b-PCL) block copolymer was synthesized. The cytotoxicity study showed that the copolymer exhibited no apparent cytotoxicity. In aqueous solution, biotin-P(NIPAAm-co-NDAPM)- b-PCL copolymer was able to self-assemble into micelles of around 60 nm in diameter with a critical micellar concentration (CMC) of 36 mg l -1 . Biotin-P(NIPAAm- co-NDAPM)-b-PCL micelles were thermo-responsive and the cloud point temperature was at 36.5 deg. C. The fluorescent group, fluorescein isothiocyanate (FITC) was further introduced to label the biotin-P(NIPAAm-co-NDAPM)- b-PCL copolymer. A cell internalization experiment was conducted and it was found that the fluorescent micelles could be internalized into the cells. The drug release behavior of drug-loading micelles was also examined and the drug-loaded biotin-P(NIPAAm-co-NDAPM)- b-PCL micelles showed slow drug release at 27 deg. C and fast drug release at 37 deg. C

  14. Data for the size of cholesterol-fat micelles as a function of bile salt concentration and the physico-chemical properties of six liquid experimental pine-derived phytosterol formulations in a cholesterol-containing artificial intestine fluid

    Directory of Open Access Journals (Sweden)

    Jinsoo Yi

    2017-02-01

    Full Text Available The data in this paper are additional information to the research article entiltled “Inhibition of cholesterol transport in an intestine cell model by pine-derived phytosterols” (Yi et al.,2016 [1]. The data derived from the measurement on six liquid formulations of commercial pine-derived phytosterol (CPP by dynamic light scattering. The data cover micelle size and the zeta-potential for formulations with cholesterol including monoglyceride, oleic acid, and bile salt. The data demonstrate the critical effect of the bile salt concentration on the size of cholesterol-digested fat micelles.

  15. Conductometric study of sodium dodecyl sulfate - nonionic surfactant (Triton X-100, Tween 20, Tween 60, Tween 80 or Tween 85 mixed micelles in aqueous solution

    Directory of Open Access Journals (Sweden)

    Ćirin Dejan M.

    2012-01-01

    Full Text Available The present study is concerned with the determination of the critical micelle concentration (cmc of mixed micelles of sodium dodecyl sulfate with one of five nonionic surfactants (Triton X-100, Tween 20, Tween 60, Tween 80 or Tween 85 from conductance measurements. Based on the calculated values of the β parameters we have noticed that SDS-nonionic surfactants mostly showed strong synergistic effect. It was found that nonionic surfactants with mainly longer and more hydrophobic tail show stronger interactions with hydrophobic part of SDS, thus expressing stronger synergism. In SDS-Tween 80 binary system the strongest synergistic effect was noticed. SDS-Tween 85 micellar system showed antagonistic effect, most probably because the presence of the double bond in its three hydrophobic tails (three C18 tails makes it sterically rigid.

  16. Förster Resonance Energy Transfer (FRET) from Triton X-100 to 4-benzothiazol-2-yl-phenol: Varying FRET efficiency with CMC of the donor (Triton X-100)

    International Nuclear Information System (INIS)

    Paul, Bijan Kumar; Ganguly, Aniruddha; Karmakar, Saswati; Guchhait, Nikhil

    2013-01-01

    A heterocyclic compound viz., 4-benzothiazol-2-yl-phenol (4B2YP) has been synthesized and its photophysics have been examined through steady-state absorption, emission and time resolved emission spectroscopic techniques, in brief. Then 4B2YP has been exploited as an acceptor in the Förster Resonance Energy Transfer (FRET) process from photoexcited benzene aromatic nucleus of Triton X-100 (TX-100) surfactant. Dependence of the energy transfer efficiency on the donor concentration with respect to its critical micelle concentration (CMC) is clearly reflected in the study. High values of Stern–Volmer constant (K SV ) for quenching of the donor fluorescence in the presence of the acceptor suggest the operation of long-range dipole–dipole interaction in the course of energy transfer process, while the inference is aptly supported from time resolved fluorescence decay results. Experimental results show maximum FRET efficiency at the CMC of the donor (TX-100). -- Highlights: • FRET from neutral surfactant Triton X-100 to chromophore 4-benzothiazol-2-yl-phenol. • Steady state and time resolved spectroscopy. • Long-range dipole–dipole interaction responsible for FRET. • FRET efficiency as a measure of CMC of surfactant

  17. Förster Resonance Energy Transfer (FRET) from Triton X-100 to 4-benzothiazol-2-yl-phenol: Varying FRET efficiency with CMC of the donor (Triton X-100)

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Bijan Kumar, E-mail: bijan.paul.chem.cu@gmail.com [Department of Chemistry, University of Calcutta, 92 A.P.C. Road, Calcutta 700009 (India); Ganguly, Aniruddha [Department of Chemistry, University of Calcutta, 92 A.P.C. Road, Calcutta 700009 (India); Karmakar, Saswati [Department of Chemistry, Sree Chaitanya College, Habra, North 24 Parganas (India); Guchhait, Nikhil, E-mail: nguchhait@yahoo.com [Department of Chemistry, University of Calcutta, 92 A.P.C. Road, Calcutta 700009 (India)

    2013-11-15

    A heterocyclic compound viz., 4-benzothiazol-2-yl-phenol (4B2YP) has been synthesized and its photophysics have been examined through steady-state absorption, emission and time resolved emission spectroscopic techniques, in brief. Then 4B2YP has been exploited as an acceptor in the Förster Resonance Energy Transfer (FRET) process from photoexcited benzene aromatic nucleus of Triton X-100 (TX-100) surfactant. Dependence of the energy transfer efficiency on the donor concentration with respect to its critical micelle concentration (CMC) is clearly reflected in the study. High values of Stern–Volmer constant (K{sub SV}) for quenching of the donor fluorescence in the presence of the acceptor suggest the operation of long-range dipole–dipole interaction in the course of energy transfer process, while the inference is aptly supported from time resolved fluorescence decay results. Experimental results show maximum FRET efficiency at the CMC of the donor (TX-100). -- Highlights: • FRET from neutral surfactant Triton X-100 to chromophore 4-benzothiazol-2-yl-phenol. • Steady state and time resolved spectroscopy. • Long-range dipole–dipole interaction responsible for FRET. • FRET efficiency as a measure of CMC of surfactant.

  18. Casein Micelle Dispersions under Osmotic Stress

    Science.gov (United States)

    Bouchoux, Antoine; Cayemitte, Pierre-Emerson; Jardin, Julien; Gésan-Guiziou, Geneviève; Cabane, Bernard

    2009-01-01

    Abstract Casein micelles dispersions have been concentrated and equilibrated at different osmotic pressures using equilibrium dialysis. This technique measured an equation of state of the dispersions over a wide range of pressures and concentrations and at different ionic strengths. Three regimes were found. i), A dilute regime in which the osmotic pressure is proportional to the casein concentration. In this regime, the casein micelles are well separated and rarely interact, whereas the osmotic pressure is dominated by the contribution from small residual peptides that are dissolved in the aqueous phase. ii), A transition range that starts when the casein micelles begin to interact through their κ-casein brushes and ends when the micelles are forced to get into contact with each other. At the end of this regime, the dispersions behave as coherent solids that do not fully redisperse when osmotic stress is released. iii), A concentrated regime in which compression removes water from within the micelles, and increases the fraction of micelles that are irreversibly linked to each other. In this regime the osmotic pressure profile is a power law of the residual free volume. It is well described by a simple model that considers the micelle to be made of dense regions separated by a continuous phase. The amount of water in the dense regions matches the usual hydration of proteins. PMID:19167314

  19. Preparation of crosslinked carboxymethylcellulose (CMC) by 60 Co γ-ray irradiation and its biodegradable properties

    International Nuclear Information System (INIS)

    Lim, Youn Mook; Lee, Joon Ho; Nho, Young Chang; Son, Tae Il

    2007-01-01

    Biodegradable and biocompatible carboxymethylcellulose (CMC) hydrogels for personal care products such as infants diapers and feminine hygiene products were prepared by a γ- irradiation crosslinking technique. Hydrogels were prepared as a function of the CMC concentration, total dose, and degree of substitution (DS), and their physical properties such as the gel fraction, swelling ratio, pH-responsibility and biodegradability were investigated. The irradiation of an aqueous CMC solution led to a gelation in an aqueous solution of more than 10 w%, and the gel percent increased as the CMC concentration, total dose and DS increased. The equilibrium swelling behaviors of the hydrogels prepared in various conditions were examined in an aqueous solution, and the pH-response at a pH of 1.2 and 6.8 was investigated. CMC hydrogels showed a high gelation at a high CMC concentration with DS 1.2. Lastly, the effects of the crosslinking degree of the CMC on the hydrolysis reaction were examined by cellulase from Trichoderma reseei. It was found that the degradable reaction depended on the degree of the crosslinking of the CMC. Intermolecular crosslinking reactions were confirmed by the ESR spectra

  20. Synthesis and immobilization of polystyreneb-polyvinyltriethoxysilane micelles

    KAUST Repository

    Zhu, Saisai

    2018-01-31

    Diblock copolymers polystyrene-block-polyvinyltriethoxysilane (PS-b-PVTES) were synthesized via atom transfer radical polymerization (ATRP), which self-assembled into spherical micelles in solvent of THF-methanol mixtures. The self-assembled micelles were immobilized by cross-linking reaction of VTES in a shell layer of micelles. The chemical structures of block copolymers and morphology of micelles were characterized in detail. It was found that the size of immobilized micelles was strongly affected by the copolymer concentration, composition of mixture solvent, and block ratios.

  1. CMC and Japanese University Students Studying English

    OpenAIRE

    Claro, Jennifer

    2008-01-01

    Computer-mediated communication (CMC) is becoming common in foreign language classes worldwide. In many countries, Japan included, students study English for years, rarely have the chance to use it. CMC has proven to be a viable and possibly even preferable alternative to face-to-face communication, providing an ideal environment in which English can be used in communicative situations. In addition to begin an environment where using learning, and modifying English takes place. CMC offers man...

  2. Study of induced cross-linking by ionizing radiation of polyvinylpyrrolidone (PVP)/carboxymethylcellulose (CMC)

    International Nuclear Information System (INIS)

    Alcantara, Mara T.S.; Chirinos, Hugo; Amaral, Renata H.; Rogero, Sizue O.; Lugao, Ademar B.

    2005-01-01

    The polymeric hydrogels are materials with capacity to absorb great amount of water. They present interesting characteristics for many applications in the industry and as biomaterials. The hydrogel membrane with PVP, poly ethylene glycol and agar, crosslinked and sterilized simultaneously by radiation was introduced in the European market and now it is reaching other regions. In this work the hydrogel studied was synthesized with PVP and CMC and crosslinked by gamma radiation. It was applied factorial planning methodology using the gel fraction as basic parameter. Antagonistic interaction was observed between PVP and CMC. High concentrations of PVP help the crosslinking and the opposite with CMC. On the other hand, for low concentrations of PVP the dose influences considerable the gel fraction what it does not happen for high concentrations. From these results it was made an analysis of response surface allowing the optimization of the concentrations of the variables PVP and CMC. (author)

  3. Control panel for CMC 8080 crate controller

    International Nuclear Information System (INIS)

    Masayuki Inokuchi

    1978-01-01

    The main features of Control Panel for CAMAC Crate Controller CMC 8080 are described. The control panel can be directly connected with CRATE CONTROLLER's front panel connector with a 50 lines cable without any changes in CMC 8080 system circuits. (author)

  4. PENGARUH PENAMBAHAN CMC SEBAGAI SENYAWA PENSTABIL TERHADAP YOGHURT TEPUNG GEMBILI

    Directory of Open Access Journals (Sweden)

    Dewi Cakrawati

    2016-12-01

    Full Text Available The study aims to determine the effect of CMC in preventing yoghurt separation in 7 days with the addition of 2% Dioscorea esculenta flour. Organoleptic test using quality hedonic was conducting to find out yoghurt with addition of CMC that had accepted characteristic by panelists. Research was carried out using regression method to determine the total titrated acid, pH and separation level of yoghurt during storage. The concentrations of CMC were added at 0.2%, 0.4%, 0.6%, 0.8%. The analysis showed the addition of 0.6% CMC showed the lowest separation with high viscosity grades of DPAs 40.25. Yoghurt storage for 7 days shows a graph of the pH value and total titrated acid were parabolic where increasing in total titrated acid value would lower the pH value. Yoghurt was damaged on the 7th day of storage at room temperature characterized by the increasing in the pH value and damage to the organoleptics properties, namely yoghurt flavor and aroma.

  5. The cmc-value of a bolalipid with two phosphocholine headgroups and a C24 alkyl chain: Unusual binding properties of fluorescence probes to bolalipid aggregates.

    Science.gov (United States)

    Kordts, Martin; Kerth, Andreas; Drescher, Simon; Ott, Maria; Blume, Alfred

    2017-09-01

    Bolalipids with a long alkyl chain and two phosphocholine polar groups self-assemble in water into two different types of aggregate structures, namely helical nanofibers at low temperature and two types of micellar aggregates at higher temperature. We tried to determine the critical aggregation concentration (cac) or critical micellar concentration (cmc) of the bolalipid tetracosane-1,24-bis(phosphocholine) (PC-C24-PC) by using different fluorescent probes. The use of pyrene or pyrene derivatives as fluorophores failed, whereas the probes 1,8-ANS and particularly bis-ANS gave consistent results. The structure of the bolalipid aggregates obviously hinders partitioning or binding of pyrene derivatives into the micellar interior, whereas 1,8-ANS and bis-ANS can bind to the surface of the aggregate structures. The observed large increase in fluorescence intensity of bis-ANS indicates that binding to the hydrophobic surface of the aggregates leads to a reduction of the dye mobility. However, binding of bis-ANS is relatively weak, so that the determination of a cac/cmc-value is difficult. Simulations of the intensity curves for PC-C24-PC lead to estimates of the cac/cmc-value of 0.3-1.0×10 -6 M, depending on the structure of the aggregates. Single molecule fluorescence correlation spectroscopy was used to determine the mobility of bis-ANS as a function of concentration of PC-C24-PC. The dye diffusion time and the molecular brightness are lower at low bolalipid concentration, when only free dye is present, and increase at higher concentration when bis-ANS is bound to the aggregates. The experimental cac/cmc-values are higher than those estimated, using an incremental method for the change in Gibbs free energy for micellization with n-alkyl-phosphocholines with only one polar group as a comparison. Apparently, for PC-C24-PC in micellar or fibrous aggregates, more CH 2 groups are exposed to water than in a conventional micelle of an n-alkyl-phosphocholine. Copyright

  6. Effect of hydrostatic pressure on gas solubilization in micelles.

    Science.gov (United States)

    Meng, Bin; Ashbaugh, Henry S

    2015-03-24

    Molecular dynamics simulations of anionic sodium decylsulfate and nonionic pentaethylene glycol monodecyl ether micelles in water have been performed to examine the impact of hydrostatic pressure on argon solubilization as a function of pressure. The potential-of-mean force between the micelles and argon demonstrates that nonpolar gases are attracted to the interiors of both micelles. The affinity of argon for micelle interiors, however, decreases with increasing pressure as a result of the comparatively higher molar volume of argon inside assemblies. We evaluate solubility enhancement coefficients, which describe the drop in the solute chemical potential as a function of the micellized surfactant concentration, to quantify the impact of micellization on gas solubilization. While argon is similarly attracted to the hydrophobic cores of both micelles, the gas is more effectively sequestered within nonionic micelles compared with anionic micelles as a result of salting out by charged head groups and accompanying counterions. The solubility enhancement coefficients of both micelles decrease with increasing pressure, reflecting the changing forces observed in the potentials-of-mean force. An analytical liquid drop model is proposed to describe the pressure dependence of argon solubilization within micelles that captures the simulation solubility enhancement coefficients after fitting an effective micelle radius for each surfactant.

  7. Surface induced ordering of micelles at the solid-liquid interface

    International Nuclear Information System (INIS)

    Gerstenberg, M.C.; Pedersen, J.S.; Smith, G.S.

    1998-01-01

    The surface induced ordering of triblock copolymer micelles in aqueous solution was measured with neutron reflectivity far above the critical micelle concentration. The scattering length density profiles showed a clear indication of ordered layers of micelles perpendicular to a quartz surface. The structure and interactions of the micelles were modeled in detail. The convolution of the center distribution of the micelles, obtained from Monte Carlo simulations of hard spheres at a hard wall, and the projected density of the micelle showed excellent agreement with the experimental profiles. copyright 1998 The American Physical Society

  8. Surface induced ordering of micelles at the solid-liquid interface

    DEFF Research Database (Denmark)

    Gerstenberg, M.C.; Pedersen, J.S.; Smith, G.S.

    1998-01-01

    The surface induced ordering of triblock copolymer micelles in aqueous solution was measured with neutron reflectivity far above the critical micelle concentration. The scattering length density profiles showed a clear indication of ordered layers of micelles perpendicular to a quartz surface....... The structure and interactions of the micelles were modeled in detail. The convolution of the center distribution of the micelles, obtained from Monte Carlo simulations of hard spheres at a hard wall, and the projected density of the micelle showed excellent agreement with the experimental profiles. [S1063-651X...

  9. Pluronic®-bile salt mixed micelles.

    Science.gov (United States)

    Patel, Vijay; Ray, Debes; Bahadur, Anita; Ma, Junhe; Aswal, V K; Bahadur, Pratap

    2018-06-01

    The present study was aimed to examine the interaction of two bile salts viz. sodium cholate (NaC) and sodium deoxycholate (NaDC) with three ethylene polyoxide-polypropylene polyoxide (PEO-PPO-PEO) triblock copolymers with similar PPO but varying PEO micelles with a focus on the effect of pH on mixed micelles. Mixed micelles of moderately hydrophobic Pluronic ® P123 were examined in the presence of two bile salts and compared with those from very hydrophobic L121 and very hydrophilic F127. Both the bile salts increase the cloud point (CP) of copolymer solution and decreased apparent micelle hydrodynamic diameter (D h ). SANS study revealed that P123 forms small spherical micelles showing a decrease in size on progressive addition of bile salts. The negatively charged mixed micelles contained fewer P123 molecules but progressively rich in bile salt. NaDC being more hydrophobic displays more pronounced effect than NaC. Interestingly, NaC shows micellar growth in acidic media which has been attributed to the formation of bile acids by protonation of carboxylate ion and subsequent solubilization. In contrast, NaDC showed phase separation at higher concentration. Nuclear Overhauser effect spectroscopy (NOESY) experiments provided information on interaction and location of bile salts in micelles. Results are discussed in terms of hydrophobicity of bile salts and Pluronics ® and the site of bile salt in polymer micelles. Proposed molecular interactions are useful to understand more about bile salts which play important role in physiological processes. Copyright © 2018 Elsevier B.V. All rights reserved.

  10. Characterization of Phospholipid Mixed Micelles by Translational Diffusion

    International Nuclear Information System (INIS)

    Chou, James J.; Baber, James L.; Bax, Ad

    2004-01-01

    The concentration dependence of the translational self diffusion rate, D s , has been measured for a range of micelle and mixed micelle systems. Use of bipolar gradient pulse pairs in the longitudinal eddy current delay experiment minimizes NOE attenuation and is found critical for optimizing sensitivity of the translational diffusion measurement of macromolecules and aggregates. For low volume fractions Φ (Φ ≤ 15% v/v) of the micelles, experimental measurement of the concentration dependence, combined with use of the D s =D o (1-3.2λΦ) relationship, yields the hydrodynamic volume. For proteins, the hydrodynamic volume, derived from D s at infinitely dilute concentration, is found to be about 2.6 times the unhydrated molecular volume. Using the data collected for hen egg white lysozyme as a reference, diffusion data for dihexanoyl phosphatidylcholine (DHPC) micelles indicate approximately 27 molecules per micelle, and a critical micelle concentration of 14 mM. Differences in translational diffusion rates for detergent and long chain phospholipids in mixed micelles are attributed to rapid exchange between free and micelle-bound detergent. This difference permits determination of the free detergent concentration, which, for a high detergent to long chain phospholipid molar ratio, is found to depend strongly on this ratio. The hydrodynamic volume of DHPC/POPC bicelles, loaded with an M2 channel peptide homolog, derived from translational diffusion, predicts a rotational correlation time that slightly exceeds the value obtained from peptide 15 N relaxation data

  11. Preparation of crosslinked carboxymethylcellulose (CMC) by {sup 60} Co γ-ray irradiation and its biodegradable properties

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Youn Mook; Lee, Joon Ho; Nho, Young Chang [Radiation Research Center for Industry and Environment, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of); Son, Tae Il [Dept. of Biotechnology, College of Industrial Science, Graduate School, Chung Ang University, Seoul (Korea, Republic of)

    2007-05-15

    Biodegradable and biocompatible carboxymethylcellulose (CMC) hydrogels for personal care products such as infants diapers and feminine hygiene products were prepared by a γ- irradiation crosslinking technique. Hydrogels were prepared as a function of the CMC concentration, total dose, and degree of substitution (DS), and their physical properties such as the gel fraction, swelling ratio, pH-responsibility and biodegradability were investigated. The irradiation of an aqueous CMC solution led to a gelation in an aqueous solution of more than 10 w%, and the gel percent increased as the CMC concentration, total dose and DS increased. The equilibrium swelling behaviors of the hydrogels prepared in various conditions were examined in an aqueous solution, and the pH-response at a pH of 1.2 and 6.8 was investigated. CMC hydrogels showed a high gelation at a high CMC concentration with DS 1.2. Lastly, the effects of the crosslinking degree of the CMC on the hydrolysis reaction were examined by cellulase from Trichoderma reseei. It was found that the degradable reaction depended on the degree of the crosslinking of the CMC. Intermolecular crosslinking reactions were confirmed by the ESR spectra.

  12. Milestones Towards Hot CMC Structures for Operational Space Rentry Vehicles

    Science.gov (United States)

    Hald, H.; Weihs, H.; Reimer, T.

    2002-01-01

    Hot structures made of ceramic matrix composites (CMC) for space reentry vehicles play a key role regarding feasibility of advanced and reusable future space transportation systems. Thus realization of applicable flight hardware concerning hot primary structures like a nose cap or body flaps and thermal protection systems (TPS) requires system competence w.r.t. sophisticated know how in material processing, manufacturing and qualification of structural components and in all aspects from process control, use of NDI techniques, arc jet testing, hot structure testing to flight concept validation. This goal has been achieved so far by DLR while following a dedicated development road map since more than a decade culminating at present in the supply of the nose cap system for NASA's X-38; the flight hardware has been installed successfully in October 2001. A number of unique hardware development milestones had to be achieved in the past to finally reach this level of system competence. It is the intention of this paper to highlight the most important technical issues and achievements from the essential projects and developments to finally provide a comprehensive insight into DLR's past and future development road map w.r.t. CMC hot structures for space reentry vehicles. Based on DLR's C/C-SiC material which is produced with the inhouse developed liquid silicon infiltration process (LSI) the development strategy first concentrated on basic material properties evaluation in various arc jet testing facilities. As soon as a basic understanding of oxidation and erosion mechanisms had been achieved further efforts concentrated on inflight verification of both materials and design concepts for hot structures. Consequently coated and uncoated C/C-SiC specimens were integrated into the ablative heat shield of Russian FOTON capsules and they were tested during two missions in 1992 and 1994. Following on, a hot structure experiment called CETEX which principally was a kind of a

  13. Characterization of enzymatically induced aggregation of casein micelles in natural concentration by in situ static light scattering and ultra low shear viscosimetry

    DEFF Research Database (Denmark)

    Lehner, D.; Worning, Peder; G, Fritz

    1999-01-01

    of multiple scattering whenthe transmission is above 0.85. Due to the very complex and porous structure of the casein aggregates theRayleigh-Debye-Gans scattering theory has been used in the data analysis. Measurements with a newinstrument using ultra low shear showed good agreement with theory. Copyright......The aggregation of casein micelles in undiluted skim milk after the addition of chymosin was studied bystatic light scattering and ultra low shear viscometry. The static light scattering measurements were madewith two different sample thicknesses, 72 and 16 mum. The scattering data were analyzed...... by indirect Fouriertransformation and by the polydispersity inversion technique which led to pair distance distributionfunctions and size distribution function, respectively. The minimum scattering angle was 1 degrees, whichallows for the determination of particle sizes up to a maximum diameter of 12 mum...

  14. A novel diblock copolymer of (monomethoxy poly [ethylene glycol]-oleate with a small hydrophobic fraction to make stable micelles/polymersomes for curcumin delivery to cancer cells

    Directory of Open Access Journals (Sweden)

    Erfani-Moghadam V

    2014-11-01

    Full Text Available Vahid Erfani-Moghadam,1,6 Alireza Nomani,2 Mina Zamani,3 Yaghoub Yazdani,4 Farhood Najafi,5 Majid Sadeghizadeh1,3 1Department of Nanobiotechnology, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran; 2Department of Pharmaceutics, Faculty of Pharmacy, Zanjan University of Medical Sciences, Zanjan, Iran; 3Department of Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran; 4Infectious Diseases Research Center and Laboratory Science Research Center, Golestan University of Medical Sciences, Gorgan, Golestan, Iran; 5Department of Resin and Additives, Institute for Color Science and Technology, Tehran, Iran; 6Department of Biotechnology, Faculty of Advanced Medical Technology, Golestan University of Medical Sciences, Gorgan, Iran Abstract: Curcumin is a potent natural anticancer agent, but its effectiveness is limited by properties such as very low solubility, high rate of degradation, and low rate of absorption of its hydrophobic molecules in vivo. To date, various nanocarriers have been used to improve the bioavailability of this hydrophobic biomaterial. This study investigates the encapsulation of curcumin in a novel nanostructure of monomethoxy poly(ethylene glycol-oleate (mPEG-OA and its anticancer effect. Tests were done to determine the critical micelle concentration (CMC, encapsulation efficiency, drug-loading efficiency, and cytotoxicity (against U87MG brain carcinoma cells and HFSF-PI3 cells as normal human fibroblasts of some nanodevice preparations. The results of fluorescence microscopy and cell-cycle analyses indicated that the in vitro bioavailability of the encapsulated curcumin was significantly greater than that of free curcumin. Cytotoxicity evaluations showed that half maximal inhibitory concentrations of free curcumin and curcumin-loaded mPEG-OA for the U87MG cancer cell line were 48 µM and 24 µM, respectively. The Annexin-V-FLUOS assay was used to quantify the apoptotic

  15. Thermodynamics of micelle formation in a water-alcohol solution of sodium tetradecyl sulfate

    Science.gov (United States)

    Shilova, S. V.; Tret'yakova, A. Ya.; Barabanov, V. P.

    2016-01-01

    The effects of addition of ethanol and propan-1-ol on sodium tetradecyl sulfate micelle formation in an aqueous solution are studied via microprobe fluorescence microscopy and conductometry. The critical micelle concentration, quantitative characteristics of micelles, and thermodynamic parameters of micelle formation are determined. Addition of 5-15 vol % of ethanol or 5-10 vol % of propan-1-ol is shown to result in a lower critical micelle concentration than in the aqueous solution, and in the formation of mixed spherical micelles whose sizes and aggregation numbers are less than those for the systems without alcohol. The contribution from the enthalpy factor to the free energy of sodium tetradecyl sulfate micelle formation is found to dominate in mixed solvents, in contrast to aqueous solutions.

  16. Structure formation in binary mixtures of surfactants: vesicle opening-up to bicelles and octopus-like micelles

    Science.gov (United States)

    Noguchi, Hiroshi

    Micelle formation in binary mixtures of surfactants is studied using a coarse-grained molecular simulation. When a vesicle composed of lipid and detergent types of molecules is ruptured, a disk-shaped micelle, the bicelle, is typically formed. It is found that cup-shaped vesicles and bicelles connected with worm-like micelles are also formed depending on the surfactant ratio and critical micelle concentration. The obtained octopus shape of micelles agree with those observed in the cryo-TEM images reported in [S. Jain and F. S. Bates, Macromol. 37, 1511 (2004).]. Two types of connection structures between the worm-like micelles and the bicelles are revealed.

  17. Novel sample preparation method for surfactant containing suppositories: effect of micelle formation on drug recovery.

    Science.gov (United States)

    Kalmár, Éva; Ueno, Konomi; Forgó, Péter; Szakonyi, Gerda; Dombi, György

    2013-09-01

    Rectal drug delivery is currently at the focus of attention. Surfactants promote drug release from the suppository bases and enhance the formulation properties. The aim of our work was to develop a sample preparation method for HPLC analysis for a suppository base containing 95% hard fat, 2.5% Tween 20 and 2.5% Tween 60. A conventional sample preparation method did not provide successful results as the recovery of the drug failed to fulfil the validation criterion 95-105%. This was caused by the non-ionic surfactants in the suppository base incorporating some of the drug, preventing its release. As guidance for the formulation from an analytical aspect, we suggest a well defined surfactant content based on the turbidimetric determination of the CMC (critical micelle formation concentration) in the applied methanol-water solvent. Our CMC data correlate well with the results of previous studies. As regards the sample preparation procedure, a study was performed of the effects of ionic strength and pH on the drug recovery with the avoidance of degradation of the drug during the procedure. Aminophenazone and paracetamol were used as model drugs. The optimum conditions for drug release from the molten suppository base were found to be 100 mM NaCl, 20-40 mM NaOH and a 30 min ultrasonic treatment of the final sample solution. As these conditions could cause the degradation of the drugs in the solution, this was followed by NMR spectroscopy, and the results indicated that degradation did not take place. The determined CMCs were 0.08 mM for Tween 20, 0.06 mM for Tween 60 and 0.04 mM for a combined Tween 20, Tween 60 system. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Synthesis, CMC Determination, Antimicrobial Activity and Nucleic Acid Binding of A Surfactant Copper(II) Complex Containing Phenanthroline and Alanine Schiff-Base.

    Science.gov (United States)

    Nagaraj, Karuppiah; Sakthinathan, Subramanian; Arunachalam, Sankaralingam

    2014-03-01

    A new water-soluble surfactant copper(II) complex [Cu(sal-ala)(phen)(DA)] (sal-ala = salicylalanine, phen = 1,10-phenanthroline, DA = dodecylamine), has been synthesized and characterized by physico-chemical and spectroscopic methods. The critical micelle concentration (CMC) values of this surfactant-copper(II) complex in aqueous solution were obtained from conductance measurements. Specific conductivity data (at 303, 308, 313. 318 and 323 K) served for the evaluation of the temperature-dependent CMC and the thermodynamics of micellization (ΔG(0)m, ΔH(0)m and ΔS(0)m). The interaction of this complex with nucleic acids (DNA and RNA) has been explored by using electronic absorption spectral titration, competitive binding experiment, cyclic voltammetry, circular dichroism (CD) spectra, and viscosity measurements. Electronic absorption studies have revealed that the complex can bind to nucleic acids by the intercalative binding mode which has been verified by viscosity measurements. The DNA binding constants have also been calculated (Kb = 1.2 × 10(5) M(-1) for DNA and Kb = 1.6 × 10(5) M(-1) for RNA). Competitive binding study with ethidium bromide (EB) showed that the complex exhibits the ability to displace the DNA-bound-EB indicating that the complex binds to DNA in strong competition with EB for the intercalative binding site. The presence of hydrophobic ligands, alanine Schiff-base, phenanthroline and long aliphatic chain amine in the complex were responsible for this strong intercalative binding. The surfactant-copper (II) complex was screened for its antibacterial and antifungal activities against various microorganisms. The results were compared with the standard drugs, amikacin(antibacterial) and ketokonazole(antifungal).

  19. Depletion interaction of casein micelles and an exocellular polysaccharide

    Science.gov (United States)

    Tuinier, R.; Ten Grotenhuis, E.; Holt, C.; Timmins, P. A.; de Kruif, C. G.

    1999-07-01

    Casein micelles become mutually attractive when an exocellular polysaccharide produced by Lactococcus lactis subsp. cremoris NIZO B40 (hereafter called EPS) is added to skim milk. The attraction can be explained as a depletion interaction between the casein micelles induced by the nonadsorbing EPS. We used three scattering techniques (small-angle neutron scattering, turbidity measurements, and dynamic light scattering) to measure the attraction. In order to connect the theory of depletion interaction with experiment, we calculated structure factors of hard spheres interacting by a depletion pair potential. Theoretical predictions and all the experiments showed that casein micelles became more attractive upon increasing the EPS concentration.

  20. CMC vane assembly apparatus and method

    Science.gov (United States)

    Schiavo, Anthony L; Gonzalez, Malberto F; Huang, Kuangwei; Radonovich, David C

    2012-10-23

    A metal vane core or strut (64) is formed integrally with an outer backing plate (40). An inner backing plate (38) is formed separately. A spring (74) with holes (75) is installed in a peripheral spring chamber (76) on the strut. Inner and outer CMC shroud covers (46, 48) are formed, cured, then attached to facing surfaces of the inner and outer backing plates (38, 40). A CMC vane airfoil (22) is formed, cured, and slid over the strut (64). The spring (74) urges continuous contact between the strut (64) and airfoil (66), eliminating vibrations while allowing differential expansion. The inner end (88) of the strut is fastened to the inner backing plate (38). A cooling channel (68) in the strut is connected by holes (69) along the leading edge of the strut to peripheral cooling paths (70, 71) around the strut. Coolant flows through and around the strut, including through the spring holes.

  1. Effect of CMC and arabic gum in the manufacture of jackfruit velva (Artocarpus heterophyllus)

    Science.gov (United States)

    Yudhistira, B.; Riyadi, N. H.; Pangestika, A. D.; Pertiwi, S. R.

    2018-03-01

    Velva is one type of frozen dessert which is made from fruit/vegetable with ice cream maker, low fat and high fiber content. Jackfruit is a raw material for the manufacture of velva because of the high fiber content of 2.31 gr. The use of a stabilizers combination of CMC and arabic gum in the manufacture of velva will provide a better gel mix than single use. The purpose of this research is to know the influence of variation of CMC and arabic gum stabilizer on the characteristics (physical, chemical, and sensory) of jackfruit velva (Artocarpus heterophyllus) and determine variations in the most appropriate combinations of stabilizers to produce jackfruit velva with the best quality. This research applied Completely Randomized Design consist of one factor which is the combination of CMC and arabic gum levels in the making of jackfruit velva with two replicates and two replications of the analysis. The data obtained then analyzed statistically using one way analysis of variance (ANOVA), when there is a significant difference, then followed by Duncan’s Multiple Range Test (DMRT) at significance level of 0.05. The results of this study concluded that the jackfruit velva with the addition of various concentrations of CMC and arabic gum is significantly affecting the taste, texture and overall parameters, but no significant difference on the color and flavor parameters of jackfruit velva. Based on the results of physical characteristics, chemical and sensory jackfruit velva with the addition of a stabilizing concentration of CMC and arabic gum 1: 1 result in best jackfruit velva. The best jackfruit velva with stabilizing the concentration of CMC and arabic gum 1: 1 contains a water content of 61.95%, dietary fiber 2.231%, total dissolved solids 20.38 °Brix, overrun 19.709%, meltdown 28.215 minutes. As for the color attribute score 3.72; Taste 4; flavor 3.60; Texture 3.68, and overall 3.88.

  2. Study of wine tartaric acid salt stabilization by addition of carboxymethylcellulose (CMC: comparison with the « protective colloids » effect

    Directory of Open Access Journals (Sweden)

    Vincent Gerbaud

    2010-12-01

    Significance and impact of the study: The OIV-OENO 366-2009 and OIV-OENO 02/2008 resolutions recently authorized the use of CMC to prevent tartaric acid salt precipitation. With no impact on health, and stable under heating and in acid solution, CMC is an efficient candidate for tartaric stabilization. The optimal concentration of 20 mg.L-1 (2 g.hL-1 should however be adapted to local wine storage conditions and KHT crystallization risk.

  3. Radiation crosslinking of CMC-Na at low dose and its application as substitute for hydrogel

    International Nuclear Information System (INIS)

    Liu Pengfei; Peng Jing; Li Jiuqiang; Wu Jilan

    2005-01-01

    The slight radiation-crosslinked CMC-Na as a substitute for hydrogel was prepared by gamma irradiation below gelation dose. The effects of various parameters such as absorbed dose, concentration of inorganic salts, pH, swelling temperature and swelling time on the swelling ratio in water were investigated in detail. This kind of slight crosslinked CMC-Na showed good water absorption below 60 deg. C, whereas, it became solution when heated up to 70 deg. C. Such CMC-Na gel is different from the true gel that is insoluble in boiled water; nevertheless, it can be used as hydrogel at room temperature and produced at low dose. Due to its low cost, it might be useful for its application in agriculture or others

  4. Calorimetric Evidence about the Application of the Concept of CMC to Asphaltene Self-Association

    DEFF Research Database (Denmark)

    Garcia, Daniel Merino; Andersen, Simon Ivar

    2005-01-01

    that asphaltenes may also have a concentration at which self-association occurs (CMC). This article presents evidence found by calorimetry and spectroscopic techniques, that suggest that this concept may not be adequate for asphaltene self-association in toluene solutions. Isothermal titration calorimetry has been...

  5. Reactivity in inverse micelles

    International Nuclear Information System (INIS)

    Brochette, Pascal

    1987-01-01

    This research thesis reports the study of the use of micro-emulsions of water in oil as reaction support. Only the 'inverse micelles' domain of the ternary mixing (water/AOT/isooctane) has been studied. The main addressed issues have been: the micro-emulsion disturbance in presence of reactants, the determination of reactant distribution and the resulting kinetic theory, the effect of the interface on electron transfer reactions, and finally protein solubilization [fr

  6. [Preparation of Coated CMC-Fe0 Using Rheological Phase Reaction Method and Research on Degradation of TCE in Water].

    Science.gov (United States)

    Fan, Wen-jing; Cheng, Yue; Yu, Shu-zhen; Fan, Xiao-feng

    2015-06-01

    The coated nanoscale zero-valent iron (coated CMC-Fe0) was synthesized with cheap and environment friendly CMC as the coating agent using rheological phase reaction. The sample was characterized by means of XRD, SEM, TEM and N2 adsorption-stripping and used to study reductive dechlorination of TCE. The experimental results indicated that the removal rate of TCE was about 100% when the CMC-Fe0 dosage was 6 g x L(-1), the initial TCE concentration was 5 mg x L(-1) and the reaction time was 40 h. The TCE degradation reaction of coated CMC-Fe0 followed a pseudo-first-order kinetic model. Finally, the product could be simply recovered.

  7. Solution structure of detergent micelles at conditions relevant to membrane protein crystallization.

    Energy Technology Data Exchange (ETDEWEB)

    Littrell, K.; Thiyagarajan, P.; Tiede, D.; Urban, V.

    1999-07-02

    In this study small angle neutron scattering was used to characterize the formation of micelles in aqueous solutions of the detergents DMG and SPC as a function of detergent concentration and ionic strength of the solvent. The effects on the micelle structure of the additives glycerol and PEG, alone as well as in combination typical for actual membrane protein crystallization, were also explored. This research suggests that the micelles are cigar-like in form at the concentrations studied. The size of the micelles was observed to increase with increasing ionic strength but decrease with the addition of glycerol or PEG.

  8. Neutral Polymeric Micelles for RNA Delivery

    Science.gov (United States)

    Lundy, Brittany B.; Convertine, Anthony; Miteva, Martina; Stayton, Patrick S.

    2013-01-01

    RNA interference (RNAi) drugs have significant therapeutic potential but delivery systems with appropriate efficacy and toxicity profiles are still needed. Here, we describe a neutral, ampholytic polymeric delivery system based on conjugatable diblock polymer micelles. The diblock copolymer contains a hydrophilic poly[N-(2-hydroxypropyl) methacrylamide-co-N-(2-(pyridin-2- yldisulfanyl)ethyl)methacrylamide) (poly[HPMA-co-PDSMA]) segment to promote aqueous stability and facilitate thiol-disulfide exchange reactions, and a second ampholytic block composed of propyl acrylic acid (PAA), dimethylaminoethyl methacrylate (DMAEMA), and butyl methacrylate (BMA). The poly[(HPMA-co-PDSMA)-b-(PAA-co-DMAEMA-co-BMA)] was synthesized using Reversible Addition-Fragmentation chain Transfer (RAFT) polymerization with an overall molecular weight of 22,000 g/mol and a PDI of 1.88. Dynamic light scattering and fluorescence measurements indicated that the diblock copolymers self-assemble under aqueous conditions to form polymeric micelles with a hydrodynamic radius and critical micelle concentration of 25 nm and 25 μg/mL respectively. Red blood cell hemolysis experiments show that the neutral hydrophilic micelles have potent membrane destabilizing activity at endosomal pH values. Thiolated siRNA targeting glyceraldehyde 3-phosphate dehydrogenase (GAPDH) was directly conjugated to the polymeric micelles via thiol exchange reactions with the pyridal disulfide groups present in the micelle corona. Maximum silencing activity in HeLa cells was observed at a 1:10 molar ratio of siRNA to polymer following a 48 h incubation period. Under these conditions 90 % mRNA knockdown and 65 % and protein knockdown of at 48 h was achieved with negligible toxicity. In contrast the polymeric micelles lacking a pH-responsive endosomalytic segment demonstrated negligible mRNA and protein knockdown under these conditions. The potent mRNA knockdown and excellent biocompatibility of the neutral siRNA conjugates

  9. Interface adsorption and micelle formation of ionic liquid 1-hexyl-3-methylimidazolium chloride in the toluene + water system

    International Nuclear Information System (INIS)

    Asadabadi, Simin; Saien, Javad; Khakizadeh, Vahid

    2013-01-01

    Highlights: • Introducing the used ionic liquid causes a significant reduction in toluene–water interfacial tension. • Temperature has a significant effect on the interfacial tension as well as forming micelle in bulk solution. • The Frumkin model provides a suitable isotherm for the studied system. • Tendency, effectiveness of adsorption and repulsive interaction vary with increasing temperature. • Under saturated interface, entropy and energy changes associated with adsorption show a maximum value at about 303.2 K. -- Abstract: The influence of synthesized ionic liquid 1-hexyl-3-methylimidazolium chloride adsorption on equilibrium interfacial tension of toluene–water was studied within concentration range of (1.00 ⋅ 10 −4 to 6.00 ⋅ 10 −1 ) mol · dm −3 and temperature range of (293.2 to 313.2) K. Very similar to conventional surfactants, the interfacial tension was decreased with both of these parameters. Meanwhile, the CMC values showed a minimum value within the temperature range studied. The Frumkin adsorption isotherm that accounts for the non-ideal adsorption at the interface showed adequately well for modeling the experimental results. Accordingly quantities like interface excess concentration, adsorption tendency and interaction parameter between adsorbed molecules were obtained at different temperatures. Entropy and energy changes associated with adsorption were also obtained from the temperature dependency of interfacial tension. The adsorption tendency and efficiency increased with temperature, and the maximum interface excess concentration and electrostatic repulsion were achieved at about T = 303.2 K

  10. A neutron scattering study of triblock copolymer micelles

    Energy Technology Data Exchange (ETDEWEB)

    Gerstenberg, M.C.

    1997-11-01

    The thesis describes the neutron scattering experiments performed on poly(ethylene oxide)/poly(propylene oxide)/poly(ethylene oxide) triblock copolymer micelles in aqueous solution. The studies concern the non-ionic triblock copolymer P85 which consists of two outer segments of 25 monomers of ethylene oxide attached to a central part of 40 monomers of propylene oxide. The amphiphilic character of P85 leads to formation of various structures in aqueous solution such as spherical micelles, rod-like structures, and a BCC liquid-crystal mesophase of spherical micelles. The present investigations are centered around the micellar structures. In the first part of this thesis a model for the micelle is developed for which an analytical scattering form factor can be calculated. The micelle is modeled as a solid sphere with tethered Gaussian chains. Good agreement was found between small-angle neutron scattering experiments and the form factor of the spherical P85 micelles. Above 60 deg. C some discrepancies were found between the model and the data which is possibly due to an elongation of the micelles. The second part focuses on the surface-induced ordering of the various micellar aggregates in the P85 concentration-temperature phase diagram. In the spherical micellar phase, neutron reflection measurements indicated a micellar ordering at the hydrophilic surface of quartz. Extensive modeling was performed based on a hard sphere description of the micellar interaction. By convolution of the distribution of hard spheres at a hard wall, obtained from Monte Carlo simulations, and the projected scattering length density of the micelle, a numerical expression was obtained which made it possible to fit the data. The hard-sphere-hard-wall model gave an excellent agreement in the bulk micellar phase. However, for higher concentrations (25 wt % P85) close to the transition from the micellar liquid into a micellar cubic phase, a discrepancy was found between the model and the

  11. A neutron scattering study of triblock copolymer micelles

    International Nuclear Information System (INIS)

    Gerstenberg, M.C.

    1997-11-01

    The thesis describes the neutron scattering experiments performed on poly(ethylene oxide)/poly(propylene oxide)/poly(ethylene oxide) triblock copolymer micelles in aqueous solution. The studies concern the non-ionic triblock copolymer P85 which consists of two outer segments of 25 monomers of ethylene oxide attached to a central part of 40 monomers of propylene oxide. The amphiphilic character of P85 leads to formation of various structures in aqueous solution such as spherical micelles, rod-like structures, and a BCC liquid-crystal mesophase of spherical micelles. The present investigations are centered around the micellar structures. In the first part of this thesis a model for the micelle is developed for which an analytical scattering form factor can be calculated. The micelle is modeled as a solid sphere with tethered Gaussian chains. Good agreement was found between small-angle neutron scattering experiments and the form factor of the spherical P85 micelles. Above 60 deg. C some discrepancies were found between the model and the data which is possibly due to an elongation of the micelles. The second part focuses on the surface-induced ordering of the various micellar aggregates in the P85 concentration-temperature phase diagram. In the spherical micellar phase, neutron reflection measurements indicated a micellar ordering at the hydrophilic surface of quartz. Extensive modeling was performed based on a hard sphere description of the micellar interaction. By convolution of the distribution of hard spheres at a hard wall, obtained from Monte Carlo simulations, and the projected scattering length density of the micelle, a numerical expression was obtained which made it possible to fit the data. The hard-sphere-hard-wall model gave an excellent agreement in the bulk micellar phase. However, for higher concentrations (25 wt % P85) close to the transition from the micellar liquid into a micellar cubic phase, a discrepancy was found between the model and the

  12. Lecithin in mixed micelles attenuates the cytotoxicity of bile salts in Caco-2 cells.

    Science.gov (United States)

    Tan, Ya'nan; Qi, Jianping; Lu, Yi; Hu, Fuqiang; Yin, Zongning; Wu, Wei

    2013-03-01

    This study was designed to investigate the cytotoxicity of bile salt-lecithin mixed micelles on the Caco-2 cell model. Cell viability and proliferation after mixed micelles treatments were evaluated with the MTT assay, and the integrity of Caco-2 cell monolayer was determined by quantitating the transepithelial electrical resistance and the flux of tracer, FITC-dextran 4400. The apoptosis induced by mixed micelles treatments was investigated with the annexin V/PI protocol. The particle size of mixed micelles was all smaller than 100 nm. The mixed micelles with lower than 0.2mM sodium deoxycholate (SDC) had no significant effects on cell viability and proliferation. When the level of SDC was higher than 0.4mM and the lecithin/SDC ratio was lower than 2:1, the mixed micelles caused significant changes in cell viability and proliferation. Furthermore, the mixed micelles affected tight junctions in a composition-dependent manner. Specifically, the tight junctions were transiently opened rather than damaged by the mixed micelles with SDC of between 0.2 and 0.6mM. The mixed micelles with more lecithin also induced less apoptosis. These results demonstrate that relatively higher concentrations of mixed micelles are toxic to Caco-2 cells, while phospholipids can attenuate the toxicity of the bile salts. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  13. Enzymatic reactions in reversed micelles

    NARCIS (Netherlands)

    Hilhorst, M.H.

    1984-01-01

    It has been recognised that enzymes in reversed micelles have potential for application in chemical synthesis. Before these expectations will be realised many problems must be overcome. This thesis deals with some of them.
    In Chapter 1 the present knowledge about reversed micelles and

  14. Amphiphilic polymeric micelles originating from 1,4-β-D-glucan-g-polyphenylene oxide as the carriers for delivery of docetaxel and the corresponding release behaviors.

    Science.gov (United States)

    Yang, Fang; Xiao, Dan; Han, Huaxin; Chen, Yuhuan; Li, Gang

    2018-07-15

    A novel amphiphilic polymeric drug carrier was synthesized through grafting polymerization of water-soluble 1,4-β-D-glucan from cotton cellulose tailored and polypropylene oxide (PPO), and then use thereof to synthesize graft copolymer 1,4-β-D-glucan-PPO-docetaxel (DTX). The products were characterized by FTIR, 1 H NMR, and 13 C NMR. The physicochemical characteristics of 1,4-β-D-glucan-PPO and 1,4-β-D-glucan-PPO-DTX such as molecular weight distribution (MWD), micro-morphology, size, critical micelle concentration (CMC), aggregation number of micelle (N), in vitro stability and drug pharmacokinetic study in vivo were investigated. The results reveal that the degree of polymerization (DP) of the water-soluble 1,4-β-D-glucan from cotton cellulose tailored is equal to 7; the 1,4-β-D-glucan-PPO surfactant possesses good surface activity while the adduct number of propylene oxide reaches appropriately to 20; the DTX is completely dispersed in water medium with 1,4-β-D-glucan-PPO-DTX micelle and the drug conjugated percent is up to 40.3%; In vitro study confirms that 1,4-β-D-glucan-PPO-DTX has the capacity for sustained drug release; In plasma, 1,4-β-D-glucan-PPO-DTX exhibits a significantly enhanced C max , AUC (0-t) and T 1/2 compared with DTX. These results demonstrate that 1,4-β-D-glucan-PPO has the potential to be used as a novel biocompatible biomaterial for drug delivery. Copyright © 2018 Elsevier B.V. All rights reserved.

  15. Ethylene glycol modified 2-(2′-aminophenyl)benzothiazoles at the amino site: the excited-state N-H proton transfer reactions in aqueous solution, micelles and potential application in live-cell imaging

    International Nuclear Information System (INIS)

    Liu, Bo-Qing; Tsai, Yi-Hsuan; Li, Yi-Jhen; Chao, Chi-Min; Liu, Kuan-Miao; Chen, Yi-Ting; Chen, Yu-Wei; Chung, Kun-You; Tseng, Huan-Wei; Chou, Pi-Tai

    2016-01-01

    Triethylene glycol monomethyl ether and poly(ethylene glycol) monomethyl ether modified 2-(2′-aminophenyl)benzothiazoles, namely ABT-P3EG, ABT-P7EG and ABT-P12EG varied by different chain length of poly(ethylene glycol) at the amino site, were synthesized to probe their photophysical and bio-imaging properties. In polar, aprotic solvents such as CH 2 Cl 2 ultrafast excited-state intramolecular proton transfer (ESIPT) takes place, resulting in a large Stokes shifted tautomer emission in the green-yellow (550 nm) region. In neutral water, ABT-P12EG forms micelles with diameters of 15  ±  3 nm under a critical micelle concentration (CMC) of ∼80 μM, in which the tautomer emission is greatly enhanced free from water perturbation. Cytotoxicity experiments showed that all ABT-PnEGs have negligible cytotoxicity against HeLa cells even at doses as high as 1 mM. Live-cell imaging experiments were also performed, the results indicate that all ABT-PnEGs are able to enter HeLa cells. While the two-photon excitation emission of ABT-P3EG in cells cytoplasm shows concentration independence and is dominated by the anion blue fluorescence, ABT-P7EG and ABT-P12EG exhibit prominent green tautomer emission at  >  CMC and in part penetrate to the nuclei, adding an additional advantage for the cell imaging. (paper)

  16. Interactions between tea catechins and casein micelles and their impact on renneting functionality.

    Science.gov (United States)

    Haratifar, Sanaz; Corredig, Milena

    2014-01-15

    Many studies have shown that tea catechins bind to milk proteins. This research focused on the association of tea polyphenols with casein micelles, and the consequences of the interactions on the renneting behaviour of skim milk. It was hypothesized that epigallocatechin-gallate (EGCG), the main catechin present in green tea, forms complexes with the casein micelles and that the association modifies the processing functionality of casein micelles. The binding of EGCG to casein micelles was quantified using HPLC. The formation of catechin-casein micelles complexes affected the rennet induced gelation of milk, and the effect was concentration dependent. Both the primary as well as the secondary stage of gelation were affected. These experiments clearly identify the need for a better understanding of the effect of tea polyphenols on the processing functionality of casein micelles, before milk products can be used as an appropriate platform for delivery of bioactive compounds. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Light Scattering Characterization of Elastin-Like Polypeptide Trimer Micelles

    Science.gov (United States)

    Tsuper, Ilona; Terrano, Daniel; Maraschky, Adam; Holland, Nolan; Streletzky, Kiril

    The elastin-like polypeptides (ELP) nanoparticles are composed of three-armed star polypeptides connected by a negatively charged foldon. Each of the three arms extending from the foldon domain includes 20 repeats of the (GVGVP) amino acid sequence. The ELP polymer chains are soluble at room temperature and become insoluble at the transition temperature (close to 50 ° C), forming micelles. The size and shape of the micelle are dependent on the temperature and the pH of the solution, and on the concentration of the phosphate buffered saline (PBS). The depolarized dynamic light scattering (DDLS) was employed to study the structure and dynamics of micelles at 62 ° C. The solution was maintained at an approximate pH level of 7.3 - 7.5, while varying PBS concentration. At low salt concentrations (60 mM) displayed an apparent elongation of the micelles evident by a significant VH signal, along with a surge in the apparent Rh. A model of micelle growth (and potential elongation) with increase in salt concentration is considered.

  18. Determination of Critical Micellar Concentration of Homologous 2-Alkoxyphenylcarbamoyloxyethyl-Morpholinium Chlorides

    Directory of Open Access Journals (Sweden)

    Lenka Stopková

    2018-05-01

    Full Text Available The critical micellar concentrations of selected alkyloxy homologues of local anesthetic 4-(2-{[(2-alkoxyphenylcarbamoyl]oxy}ethylmorpholin-4-ium chloride with nc = 2, 4, 5, 6, 7, 8, and 9 carbons in alkyloxy tail were determined by absorption spectroscopy in the UV–vis spectral region with the use of a pyrene probe. Within the homologous series of the studied amphiphilic compounds, the ln(cmc was observed to be dependent linearly on the number of carbon atoms nc in the hydrophobic tail: ln(cmc = 0.705–0.966 nc. The Gibbs free energy, necessary for the transfer of the methylene group of the alkoxy chain from the water phase into the inner part of the micelle at the temperature of 25 °C and pH ≈ 4.5–5.0, was found to be −2.39 kJ/mol. The experimentally determined cmc values showed good correlations with the predicted values of the bulkiness of the alkoxy tail expressed as the molar volume of substituent R, as well as with the surface tension of the compounds.

  19. Supercritical fluid reverse micelle separation

    Science.gov (United States)

    Fulton, J.L.; Smith, R.D.

    1993-11-30

    A method of separating solute material from a polar fluid in a first polar fluid phase is provided. The method comprises combining a polar fluid, a second fluid that is a gas at standard temperature and pressure and has a critical density, and a surfactant. The solute material is dissolved in the polar fluid to define the first polar fluid phase. The combined polar and second fluids, surfactant, and solute material dissolved in the polar fluid is maintained under near critical or supercritical temperature and pressure conditions such that the density of the second fluid exceeds the critical density thereof. In this way, a reverse micelle system defining a reverse micelle solvent is formed which comprises a continuous phase in the second fluid and a plurality of reverse micelles dispersed in the continuous phase. The solute material is dissolved in the polar fluid and is in chemical equilibrium with the reverse micelles. The first polar fluid phase and the continuous phase are immiscible. The reverse micelles each comprise a dynamic aggregate of surfactant molecules surrounding a core of the polar fluid. The reverse micelle solvent has a polar fluid-to-surfactant molar ratio W, which can vary over a range having a maximum ratio W[sub o] that determines the maximum size of the reverse micelles. The maximum ratio W[sub o] of the reverse micelle solvent is then varied, and the solute material from the first polar fluid phase is transported into the reverse micelles in the continuous phase at an extraction efficiency determined by the critical or supercritical conditions. 27 figures.

  20. The influence of carboxy methyl cellulose (CMC) on shale stability; Influencia do carboximetilcelulose (CMC) na estabilidade de folhelhos

    Energy Technology Data Exchange (ETDEWEB)

    Salles Filho, Antonio Alves de; Quezada, Augusto Eduardo Donoso [Grupo Ultra, XX (Brazil). Setor de Vendas Petroleo; Oliveira, Telma de [Grupo Ultra, XX (Brazil). Centro de Pesquisas e Desenvolvimento

    1988-12-31

    The methodology used in developing high and low viscosity purified CMC`s specific to salty and saturated drilling fluids is discussed. It is shown how CMC carboxy methyl groups, molecular weight, and uniformity of substitution affect the action of these products, decreasing overall drilling costs, substantially increasing penetration rates, and affording greater well wall stability. (author) 5 refs., 19 figs., 3 tabs.

  1. Light and neutron scattering study of strongly interacting ionic micelles

    International Nuclear Information System (INIS)

    Degiorgio, V.; Corti, M.; Piazza, R.

    1989-01-01

    Dilute solutions of ionic micelles formed by biological glycolipids (gangliosides) have been investigated at various ionic strengths by static and dynamic light scaterring and by small-angle neutron scattering. The size and shape of the micelle is not appreciably affected by the added salt concentration in the range 0-100 mM NaCL. From the measured intensity of scattered light we derive the electric charge Z of the micelle by fitting the data to a theoretical calculation which uses a screened Coulomb potential for the intermicellar interaction, and the hypernetted chain approximation for the calculation of the radial distribution function. The correlation function derived from dynamic light scattering shows the long time contribution typical of concentrated polydisperse systems (author). 15 refs.; 6 figs

  2. Glycation Reactions of Casein Micelles.

    Science.gov (United States)

    Moeckel, Ulrike; Duerasch, Anja; Weiz, Alexander; Ruck, Michael; Henle, Thomas

    2016-04-13

    After suspensions of micellar casein or nonmicellar sodium caseinate had been heated, respectively, in the presence and absence of glucose for 0-4 h at 100 °C, glycation compounds were quantitated. The formation of Amadori products as indicators for the "early" Maillard reaction were in the same range for both micellar and nonmicellar caseins, indicating that reactive amino acid side chains within the micelles are accessible for glucose in a comparable way as in nonmicellar casein. Significant differences, however, were observed concerning the formation of the advanced glycation end products (AGEs), namely, N(ε)-carboxymethyllysine (CML), pyrraline, pentosidine, and glyoxal-lysine dimer (GOLD). CML could be observerd in higher amounts in nonmicellar casein, whereas in the micelles the pyrraline formation was increased. Pentosidine and GOLD were formed in comparable amounts. Furthermore, the extent of protein cross-linking was significantly higher in the glycated casein micelles than in the nonmicellar casein samples. Dynamic light scattering and scanning electron microscopy showed that glycation has no influence on the size of the casein micelles, indicating that cross-linking occurs only in the interior of the micelles, but altered the surface morphology. Studies on glycation and nonenzymatic cross-linking can contribute to the understanding of the structure of casein micelles.

  3. Glucose-installed, SPIO-loaded PEG- b-PCL micelles as MR contrast agents to target prostate cancer cells

    Science.gov (United States)

    Theerasilp, Man; Sunintaboon, Panya; Sungkarat, Witaya; Nasongkla, Norased

    2017-11-01

    Polymeric micelles of poly(ethylene glycol)- block-poly(ɛ-caprolactone) bearing glucose analog encapsulated with superparamagnetic iron oxide nanoparticles (Glu-SPIO micelles) were synthesized as an MRI contrast agent to target cancer cells based on high-glucose metabolism. Compared to SPIO micelles (non-targeting SPIO micelles), Glu-SPIO micelles demonstrated higher toxicity to human prostate cancer cell lines (PC-3) at high concentration. Atomic absorption spectroscopy was used to determine the amount of iron in cells. It was found that the iron in cancer cells treated by Glu-SPIO micelles were 27-fold higher than cancer cells treated by SPIO micelles at the iron concentration of 25 ppm and fivefold at the iron concentration of 100 ppm. To implement Glu-SPIO micelles as a MR contrast agent, the 3-T clinical MRI was applied to determine transverse relaxivities ( r 2*) and relaxation rate (1/ T 2*) values. In vitro MRI showed different MRI signal from cancer cells after cellular uptake of SPIO micelles and Glu-SPIO micelles. Glu-SPIO micelles was highly sensitive with the r 2* in agarose gel at 155 mM-1 s-1. Moreover, the higher 1/ T 2* value was found for cancer cells treated with Glu-SPIO micelles. These results supported that glucose ligand increased the cellular uptake of micelles by PC-3 cells with over-expressing glucose transporter on the cell membrane. Thus, glucose can be used as a small molecule ligand for targeting prostate cancer cells overexpressing glucose transporter.

  4. Effect of surfactant concentration on the evaporation of droplets on cotton (Gossypium hirsutum L.) leaves.

    Science.gov (United States)

    Zhou, Zhaolu; Cao, Chong; Cao, Lidong; Zheng, Li; Xu, Jun; Li, Fengmin; Huang, Qiliang

    2018-04-05

    The evaporation kinetics of pesticide droplets deposited on a leaf surface can affect their application efficiency. Evaporation of droplets on the hydrophobic leaves has received considerable attention, but little is known about hydrophilic leaf surfaces. In this study, the effect of surfactant concentration on the evaporation of droplets deposited on cotton leaves was investigated. The evaporation time is roughly decreased for concentrations ranging from 0% to 0.01% and increased from 0.01% to 0.10%. Contrary to the widely held belief that pesticide retention on target crops can rapidly be formed only with surfactant concentrations exceeding the CMC (critical micelle concentration), this study demonstrates that, on hydrophilic cotton leaves, fast evaporation of the droplet at surfactant concentrations of 0.01% (CMC) can reduce the volume quickly, lower the loss point and enhance pesticide retention. In addition, the evolution of droplet volume, height and contact angle on the cotton leaf surface were measured to confirm this conclusion. The result presented herein can be used to guide the use of surfactants and pesticides in agriculture. Copyright © 2018 Elsevier B.V. All rights reserved.

  5. Molecular Insight into Human Lysozyme and Its Ability to Form Amyloid Fibrils in High Concentrations of Sodium Dodecyl Sulfate: A View from Molecular Dynamics Simulations.

    Directory of Open Access Journals (Sweden)

    Majid Jafari

    Full Text Available Changes in the tertiary structure of proteins and the resultant fibrillary aggregation could result in fatal heredity diseases, such as lysozyme systemic amyloidosis. Human lysozyme is a globular protein with antimicrobial properties with tendencies to fibrillate and hence is known as a fibril-forming protein. Therefore, its behavior under different ambient conditions is of great importance. In this study, we conducted two 500000 ps molecular dynamics (MD simulations of human lysozyme in sodium dodecyl sulfate (SDS at two ambient temperatures. To achieve comparative results, we also performed two 500000 ps human lysozyme MD simulations in pure water as controls. The aim of this study was to provide further molecular insight into all interactions in the lysozyme-SDS complexes and to provide a perspective on the ability of human lysozyme to form amyloid fibrils in the presence of SDS surfactant molecules. SDS, which is an anionic detergent, contains a hydrophobic tail with 12 carbon atoms and a negatively charged head group. The SDS surfactant is known to be a stabilizer for helical structures above the critical micelle concentration (CMC [1]. During the 500000 ps MD simulations, the helical structures were maintained by the SDS surfactant above its CMC at 300 K, while at 370 K, human lysozyme lost most of its helices and gained β-sheets. Therefore, we suggest that future studies investigate the β-amyloid formation of human lysozyme at SDS concentrations above the CMC and at high temperatures.

  6. Gradient Interphase, 3-D Fiber Architecture CMC's, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — A clear need exists for the next generation of Ceramic Matrix Composites (CMC) for Thermal Protection Systems (TPS), propulsion hardware, and other high temperature...

  7. Thin-walled reinforcement lattice structure for hollow CMC buckets

    Science.gov (United States)

    de Diego, Peter

    2017-06-27

    A hollow ceramic matrix composite (CMC) turbine bucket with an internal reinforcement lattice structure has improved vibration properties and stiffness. The lattice structure is formed of thin-walled plies made of CMC. The wall structures are arranged and located according to high stress areas within the hollow bucket. After the melt infiltration process, the mandrels melt away, leaving the wall structure to become the internal lattice reinforcement structure of the bucket.

  8. Attachment of Free Filament Thermocouples for Temperature Measurements on CMC

    Science.gov (United States)

    Lei, Jih-Fen; Cuy, Michael D.; Wnuk, Stephen P.

    1997-01-01

    Ceramic Matrix Composites (CMC) are being developed for use as enabling materials for advanced aeropropulsion engine and high speed civil transport applications. The characterization and testing of these advanced materials in hostile, high-temperature environments require accurate measurement of the material temperatures. Commonly used wire Thermo-Couples (TC) can not be attached to this ceramic based material via conventional spot-welding techniques. Attachment of wire TC's with commercially available ceramic cements fail to provide sufficient adhesion at high temperatures. While advanced thin film TC technology provides minimally intrusive surface temperature measurement and has good adhesion on the CMC, its fabrication requires sophisticated and expensive facilities and is very time consuming. In addition, the durability of lead wire attachments to both thin film TC's and the substrate materials requires further improvement. This paper presents a newly developed attachment technique for installation of free filament wire TC's with a unique convoluted design on ceramic based materials such as CMC's. Three CMC's (SiC/SiC CMC and alumina/alumina CMC) instrumented with type IC, R or S wire TC's were tested in a Mach 0.3 burner rig. The CMC temperatures measured from these wire TC's were compared to that from the facility pyrometer and thin film TC's. There was no sign of TC delamination even after several hours exposure to 1200 C. The test results proved that this new technique can successfully attach wire TC's on CMC's and provide temperature data in hostile environments. The sensor fabrication process is less expensive and requires very little time compared to that of the thin film TC's. The same installation technique/process can also be applied to attach lead wires for thin film sensor systems.

  9. Formation of nanoparticles on reverse micelles: SANS studies

    International Nuclear Information System (INIS)

    Sim, Jae-Hyun; Park, Jaejung; Kim, Myungwoong; Hwan Bang, Jeong; Park, Sangwook; Sohn, Daewon

    2006-01-01

    The structure of polymethyl methacrylate (PMMA) on the surface of reverse micelles was investigated by small-angle neutron scattering (SANS). The water-in-oil microemulsion containing initiators in the inner part of reverse micelle was prepared with surfactant, poly(oxyethylene) nonylphenyl ether (NP5, H(CH 2 ) 9 Ph(OC 2 H 4 ) 5 OH), water, cyclohexane and adequate initiators, sodium metabisulfate (SDS) and potassium persulfate (KPS), for aimed polymerization (PMMA). Various model fittings such as the core-shell sphere model and hard sphere model containing smearing effect reveal that polymer shell thickness changes from 52 to 60 A, respectively, with increase of monomer concentration

  10. Liquid-liquid extraction by reversed micelles in biotechnological processes

    Directory of Open Access Journals (Sweden)

    Kilikian B. V.

    2000-01-01

    Full Text Available In biotechnology there is a need for new purification and concentration processes for biologically active compounds such as proteins, enzymes, nucleic acids, or cells that combine a high selectivity and biocompatibility with an easy scale-up. A liquid-liquid extraction with a reversed micellar phase might serve these purposes owing to its capacity to solubilize specific biomolecules from dilute aqueous solutions such as fermentation and cell culture media. Reversed micelles are aggregates of surfactant molecules containing an inner core of water molecules, dispersed in a continuous organic solvent medium. These reversed micelles are capable of selectively solubilizing polar compounds in an apolar solvent. This review gives an overview of liquid-liquid extraction by reversed micelles for a better understanding of this process.

  11. Effective utilization of agro-waste by application of CMC dry-gel

    International Nuclear Information System (INIS)

    Yoshii, Fumio

    2008-01-01

    Radiation crosslinking, graft polymerization and degradation are useful technologies to improve polymer materials. Processability of radial tires and heat resistance of wire/cable is improved by crosslinking technology. Polysaccharides such as starch/cellulose of natural polymers and their derivatives are typical degradable polymers. Molecular weight of polysaccharides was remarkably reduced at lower dose, 50 kGy. To expand application field of polysaccharides, it is essential to obtain crosslinking structure. It was found that polysaccharide derivatives such as carboxymethyl cellulose (CMC) and carboxymethyl chitosan undergo crosslinking at past-like condition and form hydrogels. Concentration of past-like condition to induce crosslinking should be more than 10%. High molecular weight (Mw) and high degree of substitution (DS) is preferable for crosslinking of polysaccharide derivatives. In this paper, treatment of agro waste and improvement of Japanese traditional paper by addition of CMC dry gel is reported. (author)

  12. The thermal signature of wormlike micelles

    International Nuclear Information System (INIS)

    Ito, Thiago Heiji; Clinckspoor, Karl Jan; Nunes de Souza, Renato; Sabadini, Edvaldo

    2016-01-01

    Highlights: • Giant micelle formation has a characteristic exothermic profile, for these systems. • The enthalpy of formation is dependent on the planarity of the co-solute. • The affinity is dependent on the enthalpy and critical concentration of the species. • The higher the affinity, the higher thermal stability and size of the micelles. - Abstract: The variations in enthalpy (Δ f H WLM ) and critical concentrations associated with the formation of wormlike micelles (WLMs) from combinations of tetradecyltrimethylammonium bromide (C 14 TAB) and various aromatic co-solutes were determined using isothermal titration calorimetry (ITC). Three groups of aromatic molecules were investigated: neutral (phenol), benzoate derivatives and cinnamate derivatives. In addition, the thermal stabilities of the WLMs (of hexadecyltrimethylammonium bromide, C 16 TAB) and the aromatic co-solutes of the three groups were investigated by measuring the temperatures at which the WLMs break and lose their ability to produce hydrodynamic drag reduction. A comparison of the results was used to establish correlations between the spontaneity of WLMs formation, their thermal stability and the molecular structure of the aromatic co-solutes. A characteristic thermal pattern with four steps was observed when WLMs are formed, that depended on the co-solute structure. Micellar growth was found to be an exothermic process, related to the fusion of the end caps allied with the incorporation of more co-solutes. The co-solutes that had negative charge and were able to maintain planar configuration demonstrated stronger interactions and also showed higher thermal stability through drag reduction.

  13. Factors affecting the stability of drug-loaded polymeric micelles and strategies for improvement

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Weisai; Li, Caibin; Wang, Zhiyu; Zhang, Wenli, E-mail: zwllz@163.com; Liu, Jianping, E-mail: liujianpingljp@hotmail.com [China Pharmaceutical University, Department of Pharmaceutics (China)

    2016-09-15

    Polymeric micelles (PMs) self-assembled by amphiphilic block copolymers have been used as promising nanocarriers for tumor-targeted delivery due to their favorable properties, such as excellent biocompatibility, prolonged circulation time, favorable particle sizes (10–100 nm) to utilize enhanced permeability and retention effect and the possibility for functionalization. However, PMs can be easily destroyed due to dilution of body fluid and the absorption of proteins in system circulation, which may induce drug leakage from these micelles before reaching the target sites and compromise the therapeutic effect. This paper reviewed the factors that influence stability of micelles in terms of thermodynamics and kinetics consist of the critical micelle concentration of block copolymers, glass transition temperature of hydrophobic segments and polymer–polymer and polymer–cargo interaction. In addition, some effective strategies to improve the stability of micelles were also summarized.Graphical Abstract.

  14. Drainage Behavior in Soap Films Above and Below the CMC

    Science.gov (United States)

    Berg, S.; Adelizzi, E. A.; Troian, S. M.

    2003-11-01

    We investigate through laser interferometry the drainage behavior of Newtonian soap films initially entrained on a fiber frame at small and constant capillary number. The initial film thickness is sufficiently small that gravitational drainage is presumed minimal. The drainage of rigid soap films by capillary forces alone should proceed according to h(t) ˜ t^- 1/2. Our experimental results show much more rapid drainage with exponents as large as -2, especially for those solutions whose surfactant concentrations are below the CMC. Video recordings of the entire film surface reveal a variety of structures during the drainage process, some attributable to marginal regeneration. Though still a controversial issue, this regeneration process is believed to be caused by surfactant accumulation in the meniscus region (1). We show that modification of the relevant capillary drainage equation to account for Marangoni effects through a course-grained slip condition at the air-liquid interface produces exponents in better agreement with experimental findings. (1) V. A. Nierstrasz and G. Frens, JCIS 215, 28 (1999).

  15. Studies of bio-mimetic medium of ionic and non-ionic micelles by a simple charge transfer fluorescence probe N,N-dimethylaminonapthyl-(acrylo)-nitrile

    Science.gov (United States)

    Samanta, Anuva; Paul, Bijan Kumar; Guchhait, N.

    2011-05-01

    In this report we have studied micellization process of anionic, cationic and non-ionic surfactants using N,N-dimethylaminonapthyl-(acrylo)-nitrile (DMANAN) as an external fluorescence probe. Micropolarity, microviscosity, critical micellar concentration of these micelles based on steady state absorption and fluorescence and time resolved emission spectroscopy of the probe DMANAN show that the molecule resides in the micelle-water interface for ionic micelles and in the core for the non-ionic micelle. The effect of variation of pH of the micellar solution as well as fluorescence quenching measurements of DMANAN provide further support for the location of the probe in the micelles.

  16. Soluplus/TPGS mixed micelles for dioscin delivery in cancer therapy.

    Science.gov (United States)

    Zhao, Jing; Xu, Youwei; Wang, Changyuan; Ding, Yanfang; Chen, Manyu; Wang, Yifei; Peng, Jinyong; Li, Lei; Lv, Li

    2017-07-01

    Dioscin has shown cytotoxicity against cancer cells, but its poor solubility and stability have limited its clinical application. In this study, we designed mixed micelles composed of TPGS and Soluplus ® copolymers entrapping the poorly soluble anticancer drug dioscin. In order to improve the aqueous solubility and bioactivity of dioscin, TPGS/Soluplus ® mixed micelles with an optimal ratio were prepared using a thin-film hydration method, and their physicochemical properties were characterized. Cellular cytotoxicity and uptake of the dioscin-loaded TPGS/Soluplus ® mixed micelles were studied in MCF-7 breast cancer cells and A2780s ovarian cancer cells. The pharmacokinetics of free dioscin and dioscin-loaded TPGS/Soluplus ® mixed micelles was studied in vivo in male Sprague-Dawley rats via a single intravenous injection in the tail vein. The average size of the optimized mixed micelle was 67.15 nm, with 92.59% drug encapsulation efficiency and 4.63% drug loading efficiency. The in vitro release profile showed that the mixed micelles presented sustained release behavior compared to the anhydrous ethanol solution of dioscin. In vitro cytotoxicity assays were conducted on human cancer cell lines including A2780s ovarian cancer cells and MCF-7 breast cancer cells. The mixed micelles exhibited better antitumor activity compared to free dioscin against all cell lines, which may benefit from the significant increase in the cellular uptake of dioscin from mixed micelles compared to free dioscin. The pharmacokinetic study showed that the mixed micelle formulation achieved a 1.3 times longer mean residual time (MRT) in circulation and a 2.16 times larger area under the plasma concentration-time curve (AUC) than the free dioscin solution. Our results suggest that the dioscin-loaded mixed micelles developed in this study might be a potential nano drug-delivery system for cancer chemotherapy.

  17. Polymeric micelles for drug targeting.

    Science.gov (United States)

    Mahmud, Abdullah; Xiong, Xiao-Bing; Aliabadi, Hamidreza Montazeri; Lavasanifar, Afsaneh

    2007-11-01

    Polymeric micelles are nano-delivery systems formed through self-assembly of amphiphilic block copolymers in an aqueous environment. The nanoscopic dimension, stealth properties induced by the hydrophilic polymeric brush on the micellar surface, capacity for stabilized encapsulation of hydrophobic drugs offered by the hydrophobic and rigid micellar core, and finally a possibility for the chemical manipulation of the core/shell structure have made polymeric micelles one of the most promising carriers for drug targeting. To date, three generations of polymeric micellar delivery systems, i.e. polymeric micelles for passive, active and multifunctional drug targeting, have arisen from research efforts, with each subsequent generation displaying greater specificity for the diseased tissue and/or targeting efficiency. The present manuscript aims to review the research efforts made for the development of each generation and provide an assessment on the overall success of polymeric micellar delivery system in drug targeting. The emphasis is placed on the design and development of ligand modified, stimuli responsive and multifunctional polymeric micelles for drug targeting.

  18. Effects of surfactant micelles on viscosity and conductivity of poly(ethylene glycol) solutions

    Science.gov (United States)

    Wang, Shun-Cheng; Wei, Tzu-Chien; Chen, Wun-Bin; Tsao, Heng-Kwong

    2004-03-01

    The neutral polymer-micelle interaction is investigated for various surfactants by viscometry and electrical conductometry. In order to exclude the well-known necklace scenario, we consider aqueous solutions of low molecular weight poly(ethylene glycol) (2-20)×103, whose radial size is comparable to or smaller than micelles. The single-tail surfactants consist of anionic, cationic, and nonionic head groups. It is found that the viscosity of the polymer solution may be increased several times by micelles if weak attraction between a polymer segment and a surfactant exists, ɛmicelles. Even though ɛ is small, the interaction energy between a macromolecule and a micelle can be a few kBT due to many contacts, and thus leads to polymer adsorption on micelles' surfaces. The rapid growth of the viscosity with surfactant concentration is therefore attributed to the considerable cross links among micelles and polymers (transient network). In addition to substantial alteration of the transport properties, this weak interaction also influences the onset point of thermodynamic instability associated with polymer-surfactant solutions. The examples include the decrease of critical aggregation concentration for ionic surfactant and clouding point for nonionic surfactant due to PEG addition.

  19. Glyco-Nanoparticles Made from Self-Assembly of Maltoheptaose-block-Poly(methyl methacrylate): Micelle, Reverse Micelle, and Encapsulation.

    Science.gov (United States)

    Zepon, Karine M; Otsuka, Issei; Bouilhac, Cécile; Muniz, Edvani C; Soldi, Valdir; Borsali, Redouane

    2015-07-13

    The synthesis and the solution-state self-assembly of the "hybrid" diblock copolymers, maltoheptaose-block-poly(methyl methacrylate) (MH-b-PMMA), into large compound micelles (LCMs) and reverve micelle-type nanoparticles, are reported in this paper. The copolymers were self-assembled in water and acetone by direct dissolution method, and the morphologies of the nanoparticles were investigated by dynamic light scattering (DLS), nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), atomic force microscopy (AFM), proton nuclear magnetic resonance ((1)H NMR), and fluorescence spectroscopy as a function of the volume fraction of the copolymer hydrophobic block, copolymer concentration, stirring speed, and solvent polarity. The DLS measurements and TEM images showed that the hydrodynamic radius (Rh) of the LCMs obtained in water increases with the copolymer concentration. Apart from that, increasing the stirring speed leads to polydispersed aggregations of the LCMs. On the other hand, in acetone, the copolymers self-assembled into reverse micelle-type nanoparticles having Rh values of about 6 nm and micellar aggregates, as revealed the results obtained from DLS, AFM, and (1)H NMR analyses. The variation in micellar structure, that is, conformational inversion from LCMs to reverse micelle-type structures in response to polarity of the solvent, was investigated by apparent water contact angle (WCA) and (1)H NMR analyses. This conformational inversion of the nanoparticles was further confirmed by encapsulation and release of hydrophobic guest molecule, Nile red, characterized by fluorescence spectroscopy.

  20. Loading and release mechanisms of a biocide in polystyrene-block-poly(acrylic acid) block copolymer micelles.

    Science.gov (United States)

    Vyhnalkova, Renata; Eisenberg, Adi; van de Ven, Theo G M

    2008-07-24

    The kinetics of loading of polystyrene197-block-poly(acrylic acid)47 (PS197-b-PAA47) micelles, suspended in water, with thiocyanomethylthiobenzothiazole biocide and its subsequent release were investigated. Loading of the micelles was found to be a two-step process. First, the surface of the PS core of the micelles is saturated with biocide, with a rate determined by the transfer of solid biocide to micelles during transient micelle-biocide contacts. Next, the biocide penetrates as a front into the micelles, lowering the Tg in the process (non-Fickian case II diffusion). The slow rate of release is governed by the height of the energy barrier that a biocide molecule must overcome to pass from PS into water, resulting in a uniform biocide concentration within the micelle, until Tg is increased to the point that diffusion inside the micelles becomes very slow. Maximum loading of biocide into micelles is approximately 30% (w/w) and is achieved in 1 h. From partition experiments, it can be concluded that the biocide has a similar preference for polystyrene as for ethylbenzene over water, implying that the maximum loading is governed by thermodynamics.

  1. Responsive micellar films of amphiphilic block copolymer micelles: control on micelle opening and closing.

    Science.gov (United States)

    Chen, Zhiquan; He, Changcheng; Li, Fengbin; Tong, Ling; Liao, Xingzhi; Wang, Yong

    2010-06-01

    We reported the deliberate control on the micelle opening and closing of amphiphilic polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) micellar films by exposing them to selective solvents. We first treated the micellar films with polar solvents including ethanol and water (pH = 4, 8, and 12) that have different affinities to P2VP. We observed opening of the micelles in all the cases. Both the size of opened pores and the opening rate are dependent on the solvency of different solvents for P2VP. We then explored the closing behavior of the opened micelles using solvents having different affinities to PS. We found that the opened micelles were recovered to their initial closed micelle forms. The recovery was accompanied by a slow micelle disassociation process which gradually reduced the micelle size. The rates of the micelle closing and disassociation are also dependent on the solvency of different solvents for PS.

  2. Practical use of CMC-amended rhizobial inoculant for Mucuna pruriens cultivation to enhance the growth and protection against Macrophomina phaseolina.

    Science.gov (United States)

    Aeron, Abhinav; Khare, Ekta; Kumar Arora, Naveen; Kumar Maheshwari, Dinesh

    2012-01-01

    In many parts of the world Mucuna pruriens is used as an important medicinal, forage and green manure crop. In the present investigation the effect of the addition of CMC in carrier during development of bioformulation on shelflife, plant growth promotive and biocontrol activity against Macrophomina phaseolina was screened taking M. pruriens as a test crop. Ensifer meliloti RMP6(Ery+Kan+) and Bradyrhizobium sp. BMP7(Tet+Kan+) (kanamycin resistance engineered by Tn5 transposon mutagenesis) used in the study showed production of siderophore, IAA, solubilizing phosphate and biocontrol of M. phaseolina. RMP6(Ery+Kan+) also showed ACC deaminase activity. The survival of both the strains in sawdust-based bioformulation was enhanced with an increase in the concentration of CMC from 0 to 1%. At 0% CMC Bradyrhizobium sp. BMP7(Tet+Kan+) showed more increase in nodule number/plant (500.00%) than E. meliloti RMP6(Ery+Kan+) (52.38%), over the control in M. phaseolina-infested soil. There was 185.94% and 59.52% enhancement in nodule number/plant by RMP6(Ery+Kan+) and BMP7(Tet+Kan+) with an increase in the concentration of CMC from 0% to 1% in the bioformulations. However further increase in concentration of CMC did not result in enhancement in survival of either the strains or nodule number/plant.

  3. Radiation synthesis of superabsorbent CMC based hydrogels for agriculture applications

    International Nuclear Information System (INIS)

    Raafat, Amany I.; Eid, Mona; El-Arnaouty, Magda B.

    2012-01-01

    A series of superabsorbent hydrogel based on carboxymethylcellulose (CMC) and polyvinylpyrrolidone (PVP) crosslinked with gamma irradiation have been proposed for agriculture application. The effect of preparation conditions such as feed solution composition and absorbed irradiation dose on the gelation and swelling degree was evaluated. The structure and the morphology of the superabsorbent CMC/PVP hydrogel were characterized using Fourier transform infrared spectroscopy technique (FTIR), and scanning electron microscope (SEM). Effect of ionic strength and cationic and anionic kinds on the swelling behavior of the obtained hydrogel was investigated. Urea as an agrochemical model was loaded onto the obtained hydrogel to provide nitrogen (N) nutrients. The water retention capability and the urea release behavior of the CMC/PVP hydrogels were investigated. It was found that, the obtained CMC/PVP hydrogels have good swelling degree that greatly affected by its composition and absorbed dose. The swelling was also extremely sensitive to the ionic strength and cationic kind. Owing to its considerable slow urea release, good water retention capacity, being economical, and environment-friendly, it might be useful for its application in agriculture field.

  4. Radiation synthesis of superabsorbent CMC based hydrogels for agriculture applications

    Science.gov (United States)

    Raafat, Amany I.; Eid, Mona; El-Arnaouty, Magda B.

    2012-07-01

    A series of superabsorbent hydrogel based on carboxymethylcellulose (CMC) and polyvinylpyrrolidone (PVP) crosslinked with gamma irradiation have been proposed for agriculture application. The effect of preparation conditions such as feed solution composition and absorbed irradiation dose on the gelation and swelling degree was evaluated. The structure and the morphology of the superabsorbent CMC/PVP hydrogel were characterized using Fourier transform infrared spectroscopy technique (FTIR), and scanning electron microscope (SEM). Effect of ionic strength and cationic and anionic kinds on the swelling behavior of the obtained hydrogel was investigated. Urea as an agrochemical model was loaded onto the obtained hydrogel to provide nitrogen (N) nutrients. The water retention capability and the urea release behavior of the CMC/PVP hydrogels were investigated. It was found that, the obtained CMC/PVP hydrogels have good swelling degree that greatly affected by its composition and absorbed dose. The swelling was also extremely sensitive to the ionic strength and cationic kind. Owing to its considerable slow urea release, good water retention capacity, being economical, and environment-friendly, it might be useful for its application in agriculture field.

  5. Radiation synthesis of superabsorbent CMC based hydrogels for agriculture applications

    Energy Technology Data Exchange (ETDEWEB)

    Raafat, Amany I., E-mail: ismaelraafat_a@hotmail.com [Polymer Chemistry Department, National Center for Radiation Research and Technology, P.O. Box 29, Nasr City, Cairo (Egypt); Eid, Mona; El-Arnaouty, Magda B. [Polymer Chemistry Department, National Center for Radiation Research and Technology, P.O. Box 29, Nasr City, Cairo (Egypt)

    2012-07-15

    A series of superabsorbent hydrogel based on carboxymethylcellulose (CMC) and polyvinylpyrrolidone (PVP) crosslinked with gamma irradiation have been proposed for agriculture application. The effect of preparation conditions such as feed solution composition and absorbed irradiation dose on the gelation and swelling degree was evaluated. The structure and the morphology of the superabsorbent CMC/PVP hydrogel were characterized using Fourier transform infrared spectroscopy technique (FTIR), and scanning electron microscope (SEM). Effect of ionic strength and cationic and anionic kinds on the swelling behavior of the obtained hydrogel was investigated. Urea as an agrochemical model was loaded onto the obtained hydrogel to provide nitrogen (N) nutrients. The water retention capability and the urea release behavior of the CMC/PVP hydrogels were investigated. It was found that, the obtained CMC/PVP hydrogels have good swelling degree that greatly affected by its composition and absorbed dose. The swelling was also extremely sensitive to the ionic strength and cationic kind. Owing to its considerable slow urea release, good water retention capacity, being economical, and environment-friendly, it might be useful for its application in agriculture field.

  6. Does CMC Promote Language Play? Exploring Humor in Two Modalities

    Science.gov (United States)

    Vandergriff, Ilona; Fuchs, Carolin

    2009-01-01

    In view of the growing body of research on humor and language play in computer-mediated communication (CMC) which--more than any other medium--has been associated with goofing off, joking, and other nonserious communication, this paper compares spontaneous foreign language play (L2 play) in text-only synchronous computer-mediated versus…

  7. CMC Hypersurfaces on Riemannian and Semi-Riemannian Manifolds

    International Nuclear Information System (INIS)

    Perdomo, Oscar M.

    2012-01-01

    In this paper we generalize the explicit formulas for constant mean curvature (CMC) immersion of hypersurfaces of Euclidean spaces, spheres and hyperbolic spaces given in Perdomo (Asian J Math 14(1):73–108, 2010; Rev Colomb Mat 45(1):81–96, 2011) to provide explicit examples of several families of immersions with constant mean curvature and non constant principal curvatures, in semi-Riemannian manifolds with constant sectional curvature. In particular, we prove that every h is an element of [-1,-(2√n-1/n can be realized as the constant curvature of a complete immersion of S 1 n-1 x R in the (n + 1)-dimensional de Sitter space S 1 n+1 . We provide 3 types of immersions with CMC in the Minkowski space, 5 types of immersion with CMC in the de Sitter space and 5 types of immersion with CMC in the anti de Sitter space. At the end of the paper we analyze the families of examples that can be extended to closed hypersurfaces.

  8. Recombinant Amphiphilic Protein Micelles for Drug Delivery

    OpenAIRE

    Kim, Wookhyun; Xiao, Jiantao; Chaikof, Elliot L.

    2011-01-01

    Amphiphilic block polypeptides can self-assemble into a range of nanostructures in solution, including micelles and vesicles. Our group has recently described the capacity of recombinant amphiphilic diblock copolypeptides to form highly stable micelles. In this report, we demonstrate the utility of protein nanoparticles to serve as a vehicle for controlled drug delivery. Drug-loaded micelles were produced by encapsulating dipyridamole as a model hydrophobic drug with anti-inflammatory activit...

  9. Controlling the Size and Shape of the Elastin-Like Polypeptide based Micelles

    Science.gov (United States)

    Streletzky, Kiril; Shuman, Hannah; Maraschky, Adam; Holland, Nolan

    Elastin-like polypeptide (ELP) trimer constructs make reliable environmentally responsive micellar systems because they exhibit a controllable transition from being water-soluble at low temperatures to aggregating at high temperatures. It has been shown that depending on the specific details of the ELP design (length of the ELP chain, pH and salt concentration) micelles can vary in size and shape between spherical micelles with diameter 30-100 nm to elongated particles with an aspect ratio of about 10. This makes ELP trimers a convenient platform for developing potential drug delivery and bio-sensing applications as well as for understanding micelle formation in ELP systems. Since at a given salt concentration, the headgroup area for each foldon should be constant, the size of the micelles is expected to be proportional to the volume of the linear ELP available per foldon headgroup. Therefore, adding linear ELPs to a system of ELP-foldon should result in changes of the micelle volume allowing to control micelle size and possibly shape. The effects of addition of linear ELPs on size, shape, and molecular weight of micelles at different salt concentrations were studied by a combination of Dynamic Light Scattering and Static Light Scattering. The initial results on 50 µM ELP-foldon samples (at low salt) show that Rh of mixed micelles increases more than 5-fold as the amount of linear ELP raised from 0 to 50 µM. It was also found that a given mixture of linear and trimer constructs has two temperature-based transitions and therefore displays three predominant size regimes.

  10. Influence of gold nanoparticles of varying size in improving the lipase activity within cationic reverse micelles.

    Science.gov (United States)

    Maiti, Subhabrata; Das, Dibyendu; Shome, Anshupriya; Das, Prasanta Kumar

    2010-02-08

    Herein, we report the effect of gold nanoparticles (GNPs) in enhancing lipase activity in reverse micelles of cetyltrimethylammonium bromide (CTAB)/water/isooctane/n-hexanol. The size and concentration of the nanoparticles were varied and their specific roles were assessed in detail. An overall enhancement of activity was observed in the GNP-doped CTAB reverse micelles. The improvement in activity becomes more prominent with increasing concentration and size of the GNPs (0-52 microM and ca. 3-30 nm, respectively). The observed highest lipase activity (k(2)=1070+/-12 cm(3) g(-1) s(-1)) in GNP-doped CTAB reverse micelles ([GNP]: 52 microm, ca. 20 nm) is 2.5-fold higher than in CTAB reverse micelles without GNPs. Improvement in the lipase activity is only specific to the GNP-doped reverse micellar media, whereas GNP deactivates and structurally deforms the enzyme in aqueous media. The reason for this activation is probably due to the formation of larger-sized reverse micelles in which the GNP acts as a polar core and the surfactants aggregate around the nanoparticle ('GNP pool') instead of only water. Lipase at the augmented interface of the GNP-doped reverse micelle showed improved activity because of enhancement in both the substrate and enzyme concentrations and increased flexibility in the lipase conformation. The extent of the activation is greater in the case of the larger-sized GNPs. A correlation has been established between the activity of lipase and its secondary structure by using circular dichroism and FTIR spectroscopic analysis. The generalized influence of GNP is verified in the reverse micelles of another surfactant, namely, cetyltripropylammonium bromide (CTPAB). TEM, dynamic light scattering (DLS), and UV/Vis spectroscopic analysis were utilized to characterize the GNPs and the organized aggregates. For the first time, CTAB-based reverse micelles have been found to be an excellent host for lipase simply by doping with appropriately sized GNPs.

  11. Kappa-casein micelles: structure, interaction and gelling studied by small-angle neutron scattering.

    Science.gov (United States)

    de Kruif, C G; May, R P

    1991-09-01

    Small-angle neutron scattering (SANS) measurements on dilute and concentrated dispersions of kappa-casein micelles in a buffer at pH = 6.7 were made using the D11 diffractometer in Grenoble. Results indicate that the micelles have a dense core with a fluffy outer layer. This outer layer appears to give rise to a steeply repulsive interaction on contact. In fact, the hard-sphere model best fits the measured scattering intensities. Adding chymosin to the dispersion initiated a fractal flocculation of the micelles and consecutively a coalescence of the micelles. This unexpected second process resembled that of spinodal demixing. The dispersion phase thus separates into a water and a protein phase on a time scale of hours. The observed phenomona contribute to the understanding of the cheese-making process.

  12. Removal of Cr(VI) from Aqueous Environments Using Micelle-Clay Adsorption

    Science.gov (United States)

    Qurie, Mohannad; Khamis, Mustafa; Manassra, Adnan; Ayyad, Ibrahim; Nir, Shlomo; Scrano, Laura; Bufo, Sabino A.; Karaman, Rafik

    2013-01-01

    Removal of Cr(VI) from aqueous solutions under different conditions was investigated using either clay (montmorillonite) or micelle-clay complex, the last obtained by adsorbing critical micelle concentration of octadecyltrimethylammonium ions onto montmorillonite. Batch experiments showed the effects of contact time, adsorbent dosage, and pH on the removal efficiency of Cr(VI) from aqueous solutions. Langmuir adsorption isotherm fitted the experimental data giving significant results. Filtration experiments using columns filled with micelle-clay complex mixed with sand were performed to assess Cr(VI) removal efficiency under continuous flow at different pH values. The micelle-clay complex used in this study was capable of removing Cr(VI) from aqueous solutions without any prior acidification of the sample. Results demonstrated that the removal effectiveness reached nearly 100% when using optimal conditions for both batch and continuous flow techniques. PMID:24222757

  13. Effect of substitution on aniline in inducing growth of anionic micelles

    International Nuclear Information System (INIS)

    Garg, Gunjan; Kulshreshtha, S.K.; Hassan, P.A.; Aswal, V.K.

    2004-01-01

    Small-angle neutron scattering (SANS) measurements were carried out on sodium dodecyl sulfate (SDS) micelles in the presence of three different hydrophobic salts, i.e. aniline hydrochloride, o-toluidine hydrochloride and m-toluidine hydrochloride. All these salts induce a uniaxial growth of micelles to form prolate ellipsoidal structures. A progressive decrease in the surface charge of the micelles was observed with the addition of salts followed by a rapid growth of the micelles. The presence of a methyl substitution at the ortho position of aniline does not alter the growth behavior significantly. However, when the substitution is at meta position micellar growth is favored at lower salt concentration than that is observed for aniline. This can be explained in terms of the difference in the chemical environments of the substituents at the ortho and meta positions. (author)

  14. Steady state and time-resolved fluorescence spectroscopy of quinine sulfate dication bound to sodium dodecylsulfate micelles: Fluorescent complex formation

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Sunita; Pant, Debi D., E-mail: ddpant@pilani.bits-pilani.ac.in

    2014-01-15

    Interaction of quinine sulfate dication (QSD) with anionic, sodium dodecylsulphate (SDS) surfactant has been studied at different premicellar, micellar and postmicellar concentrations in aqueous phase using steady state, time-resolved fluorescence and fluorescence anisotropy techniques. At premicellar concentrations of SDS, the decrease in absorbance, appearance of an extra fluorescence band at lower wavelengths and tri-exponential decay behavior of fluorescence, are attributed to complex formation between QSD molecules and surfactant monomers. At postmicellar concentrations the red shift in fluorescence spectrum, increase in quantum yield and increase in fluorescence lifetimes are attributed to incorporation of solute molecules to micelles. At lower concentrations of SDS, a large shift in fluorescence is observed on excitation at the red edge of absorption spectrum and this is explained in terms of distribution of ion pairs of different energies in the ground state and the observed fluorescence lifetime behavior corroborates with this model. The temporal fluorescence anisotropy decay of QSD in SDS micelles allowed determination of restriction on the motion of the fluorophore. All the different techniques used in this study reveal that the photophysics of QSD is very sensitive to the microenvironments of SDS micelles and QSD molecules reside at the water-micelle interface. -- Highlights: • Probe molecule is very sensitive to microenvironment of micelles. • Highly fluorescent ion-pair formation has been observed. • Modulated photophysics of probe molecule in micellar solutions has been observed. • Probe molecules strongly bind with micelles and reside at probe–micelle interface.

  15. Improvement of in vivo efficacy of recombinant human erythropoietin by encapsulation in PEG–PLA micelle

    Directory of Open Access Journals (Sweden)

    Shi YN

    2012-12-01

    Full Text Available Yanan Shi,1,2,* Wan Huang,1,* Rongcai Liang,1–3 Kaoxiang Sun,2,3 Fangxi Zhang,2,3 Wanhui Liu,2,3 Youxin Li1–31College of Life Science, Jilin University, Changchun, China; 2State Key Laboratory of Long-acting and Targeting Drug Delivery System, Luye Pharmaceutical Co, Ltd, Yantai, China; 3School of Pharmacy, Yantai University, Yantai, China*These authors contributed equally to this workAbstract: To improve the pharmacokinetics and stability of recombinant human erythropoietin (rhEPO, rhEPO was successfully formulated into poly(ethylene glycol–poly(d,l-lactide (PEG–PLA di-block copolymeric micelles at diameters ranging from 60 to 200 nm with narrow polydispersity indices (PDIs; PDI < 0.3 and trace amount of protein aggregation. The zeta potential of the spherical micelles was in the range of −3.78 to 4.65 mV and the highest encapsulation efficiency of rhEPO in the PEG–PLA micelles was about 80%. In vitro release profiles indicated that the stability of rhEPO in the micelles was improved significantly and only a trace amount of aggregate was found. Pharmacokinetic studies in rats showed highly enhanced plasma retention time of the rhEPO-loaded PEG-PLA micelles in comparison with the native rhEPO group. Increased hemoglobin concentrations were also found in the rat study. Native polyacrylamide gel electrophoresis results demonstrated that rhEPO was successfully encapsulated into the micelles, which was stable in phosphate buffered saline with different pHs and concentrations of NaCl. Therefore, PEG–PLA micelles can be a potential protein drug delivery system.Keywords: rhEPO, PEG–PLA micelle, in vitro, pharmacokinetics, pharmacodynamics

  16. Nanoparticle packing within block copolymer micelles prepared by the interfacial instability method.

    Science.gov (United States)

    Nabar, Gauri M; Winter, Jessica O; Wyslouzil, Barbara E

    2018-05-02

    The interfacial instability method has emerged as a viable approach for encapsulating high concentrations of nanoparticles (NPs) within morphologically diverse micelles. In this method, transient interfacial instabilities at the surface of an emulsion droplet guide self-assembly of block co-polymers and NP encapsulants. Although used by many groups, there are no systematic investigations exploring the relationship between NP properties and micelle morphology. Here, the effect of quantum dot (QD) and superparamagnetic iron oxide NP (SPION) concentration on the shape, size, and surface deformation of initially spherical poly(styrene-b-ethylene oxide) (PS-b-PEO) micelles was examined. Multi-NP encapsulation and uniform dispersion within micelles was obtained even at low NP concentrations. Increasing NP concentration initially resulted in larger numbers of elongated micelles and cylinders with tightly-controlled diameters smaller than those of spherical micelles. Beyond a critical NP concentration, micelle formation was suppressed; the dominant morphology became densely-loaded NP structures that were coated with polymer and exhibited increased polydispersity. Transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS) revealed that NPs in densely-loaded structures can be well-ordered, with packing volume fractions of up to 24%. These effects were enhanced in magnetic composites, possibly by dipole interactions. Mechanisms governing phase transitions triggered by NP loading in the interfacial instability process were proposed. The current study helps establish and elucidate the active role played by NPs in directing block copolymer assembly in the interfacial instability process, and provides important guiding principles for the use of this approach in generating NP-loaded block copolymer composites.

  17. Vibrational dynamics of ice in reverse micelles

    NARCIS (Netherlands)

    Dokter, A.M.; Petersen, C.; Woutersen, S.; Bakker, H.J.

    2008-01-01

    he ultrafast vibrational dynamics of HDO:D2O ice at 180 K in anionic reverse micelles is studied by midinfrared femtosecond pump-probe spectroscopy. Solutions containing reverse micelles are cooled to low temperatures by a fast-freezing procedure. The heating dynamics of the micellar solutions is

  18. Vitamin E succinate-conjugated F68 micelles for mitoxantrone delivery in enhancing anticancer activity

    Directory of Open Access Journals (Sweden)

    Liu Y

    2016-07-01

    Full Text Available Yuling Liu,1,* Yingqi Xu,2,* Minghui Wu,3 Lijiao Fan,1 Chengwei He,2 Jian-Bo Wan,2 Peng Li,2 Meiwan Chen,2 Hui Li11Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, People’s Republic of China; 2State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau, People’s Republic of China; 3Department of Cell Biology and Anatomy, School of Medicine, University of Florida, Gainesville, FL, USA *These authors contributed equally to this work Abstract: Mitoxantrone (MIT is a chemotherapeutic agent with promising anticancer efficacy. In this study, Pluronic F68-vitamine E succinate (F68-VES amphiphilic polymer micelles were developed for delivering MIT and enhancing its anticancer activity. MIT-loaded F68–VES (F68–VES/MIT micelles were prepared via the solvent evaporation method with self-assembly under aqueous conditions. F68–VES/MIT micelles were found to be of optimal particle size with the narrow size distribution. Transmission electron microscopy images of F68–VES/MIT micelles showed homogeneous spherical shapes and smooth surfaces. F68–VES micelles had a low critical micelle concentration value of 3.311 mg/L, as well as high encapsulation efficiency and drug loading. Moreover, F68–VES/MIT micelles were stable in the presence of fetal bovine serum for 24 hours and maintained sustained drug release in vitro. Remarkably, the half maximal inhibitory concentration (IC50 value of F68–VES/MIT micelles was lower than that of free MIT in both MDA-MB-231 and MCF-7 cells (two human breast cancer cell lines. In addition, compared with free MIT, there was an increased trend of apoptosis and cellular uptake of F68–VES/MIT micelles in MDA-MB-231 cells. Taken together, these results indicated that F68–VES polymer micelles were able to effectively deliver MIT and largely improve its potency in cancer therapy. Keywords: F68, vitamin E

  19. Dominant role of wormlike micelles in temperature-responsive viscoelastic properties of their mixtures with polymeric chains

    KAUST Repository

    Molchanov, Vyacheslav S.; Philippova, Olga E.

    2013-01-01

    Temperature effects on the rheological properties of viscoelastic solutions containing entangled wormlike micelles of potassium oleate and hydrophobically modified polyacrylamide were studied in a wide range of polymer concentrations. A very

  20. Rationale for Haze Formation after Carboxymethyl Cellulose (CMC) Addition to Red Wine.

    Science.gov (United States)

    Sommer, Stephan; Dickescheid, Christian; Harbertson, James F; Fischer, Ulrich; Cohen, Seth D

    2016-09-14

    The aim of this study was to identify the source of haze formation in red wine after the addition of carboxymethyl cellulose (CMC) and to characterize the dynamics of precipitation. Ninety commercial wines representing eight grape varieties were collected, tested with two commercial CMC products, and analyzed for susceptibility to haze formation. Seventy-four of these wines showed a precipitation within 14 days independent of the CMC product used. The precipitates of four representative samples were further analyzed for elemental composition (CHNS analysis) and solubility under different conditions to determine the nature of the solids. All of the precipitates were composed of approximately 50% proteins and 50% CMC and polyphenols. It was determined that the interactions between CMC and bovine serum albumin are pH dependent in wine-like model solution. Furthermore, it was found that the color loss associated with CMC additions required the presence of proteins and cannot be observed with CMC and anthocyanins alone.

  1. The development of phytosterol-lecithin mixed micelles and organogels.

    Science.gov (United States)

    Matheson, Andrew B; Dalkas, Georgios; Gromov, Andrei; Euston, Stephen R; Clegg, Paul S

    2017-12-13

    We demonstrate that by mixing the phytosterol-ester oryzanol with lecithin in an organic solvent, both components may be dispersed at much higher concentrations than they may be individually. Dynamic light scattering and molecular dynamics simulations show that the mechanism for this is the formation of r ∼ 4 nm mixed micelles. Infrared spectroscopy and simulations suggest that these micelles are formed due in part to hydrogen bonding of the phosphate of the lecithin head-group, and the phenol group of the oryzanol. Rheology shows that by mixing these materials at an equimolar ratio, highly viscous suspensions are created. Furthermore, by adding water to these samples, a solid-like gel may be formed which offers mechanical properties close to those desired for a margarine type spread, whilst still solubilizing the oryzanol.

  2. SYLRAMICTM SiC fibers for CMC reinforcement

    International Nuclear Information System (INIS)

    Jones, Richard E.; Petrak, Dan; Rabe, Jim; Szweda, Andy

    2000-01-01

    Dow Corning researchers developed SYLRAMIC SiC fiber specifically for use in ceramic-matrix composite (CMC) components for use in turbine engine hot sections where excellent thermal stability, high strength and high thermal conductivity are required. This is a stoichiometric SiC fiber with a high degree of crystallinity, high tensile strength, high tensile modulus and good thermal conductivity. Owing to the small diameter, this textile-grade fiber can be woven into 2-D and 3-D structures for CMC fabrication. These properties are also of high interest to the nuclear community. Some initial studies have shown that SYLRAMIC fiber shows very good dimensional stability in a neutron flux environment, which offers further encouragement. This paper will review the properties of SYLRAMIC SiC fiber and then present the properties of polymer impregnation and pyrolysis (PIP) processed CMC made with this fiber at Dow Corning. While these composites may not be directly applicable to applications of interest to this audience, we believe that the properties shown will give good evidence that the fiber should be suitable for high temperature structural applications in the nuclear arena

  3. Polymeric microcapsules assembled from a cationic/zwitterionic pair of responsive block copolymer micelles.

    Science.gov (United States)

    Addison, Timothy; Cayre, Olivier J; Biggs, Simon; Armes, Steven P; York, David

    2010-05-04

    Using a layer-by-layer (LbL) approach, this work presents the preparation of hollow microcapsules with a membrane constructed entirely from a cationic/zwitterionic pair of pH-responsive block copolymer micelles. Our previous work with such systems highlighted that, in order to retain the responsive nature of the individual micelles contained within the multilayer membranes, it is important to optimize the conditions required for the selective dissolution of the sacrificial particulate templates. Consequently, here, calcium carbonate particles have been employed as colloidal templates as they can be easily dissolved in aqueous environments with the addition of chelating agents such as ethylenediaminetetraacetic acid (EDTA). Furthermore, the dissolution can be carried out in solutions buffered to a desirable pH so not to adversely affect the pH sensitive micelles forming the capsule membranes. First, we have deposited alternating layers of anionic poly[2-(dimethylamino)ethyl methacrylate-block-poly(2-(diethylamino)ethyl methacrylate)] (PDMA-PDEA) and cationic poly(2-(diethylamino)ethyl)methacrylate-block-poly(methacrylic acid) (PDEA-PMAA) copolymer micelles onto calcium carbonate colloidal templates. After deposition of five micelle bilayers, addition of dilute EDTA solution resulted in dissolution of the calcium carbonate and formation of hollow polymer capsules. The capsules were imaged using atomic force microscopy (AFM) and scanning electron microscopy (SEM), which shows that the micelle/micelle membrane is sufficiently robust to withstand dissolution of the supporting template. Quartz crystal microbalance studies were conducted and provide good evidence that the micelle multilayer structure is retained after EDTA treatment. In addition, a hydrophobic dye was incorporated into the micelle cores prior to adsorption. After dissolution of the particle template, the resulting hollow capsules retained a high concentration of dye, suggesting that the core

  4. Light Scattering Study of Mixed Micelles Made from Elastin-Like Polypeptide Linear Chains and Trimers

    Science.gov (United States)

    Terrano, Daniel; Tsuper, Ilona; Maraschky, Adam; Holland, Nolan; Streletzky, Kiril

    Temperature sensitive nanoparticles were generated from a construct (H20F) of three chains of elastin-like polypeptides (ELP) linked to a negatively charged foldon domain. This ELP system was mixed at different ratios with linear chains of ELP (H40L) which lacks the foldon domain. The mixed system is soluble at room temperature and at a transition temperature (Tt) will form swollen micelles with the hydrophobic linear chains hidden inside. This system was studied using depolarized dynamic light scattering (DDLS) and static light scattering (SLS) to determine the size, shape, and internal structure of the mixed micelles. The mixed micelle in equal parts of H20F and H40L show a constant apparent hydrodynamic radius of 40-45 nm at the concentration window from 25:25 to 60:60 uM (1:1 ratio). At a fixed 50 uM concentration of the H20F, varying H40L concentration from 5 to 80 uM resulted in a linear growth in the hydrodynamic radius from about 11 to about 62 nm, along with a 1000-fold increase in VH signal. A possible simple model explaining the growth of the swollen micelles is considered. Lastly, the VH signal can indicate elongation in the geometry of the particle or could possibly be a result from anisotropic properties from the core of the micelle. SLS was used to study the molecular weight, and the radius of gyration of the micelle to help identify the structure and morphology of mixed micelles and the tangible cause of the VH signal.

  5. Radiolabeling of liposomes and polymeric micelles with PET-isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Ingemann Jensen, A.T.

    2013-06-01

    glycerolipid and a cholesteryl ether were synthesized with free primary alcohols and a series of their sulphonates (Ms, Ts, Tf) were prepared. [18F]Radiofluorination of these substrates was performed on fully automated equipment using a classic Kryptofix222-mediated procedure in DMSO. Yields were poor, 3-17% depending on conditions. The [18F]fluorinated probes were purified in-situ on SEP-Paks. The cholesteryl ether mesylate performed best. This substrate was radiolabeled and formulated in long-circulating liposomes by drying the probe and the lipids together, followed by hydration by magnetic stirring. The liposomes were extruded through 100 nm filter on fully automated equipment. Animal studies were done in tumor-bearing mice, and PET-scans were performed over 8 hours. Clear tumor uptake, as well as hepatic and splenic uptake, was observed, corresponding to expected liposomal pharmacokinetics. Tumor uptake was quantifiable (tumor-tomuscle ratio at 8 h: 2.20), showing that the maximum scan duration with 18F is sufficient for visualizing tumor tissue. Because of the low [18F]radiofluorination yields obtained, we investigated ways of labeling lipophilic substrates in nonpolar solvents. This involved the transfer of [18]HF gas from a solution of concentrated sulphuric acid into a receiving vial containing the substrate in toluene. A phosphazene base was present to bind [18]HF and mediate fluorination. This procedure made it possible to fluorinate highly lipophilic substrates in 71% yields. Chapter 3. Radiolabeling of polymeric micelles with 64Cu (18% positron decay, T = 12.7 h) was investigated. 64Cu allows longer scans (up to 48 hours), which mirrors the duration of nanoparticle pharmacokinetics. It is a metal and must be attached to polymeric micelles by covalently conjugated chelators. DOTA and CB-TE2A are two such chelators, but DOTA is widely believed to be unstable in-vivo. DOTA and CB-TE2A were conjugated to triblock polymeric micelles in the shellregion. Here, they were

  6. Radiolabeling of liposomes and polymeric micelles with PET-isotopes

    International Nuclear Information System (INIS)

    Ingemann Jensen, A.T.

    2013-01-01

    glycerolipid and a cholesteryl ether were synthesized with free primary alcohols and a series of their sulphonates (Ms, Ts, Tf) were prepared. [18F]Radiofluorination of these substrates was performed on fully automated equipment using a classic Kryptofix222-mediated procedure in DMSO. Yields were poor, 3-17% depending on conditions. The [18F]fluorinated probes were purified in-situ on SEP-Paks. The cholesteryl ether mesylate performed best. This substrate was radiolabeled and formulated in long-circulating liposomes by drying the probe and the lipids together, followed by hydration by magnetic stirring. The liposomes were extruded through 100 nm filter on fully automated equipment. Animal studies were done in tumor-bearing mice, and PET-scans were performed over 8 hours. Clear tumor uptake, as well as hepatic and splenic uptake, was observed, corresponding to expected liposomal pharmacokinetics. Tumor uptake was quantifiable (tumor-tomuscle ratio at 8 h: 2.20), showing that the maximum scan duration with 18F is sufficient for visualizing tumor tissue. Because of the low [18F]radiofluorination yields obtained, we investigated ways of labeling lipophilic substrates in nonpolar solvents. This involved the transfer of [18]HF gas from a solution of concentrated sulphuric acid into a receiving vial containing the substrate in toluene. A phosphazene base was present to bind [18]HF and mediate fluorination. This procedure made it possible to fluorinate highly lipophilic substrates in 71% yields. Chapter 3. Radiolabeling of polymeric micelles with 64Cu (18% positron decay, T = 12.7 h) was investigated. 64Cu allows longer scans (up to 48 hours), which mirrors the duration of nanoparticle pharmacokinetics. It is a metal and must be attached to polymeric micelles by covalently conjugated chelators. DOTA and CB-TE2A are two such chelators, but DOTA is widely believed to be unstable in-vivo. DOTA and CB-TE2A were conjugated to triblock polymeric micelles in the shellregion. Here, they were

  7. Chemical reactions in reverse micelle systems

    Science.gov (United States)

    Matson, Dean W.; Fulton, John L.; Smith, Richard D.; Consani, Keith A.

    1993-08-24

    This invention is directed to conducting chemical reactions in reverse micelle or microemulsion systems comprising a substantially discontinuous phase including a polar fluid, typically an aqueous fluid, and a microemulsion promoter, typically a surfactant, for facilitating the formation of reverse micelles in the system. The system further includes a substantially continuous phase including a non-polar or low-polarity fluid material which is a gas under standard temperature and pressure and has a critical density, and which is generally a water-insoluble fluid in a near critical or supercritical state. Thus, the microemulsion system is maintained at a pressure and temperature such that the density of the non-polar or low-polarity fluid exceeds the critical density thereof. The method of carrying out chemical reactions generally comprises forming a first reverse micelle system including an aqueous fluid including reverse micelles in a water-insoluble fluid in the supercritical state. Then, a first reactant is introduced into the first reverse micelle system, and a chemical reaction is carried out with the first reactant to form a reaction product. In general, the first reactant can be incorporated into, and the product formed in, the reverse micelles. A second reactant can also be incorporated in the first reverse micelle system which is capable of reacting with the first reactant to form a product.

  8. Casein micelle structure: a concise review

    Directory of Open Access Journals (Sweden)

    Chanokphat Phadungath

    2005-01-01

    Full Text Available Milk is a complex biological fluid with high amount of proteins, lipid and minerals. The function of milk is to supply nutrients such as essential amino acids required for the growth of the newborn. In addition, due to the importance of casein and casein micelles for the functional behavior of dairy products, the nature and structure of casein micelles have been studied extensively. However, the exact structure of casein micelles is still under debate. Various models for casein micelle structure have been proposed. Most of the proposedmodels fall into three general categories, which are: coat-core, subunit (sub-micelles, and internal structure models. The coat-core models, proposed by Waugh and Nobel in 1965, Payens in 1966, Parry and Carroll in 1969, and Paquin and co-workers in 1987, describe the micelle as an aggregate of caseins with outer layer differing in composition form the interior, and the structure of the inner part is not accurately identified. The sub-micelle models, proposed by Morr in 1967, Slattery and Evard in 1973, Schmidt in 1980, Walstra in1984, and Ono and Obata in 1989, is considered to be composed of roughly spherical uniform subunits. The last models, the internal structure models, which were proposed by Rose in 1969, Garnier and Ribadeau- Dumas in 1970, Holt in 1992, and Horne in 1998, specify the mode of aggregation of the different caseins.

  9. Carboxymethyl cellulose (CMC whey product as protein source for growing pigs 

    Directory of Open Access Journals (Sweden)

    Matti Näsi

    1982-12-01

    Full Text Available A digestibility and balance trial was performed with three growing pigs to evaluate the nutritive value and protein utilization of a carboxymethyl cellulose(CMC whey product used to replace 50 % or 100 % of the dried skim supplement in a barley-based diet. The effect of CMC whey on clinical chemical blood parameters was also investigated. The CMC whey protein contained 39.6 % crude protein and 36.0 % true protein in DM. The proportion of CMC in the product was 18.3% of DM. CMC whey had high contents of lysine, cystine, methionine and threonine: 10.3, 2.9, 2.1 and 5.6 g/16 g N, respectively. NFE digestibility was lower on the CMC whey diet than on the skim milk diet (P < 0.05. Faecal excretion of CMC averaged 59.0 %. Protein utilization was effective on the CMC whey diet: 69.9 % of absorbed N was retained. Judging from the blood analyses, the CMC whey product did not have any detrimental effect on the metabolism or health of the pigs. The CMC whey product is well suited as a protein supplement in pig feeding because of its high contents of essential amino acids.

  10. Preparation of a folate-mediated tumor targeting ultraparamagnetic polymeric micelles and its in vitro experimental study

    International Nuclear Information System (INIS)

    Hong Guobin; Zhou Jingxing; Shen Jun; Liang Biling; Yuan Renxu; Shuai Xintao

    2008-01-01

    Objective: To evaluate the tumor targeting characteristic of the Folate-SPIO-DOX- Micelles by in vitro studies, and to test the feasibility of monitor tumor targeting using it and clinical MRI. Methods: The polymeric micelles, Folate-SPIO-DOXO-Micelles were prepared. The in vitro tumor cell targeting efficacy of these folate modified and DOX or SPIO-loaded micelles (Folate-SPIO-DOX- MiceUes) was evaluated by observing the cellular uptake of micelles by human hepatic carcinoma cells (Bel 7402 cells) which overexpressed folate surface receptors. Cell suspensions were incubated with Folate-SPIO- DOXO-Micelles for 1 h. Prussian blue staining was performed to show intracellular irons. Flow cytometry was used to further quantify the cellular uptake of the nanoparticles into Bel 7402 cells. MRI was performed to show the signal intensity changes by using T 2 WI sequences at a clinical 1.5 T MR system. Results Prussian blue staining showed much more intracellular iron in cells incubated with Folate-SPIO-DOX- Micelles than the cells incubated with the non-targeting SPIO-DOX-Micelles. As revealed by flow cytometry, the mean fluorescence intensity of cells in the folate group and the non-folate group were 117.88 and 46. 33, respectively. The T 2 signal intensity in MRI of cells treated with the folate targeting micelles decreased significantly(when the concentration of SPIO in cell culture medium was 5, 10, 20, 40, and 80 μg/ml, respectively, T 2 signal intensity decreased by -5.02%, -23.58%, -45.89%, -70.34%, and -92.41%, respectively). In contrast, T 2 signal intensity did not show obvious decrease for cells treated with the folate-free micelles (when the concentration of SPIO in cell culture medium was at 5, 10, 20, 40, and 80 μg/ml, respectively, T 2 signal intensity decreased by -3.77%, -2.16%, -2.18%, -2.74% and -19.77%, respectively). Conclusion: The polymeric micelles, Folate-SPIO-DOX-Micelles has good targeting ability to the hepatic carcinoma cells in vitro, and

  11. Solubilization of poorly soluble photosensitizer hypericin by polymeric micelles and polyethylene glycol.

    Science.gov (United States)

    Búzová, Diana; Kasák, Peter; Miškovský, Pavol; Jancura, Daniel

    2013-06-01

    Hypericin (Hyp) is a promising photosensitizer for photodiagnostic and photodynamic therapy of cancer. However, Hyp has a large conjugated system and in aqueous solutions forms insoluble aggregates which do not possess biological activity. This makes intravenous injection of Hyp problematic and restricts its medical applications. To overcome this problem, Hyp is incorporated into drug delivery systems which can increase its solubility and bioavailability. One of the possibilities is utilization of polymeric micelles. The most used hydrophilic block for preparation of polymeric micelles is polyethylen glycol (PEG). PEG is a polymer which for its lack of immunogenicity, antigenicity and toxicity obtained approval for use in human medicine. In this work we have studied the solubilization of Hyp aggregates in the presence of PEG-PE and PEG-cholesterol micelles. The concentration of polymeric micelles which allows total monomerization of Hyp corresponds to the critical micellar concentration of these micelles (~10(-6) M). We have also investigated the effect of the molecular weight and concentration of PEG on the transition of aggregated Hyp to its monomeric form. PEGs with low molecular weight ( 2000 g/mol efficiently transform Hyp aggregates to the monomeric state of this photosensitizer.

  12. Retention of bile salts in micellar electrokinetic chromatography: relation of capacity factor to octanol-water partition coefficient and critical micellar concentration.

    Science.gov (United States)

    Lucangioli, S E; Carducci, C N; Tripodi, V P; Kenndler, E

    2001-12-25

    The capacity factors of 16 anionic cholates (from six bile salts, including their glyco- and tauro-conjugates) were determined in a micellar electrokinetic chromatography (MEKC) system consisting of buffer, pH 7.5 (phosphate-boric acid; 20 mmol/l) with 50 mmol/l sodium dodecyl sulfate (SDS) as micelle former and 10% acetonitrile as organic modifier. The capacity factors of the fully dissociated, negatively charged analytes (ranging between 0.2 and 60) were calculated from their mobilities, with a reference background electrolyte (BGE) without SDS representing "free" solution. For comparison, the capacity factors were derived for a second reference BGE where the SDS concentration (5 mmol/l) is close to the critical micellar concentration (CMC). The capacity factors are compared with the logarithm of the octanol-water partition coefficient, log Pow, as measure for lipophilicity. Clear disagreement between these two parameters is found especially for epimeric cholates with the hydroxy group in position 7. In contrast, fair relation between the capacity factor of the analytes and their CMC is observed both depending strongly on the orientation of the OH groups, and tauro-conjugation as well. In this respect the retention behaviour of the bile salts in MEKC seems to reflect their role as detergents in living systems, and might serve as model parameter beyond lipophilicity.

  13. Negative adsorption due to electrostatic exclusion of micelles.

    Science.gov (United States)

    Somasundaran, P; Ananthapadmanabhan, K P; Deo, Puspendu

    2005-10-15

    Interactions of surfactants with solid substrates are important in the controlling of processes such as flotation, coating, flocculation and sedimentation. These interactions usually lead to adsorption on solids, but can also result in an exclusion of the reagents with dire consequences. In this work electrostatic exclusion of negatively charged dodecylbenzene sulfonate micelles from quartz/water, Bio-Sil/water and alumina/water interfaces has been investigated as a function of pH and ionic strength. Measurable negative adsorption of these surfactants from similarly charged solid/liquid interface was observed in the micellar region. In the case of porous samples with large surface area, comparison of pore size with the micelle size is necessary to avoid any erroneous conclusions regarding the role of electrostatic exclusion in a given system. A theoretical model for the electrostatic exclusion of micelles is developed and used to calculate the adsorption of negatively charged dodecylbenzene sulfonate on negatively charged quartz (pH 7), silica (Bio-Sil A, pH 3) and alumina (pH 11) in the micellar concentration region. The micellar exclusion values calculated using the model are in excellent agreement with the experimental results.

  14. Effect of the addition of CMC on the aggregation behaviour of proteins

    International Nuclear Information System (INIS)

    Yu, H.; Sabato, S.F.; D'Aprano, G.; Lacroix, M.

    2004-01-01

    The effect of carboxymethylcellulose (CMC) on the aggregation of formulation based on calcium caseinate, commercial whey protein (WPC), and a 1:1 mixture of soy protein isolate (SPI) and whey protein isolate (WPI) was investigated. Protein aggregation could be observed upon addition of CMC, as demonstrated by size-exclusion chromatography. This aggregation behaviour was enhanced by means of physical treatments, such as heating at 90 deg. C for 30 min or gamma-irradiation at 32 kGy. A synergy resulted from the combination of CMC to gamma-irradiation in Caseinate/CMC and SPI/WPI/CMC formulations. Furthermore, CMC prevented precipitation in irradiated protein solutions for a period of more than 3 months at 4 deg. C

  15. Effect of the addition of CMC on the aggregation behaviour of proteins

    Energy Technology Data Exchange (ETDEWEB)

    Yu, H.; Sabato, S.F.; D' Aprano, G.; Lacroix, M. E-mail: monique.lacroix@inrs-iaf.uquebec.ca

    2004-10-01

    The effect of carboxymethylcellulose (CMC) on the aggregation of formulation based on calcium caseinate, commercial whey protein (WPC), and a 1:1 mixture of soy protein isolate (SPI) and whey protein isolate (WPI) was investigated. Protein aggregation could be observed upon addition of CMC, as demonstrated by size-exclusion chromatography. This aggregation behaviour was enhanced by means of physical treatments, such as heating at 90 deg. C for 30 min or gamma-irradiation at 32 kGy. A synergy resulted from the combination of CMC to gamma-irradiation in Caseinate/CMC and SPI/WPI/CMC formulations. Furthermore, CMC prevented precipitation in irradiated protein solutions for a period of more than 3 months at 4 deg. C.

  16. Polysaccharide-Based Micelles for Drug Delivery

    Directory of Open Access Journals (Sweden)

    Nan Zhang

    2013-05-01

    Full Text Available Delivery of hydrophobic molecules and proteins has been an issue due to poor bioavailability following administration. Thus, micelle carrier systems are being investigated to improve drug solubility and stability. Due to problems with toxicity and immunogenicity, natural polysaccharides are being explored as substitutes for synthetic polymers in the development of new micelle systems. By grafting hydrophobic moieties to the polysaccharide backbone, self-assembled micelles can be readily formed in aqueous solution. Many polysaccharides also possess inherent bioactivity that can facilitate mucoadhesion, enhanced targeting of specific tissues, and a reduction in the inflammatory response. Furthermore, the hydrophilic nature of some polysaccharides can be exploited to enhance circulatory stability. This review will highlight the advantages of polysaccharide use in the development of drug delivery systems and will provide an overview of the polysaccharide-based micelles that have been developed to date.

  17. Overview of Cooperative Monitoring Concepts and the CMC

    International Nuclear Information System (INIS)

    Biringer, Kent L.

    1999-01-01

    Cooperative monitoring holds the promise of utilizing many technologies from conflicts of the past to implement agreements of peace in the future. Important approaches to accomplish this are to develop the framework for assessing monitoring opportunities and to provide education and training on the technologies and experience available for sharing with others. The Cooperative Monitoring Center (CMC) at Sandia National Laboratories is working closely with agencies throughout the federal government, academics at home and abroad, and regional organizations to provide the technical tools needed to assess, design, analyze, and implement these cooperative agreements. In doing so, the goals of building regional confidence and increasing trust and communication can be furthered

  18. Biotoxicity and bioavailability of hydrophobic organic compounds solubilized in nonionic surfactant micelle phase and cloud point system.

    Science.gov (United States)

    Pan, Tao; Liu, Chunyan; Zeng, Xinying; Xin, Qiao; Xu, Meiying; Deng, Yangwu; Dong, Wei

    2017-06-01

    A recent work has shown that hydrophobic organic compounds solubilized in the micelle phase of some nonionic surfactants present substrate toxicity to microorganisms with increasing bioavailability. However, in cloud point systems, biotoxicity is prevented, because the compounds are solubilized into a coacervate phase, thereby leaving a fraction of compounds with cells in a dilute phase. This study extends the understanding of the relationship between substrate toxicity and bioavailability of hydrophobic organic compounds solubilized in nonionic surfactant micelle phase and cloud point system. Biotoxicity experiments were conducted with naphthalene and phenanthrene in the presence of mixed nonionic surfactants Brij30 and TMN-3, which formed a micelle phase or cloud point system at different concentrations. Saccharomyces cerevisiae, unable to degrade these compounds, was used for the biotoxicity experiments. Glucose in the cloud point system was consumed faster than in the nonionic surfactant micelle phase, indicating that the solubilized compounds had increased toxicity to cells in the nonionic surfactant micelle phase. The results were verified by subsequent biodegradation experiments. The compounds were degraded faster by PAH-degrading bacterium in the cloud point system than in the micelle phase. All these results showed that biotoxicity of the hydrophobic organic compounds increases with bioavailability in the surfactant micelle phase but remains at a low level in the cloud point system. These results provide a guideline for the application of cloud point systems as novel media for microbial transformation or biodegradation.

  19. Oleyl-hyaluronan micelles loaded with upconverting nanoparticles for bio-imaging

    Energy Technology Data Exchange (ETDEWEB)

    Pospisilova, Martina, E-mail: martina.pospisilova@contipro.com; Mrazek, Jiri; Matuska, Vit; Kettou, Sofiane; Dusikova, Monika; Svozil, Vit; Nesporova, Kristina; Huerta-Angeles, Gloria; Vagnerova, Hana; Velebny, Vladimir [Contipro Biotech (Czech Republic)

    2015-09-15

    Hyaluronan (HA) represents an interesting polymer for nanoparticle coating due to its biocompatibility and enhanced cell interaction via CD44 receptor. Here, we describe incorporation of oleate-capped β–NaYF{sub 4}:Yb{sup 3+}, Er{sup 3+} nanoparticles (UCNP-OA) into amphiphilic HA by microemulsion method. Resulting structures have a spherical, micelle-like appearance with a hydrodynamic diameter of 180 nm. UCNP-OA-loaded HA micelles show a good stability in PBS buffer and cell culture media. The intensity of green emission of UCNP-OA-loaded HA micelles in water is about five times higher than that of ligand-free UCNP, indicating that amphiphilic HA effectively protects UCNP luminescence from quenching by water molecules. We found that UCNP-OA-loaded HA micelles in concentrations up to 50 μg mL{sup −1} increase cell viability of normal human dermal fibroblasts (NHDF), while viability of human breast adenocarcinoma cells MDA–MB–231 is reduced at these concentrations. The utility of UCNP-OA-loaded HA micelles as a bio-imaging probe was demonstrated in vitro by successful labelling of NHDF and MDA–MB–231 cells overexpressing the CD44 receptor.

  20. Tailor-made dimensions of diblock copolymer truncated micelles on a solid by UV irradiation.

    Science.gov (United States)

    Liou, Jiun-You; Sun, Ya-Sen

    2015-09-28

    We investigated the structural evolution of truncated micelles in ultrathin films of polystyrene-block-poly(2-vinylpyridine), PS-b-P2VP, of monolayer thickness on bare silicon substrates (SiOx/Si) upon UV irradiation in air- (UVIA) and nitrogen-rich (UVIN) environments. The structural evolution of micelles upon UV irradiation was monitored using GISAXS measurements in situ, while the surface morphology was probed using atomic force microscopy ex situ and the chemical composition using X-ray photoelectron spectroscopy (XPS). This work provides clear evidence for the interpretation of the relationship between the structural evolution and photochemical reactions in PS-b-P2VP truncated micelles upon UVIA and UVIN. Under UVIA treatment, photolysis and cross-linking reactions coexisted within the micelles; photolysis occurred mainly at the top of the micelles, whereas cross-linking occurred preferentially at the bottom. The shape and size of UVIA-treated truncated micelles were controlled predominantly by oxidative photolysis reactions, which depended on the concentration gradient of free radicals and oxygen along the micelle height. Because of an interplay between photolysis and photo-crosslinking, the scattering length densities (SLD) of PS and P2VP remained constant. In contrast, UVIN treatments enhanced the contrast in SLD between the PS shell and the P2VP core as cross-linking dominated over photolysis in the presence of nitrogen. The enhancement of the SLD contrast was due to the various degrees of cross-linking under UVIN for the PS and P2VP blocks.

  1. PEG-b-PCL polymeric nano-micelle inhibits vascular angiogenesis by activating p53-dependent apoptosis in zebrafish.

    Science.gov (United States)

    Zhou, Tian; Dong, Qinglei; Shen, Yang; Wu, Wei; Wu, Haide; Luo, Xianglin; Liao, Xiaoling; Wang, Guixue

    Micro/nanoparticles could cause adverse effects on cardiovascular system and increase the risk for cardiovascular disease-related events. Nanoparticles prepared from poly(ethylene glycol) (PEG)- b -poly( ε -caprolactone) (PCL), namely PEG- b -PCL, a widely studied biodegradable copolymer, are promising carriers for the drug delivery systems. However, it is unknown whether polymeric PEG- b -PCL nano-micelles give rise to potential complications of the cardiovascular system. Zebrafish were used as an in vivo model to evaluate the effects of PEG- b -PCL nano-micelle on cardiovascular development. The results showed that PEG- b -PCL nano-micelle caused embryo mortality as well as embryonic and larval malformations in a dose-dependent manner. To determine PEG- b -PCL nano-micelle effects on embryonic angiogenesis, a critical process in zebrafish cardiovascular development, growth of intersegmental vessels (ISVs) and caudal vessels (CVs) in flk1-GFP transgenic zebrafish embryos using fluorescent stereomicroscopy were examined. The expression of fetal liver kinase 1 (flk1), an angiogenic factor, by real-time quantitative polymerase chain reaction (qPCR) and in situ whole-mount hybridization were also analyzed. PEG- b -PCL nano-micelle decreased growth of ISVs and CVs, as well as reduced flk1 expression in a concentration-dependent manner. Parallel to the inhibitory effects on angiogenesis, PEG- b -PCL nano-micelle exposure upregulated p53 pro-apoptotic pathway and induced cellular apoptosis in angiogenic regions by qPCR and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) apoptosis assay. This study further showed that inhibiting p53 activity, either by pharmacological inhibitor or RNA interference, could abrogate the apoptosis and angiogenic defects caused by PEG- b -PCL nano-micelles, indicating that PEG- b -PCL nano-micelle inhibits angiogenesis by activating p53-mediated apoptosis. This study indicates that polymeric PEG- b -PCL nano-micelle could

  2. Synthesis and characterization of CMC from water hyacinth for lithium-ion battery applications

    Science.gov (United States)

    Hidayat, Sahrul; Susanty, Riveli, Nowo; Suroto, Bambang Joko; Rahayu, Iman

    2018-02-01

    Recently, the most dominating power supply on the mobile electronics market are rechargeable Lithium-ion batteries. This is because of a higher energy density and longer lifetime compared to similar rechargeable battery systems. One of the components that determine the performance of a lithium ion battery is the binder material, whether at the anode or the cathode. In commercial batteries, the material used as the binder is Polyvinylidene Difluoride (PVDF), with n-methyl-2-phyrrolidone (NMP) as the solvent. Both are synthetic materials that are expensive, toxic and harmful to the environment. An alternative binder material for lithium-ion battery electrodes is CMC (carboxymethyl cellulose) in a water solvent. CMC is cheaper than PVDF, non-toxic and more environmental friendly. CMC can be synthesized from several types of plants, such as water hyacinth, which is a weed plant with high cellulose content. The synthesis of CMC consists of three main steps, namely 1) the isolation process from water hyacinth, 2) the alkalization and carboxymethylation process and 3) the purification process to obtain CMC in high purity. FTIR characterization of the CMC shows five region of absorption bands. The bands in the region 1330-1400 cm-1 are due to symmetrical deformations of CH2 and OH groups. The ether bonds in CMC occur in the fingerprint region of 1250-1060 cm-1. The presence of new and strong absorption band around 1600 cm-1 is confirmed to the stretching vibration of the carboxyl group (COO-), while the one around 1415 cm-1 is assigned to carboxyl groups as it salts. The broad absorption band above 3400 cm-1 is due to the stretching frequency of the hydroxyl group (-OH). Purity test on three samples (CMC mesh-100, CMC mesh-60 and CMC, mesh-40) gives purity values of 99.89%, 99.99% and 99.89%, respectively. This proves that CMC have actually been formed with high purity.

  3. Solubilization of docetaxel in poly(ethylene oxide)-block-poly(butylene/styrene oxide) micelles.

    Science.gov (United States)

    Elsabahy, Mahmoud; Perron, Marie-Eve; Bertrand, Nicolas; Yu, Ga-Er; Leroux, Jean-Christophe

    2007-07-01

    Poly(ethylene oxide)-block-poly(styrene oxide) (PEO-b-PSO) and PEO-b-poly(butylene oxide) (PEO-b-PBO) of different chain lengths were synthesized and characterized for their self-assembling properties in water by dynamic/static light scattering, spectrofluorimetry, and transmission electron microscopy. The resulting polymeric micelles were evaluated for their ability to solubilize and protect the anticancer drug docetaxel (DCTX) from degradation. The drug release kinetics as well as the cytotoxicity of the loaded micelles were assessed in vitro. All polymers formed micelles with a highly viscous core at low critical association concentrations (hydrolysis under accelerated stability testing conditions. Only PEO-b-PBO bearing 24 BO units afforded significant protection against degradation. In vitro, DCTX was released slower from the latter micelles, but all formulations possessed a similar cytotoxic effect against PC-3 prostate cancer cells. These data suggest that PEO-b-P(SO/BO) micelles could be used as alternatives to conventional surfactants for the solubilization of taxanes.

  4. Entropic effects, shape, and size of mixed micelles formed by copolymers with complex architectures

    Science.gov (United States)

    Kalogirou, Andreas; Gergidis, Leonidas N.; Moultos, Othonas; Vlahos, Costas

    2015-11-01

    The entropic effects in the comicellization behavior of amphiphilic A B copolymers differing in the chain size of solvophilic A parts were studied by means of molecular dynamics simulations. In particular, mixtures of miktoarm star copolymers differing in the molecular weight of solvophilic arms were investigated. We found that the critical micelle concentration values show a positive deviation from the analytical predictions of the molecular theory of comicellization for chemically identical copolymers. This can be attributed to the effective interactions between copolymers originated from the arm size asymmetry. The effective interactions induce a very small decrease in the aggregation number of preferential micelles triggering the nonrandom mixing between the solvophilic moieties in the corona. Additionally, in order to specify how the chain architecture affects the size distribution and the shape of mixed micelles we studied star-shaped, H-shaped, and homo-linked-rings-linear mixtures. In the first case the individual constituents form micelles with preferential and wide aggregation numbers and in the latter case the individual constituents form wormlike and spherical micelles.

  5. Antiproliferative activity of tea catechins associated with casein micelles, using HT29 colon cancer cells.

    Science.gov (United States)

    Haratifar, S; Meckling, K A; Corredig, M

    2014-02-01

    Numerous studies have shown that green tea polyphenols display anticancer activities in many organ sites by using different experimental models in rodents and in cultured cell lines in vitro. The present study tested the ability of casein micelles to deliver biologically active concentrations of polyphenols to HT-29 colon cancer cells. Epigallocatechin gallate (EGCG), the major catechin found in green tea, was used as the model molecule, as it has been shown to have antiproliferative activity on colon cancer cells. In the present work, we hypothesized that due to the binding of caseins with EGCG, casein micelles may be an ideal platform for the delivery of this bioactive molecule and that the binding would not affect the bioaccessibility of EGCG. The cytotoxicity and proliferation behavior of HT-29 colon cancer cells when exposed to free EGCG was compared with that of nanoencapsulated EGCG in casein micelles of skim milk. Epigallocatechin gallate-casein complexes were able to decrease the proliferation of HT-29 cancer cells, demonstrating that bioavailability may not be reduced by the nanoencapsulation. As casein micelles may act as protective carriers for EGCG in foods, it was concluded that nanoencapsulation of tea catechins in casein micelles may not diminish their antiproliferative activity on colon cancer cells compared with free tea catechins. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  6. Freezing polystyrene-b-poly(2-vinylpyridine) micelle nanoparticles with different nanostructures and sizes.

    Science.gov (United States)

    Fan, Hailong; Jin, Zhaoxia

    2014-04-28

    Herein we report how to control the nanostructures and sizes of polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) nanoparticles via manipulating freezing in solvent-exchange. By characterizing and analyzing the distinct structural features of the obtained nanoparticles, we recognized that micelle self-assembly happens in the precipitation of PS-b-P2VP when water is added into the block copolymer (BCP) solution. Solvent properties significantly influence micelle types that are vesicles in acetone/H2O and spherical micelles in tetrahydrofuran/H2O, respectively, thus further inducing different frozen nanostructures of the obtained nanoparticles, onion-like in acetone/H2O and large compound micelles in tetrahydrofuran/H2O. By changing the concentration of the block copolymers and the Vsolvent/VH2O ratio to modify the freezing stage at which block copolymer micelles are frozen, we can further control the size of the nanoparticles. Moreover, small molecules (phosphotungstic acid, pyrene, 1-pyrenebutyric acid) can be trapped into the block copolymer nanoparticles via the freezing process. Their distribution in the nanoparticles relies not only on the solvent property, but also on their interactions with block copolymers. The hybrid nanoparticles with ordered distribution of small molecules can be further changed to partially-void nanoparticles. Our study demonstrated that manipulating the freezing of block copolymers in the solvent exchange process is a simple and controllable fabrication method to generate BCP nanoparticles with different architectures.

  7. Enhanced transmucosal delivery of itraconazole by thiolated d-ɑ-tocopheryl poly(ethylene glycol) 1000 succinate micelles for the treatment of Candida albicans.

    Science.gov (United States)

    Suksiriworapong, Jiraphong; Mingkwan, Thawanrat; Chantasart, Doungdaw

    2017-11-01

    This study aimed to investigate the transmucosal delivery of itraconazole (ITZ) by thiolated d-ɑ-tocopheryl poly(ethylene glycol) 1000 succinate (TPGS-Cys) micelles. TPGS-Cys polymer was successfully synthesized by the simple coupling between carboxyl-activated TPGS and Cys as confirmed by NMR and FTIR techniques. Afterwards, the TPGS/TPGS-Cys micelles were prepared using the blend of TPGS and TPGS-Cys at 10:0, 7:3, 5:5, 3:7 and 0:10mass ratios. All micelles had the size ranged from 8 to 10nm with narrow size distribution and showed spherical in shape. The surface of the 10:0 TPGS micelles exhibited negatively charge while, the TPGS-Cys micelles demonstrated the slightly positive surface charge. The critical micelle concentration, loading capacity and release profiles of TPGS/TPGS-Cys micelles were comparable to the TPGS micelles. The release of ITZ from all micelles was biphasic and sustained in simulated saliva fluid over 48h. The 3:7 and 0:10 TPGS/TPGS-Cys micelles had a good mucoadhesive property. Meanwhile, only 0:10 TPGS/TPGS-Cys micelles enhanced the permeability through buccal mucosa and potentiated the antifungal activity of ITZ against Candida albicans by at least 1.35 folds as compared to ITZ alone. Therefore, this formulation can be further developed for the transmucosal delivery of ITZ for the treatment of C. albicans. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Self-assembly of micelles in organic solutions of lecithin and bile salt: Mesoscale computer simulation

    Science.gov (United States)

    Markina, A.; Ivanov, V.; Komarov, P.; Khokhlov, A.; Tung, S.-H.

    2016-11-01

    We propose a coarse-grained model for studying the effects of adding bile salt to lecithin organosols by means of computer simulation. This model allows us to reveal the mechanisms of experimentally observed increasing of viscosity upon increasing the bile salt concentration. We show that increasing the bile salt to lecithin molar ratio induces the growth of elongated micelles of ellipsoidal and cylindrical shape due to incorporation of disklike bile salt molecules. These wormlike micelles can entangle into transient network displaying perceptible viscoelastic properties.

  9. Reduction-Triggered Transformation of Crosslinking Modules of Disulfide-Containing Micelles with Chemically Tunable Rates.

    Science.gov (United States)

    Deng, Zhengyu; Yuan, Shuai; Xu, Ronald X; Liang, Haojun; Liu, Shiyong

    2018-05-16

    A dilemma exists between the circulation stability and cargo release/mass diffusion at desired sites for designing delivery nanocarriers and in vivo nanoreactors. We herein report disulfide-crosslinked (DCL) micelles exhibiting reduction-triggered switching of crosslinking modules and synchronized hydrophobic-to-hydrophilic transition. Tumor cell-targeted DCL micelles undergo cytoplasmic milieu-triggered disulfide cleavage and cascade self-immolative decaging reactions at chemically adjustable rates, generating primary amine moieties. Extensive amidation reactions with neighboring ester moieties then occur due to high local concentrations and suppression of apparent amine pKa within hydrophobic cores, leading to the transformation of crosslinking modules and formation of tracelessly crosslinked (TCL) micelles with hydrophilic cores inside live cells. We further integrate this design principle with theranostic nanocarriers for selective intracellular drug transport guided by enhanced magnetic resonance (MR) imaging performance. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Characterization of lipase in reversed micelles formulated by Cibacron Blue F-3GA modified Span 85

    DEFF Research Database (Denmark)

    Zhang, Dong Hao; Guo, Zheng; Sun, Yan

    2007-01-01

    Sorbitan trioleate (Span 85) modified by Cibacron Blue F-3GA (CB) was prepared and used as an affinity surfactant to formulate a reversed micellar system for Candida rugosa lipase (CRL) solubilization. The system was characterized and evaluated by employing CRL-catalyzed hydrolysis of olive oil...... of the encapsulated lipase remained unchanged, but the apparent activity was significantly higher than that of the native enzyme in bulk solution. Kinetic studies indicated that the encapsulated lipase in the reversed micelles of CB-formulated Span 85 followed the Michaelis-Menten equation. The Michaelis constant...... was found to decrease with increasing surfactant concentration, suggesting an increase of the enzyme affinity for the substrate. Stability of the lipase in the reversed micelles was negatively correlated to W0. Introduction Reversed micelles are nanometer-scale transparent aggregates of water and surfactant...

  11. Theory of the Flower Micelle Formation of Amphiphilic Random and Periodic Copolymers in Solution

    Directory of Open Access Journals (Sweden)

    Takahiro Sato

    2018-01-01

    Full Text Available The mixing Gibbs energy Δgm for the flower-micelle phase of amphiphilic random and periodic (including alternating copolymers was formulated on the basis of the lattice model. The formulated Δgm predicts (1 the inverse proportionality of the aggregation number to the degree of polymerization of the copolymer, (2 the increase of the critical micelle concentration with decreasing the hydrophobe content, and (3 the crossover from the micellization to the liquid–liquid phase separation as the hydrophobe content increases. The transition from the uni-core flower micelle to the multi-core flower necklace as the degree of polymerization increases was also implicitly indicated by the theory. These theoretical results were compared with experimental results for amphiphilic random and alternating copolymers reported so far.

  12. Study of the interaction of potassium ion channel protein with micelle by molecular dynamics simulation

    Science.gov (United States)

    Shantappa, Anil; Talukdar, Keka

    2018-04-01

    Ion channels are proteins forming pore inside the body of all living organisms. This potassium ion channel known as KcsA channel and it is found in the each cell and nervous system. Flow of various ions is regulated by the function of the ion channels. The nerve ion channel protein with protein data bank entry 1BL8, which is basically an ion channel protein in Streptomyces Lividans and which is taken up to form micelle-protein system and the system is analyzed by using molecular dynamics simulation. Firstly, ion channel pore is engineered by CHARMM potential and then Micelle-protein system is subjected to molecular dynamics simulation. For some specific micelle concentration, the protein unfolding is observed.

  13. Computer-Mediated Communication (CMC) in L2 Oral Proficiency Development: A Meta-Analysis

    Science.gov (United States)

    Lin, Huifen

    2015-01-01

    The ever growing interest in the development of foreign or second (L2) oral proficiency in a computer-mediated communication (CMC) classroom has resulted in a large body of studies looking at both the direct and indirect effects of CMC interventions on the acquisition of oral competences. The present study employed a quantitative meta-analytic…

  14. Structural properties of self-assembled polymeric micelles

    DEFF Research Database (Denmark)

    Mortensen, K.

    1998-01-01

    At present, the thermodynamic understanding of complex copolymer systems is undergoing important developments. Block copolymers aggregate in selective solvents into micelles of various form and size depending on molecular architecture and interaction parameters. The micelles constitute the basis ...

  15. Corrosion Performance of Carbon Steel in Simulated Pore Solution in the Presence of Micelles

    NARCIS (Netherlands)

    Hu, J.; Koleva, D.A.; De Wit, J.H.W.; Kolev, H.; Van Breugel, K.

    2011-01-01

    This study presents the results on the investigation of the corrosion behavior of carbon steel in model alkaline medium in the presence of very low concentration of polymeric nanoaggregates [0.0024 wt % polyethylene oxide (PEO)113-b-PS70 micelles]. The steel electrodes were investigated in chloride

  16. The structure of P85 pluronic block copolymer micelles determined by small-angle neutron scattering

    DEFF Research Database (Denmark)

    Pedersen, J.S.; Gerstenberg, M.C.

    2003-01-01

    a spherical core of poly(propylene oxide) (PPO) with some water surrounded by a corona of the poly(ethylene oxide) (PEO) block. The latter are non-interacting and obey Gaussian statistics, but are expelled from the core region. The analysis shows that the micelles are fairly concentration and temperature...

  17. Study of the emission oxidative reactions of ruthenium (II) complex by cationic compounds in anionic micelles

    International Nuclear Information System (INIS)

    Bonilha, J.B.S.

    1985-01-01

    The oxidative quenching of the emission of the tetraanionic complex tris (4,4' dicarboxylate - 2,2' - bipyridine ruthenium (II) in aqueous solution, by both organic and inorganic compounds in presence of anionic detergents, above and below the critical micelle concentration is studied. The organic cations, the inorganic ion and detergents used are shown. (M.J.C.) [pt

  18. pKa values of hyodeoxycholic and cholic acids in the binary mixed micelles sodium-hyodeoxycholate-Tween 40 and sodium-cholate-Tween 40: Thermodynamic stability of the micelle and the cooperative hydrogen bond formation with the steroid skeleton.

    Science.gov (United States)

    Poša, Mihalj; Pilipović, Ana; Bećarević, Mirjana; Farkaš, Zita

    2017-01-01

    Due to a relatively small size of bile acid salts, their mixed micelles with nonionic surfactants are analysed. Of the special interests are real binary mixed micelles that are thermodynamically more stable than ideal mixed micelles. Thermodynamic stability is expressed with an excess Gibbs energy (G E ) or over an interaction parameter (β ij ). In this paper sodium salts of cholic (C) and hyodeoxycholic acid (HD) in their mixed micelles with Tween 40 (T40) are analysed by potentiometric titration and their pKa values are determined. Examined bile acids in mixed micelles with T40 have higher pKa values than free bile acids. The increase of ΔpKa acid constant of micellary bound C and HD is in a correlation with absolute values of an interaction parameter. According to an interaction parameter and an excess Gibbs energy, mixed micelle HD-T40 are thermodynamically more stable than mixed micelles C-T40. ΔpKa values are higher for mixed micelles with Tween 40 whose second building unit is HD, related to the building unit C. In both micellar systems, ΔpKa increases with the rise of a molar fraction of Tween 40 in binary mixtures of surfactants with sodium salts of bile acids. This suggests that, ΔpKa can be a measure of a thermodynamic stabilization of analysed binary mixed micelles as well as an interaction parameter. ΔpKa values are confirmed by determination of a distribution coefficient of HD and C in systems: water phase with Tween 40 in a micellar concentration and 1-octanol, with a change of a pH value of a water phase. Conformational analyses suggests that synergistic interactions between building units of analysed binary micelles originates from formation of hydrogen bonds between steroid OH groups and polyoxyethylene groups of the T40. Relative similarity and spatial orientation of C 3 and C 6 OH group allows cooperative formation of hydrogen bonds between T40 and HD - excess entropy in formation of mixed micelle. If a water solution of analysed binary

  19. A CMC conference-focus heads-up. Paper A

    International Nuclear Information System (INIS)

    Plourde, J.

    2011-01-01

    'Predictability' [definition - 'Dependable Outcomes Based on Pre-Verified Plans and Processes'] - is key to nuclear industry public and stakeholder confidence - predictability in public, employee, and environmental safety; in reliable production; in improvement and refurbishment project execution; and in overall financial performance. CMC 2011 addresses this by focusing on; Utility experience with optimally-managed outages in well-run plants, on the ways-of-working processes, tools and behaviors required by the industry to succeed; applying lessons-learned to hugely-complex and scope-expansion prone projects like refurbishments- and eventually new-build. Configuration management, operating chemistry, Utility/Service-Provider interfaces, and intelligent replication are explored along the way. (author)

  20. Analysis of cash flow ratios: A study on CMC

    Directory of Open Access Journals (Sweden)

    Somnath Das

    2018-01-01

    Full Text Available Cash flow ratios help financial users get relevant information about financial resources for a given time. Cash flow ratios are now used more than the traditional ones because it is more effective and justified. Cash flow based ratios are especially surprising because they do not only play a significant role in the credit rating of evaluation, but also forecast the failure of a corporation. In this study, we perform an empirical investigation on a company named CMC. From the study, it is clear that the liquidity and solvency positions of the company were moderate whereas the company maintained low profitability. On the other hand, the efficiency and sufficiency ratios of the study give us a new look on financial judgement.

  1. A CMC conference-focus heads-up. Paper A

    Energy Technology Data Exchange (ETDEWEB)

    Plourde, J. [J.A. Plourde Performance Ltd., Oshawa, Ontario (Canada)

    2011-07-01

    'Predictability' [definition - 'Dependable Outcomes Based on Pre-Verified Plans and Processes'] - is key to nuclear industry public and stakeholder confidence - predictability in public, employee, and environmental safety; in reliable production; in improvement and refurbishment project execution; and in overall financial performance. CMC 2011 addresses this by focusing on; Utility experience with optimally-managed outages in well-run plants, on the ways-of-working processes, tools and behaviors required by the industry to succeed; applying lessons-learned to hugely-complex and scope-expansion prone projects like refurbishments- and eventually new-build. Configuration management, operating chemistry, Utility/Service-Provider interfaces, and intelligent replication are explored along the way. (author)

  2. In situ electron-beam polymerization stabilized quantum dot micelles.

    Science.gov (United States)

    Travert-Branger, Nathalie; Dubois, Fabien; Renault, Jean-Philippe; Pin, Serge; Mahler, Benoit; Gravel, Edmond; Dubertret, Benoit; Doris, Eric

    2011-04-19

    A polymerizable amphiphile polymer containing PEG was synthesized and used to encapsulate quantum dots in micelles. The quantum dot micelles were then polymerized using a "clean" electron beam process that did not require any post-irradiation purification. Fluorescence spectroscopy revealed that the polymerized micelles provided an organic coating that preserved the quantum dot fluorescence better than nonpolymerized micelles, even under harsh conditions. © 2011 American Chemical Society

  3. Targeted therapy for human hepatic carcinoma cells using folate-functionalized polymeric micelles loaded with superparamagnetic iron oxide and sorafenib in vitro

    Directory of Open Access Journals (Sweden)

    Zhang L

    2013-04-01

    Full Text Available Lei Zhang,1 Faming Gong,2 Fang Zhang,3 Jing Ma,1 Peidong Zhang,1 Jun Shen3 1Department of Hepatobiliary and Pancreatic Surgery, 2PCFM Laboratory of Ministry of Education, School of Chemistry and Chemical Engineering, 3Department of Radiology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, People's Republic of China Background: The purpose of this study was to evaluate the inhibitory effect of targeted folate-functionalized micelles containing superparamagnetic iron oxide nanoparticles (SPIONs and sorafenib on human hepatic carcinoma (HepG2 cells in vitro, and to observe the feasibility of surveillance of this targeting therapeutic effect by magnetic resonance imaging. Methods: Sorafenib and SPIONs were loaded into polymeric micelles. The targeted nanocarrier was synthesized by functionalizing the micelles with folate. Folate-free micelles loaded with sorafenib and SPIONs were used as control (nontargeted micelles. Uptake of the nanocarrier by cells was assessed using Prussian blue staining after 1 hour of incubation with the polymeric micelles. The inhibitory effect of the targeted micelles on HepG2 cell proliferation at various concentrations of sorafenib was assessed in vitro using the methyl thiazolyl tetrazolium (MTT assay and apoptotic analysis using flow cytometry. Magnetic resonance imaging using a clinical 1.5 T scanner was performed to detect changes in the signal intensity of cells after incubation with the targeted micelles. Results: Prussian blue staining showed significantly more intracellular SPIONs in cells incubated with the targeted micelles than those incubated with nontargeted micelles. The MTT assay showed that the average inhibitory ratio in the targeted group was significantly higher than that in the nontargeted group (38.13% versus 22.54%, P = 0.028. The mean apoptotic rate in the targeted cells, nontargeted cells, and untreated cells was 17.01%, 11.04%, and 7.89%, respectively. The apoptotic rate in the

  4. Radiochromic leuco dye micelle hydrogels: I. Initial investigation

    International Nuclear Information System (INIS)

    Jordan, Kevin; Avvakumov, Nikita

    2009-01-01

    This investigation reports the use of surfactants and colorless leuco triarylmethane dyes to form a new class of radiochromic micelle hydrogels for three-dimensional (3D) water-equivalent dosimetry. Gelatin gel samples with several surfactants and leuco dyes were prepared and evaluated for optical transparency, dose sensitivity and diffusion rates. The addition of Triton X-100, a non-ionic surfactant, at levels exceeding the critical micelle concentration provides a transparent hydrogel in which the water insoluble leuco Malachite Green (LMG) can dissolve. During irradiation, the LMG dye precursor converts to Malachite Green (MG + ). The most sensitive reported LMG gel formulation contains 0.3 mM LMG leuco dye, 16 mM trichloroacetic acid, 7 mM Triton X-100 and 4% w/w gelatin. A diffusion coefficient of 0.14 mm 2 h -1 was determined for MG + in this gel by fitting the time-dependent degradation of the transmission profile after irradiating half of the sample. The diffusion rate was three times lower than the standard radiochromic ferrous xylenol-orange (FX) gel. The primary feature of this 3D hydrogel is that it introduces transparent, radiochromic, micelle hydrogels. The radiochromic response to dose is instantaneous and images are stable for several hours. A dosimetric characterization revealed that the dose response is reproducible to within 10% over five separate batches and independent of both energy and dose rate. Uniform pre-irradiation of samples to 5 Gy provided a subsequent near linear response to greater than 110 Gy. LMG gels when read with a fast optical CT scanner can provide full 3D dose distributions in less than 30 min post-irradiation. LMG micelle gels scanned with a 633 nm light source are a promising system for quantitative water- or tissue-equivalent 3D dose verification in the 5-100 Gy dose range. These gels are useful for the scanning of larger volume dosimeters (i.e. >15 cm diameter) since they are easily prepared with inexpensive ingredients

  5. "Non-equilibrium" block copolymer micelles with glassy cores: a predictive approach based on theory of equilibrium micelles.

    Science.gov (United States)

    Nagarajan, Ramanathan

    2015-07-01

    Micelles generated in water from most amphiphilic block copolymers are widely recognized to be non-equilibrium structures. Typically, the micelles are prepared by a kinetic process, first allowing molecular scale dissolution of the block copolymer in a common solvent that likes both the blocks and then gradually replacing the common solvent by water to promote the hydrophobic blocks to aggregate and create the micelles. The non-equilibrium nature of the micelle originates from the fact that dynamic exchange between the block copolymer molecules in the micelle and the singly dispersed block copolymer molecules in water is suppressed, because of the glassy nature of the core forming polymer block and/or its very large hydrophobicity. Although most amphiphilic block copolymers generate such non-equilibrium micelles, no theoretical approach to a priori predict the micelle characteristics currently exists. In this work, we propose a predictive approach for non-equilibrium micelles with glassy cores by applying the equilibrium theory of micelles in two steps. In the first, we calculate the properties of micelles formed in the mixed solvent while true equilibrium prevails, until the micelle core becomes glassy. In the second step, we freeze the micelle aggregation number at this glassy state and calculate the corona dimension from the equilibrium theory of micelles. The condition when the micelle core becomes glassy is independently determined from a statistical thermodynamic treatment of diluent effect on polymer glass transition temperature. The predictions based on this "non-equilibrium" model compare reasonably well with experimental data for polystyrene-polyethylene oxide diblock copolymer, which is the most extensively studied system in the literature. In contrast, the application of the equilibrium model to describe such a system significantly overpredicts the micelle core and corona dimensions and the aggregation number. The non-equilibrium model suggests ways to

  6. Fabrication and characterization of nuclear localization signal-conjugated glycol chitosan micelles for improving the nuclear delivery of doxorubicin

    Directory of Open Access Journals (Sweden)

    Zhao J

    2012-09-01

    Full Text Available Jingmou Yu,1 Xin Xie,1 Meirong Zheng,1 Ling Yu,2 Lei Zhang,1 Jianguo Zhao,1 Dengzhao Jiang,1 Xiangxin Che11Key Laboratory of Systems Biology Medicine of Jiangxi Province, College of Basic Medical Science, Jiujiang University, Jiujiang, 2Division of Nursing, 2nd Affiliated Hospital, Yichun University, Yichun, People's Republic of ChinaBackground: Supramolecular micelles as drug-delivery vehicles are generally unable to enter the nucleus of nondividing cells. In the work reported here, nuclear localization signal (NLS-modified polymeric micelles were studied with the aim of improving nuclear drug delivery.Methods: In this research, cholesterol-modified glycol chitosan (CHGC was synthesized. NLS-conjugated CHGC (NCHGC was synthesized and characterized using proton nuclear magnetic resonance spectroscopy, dynamic light scattering, and fluorescence spectroscopy. Doxorubicin (DOX, an anticancer drug with an intracellular site of action in the nucleus, was chosen as a model drug. DOX-loaded micelles were prepared by an emulsion/solvent evaporation method. The cellular uptake of different DOX formulations was analyzed by flow cytometry and confocal laser scanning microscopy. The cytotoxicity of blank micelles, free DOX, and DOX-loaded micelles in vitro was investigated by 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT assay in HeLa and HepG2 cells.Results: The degree of substitution was 5.9 cholesterol and 3.8 NLS groups per 100 sugar residues of the NCHGC conjugate. The critical aggregation concentration of the NCHGC micelles in aqueous solution was 0.0209 mg/mL. The DOX-loaded NCHGC (DNCHGC micelles were observed as being almost spherical in shape under transmission electron microscopy, and the size was determined as 248 nm by dynamic light scattering. The DOX-loading content of the DNCHGC micelles was 10.1%. The DOX-loaded micelles showed slow drug-release behavior within 72 hours in vitro. The DNCHGC micelles exhibited greater

  7. Stability of casein micelles in milk

    Science.gov (United States)

    Tuinier, R.; de Kruif, C. G.

    2002-07-01

    Casein micelles in milk are proteinaceous colloidal particles and are essential for the production of flocculated and gelled products such as yogurt, cheese, and ice-cream. The colloidal stability of casein micelles is described here by a calculation of the pair potential, containing the essential contributions of brush repulsion, electrostatic repulsion, and van der Waals attraction. The parameters required are taken from the literature. The results are expressed by the second osmotic virial coefficient and are quite consistent with experimental findings. It appears that the stability is mainly attributable to a steric layer of κ-casein, which can be described as a salted polyelectrolyte brush.

  8. Nitrile group as infrared probe for the characterization of the conformation of bovine serum albumin solubilized in reverse micelles.

    Science.gov (United States)

    Xue, Luyan; Zou, Feixue; Zhao, Yin; Huang, Xirong; Qu, Yinbo

    2012-11-01

    Infrared spectroscopy is a powerful technique for structure characterization. For a protein hosted in a reversed micellar medium, the spectral features of the protein are always interfered by the IR absorption bands of the medium in addition to the congestion in their IR spectra. Fortunately, there is a transparent window in the 2500-2200 cm(-1) region. Incorporation of a vibrational probe with IR absorption frequencies in this region into proteins represents a promising strategy for the study of the conformation of a protein in a reverse micelle. In the present work, we incorporated 4-cyanobenzyl group (CN) into bovine serum albumin (BSA) via cysteine alkylation reactions under mild conditions. Circular dichroism spectroscopy showed that the CN modified BSA (CNBSA) could retain its conformation. When CNBSA was hosted in AOT reverse micelle, it was found that the nitrile group on BSA was sensitive to the conformational change of BSA induced by urea as an additive in the reverse micelle. The peak splitting of nitrile group was also observed when the size of AOT reverse micelle and the concentration of an electrolyte were varied. Obviously, the shift of the IR absorption peak and/or peak splitting of nitrile group on BSA are correlated with the change of BSA conformation in AOT reverse micelle. So we conclude that the nitrile infrared probe can be used to study protein conformation in a reverse micelle. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Bioavailability Enhancement of Paclitaxel via a Novel Oral Drug Delivery System: Paclitaxel-Loaded Glycyrrhizic Acid Micelles

    Directory of Open Access Journals (Sweden)

    Fu-Heng Yang

    2015-03-01

    Full Text Available Paclitaxel (PTX, taxol, a classical antitumor drug against a wide range of tumors, shows poor oral bioavailability. In order to improve the oral bioavailability of PTX, glycyrrhizic acid (GA was used as the carrier in this study. This was the first report on the preparation, characterization and the pharmacokinetic study in rats of PTX-loaded GA micelles The PTX-loaded micelles, prepared with ultrasonic dispersion method, displayed small particle sizes and spherical shapes. Differential scanning calorimeter (DSC thermograms indicated that PTX was entrapped in the GA micelles and existed as an amorphous state. The encapsulation efficiency was about 90%, and the drug loading rate could reach up to 7.90%. PTX-loaded GA micelles displayed a delayed drug release compared to Taxol in the in vitro release experiment. In pharmacokinetic study via oral administration, the area under the plasma concentration-time curve (AUC0→24 h of PTX-loaded GA micelles was about six times higher than that of Taxol (p < 0.05. The significant oral absorption enhancement of PTX from PTX-loaded GA micelles could be largely due to the increased absorption in jejunum and colon intestine. All these results suggested that GA would be a promising carrier for the oral delivery of PTX.

  10. In vitro and in vivo evaluation of docetaxel-loaded stearic acid-modified Bletilla striata polysaccharide copolymer micelles.

    Directory of Open Access Journals (Sweden)

    Qingxiang Guan

    Full Text Available Bletilla striata polysaccharides (BSPs have been used in pharmaceutical and biomedical industry, the aim of the present study was to explore a BSPs amphiphilic derivative to overcome its application limit as poorly water-soluble drug carriers due to water-soluble polymers. Stearic acid (SA was selected as a hydrophobic block to modify B. striata polysaccharides (SA-BSPs. Docetaxel (DTX-loaded SA-BSPs (DTX-SA-BSPs copolymer micelles were prepared and characterized. The DTX release percentage in vitro and DTX concentration in vivo was carried out by using high performance liquid chromatography. HepG2 and HeLa cells were subjected to MTT (3-(4, 5-dimethylthiazol-2-yl-2, 5-diphenyl tetrazonium bromide assay to evaluate the cell viability. In vitro evaluation of copolymer micelles showed higher drug encapsulation and loading capacity. The release percentage of DTX from DTX-SA-BSPs copolymer micelles and docetaxel injection was 66.93 ± 1.79% and 97.06 ± 1.56% in 2 days, respectively. The DTX-SA-BSPs copolymer micelles exhibited a sustained release of DTX. A 50% increase in growth inhibition was observed for HepG2 cells treated with DTX-SA-BSPs copolymer micelles as compared to those treated with docetaxel injection for 72 h. DTX-SA-BSPs copolymer micelles presented a similar growth inhibition effect on Hela cells. Furthermore, absolute bioavailability of DTX-SA-BSPs copolymer micelles was shown to be 1.39-fold higher than that of docetaxel injection. Therefore, SA-BSPs copolymer micelles may be used as potential biocompatible polymers for cancer chemotherapy.

  11. Qualification Approach for the CMC Nose Cap of X-38

    Science.gov (United States)

    Weihs, H.; Gülhan, A.

    2002-01-01

    In October 2001 the flight hardware of the TPS nose assembly of X-38 has been installed at the main structure of the X-38 V201 vehicle at NASA's Johnson Space Center, Houston Texas. X-38 is a test vehicle for the planned Crew Return Vehicle CRV for the International Space Station ISS. Currently the flight of the X-38 is scheduled for 2005. Besides the Body flaps (MAN-T) and the nose skirt system (ASTRIUM, MAN-T) the nose cap system is one of the essential hot structure components that were developed within Germany's national TETRA (Technologies for future space transportation systems) programme. The integration of the hardware was an important milestone for the nose cap development which started approx. 5 years ago. DLR-Stuttgart is responsible for the design and manufacturing of the CMC based nose cap system, which has to withstand the extreme thermal loads during re-entry which will induce a maximum temperature up to 1750 °C on the surface of the cap. Thus, the shell of the cap system is designed and manufactured using DLR's C/C-SiC material which is a special kind of carbon based ceramic matrix composite (CMC) material produced via the in house liquid silicon infiltration process of DLR. This material has demonstrated its good temperature resistance during FOTON and EXPRESS re-entry capsule missions. Besides the design and manufacturing of the nose cap system, the qualification approach was an important effort of the development work. Missing a test facility which is able to simulate all loading conditions from lift off to re-entry and landing, is was necessary to separate the loads and to use different test facilities. Considering the limitations of the facilities, the budget and time constraints, an optimized test philosophy has been established. The goal was to use a full scale qualification unit including all TPS components of the nose area for most of the tests. These were the simulation of ascent loads given by the shuttle requirements and descent loads

  12. Reverse micelles as a tool for probing solvent modulation of protein dynamics: Reverse micelle encapsulated hemoglobin☆

    OpenAIRE

    Roche, Camille J.; Dantsker, David; Heller, Elizabeth R.; Sabat, Joseph E.; Friedman, Joel M.

    2013-01-01

    Hydration waters impact protein dynamics. Dissecting the interplay between hydration waters and dynamics requires a protein that manifests a broad range of dynamics. Proteins in reverse micelles (RMs) have promise as tools to achieve this objective because the water content can be manipulated. Hemoglobin is an appropriate tool with which to probe hydration effects. We describe both a protocol for hemoglobin encapsulation in reverse micelles and a facile method using PEG and cosolvents to mani...

  13. Mechano-responsive hydrogels crosslinked by reactive block copolymer micelles

    Science.gov (United States)

    Xiao, Longxi

    Hydrogels are crosslinked polymeric networks that can swell in water without dissolution. Owing to their structural similarity to the native extracelluar matrices, hydrogels have been widely used in biomedical applications. Synthetic hydrogels have been designed to respond to various stimuli, but mechanical signals have not incorporated into hydrogel matrices. Because most tissues in the body are subjected to various types of mechanical forces, and cells within these tissues have sophisticated mechano-transduction machinery, this thesis is focused on developing hydrogel materials with built-in mechano-sensing mechanisms for use as tissue engineering scaffolds or drug release devices. Self-assembled block copolymer micelles (BCMs) with reactive handles were employed as the nanoscopic crosslinkers for the construction of covalently crosslinked networks. BCMs were assembled from amphiphilic diblock copolymers of poly(n-butyl acrylate) and poly(acrylic acid) partially modified with acrylate. Radical polymerization of acrylamide in the presence of micellar crosslinkers gave rise to elastomeric hydrogels whose mechanical properties can be tuned by varying the BCM composition and concentration. TEM imaging revealed that the covalently integrated BCMs underwent strain-dependent reversible deformation. A model hydrophobic drug, pyrene, loaded into the core of BCMs prior to the hydrogel formation, was dynamically released in response to externally applied mechanical forces, through force-induced reversible micelle deformation and the penetration of water molecules into the micelle core. The mechano-responsive hydrogel has been studied for tissue repair and regeneration purposes. Glycidyl methacrylate (GMA)-modified hyaluronic acid (HA) was photochemically crosslinked in the presence of dexamethasone (DEX)-loaded crosslinkable BCMs. The resultant HA gels (HAxBCM) contain covalently integrated micellar compartments with DEX being sequestered in the hydrophobic core. Compared

  14. Micelle-encapsulated fullerenes in aqueous electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Ala-Kleme, T., E-mail: timo.ala-kleme@utu.fi [Department of Chemistry, University of Turku, 20014 Turku (Finland); Maeki, A.; Maeki, R.; Kopperoinen, A.; Heikkinen, M.; Haapakka, K. [Department of Chemistry, University of Turku, 20014 Turku (Finland)

    2013-03-15

    Different micellar particles Mi(M{sup +}) (Mi=Triton X-100, Triton N-101 R, Triton CF-10, Brij-35, M{sup +}=Na{sup +}, K{sup +}, Cs{sup +}) have been prepared in different aqueous H{sub 3}BO{sub 3}/MOH background electrolytes. It has been observed that these particles can be used to disperse the highly hydrophobic spherical [60]fullerene (1) and ellipsoidal [70]fullerene (2). This dispersion is realised as either micelle-encapsulated monomers Mi(M{sup +})1{sub m} and Mi(M{sup +})2{sub m} or water-soluble micelle-bound aggregates Mi(M{sup +})1{sub agg} and Mi(M{sup +})2{sub agg}, where especially the hydration degree and polyoxyethylene (POE) thickness of the micellar particle seems to play a role of vital importance. Further, the encapsulation microenvironment of 1{sub m} was found to depend strongly on the selected monovalent electrolyte cation, i.e., the encapsulated 1{sub m} is accommodated in the more hydrophobic microenvironment the higher the cationic solvation number is. - Highlights: Black-Right-Pointing-Pointer Different micellar particles is used to disperse [60]fullerene and [70]fullerene. Black-Right-Pointing-Pointer Fullerene monomers or aggregates are dispersed encaging or bounding by micelles. Black-Right-Pointing-Pointer Effective facts are hydration degree and polyoxyethylene thickness of micelle.

  15. Hyaluronan polymeric micelles for topical drug delivery

    Czech Academy of Sciences Publication Activity Database

    Šmejkalová, D.; Muthný, T.; Nešporová, K.; Hermannová, M.; Achbergerová, E.; Huerta-Angelesa, G.; Marek Svoboda, M.; Čepa, M.; Machalová, V.; Luptáková, Dominika; Velebný, V.

    2017-01-01

    Roč. 156, JAN 20 (2017), s. 86-96 ISSN 0144-8617 Institutional support: RVO:61388971 Keywords : Skin penetration * Polymeric micelle * Hyaluronan Subject RIV: CE - Biochemistry OBOR OECD: Biochemistry and molecular biology Impact factor: 4.811, year: 2016

  16. SANS analysis of aqueous ionic perfluoropolyether micelles

    CERN Document Server

    Gambi, C M C; Chittofrati, A; Pieri, R; Baglioni, P; Teixeira, J

    2002-01-01

    Preliminary SANS results of ionic chlorine terminated perfluoropolyether micelles in water are given. The experimental spectra have been analyzed by a two-shell ellipsoidal model for the micellar form factor and a screened Coulombic plus hard-sphere repulsion potential for the structure factor. (orig.)

  17. Co-assembly towards Janus micelles

    NARCIS (Netherlands)

    Voets, I.K.; Leermakers, F.A.M.; Keizer, de A.; Charlaganov, M.; Cohen Stuart, M.A.

    2011-01-01

    In this paper, we report on our recent findings concerning the structure of complex coacervate core micelles composed of two types of (complementary) block copolymers. Both copolymers have a polyelectrolyte (one cationic and the other anionic) block combined with a neutral one. The opposite charges

  18. Effect of sucrose ester concentration on the interfacial characteristics and physical properties of sodium caseinate-stabilized oil-in-water emulsions.

    Science.gov (United States)

    Zhao, Qiangzhong; Liu, Daolin; Long, Zhao; Yang, Bao; Fang, Min; Kuang, Wanmei; Zhao, Mouming

    2014-05-15

    The effect of sucrose ester (SE) concentration on interfacial tension and surface dilatational modulus of SE and sodium caseinate (NaCas)-SE solutions were investigated. The critical micelle concentration (CMC) of SE was presumed to be 0.05% by measuring interfacial tension of SE solution. The interfacial tension of NaCas-SE solution decreased with increased SE concentration. A sharp increase in surface dilatational modulus of NaCas solution was observed when 0.01% SE was added and a decline was occurred at higher SE level. The influence of SE concentration on droplet size and confocal micrograph, surface protein concentration, ζ-potential and rheological properties of oil-in-water (O/W) emulsions prepared with 1% NaCas was also examined. The results showed that addition of SE reduced droplet size and surface protein concentration of the O/W emulsions. The ζ-potential of the O/W emulsions increased initially and decreased afterward with increased SE concentration. All the O/W emulsions exhibited a shear-thinning behaviour and the data were well-fitted into the Herschel-Bulkley model. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Casein maps: Effect of ethanol, pH, temperature, and CaCl2 on the particle size of reconstituted casein micelles

    Science.gov (United States)

    Ye, Ran; Harte, Federico

    2015-01-01

    Although conditions favoring casein micelle aggregation are well known, factors promoting the dissociation of the casein micelle are not fully understood. It was our objective to investigate the ethanol-induced dissociation of micellar casein as affected by temperature and a wide range of pH, along with the concentrations of calcium and casein. Two different concentrations of casein micelles were dispersed in imidazole buffer with 0 to 80% ethanol (vol/vol) and 2 and 10 mM calcium. Apparent micelle size was determined by dynamic light scattering at 5, 30, and 60°C. In the absence of ethanol, casein precipitation occurred at pH 4.6 in imidazole buffer. Ten to forty percent ethanol promoted casein aggregation (>1,000 nm) and higher temperature (30 and 60°C) enhanced this effect. Higher ethanol concentrations at 50 to 80% induced the dissociation (casein micelle upon acidification (pH 8) in imidazole buffer. In addition, higher concentrations of casein (0.25 mg/mL) and calcium (20 mM) caused the formation of larger aggregates (>1,000 nm) in the presence of ethanol when comparing with the initial lower concentrations of casein (0.1 mg/mL) and calcium (2 mM). Casein micelle dissociation can be achieved near the isoelectric pH by modifying the solvent composition and temperature. PMID:23200467

  20. Peer Evaluation in CMC Learning Environment and Writing Skill

    Directory of Open Access Journals (Sweden)

    Morteza Mellati

    2014-09-01

    Full Text Available Peer evaluation and technology-based instruction as the various domains of language teaching perspectives might affect language development. Group work in a technology-based environment might be more successful when learners are involved in developing the assessment process particularly peer assessment. This study investigated the effectiveness of peer evaluation in technology-based language environment and its effects on English writing ability. To reach this goal, 70 Iranian learners were participated in English language writing context. They were divided into two groups, one group assigned to CMC (Computer-Mediated Communication language learning context and the other assigned to a traditional learning environment. Both groups were encouraged to evaluate their classmates’ writing tasks. In addition, interviews were conducted with two learners. Comparing these two groups provides comprehensive guidelines for teachers as well as curriculum designers to set adjusted writing language environment for more effective and creative language teaching and learning. E-collaboration classroom tasks have high intrinsic motivation as well as significant effects on learners’ outcomes. Cooperative tasks specifically in technology-based environment lead learners to group working and consequently group learning. Computer-Mediated Communication is meaningful, especially in contexts in which teachers stimulate group work activities.

  1. Bactericidal Effect of Lauric Acid-Loaded PCL-PEG-PCL Nano-Sized Micelles on Skin Commensal Propionibacterium acnes

    Directory of Open Access Journals (Sweden)

    Thi-Quynh-Mai Tran

    2016-08-01

    Full Text Available Acne is the over growth of the commensal bacteria Propionibacterium acnes (P. acnes on human skin. Lauric acid (LA has been investigated as an effective candidate to suppress the activity of P. acnes. Although LA is nearly insoluble in water, dimethyl sulfoxide (DMSO has been reported to effectively solubilize LA. However, the toxicity of DMSO can limit the use of LA on the skin. In this study, LA-loaded poly(ɛ-caprolactone-poly(ethylene glycol-poly(ɛ-caprolactone micelles (PCL-PEG-PCL were developed to improve the bactericidal effect of free LA on P. acnes. The block copolymers mPEG-PCL and PCL-PEG-PCL with different molecular weights were synthesized and characterized using 1H Nuclear Magnetic Resonance spectroscopy (1H NMR, Fourier-transform infrared spectroscopy (FT-IR, Gel Permeation Chromatography (GPC, and Differential Scanning Calorimetry (DSC. In the presence of LA, mPEG-PCL diblock copolymers did not self-assemble into nano-sized micelles. On the contrary, the average particle sizes of the PCL-PEG-PCL micelles ranged from 50–198 nm for blank micelles and 27–89 nm for LA-loaded micelles. The drug loading content increased as the molecular weight of PCL-PEG-PCL polymer increased. Additionally, the minimum inhibitory concentration (MIC and the minimum bactericidal concentration (MBC of free LA were 20 and 80 μg/mL, respectively. The MICs and MBCs of the micelles decreased to 10 and 40 μg/mL, respectively. This study demonstrated that the LA-loaded micelles are a potential treatment for acne.

  2. A case study of learning writing in service-learning through CMC

    Science.gov (United States)

    Li, Yunxiang; Ren, LiLi; Liu, Xiaomian; Song, Yinjie; Wang, Jie; Li, Jiaxin

    2011-06-01

    Computer-mediated communication ( CMC ) through online has developed successfully with its adoption by educators. Service Learning is a teaching and learning strategy that integrates community service with academic instruction and reflection to enrich students further understanding of course content, meet genuine community needs, develop career-related skills, and become responsible citizens. This study focuses on an EFL writing learning via CMC in an online virtual environment of service places by taking the case study of service Learning to probe into the scoring algorithm in CMC. The study combines the quantitative and qualitative research to probe into the practical feasibility and effectiveness of EFL writing learning via CMC in service learning in China.

  3. Calibration of 3D Woven Preform Design Code for CMC Materials, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Mechanical and thermal performance of CMC components benefit from low part count, integrally fabricated designs of 3D woven reinforcement. The advantages of these...

  4. Statistical applications for chemistry, manufacturing and controls (CMC) in the pharmaceutical industry

    CERN Document Server

    Burdick, Richard K; Pfahler, Lori B; Quiroz, Jorge; Sidor, Leslie; Vukovinsky, Kimberly; Zhang, Lanju

    2017-01-01

    This book examines statistical techniques that are critically important to Chemistry, Manufacturing, and Control (CMC) activities. Statistical methods are presented with a focus on applications unique to the CMC in the pharmaceutical industry. The target audience consists of statisticians and other scientists who are responsible for performing statistical analyses within a CMC environment. Basic statistical concepts are addressed in Chapter 2 followed by applications to specific topics related to development and manufacturing. The mathematical level assumes an elementary understanding of statistical methods. The ability to use Excel or statistical packages such as Minitab, JMP, SAS, or R will provide more value to the reader. The motivation for this book came from an American Association of Pharmaceutical Scientists (AAPS) short course on statistical methods applied to CMC applications presented by four of the authors. One of the course participants asked us for a good reference book, and the only book recomm...

  5. Canadian Meteorological Centre (CMC) Daily Snow Depth Analysis Data, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set consists of a Northern Hemisphere subset of the Canadian Meteorological Centre (CMC) operational global daily snow depth analysis. Data include daily...

  6. Proximity and Force Characteristics of CMC Touch Sensor with Square/Dome-shaped Sensor Elements

    International Nuclear Information System (INIS)

    Kawamura, T; Inaguma, N; Kakizaki, Y; Yamada, H; Tani, K

    2013-01-01

    A tactile sensor called Carbon Micro Coil (CMC) touch sensor was developed by CMC Technology Development Co., Ltd. The sensor's elements used in the experiments of this paper are made of silicon rubber containing CMCs several micrometers in diameter. One of the elements is molded into a square 30 mm on a side and 3 mm thick; the other is a dome 16 mm in diameter and 2 mm height. CMCs in the sensor element contribute to the electrical conductivity and the sensor element is considered to constitute an LCR circuit. When an object approaches to the sensor element or the sensor element is deformed mechanically, the impedance changes, and the CMC sensor detects the impedance changes by measuring the modulation of amplitude and phase of an input excitation signal to the sensor element. The CMC sensor also creates voltage signals of the R- and LC-components separately according to the amplitude and phase modulation. In this paper, the characteristics of the CMC sensor with respect to its proximity and force senses are investigated. First, the output of the CMC sensor with the square-shaped sensor element is measured when an object approaches to the sensor element. Next, the output of the CMC sensor with the dome-shaped sensor element is measured when fine deformations of 1 to 5 μm are applied to the sensor element under variable compression force. The results suggest that the CMC sensor can measure the force variance applied to the sensor element as well as the distance between the sensor element and an object.

  7. The dynamic magnetoviscoelastic properties of biomineralized (Fe3O4) PVP-CMC hydrogel

    Science.gov (United States)

    Ray, Ayan; Saha, Nabanita; Saha, Petr

    2017-05-01

    The Polyvinylpyrrolidone (PVP) and carboxymethylcellulose (CMC) based polymer matrix was used as a template for the preparation of magnetic hydrogel. This freshly prepared PVP-CMC hydrogel template was successfully mineralized by in situ synthesis of magnetic nanoparticles (Fe3O4) via chemical co-precipitation reaction using liquid diffusion method. The present study emphasizes on the rheological behavior of non-mineralized and mineralized PVP-CMC hydrogels. Scanning Electron Microscopy (SEM), transmission electron microscopy (TEM), X-ray Diffraction (XRD) pattern, Fourier transform infrared spectroscopy (FT-TR), Vibrating sample magnetometer (VSM) and dynamic magneto rheometer were used to study the morphological, physical, chemical and magnetic properties of nanoparticle (Fe3O4) filled PVP-CMC hydrogel respectively in order to monitor how Fe3O4 magnetic nanoparticles affects the mechanical properties of the hydrogel network. The storage (G') and loss (G") moduli with a complex viscosity of the system was measured using a parallel plate rheometer. Frequency and amplitude sweep with temperature variation was performed to determine the frequency and amplitude dependent magneto viscoelastic moduli for both hydrogel samples. A strong shear thinning effect was observed in both (non-mineralized and mineralized) PVP-CMC hydrogels, which confirm that Fe3O4 filled magnetic hydrogels, are pseudoplastic in nature. This Fe3O4 filled PVP-CMC hydrogel can be considered as stimuli-responsive soft matter that may be used as an actuator in medical devices.

  8. Specific interactions within micelle microenvironment in different charged dye/surfa

    Directory of Open Access Journals (Sweden)

    Adina Roxana Petcu

    2016-01-01

    Full Text Available The interactions of two ionic dyes, Crystal Violet and Methyl Orange, with different charged surfactants and also with a nonionic surfactant were investigated using surface tension measurements and visible spectroscopy in pre-micellar and post-micellar regions. It was found that for the water dominant phase systems the dye was localized between the polar heads, at the exterior of the direct micelle shells for all the systems. For the oil dominant phase systems, in case of the same charged dye/surfactant couples, the dye was localized in the micelle shell between the hydrocarbon chain of the surfactant nearby the hydrophilic head groups while for nonionic surfactant and oppositely charged dye/surfactant, localization of dye was between the oxyethylenic head groups towards the interior of the micelle core. Mixed aggregates of the dye and surfactant (below the critical micellar concentration of cationic surfactant, dye-surfactant ion pair and surfactant-micelles were present. The values of equilibrium constants (for TX-114/MO and TX-114/CV systems were 0.97 and 0.98, respectively, partition coefficients between the micellar and bulk water phases and standard free energy (for the nonionic systems were −12.59 kJ/mol for MO and −10.97 kJ/mol for CV were calculated for all the studied systems. The partition processes were exothermic and occurred spontaneously.

  9. Time-resolved fluorescence quenching studies of sodium lauryl ether sulfate micelles

    International Nuclear Information System (INIS)

    Friedrich, Leidi C.; Silva, Volnir O.; Quina, Frank H.; Moreira Junior, Paulo F.; Tcacenco, Celize M.

    2013-01-01

    Aggregation numbers (N Ag ) of micelles of the commercial anionic detergent sodium lauryl ether sulfate (SLES), with an average of two ethylene oxide subunits, were determined at 30 and 40 deg C by the time-resolved fluorescence quenching method with pyrene as the fluorescent probe and the N-hexadecylpyridinium ion as the quencher. The added-salt dependent growth of SLES micelles (γ = 0.11-0.15, where γ is the slope of a plot of log aggregation number vs. log [Y aq ] and [Y aq ] is the sodium counterion concentration free in the intermicellar aqueous phase) is found to be significantly lower than that of sodium alkyl sulfate micelles (γ ca. 0.25), a difference attributed to the larger headgroup size of SLES. The I 1 /I 3 vibronic intensity ratio and the rate constant for intramicellar quenching of pyrene show that the pyrene solubilization microenvironment and the intramicellar microviscosity are insensitive to micelle size or the presence of added salt. (author)

  10. New thiol-responsive mono-cleavable block copolymer micelles labeled with single disulfides.

    Science.gov (United States)

    Sourkohi, Behnoush Khorsand; Schmidt, Rolf; Oh, Jung Kwon

    2011-10-18

    Thiol-responsive symmetric triblock copolymers having single disulfide linkages in the middle blocks (called mono-cleavable block copolymers, ss-ABP(2)) were synthesized by atom transfer radical polymerization in the presence of a disulfide-labeled difunctional Br-initiator. These brush-like triblock copolymers consist of a hydrophobic polyacrylate block having pendent oligo(propylene oxide) and a hydrophilic polymethacrylate block having pendent oligo(ethylene oxide). Gel permeation chromatography and (1)H NMR results confirmed the synthesis of well-defined mono-cleavable block copolymers and revealed that polymerizations were well controlled. Because of amphiphilic nature, these copolymers self-assembled to form colloidally stable micelles above critical micellar concentration of 0.032 mg · mL(-1). In response to reductive reactions, disulfides in thiol-responsive micelles were cleaved. Atomic force microscopy and dynamic light scattering analysis suggested that the cleavage of disulfides caused dissociation of micelles to smaller-sized assembled structures in water. Moreover, in a biomedical perspective, the mono-cleavable block copolymer micelles are not cytotoxic and thus biocompatible. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Glutathione responsive micelles incorporated with semiconducting polymer dots and doxorubicin for cancer photothermal-chemotherapy

    Science.gov (United States)

    Cai, Zhixiong; Zhang, Da; Lin, Xinyi; Chen, Yunzhu; Wu, Ming; Wei, Zuwu; Zhang, Zhenxi; Liu, Xiaolong; Yao, Cuiping

    2017-10-01

    Nanoplatform integrated with photothermal therapy (PTT) and chemotherapy has been recognized a promising agent for enhancing cancer therapeutic outcomes, but still suffer from less controllability for optimizing their synergistic effects. We fabricated glutathione (GSH) responsive micelles incorporated with semiconducting polymer dots and doxorubicin (referred as SPDOX NPs) for combining PTT with chemotherapy to enhance cancer therapeutic efficiency. These micelles, with excellent water dispersibility, comprises of three distinct functional components: (1) the monomethoxy-poly(ethylene glycol)-S-S-hexadecyl (mPEG-S-S-C16), which forms the micelles, can render hydrophobic substances water-soluble and improve the colloidal stability; (2) disulfide linkages can be cleaved in a reductive environment for tumor specific drug release due to the high GSH concentrations of tumor micro-environment; (3) PCPDTBT dots and anti-cancer drug DOX that are loaded inside the hydrophobic core of the micelle can be applied to simultaneously perform PTT and chemotherapy to achieve significantly enhanced tumor killing efficiency both in vitro and in vivo. In summary, our studies demonstrated that our SPDOX NPs with simultaneous photothermal-chemotherapy functions could be a promising platform for a tumor specific responsive drug delivery system.

  12. Structural investigation of diglycerol monolaurate reverse micelles in nonpolar oils cyclohexane and octane

    International Nuclear Information System (INIS)

    Shrestha, Lok Kumar; Aramaki, Kenji

    2009-01-01

    Structure of diglycerol monolaurate (abbreviated as C 12 G 2 ) micelles in nonpolar oils cyclohexane and n-octane as a function of compositions, temperatures, and surfactant chain length has been investigated by small-angle X-ray scattering (SAXS). The SAXS data were evaluated by the generalized indirect Fourier transformation (GIFT) method and real-space structural information of particles was achieved. Conventional poly(oxyethylene) type nonionic surfactants do not form reverse micelles in oils unless a trace water is added. However, present surfactant C 12 G 2 formed reverse micelle (RM) in cyclohexane and n-octane without addition of water at normal room temperature. A clear signature of one dimensional (1-D) micellar growth was found with increasing C 12 G 2 concentration. On the other hand, increasing temperature or hydrocarbon chain length of surfactant shorten the length of RM, which is essentially a cylinder-to-sphere type transition in the aggregate structure. Drastic changes in the structure of RM, namely, transition of ellipsoidal prolate to long rod-like micelles was observed upon changing oil from cyclohexane to octane. All the microstructural transitions were explained in terms of critical packing parameter. (author)

  13. Time-resolved fluorescence quenching studies of sodium lauryl ether sulfate micelles

    Energy Technology Data Exchange (ETDEWEB)

    Friedrich, Leidi C.; Silva, Volnir O.; Quina, Frank H., E-mail: quina@usp.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto de Quimica; Moreira Junior, Paulo F. [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Escola Politecnica. Departamento de Engenharia Quimica; Tcacenco, Celize M. [Fundacao Instituto de Ensino para Osasco (FIEO/UNIFIEO), SP (Brazil). Centro Universitario FIEO. Centro de Estudos Quimicos

    2013-02-15

    Aggregation numbers (N{sub Ag}) of micelles of the commercial anionic detergent sodium lauryl ether sulfate (SLES), with an average of two ethylene oxide subunits, were determined at 30 and 40 deg C by the time-resolved fluorescence quenching method with pyrene as the fluorescent probe and the N-hexadecylpyridinium ion as the quencher. The added-salt dependent growth of SLES micelles ({gamma} = 0.11-0.15, where {gamma} is the slope of a plot of log aggregation number vs. log [Y{sub aq}] and [Y{sub aq}] is the sodium counterion concentration free in the intermicellar aqueous phase) is found to be significantly lower than that of sodium alkyl sulfate micelles ({gamma} ca. 0.25), a difference attributed to the larger headgroup size of SLES. The I{sub 1}/I{sub 3} vibronic intensity ratio and the rate constant for intramicellar quenching of pyrene show that the pyrene solubilization microenvironment and the intramicellar microviscosity are insensitive to micelle size or the presence of added salt. (author)

  14. Controlled release of 9-nitro-20(S)-camptothecin from methoxy poly(ethylene glycol)-poly(D,L-lactide) micelles

    Energy Technology Data Exchange (ETDEWEB)

    Gao, J M [College of Material Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Ming, J [Department of Medicament, The Second People' s Hospital of Sichuan, Chengdu 610041 (China); He, B; Gu, Z W; Zhang, X D [National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064 (China)], E-mail: zwgu@scu.edu.cn

    2008-03-01

    9-nitro-20(S)-camptothecin (9-NC) is a potent topoisomerase-I inhibitor, and it was applied for clinical trials in cancer treatment. However, the applications of 9-NC were limited by its poor solubility and instability. In order to overcome these disadvantages, 9-NC was encapsulated in amphiphilic copolymer micelles composed of methoxy poly(ethylene glycol)-b-poly(D,L-lactide) (mPEG-PDLLA, PELA). Three diblock copolymers with different PDLLA chain lengths were synthesized. The critical micelle concentration was varied from 10{sup -4} g L{sup -1} to 10{sup -2} g L{sup -1}. The 9-NC loaded micelles were nanospheres with diameters ranging from 30 nm to 60 nm. The relationship between the composition of copolymers and the drug loading content was discussed. The encapsulation of micelles improved the solubility of 9-NC greatly. The solubility of 9-NC in micelle M1 was about 250 times higher than that of 9-NC in a phosphate buffer solution (PBS). The stability of 9-NC in micelles was also promoted. After being incubated in PBS for 160 min, 80% of 9-NC in micelles existed as an active lactone form, while 85% of 9-NC in PBS were transferred to an inactive carboxylate salt form. The release experiments were carried out in PBS and the results showed that the release processes were controllable.

  15. Potential of L-fucose isolated from Brown Seaweeds as Promising Natural Emulsifier compare to Carboxymethyl Cellulose (CMC)

    Science.gov (United States)

    Al-Baarri, A. N.; Legowo, A. M.; Widayat; Abduh, S. B. M.; Lestari, F. P.; Desnasari, D.; Santoso, I. P. M.

    2018-02-01

    L-fucose has been understood as sulfated polysaccharides and it could be extracted and fractionated from brown algae. These polysaccharides contains carbohydrate, sulfate, and protein that may be used as emulsifier. This research was aimed to study the emulsification properties of L-fucose through the determination of total dissolved solids (TDS), color CIE L*a*b* and stability of oil-in-water emulsion. As much as 0.5% of high concentrated L-fucose and 0.5% of carboxymethyl cellulose (CMC) were used as emulsifier in a 10% (v/v) oil-in-water (O/W) emulsion. The emulsifier was added to O/W emulsions and then heated at 72°C. Result of stability emulsion and TDS showed that L-fucose was comparable to the CMC but remarkable changed the color of O/W emulsion. Heating process significantly reduced the stability O/W emulsion when L-fucose was applied. As conclusion, L-fucose might be used as natural emulsifier in O/W emulsion but in the low heat treatment of food processing. This study may provide valuable information for utilizing natural emulsifier from abundant resources from nature.

  16. Aggregation work at polydisperse micellization: ideal solution and "dressed micelle" models comparing to molecular dynamics simulations.

    Science.gov (United States)

    Burov, S V; Shchekin, A K

    2010-12-28

    General thermodynamic relations for the work of polydisperse micelle formation in the model of ideal solution of molecular aggregates in nonionic surfactant solution and the model of "dressed micelles" in ionic solution have been considered. In particular, the dependence of the aggregation work on the total concentration of nonionic surfactant has been analyzed. The analogous dependence for the work of formation of ionic aggregates has been examined with regard to existence of two variables of a state of an ionic aggregate, the aggregation numbers of surface active ions and counterions. To verify the thermodynamic models, the molecular dynamics simulations of micellization in nonionic and ionic surfactant solutions at two total surfactant concentrations have been performed. It was shown that for nonionic surfactants, even at relatively high total surfactant concentrations, the shape and behavior of the work of polydisperse micelle formation found within the model of the ideal solution at different total surfactant concentrations agrees fairly well with the numerical experiment. For ionic surfactant solutions, the numerical results indicate a strong screening of ionic aggregates by the bound counterions. This fact as well as independence of the coefficient in the law of mass action for ionic aggregates on total surfactant concentration and predictable behavior of the "waterfall" lines of surfaces of the aggregation work upholds the model of "dressed" ionic aggregates.

  17. Smart wormlike micelles design, characteristics and applications

    CERN Document Server

    Feng, Yujun; Dreiss, Cécile A

    2015-01-01

    This Brief provides an up-to-date overview of smart surfactants and describes a broad spectrum of triggers that induce the formation of wormlike micelles or reversibly tune the morphology of surfactant aggregates from wormlike micelles to another state, or vice versa. Combining the fields of chemistry, physics, polymer science, and nanotechnology, its primary focus is on the design, formulation, and processing of intelligent viscoelastic surfactant solutions, covering the scientific principles governing responsiveness to one or more particular triggers, down to the end-use-driven functions. The first chapter explains why and how surfactants self-assemble into viscoelastic wormlike micellar solutions reminiscent of polymer solutions, while the following chapters show how the response to a given trigger translates into macroscopic rheological changes, including temperature, light, pH, CO2, redox, hydrocarbon, etc. The last chapter demonstrates the applications of these viscoelastic assemblies in oil and gas pro...

  18. A cremophor-free formulation for tanespimycin (17-AAG) using PEO-b-PDLLA micelles: characterization and pharmacokinetics in rats.

    Science.gov (United States)

    Xiong, May P; Yáñez, Jaime A; Kwon, Glen S; Davies, Neal M; Forrest, M Laird

    2009-04-01

    Tanespimycin (17-allylamino-17-demethoxygeldanamycin or 17-AAG) is a promising heat shock protein 90 inhibitor currently undergoing clinical trials for the treatment of cancer. Despite its selective mechanism of action on cancer cells, 17-AAG faces challenging issues due to its poor aqueous solubility, requiring formulation with Cremophor EL (CrEL) or ethanol (EtOH). Therefore, a CrEL-free formulation of 17-AAG was prepared using amphiphilic diblock micelles of poly(ethylene oxide)-b-poly(D,L-lactide) (PEO-b-PDLLA). Dynamic light scattering revealed PEO-b-PDLLA (12:6 kDa) micelles with average sizes of 257 nm and critical micelle concentrations of 350 nM, solubilizing up to 1.5 mg/mL of 17-AAG. The area under the curve (AUC) of PEO-b-PDLLA micelles was 1.3-fold that of the standard formulation. The renal clearance (CL(renal)) increased and the hepatic clearance (CL(hepatic)) decreased with the micelle formulation, as compared to the standard vehicle. The micellar formulation showed a 1.3-fold increase in the half-life (t(1/2)) of the drug in serum and 1.2-fold increase in t(1/2) of urine. As expected, because it circulated longer in the blood, we also observed a 1.7-fold increase in the volume of distribution (V(d)) with this micelle formulation compared to the standard formulation. Overall, the new formulation of 17-AAG in PEO-b-PDLLA (12:6 kDa) micelles resulted in a favorable 150-fold increase in solubility over 17-AAG alone, while retaining similar properties to the standard formulation. Our data indicates that the nanocarrier system can retain the pharmacokinetic disposition of 17-AAG without the need for toxic agents such as CrEL and EtOH.

  19. Renewable poly(δ-decalactone based block copolymer micelles as drug delivery vehicle: in vitro and in vivo evaluation

    Directory of Open Access Journals (Sweden)

    Kuldeep K. Bansal

    2018-03-01

    Full Text Available Polymers from natural resources are attracting much attention in various fields including drug delivery as green alternatives to fossil fuel based polymers. In this quest, novel block copolymers based on renewable poly(δ-decalactone (PDL were evaluated for their drug delivery capabilities and compared with a fossil fuel based polymer i.e. methoxy-poly(ethylene glycol-b-poly(ε-caprolactone (mPEG-b-PCL. Using curcumin as a hydrophobic drug model, micelles of PDL block copolymers with different orientation i.e. AB (mPEG-b-PDL, ABA (PDL-b-PEG-b-PDL, ABC (mPEG-b-PDL-b-poly(pentadecalactone and (mPEG-b-PCL were prepared by nanoprecipitation method. The size, drug loading and curcumin stability studies results indicated that mPEG-b-PDL micelles was comparable to its counterpart mPEG-b-PCL micelles towards improved delivery of curcumin. Therefore, mixed micelles using these two copolymers were also evaluated to see any change in size, loading and drug release. Drug release studies proposed that sustained release can be obtained using poly(pentadecalactone as crystalline core whereas rapid release can be achieved using amorphous PDL core. Further, mPEG-b-PDL micelles were found to be non-haemolytic, up to the concentration of 40 mg/mL. In vivo toxicity studies on rats advised low-toxic behaviour of these micelles up to 400 mg/kg dose, as evident by histopathological and biochemical analysis. In summary, it is anticipated that mPEG-b-PDL block copolymer micelles could serve as a renewable alternative for mPEG-b-PCL copolymers in drug delivery applications.

  20. SANS study of coated block copolymer micelles

    Czech Academy of Sciences Publication Activity Database

    Pleštil, Josef; Kříž, Jaroslav; Koňák, Čestmír; Pospíšil, Herman; Kadlec, Petr; Sedláková, Zdeňka; Grillo, I.; Cubitt, R.

    2005-01-01

    Roč. 206, č. 12 (2005), s. 1206-1215 ISSN 1022-1352 R&D Projects: GA ČR GA203/03/0600; GA AV ČR IAA1050201; GA AV ČR KSK4050111 Institutional research plan: CEZ:AV0Z40500505 Keywords : block copolymer micelles * core-shell polymers * nanoparticles Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.111, year: 2005

  1. Thermoresponsive polymer micelles as potential nanosized cancerostatics

    Czech Academy of Sciences Publication Activity Database

    Laga, Richard; Janoušková, Olga; Ulbrich, Karel; Pola, Robert; Blažková, Jana; Filippov, Sergey K.; Etrych, Tomáš; Pechar, Michal

    2015-01-01

    Roč. 16, č. 8 (2015), s. 2493-2505 ISSN 1525-7797 R&D Projects: GA MŠk(CZ) EE2.3.30.0029; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61389013 Keywords : RAFT polymerization * polymer therapeutics * thermo-responsive micelles Subject RIV: CE - Biochemistry Impact factor: 5.583, year: 2015

  2. Polymeric micelles as a drug carrier for tumor targeting

    Directory of Open Access Journals (Sweden)

    Neha M Dand

    2013-01-01

    Full Text Available Polymeric micelle can be targeted to tumor site by passive and active mechanism. Some inherent properties of polymeric micelle such as size in nanorange, stability in plasma, longevity in vivo, and pathological characteristics of tumor make polymeric micelles to be targeted at the tumor site by passive mechanism called enhanced permeability and retention effect. Polymeric micelle formed from the amphiphilic block copolymer is suitable for encapsulation of poorly water soluble, hydrophobic anticancer drugs. Other characteristics of polymeric micelles such as separated functionality at the outer shell are useful for targeting the anticancer drug to tumor by active mechanisms. Polymeric micelles can be conjugated with many ligands such as antibodies fragments, epidermal growth factors, α2 -glycoprotein, transferrine, and folate to target micelles to cancer cells. Application of heat and ultrasound are the alternative methods to enhance drug accumulation in tumoral cells. Targeting using micelles can also be done to tumor angiogenesis which is the potentially promising target for anticancer drugs. This review summarizes about recently available information regarding targeting the anticancer drug to the tumor site using polymeric micelles.

  3. Diclofenac/biodegradable polymer micelles for ocular applications

    Science.gov (United States)

    Li, Xingyi; Zhang, Zhaoliang; Li, Jie; Sun, Shumao; Weng, Yuhua; Chen, Hao

    2012-07-01

    In this paper, methoxypoly(ethylene glycol)-poly(ε-caprolactone) (MPEG-PCL) micelle formulations as promising nano-carriers for poorly water soluble drugs were investigated for the delivery of diclofenac to the eye. Diclofenac loaded MPEG-PCL micelles were prepared by a simple solvent-diffusion method and characterized by dynamic light scattering (DLS), atomic force microscopy (AFM), Fourier transform infra-red (FTIR), X-ray diffraction (XRD), differential scanning calorimetery (DSC), etc. With the analysis of XRD and DSC, the diclofenac was present as an amorphous state in the formulation. The in vitro release profile indicated a sustained release manner of diclofenac from the micelles. Meanwhile, in vivo studies on eye irritation were performed with blank MPEG-PCL micelles (200 mg ml-1). The results showed that the developed MPEG-PCL micelles were non-irritants to the eyes of rabbits. In vitro penetration studies across the rabbit cornea demonstrated that the micelle formulations exhibited a 17-fold increase in penetration compared with that of diclofenac phosphate buffered saline (PBS) solution. The in vivo pharmacokinetics profile of the micelle parent drug in the aqueous humor of the rabbit was evaluated and the data showed that the diclofenac loaded MPEG-PCL micelles exhibited a 2-fold increase in AUC0-24 h than that of the diclofenac PBS solution eye drops. These results suggest a great potential of our micelle formulations as a novel ocular drug delivery system to improve the bioavailability of the drugs.

  4. Development of fisetin-loaded folate functionalized pluronic micelles for breast cancer targeting.

    Science.gov (United States)

    Pawar, Atmaram; Singh, Srishti; Rajalakshmi, S; Shaikh, Karimunnisa; Bothiraja, C

    2018-01-15

    The natural flavonoid fisetin (FS) has shown anticancer properties but its in-vivo administration remains challenging due to its poor aqueous solubility. The aim of the study was to develop FS loaded pluronic127 (PF)-folic acid (FA) conjugated micelles (FS-PF-FA) by the way of increasing solubility, bioavailability and active targetability of FS shall increase its therapeutic efficacy. FA-conjugated PF was prepared by carbodiimide crosslinker chemistry. FS-PF-FA micelles were prepared by thin-film hydration method and evaluated in comparison with free FS and FS loaded PF micelles (FS-PF). The smooth surfaces with spherical in shape of FS-PF-PF micelles displayed smaller in size (103.2 ± 6.1 nm), good encapsulation efficiency (82.50 ± 1.78%), zeta potential (-26.7 ± 0.44 mV) and sustained FS release. Bioavailability of FS from FS-PF-PF micelles was increased by 6-fold with long circulation time, slower plasma elimination and no sign of tissue toxicity as compared to free FS. Further, the FS-PF-FA micelles demonstrated active targeting effect on folate overexpressed human breast cancer MCF-7 cells. The concentration of the drug needed for growth inhibition of 50% of cells in a designed time period (GI50) was 14.3 ± 1.2 µg/ml for FS while it was greatly decreased to 9.8 ± 0.78 µg/ml, i.e. a 31.46% decrease for the FS-PF. Furthermore, the GI50 value for FS-PF-FA was 4.9 ± 0.4 µg/ml, i.e. a 65.737% decrease compared to FS and 50% decrease compare to FS-PF. The results indicate that the FS-PF-FA micelles have the potential to be applied for targeting anticancer drug delivery.

  5. Curcumin-loaded mixed micelles: preparation, optimization, physicochemical properties and cytotoxicity in vitro.

    Science.gov (United States)

    Duan, Yuwei; Wang, Juan; Yang, Xiaoye; Du, Hongliang; Xi, Yanwei; Zhai, Guangxi

    2015-01-01

    Although curcumin (CUR) can inhibit proliferation and induce apoptosis of tumors, the poor water solubility restricted its clinical application. The aim of this study was to improve the aqueous solubility of CUR and make more favorable changes to bioactivity by preparing curcumin-loaded phospholipid-sodium deoxycholate-mixed micelles (CUR-PC-SDC-MMs). CUR-PC-SDC-MMs were prepared by the thin-film dispersion method. Based on the results of single factor exploration, the preparation technology was optimized using the central composite design-response surface methodology with drug loading and entrapment efficiency (EE%) as indicators. The images of transmission electron microscopy showed that the optimized CUR-PC-SDC-MMs were spherical and well dispersed. The average size of the mixed micelles was 66.5 nm, the zeta potential was about -26.96 mV and critical micelle concentration was 0.0087 g/l. CUR was encapsulated in PC-SDC-MMs with loading capacity of 13.12%, EE% of 87.58%, and the solubility of CUR in water was 3.14 mg/ml. The release results in vitro showed that the mixed micelles presented sustained release behavior compared to the propylene glycol solution of CUR. The IC50 values of CUR-loaded micelles and free drug in human breast carcinoma cell lines were 4.10 μg/ml and 6.93 µg/ml, respectively. It could be concluded from the above results that the CUR-PC-SDC-MMs system might serve as a promising nanocarrier to improve the solubility and bioactivity of CUR.

  6. Invited review: Caseins and the casein micelle: their biological functions, structures, and behavior in foods.

    Science.gov (United States)

    Holt, C; Carver, J A; Ecroyd, H; Thorn, D C

    2013-10-01

    A typical casein micelle contains thousands of casein molecules, most of which form thermodynamically stable complexes with nanoclusters of amorphous calcium phosphate. Like many other unfolded proteins, caseins have an actual or potential tendency to assemble into toxic amyloid fibrils, particularly at the high concentrations found in milk. Fibrils do not form in milk because an alternative aggregation pathway is followed that results in formation of the casein micelle. As a result of forming micelles, nutritious milk can be secreted and stored without causing either pathological calcification or amyloidosis of the mother's mammary tissue. The ability to sequester nanoclusters of amorphous calcium phosphate in a stable complex is not unique to caseins. It has been demonstrated using a number of noncasein secreted phosphoproteins and may be of general physiological importance in preventing calcification of other biofluids and soft tissues. Thus, competent noncasein phosphoproteins have similar patterns of phosphorylation and the same type of flexible, unfolded conformation as caseins. The ability to suppress amyloid fibril formation by forming an alternative amorphous aggregate is also not unique to caseins and underlies the action of molecular chaperones such as the small heat-shock proteins. The open structure of the protein matrix of casein micelles is fragile and easily perturbed by changes in its environment. Perturbations can cause the polypeptide chains to segregate into regions of greater and lesser density. As a result, the reliable determination of the native structure of casein micelles continues to be extremely challenging. The biological functions of caseins, such as their chaperone activity, are determined by their composition and flexible conformation and by how the casein polypeptide chains interact with each other. These same properties determine how caseins behave in the manufacture of many dairy products and how they can be used as functional

  7. Sodium deoxycholate mediated enhanced solubilization and stability of hydrophobic drug Clozapine in pluronic micelles

    Science.gov (United States)

    Singla, Pankaj; Singh, Onkar; Chabba, Shruti; Aswal, V. K.; Mahajan, Rakesh Kumar

    2018-02-01

    In this report, the solubilization behaviour of a hydrophobic drug Clozapine (CLZ) in micellar suspensions of pluronics having different hydrophilic lipophilic balance (HLB) ratios viz. P84, F127 and F108 in the absence and presence of bile salt sodium deoxycholate (SDC) has been studied. UV-Vis spectroscopy has been exploited to determine the solubilization capacity of the investigated micellar systems in terms of drug loading efficiency, average number of drug molecules solubilized per micelle (ns), partition coefficient (P) and standard free energy of solubilization (Δ G°). The morphological and structural changes taking place in pluronics in different concentration regimes of SDC and with the addition of drug CLZ has been explored using dynamic light scattering (DLS) and small angle neutron scattering (SANS) measurements. The SANS results revealed that aggregation behaviour of pluronic-SDC mixed micelles gets improved in the presence of drug. The micropolarity measurements have been performed to shed light on the locus of solubilization of the drug in pure and mixed micellar systems. The compatibility between CLZ and drug carriers (pluronics and SDC) was confirmed using powder X-ray diffraction (PXRD) and Fourier transform infrared spectroscopy (FTIR) techniques. Among the investigated systems, P84-SDC mixed system was found to be highly efficient for CLZ loading. The long term stability data indicated that CLZ loaded P84-SDC mixed micellar formulation remained stable for 3 months at room temperature. Further, it was revealed that the CLZ loaded P84-SDC mixed micelles are converted into CLZ loaded pure P84 micelles at 30-fold dilutions which remain stable up to 48-fold dilutions. The results from the present studies suggest that P84-SDC mixed micelles can serve as suitable delivery vehicles for hydrophobic drug CLZ.

  8. Optimization of protein extraction process from jackfruit seed flour by reverse micelle system

    Directory of Open Access Journals (Sweden)

    Maycon Fagundes Teixeira Reis

    2016-06-01

    Full Text Available The extraction of protein from flour of jackfruit seeds by reverse micelles was evaluated. Reverse micelle system was composed of sodium dodecyl sulfate (SDS as surfactant, butanol as solvent, and water. The effects of stirring time, temperature, molar ratio H2O SDS-1, concentration of butanol (mass percentage and flour mass were tested in batch systems. Based on the adjusted linear regression model, only butanol concentration provided optimum extraction conditions (41.16%. Based on the analysis of surface response, the best extraction yield could be obtained at 25°C, stirring time of 120 min, mass of flour of 100 mg, and a ratio H2O SDS-1 of 50. Experimental results showed that a 79.00% extraction yield could be obtained.

  9. Microencapsulation of superoxide dismutase into poly(epsilon-caprolactone) microparticles by reverse micelle solvent evaporation.

    Science.gov (United States)

    Youan, Bi-Botti Célestin

    2003-01-01

    The aim of this work was to encapsulate superoxide dismutase (SOD) in poly(epsilon-caprolactone) (PCL) microparticles by reverse micelle solvent evaporation. The concentration of PCL, the hydrophile-lipophile balance (HLB), and concentration of the sucrose ester used as surfactant in the organic phase were investigated as formulation variables. Relatively higher encapsulation efficiency (approximately 48%) and retained enzymatic activity (>90%) were obtained with microparticle formulation made from the 20% (w/v) PCL and 0.05% (w/v) sucrose ester of HLB = 6. This formulation allowed the in vitro release of SOD for at least 72 hr. These results showed that reverse micelle solvent evaporation can be used to efficiently encapsulate SOD in PCL microparticles. Such formulations may improve the bioavailability of SOD.

  10. Structure factor of polymers interacting via a short range repulsive potential: Application to hairy wormlike micelles

    International Nuclear Information System (INIS)

    Massiera, Gladys; Ramos, Laurence; Ligoure, Christian; Pitard, Estelle

    2003-01-01

    We use the random phase approximation to compute the structure factor S(q) of a solution of chains interacting through a soft and short range repulsive potential V. Above a threshold polymer concentration, whose magnitude is essentially controlled by the range of the potential, S(q) exhibits a peak whose position depends on the concentration. We take advantage of the close analogy between polymers and wormlike micelles and apply our model, using a Gaussian function for V, to quantitatively analyze experimental small angle neutron scattering profiles of solutions of hairy wormlike micelles. These samples, which consist in surfactant self-assembled flexible cylinders decorated by amphiphilic copolymer, provide indeed an appropriate experimental model system to study the structure of sterically interacting polymer solutions

  11. Statistical Analysis of CMC Constituent and Processing Data

    Science.gov (United States)

    Fornuff, Jonathan

    2004-01-01

    Ceramic Matrix Composites (CMCs) are the next "big thing" in high-temperature structural materials. In the case of jet engines, it is widely believed that the metallic superalloys currently being utilized for hot structures (combustors, shrouds, turbine vanes and blades) are nearing their potential limits of improvement. In order to allow for increased turbine temperatures to increase engine efficiency, material scientists have begun looking toward advanced CMCs and SiC/SiC composites in particular. Ceramic composites provide greater strength-to-weight ratios at higher temperatures than metallic alloys, but at the same time require greater challenges in micro-structural optimization that in turn increases the cost of the material as well as increases the risk of variability in the material s thermo-structural behavior. to model various potential CMC engine materials and examines the current variability in these properties due to variability in component processing conditions and constituent materials; then, to see how processing and constituent variations effect key strength, stiffness, and thermal properties of the finished components. Basically, this means trying to model variations in the component s behavior by knowing what went into creating it. inter-phase and manufactured by chemical vapor infiltration (CVI) and melt infiltration (MI) were considered. Examinations of: (1) the percent constituents by volume, (2) the inter-phase thickness, (3) variations in the total porosity, and (4) variations in the chemical composition of the Sic fiber are carried out and modeled using various codes used here at NASA-Glenn (PCGina, NASALife, CEMCAN, etc...). The effects of these variations and the ranking of their respective influences on the various thermo-mechanical material properties are studied and compared to available test data. The properties of the materials as well as minor changes to geometry are then made to the computer model and the detrimental effects

  12. Extracting Aggregation Free Energies of Mixed Clusters from Simulations of Small Systems: Application to Ionic Surfactant Micelles.

    Science.gov (United States)

    Zhang, X; Patel, L A; Beckwith, O; Schneider, R; Weeden, C J; Kindt, J T

    2017-11-14

    Micelle cluster distributions from molecular dynamics simulations of a solvent-free coarse-grained model of sodium octyl sulfate (SOS) were analyzed using an improved method to extract equilibrium association constants from small-system simulations containing one or two micelle clusters at equilibrium with free surfactants and counterions. The statistical-thermodynamic and mathematical foundations of this partition-enabled analysis of cluster histograms (PEACH) approach are presented. A dramatic reduction in computational time for analysis was achieved through a strategy similar to the selector variable method to circumvent the need for exhaustive enumeration of the possible partitions of surfactants and counterions into clusters. Using statistics from a set of small-system (up to 60 SOS molecules) simulations as input, equilibrium association constants for micelle clusters were obtained as a function of both number of surfactants and number of associated counterions through a global fitting procedure. The resulting free energies were able to accurately predict micelle size and charge distributions in a large (560 molecule) system. The evolution of micelle size and charge with SOS concentration as predicted by the PEACH-derived free energies and by a phenomenological four-parameter model fit, along with the sensitivity of these predictions to variations in cluster definitions, are analyzed and discussed.

  13. Quantum-Dot-Based Theranostic Micelles Conjugated with an Anti-EGFR Nanobody for Triple-Negative Breast Cancer Therapy.

    Science.gov (United States)

    Wang, Yuyuan; Wang, Yidan; Chen, Guojun; Li, Yitong; Xu, Wei; Gong, Shaoqin

    2017-09-13

    A quantum-dot (QD)-based micelle conjugated with an anti-epidermal growth factor receptor (EGFR) nanobody (Nb) and loaded with an anticancer drug, aminoflavone (AF), has been engineered for EGFR-overexpressing cancer theranostics. The near-infrared (NIR) fluorescence of the indium phosphate core/zinc sulfide shell QDs (InP/ZnS QDs) allowed for in vivo nanoparticle biodistribution studies. The anti-EGFR nanobody 7D12 conjugation improved the cellular uptake and cytotoxicity of the QD-based micelles in EGFR-overexpressing MDA-MB-468 triple-negative breast cancer (TNBC) cells. In comparison with the AF-encapsulated nontargeted (i.e., without Nb conjugation) micelles, the AF-encapsulated Nb-conjugated (i.e., targeted) micelles accumulated in tumors at higher concentrations, leading to more effective tumor regression in an orthotopic triple-negative breast cancer xenograft mouse model. Furthermore, there was no systemic toxicity observed with the treatments. Thus, this QD-based Nb-conjugated micelle may serve as an effective theranostic nanoplatform for EGFR-overexpressing cancers such as TNBCs.

  14. Effect of a Long Chain Carboxylate Acid on Sodium Dodecyl Sulfate Micelle Structure: A Small-angle Neutron Scattering Study

    International Nuclear Information System (INIS)

    Arum Patriati; Edy Giri Rachman Putra

    2009-01-01

    The effect of different hydrocarbon chain length of carboxylate acid, i.e. dodecanoic acid, CH 3 (CH 2 ) 10 COOH and hexadecanoic acid, CH 3 (CH 2 ) 14 COOH as a co-surfactant in the 0.3M SDS micellar solution has been studied using small angle neutron scattering (SANS). Here, the present of dodecanoic acid has induced the SDS structural micelles. The ellipsoid micelles structures changed significantly in length (major axis) from 21.7 Armstrong to 35.5 Armstrong at a fixed minor axis of 16.7 Armstrong in the present of 0.005M to 0.1M dodecanoic acid. Nevertheless, this effect was not shown in the present of hexadecanoic acid with the same concentration range. The present of hexadecanoic acid molecules gave a small effect on growth of SDS micelles where the major axis of the micelle was simply elongated from 21.5 Armstrong to 23.5 Armstrong. It showed that the appropriate hydrocarbon chain length between surfactant and co-surfactant molecules is one of the determining factors in forming a mixed micelles structure. (author)

  15. Structure formation of lipid membranes: Membrane self-assembly and vesicle opening-up to octopus-like micelles

    Science.gov (United States)

    Noguchi, Hiroshi

    2013-02-01

    We briefly review our recent studies on self-assembly and vesicle rupture of lipid membranes using coarse-grained molecular simulations. For single component membranes, lipid molecules self-assemble from random gas states to vesicles via disk-shaped clusters. Clusters aggregate into larger clusters, and subsequently the large disks close into vesicles. The size of vesicles are determined by kinetics than by thermodynamics. When a vesicle composed of lipid and detergent types of molecules is ruptured, a disk-shaped micelle called bicelle can be formed. When both surfactants have negligibly low critical micelle concentration, it is found that bicelles connected with worm-like micelles are also formed depending on the surfactant ratio and spontaneous curvature of the membrane monolayer.

  16. Purification of nattokinase by reverse micelles extraction from fermentation broth: effect of temperature and phase volume ratio.

    Science.gov (United States)

    Liu, Jun-Guo; Xing, Jian-Min; Chang, Tian-Shi; Liu, Hui-Zhou

    2006-03-01

    Nattokinase is a novel fibrinolytic enzyme that is considered to be a promising agent for thrombosis therapy. In this study, reverse micelles extraction was applied to purify and concentrate nattokinase from fermentation broth. The effects of temperature and phase volume ratio used for the forward and backward extraction on the extraction process were examined. The optimal temperature for forward and backward extraction were 25 degrees C and 35 degrees C respectively. Nattokinase became more thermosensitive during reverse micelles extraction. And it could be enriched in the stripping phase eight times during backward extraction. It was found that nattokinase could be purified by AOT reverse micelles with up to 80% activity recovery and with a purification factor of 3.9.

  17. Photophysical properties of pyronin dyes in reverse micelles of AOT

    Energy Technology Data Exchange (ETDEWEB)

    Bayraktutan, Tuğba; Meral, Kadem; Onganer, Yavuz, E-mail: yonganer@atauni.edu.tr

    2014-01-15

    The photophysical properties of pyronin B (PyB) and pyronin Y (PyY) in reverse micelles formed with water/sodium bis (2-ethyl-1-hexyl) sulfosuccinate (AOT)/n-heptane were investigated by UV–vis absorption, steady-state and time-resolved fluorescence spectroscopy techniques. This study was carried out a wide range of reverse micelle sizes, with hydrodynamic radii ranging from 1.85 to 9.38 nm. Significant photophysical parameters as band shifts, fluorescence quantum yields and fluorescence lifetimes were determined to understand how photophysical and spectroscopic features of the dye compounds were affected by the variation of reverse micelle sizes. In this regard, control of reverse micelle size by changing W{sub 0}, the molar ratio of water to surfactant, allowed tuning the photophysical properties of the dyes in organic solvent via reverse micelle. Non-fluorescent H-aggregates of pyronin dyes were observed for the smaller reverse micelles whereas an increase in the reverse micelle size induced an increment in the amount of dye monomers instead of dye aggregates. Thus, the fluorescence intensities of the dyes were improved by increasing W{sub 0} due to the predomination of the fluorescent dye monomers. As a result, the fluorescence quantum yields also increased. The fluorescence lifetimes of the dyes in the reverse micelles were determined by the time-resolved fluorescence decay studies. Evaluation of the fluorescence lifetimes calculated for pyronin dyes in the reverse micelles showed that the size of reverse micelle affected the fluorescence lifetimes of pyronin dyes. -- Highlights: • The photophysical properties of pyronin dyes were examined by spectroscopic techniques. • Optical properties of the dyes were tuned by changing of W{sub 0} values. • The fluorescence lifetime and quantum yield values of the dyes in reverse micelles were discussed.

  18. Microstructural Characterization of Reinforced Mortar after Corrosion and Cathodic Prevention in the Presence of Core-Shell Micelles

    NARCIS (Netherlands)

    Koleva, D.A.

    2010-01-01

    This work reports on the microstructural properties of reinforced mortar after chloride-induced corrosion and two regimes of cathodic prevention. Additionally, the impact of a very low concentration polymeric nano-aggregates (core-shell micelles from PEO113-b-PS218), admixed in the mortar mixture is

  19. Micelle-induced depletion interaction and resultant structure in charged colloidal nanoparticle system

    Energy Technology Data Exchange (ETDEWEB)

    Ray, D.; Aswal, V. K., E-mail: vkaswal@barc.gov.in [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Kohlbrecher, J. [Laboratory for Neutron Scattering, Paul Scherrer Institut, CH-5232 PSI Villigen (Switzerland)

    2015-04-28

    The evolution of the interaction and the resultant structure in the mixed system of anionic silica nanoparticles (Ludox LS30) and non-ionic surfactant decaethylene glycol monododecylether (C12E10), undergoing phase separation, have been studied using small-angle neutron scattering and dynamic light scattering. The measurements have been carried out for a fixed concentration of nanoparticle (1 wt. %) with varying concentration of surfactant (0 to 1 wt. %), in the absence and presence of an electrolyte. It is found that the micelles of non-ionic surfactant adsorb on the nanoparticle in the absence of electrolyte (form stable system), whereas these micelles become non-adsorbing in the presence of electrolyte (show phase separation). The phase separation arises because of C12E10 micelles, causing depletion interaction between nanoparticles and leading to their aggregation. The interaction is modeled by double Yukawa potential accounting for attractive depletion as well as repulsive electrostatic forces. Both the interactions (attraction and repulsion) are found to be of long-range. The nanoparticle aggregation (phase separation) is governed by the increase in the magnitude and the range of the depletion attraction with the increase in the surfactant concentration. The nanoparticle aggregates formed are quite large in size (order of micron) and are characterized by the surface fractal having simple cubic packing of nanoparticles within the aggregates.

  20. Preparation of CMC-modified melamine resin spherical nano-phase change energy storage materials.

    Science.gov (United States)

    Hu, Xiaofeng; Huang, Zhanhua; Zhang, Yanhua

    2014-01-30

    A novel carboxymethyl cellulose (CMC)-modified melamine-formaldehyde (MF) phase change capsule with excellent encapsulation was prepared by in situ polymerization. Effects of CMC on the properties of the capsules were studied by Fourier transformation infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electronic microscopy (SEM), X-ray diffractometry (XRD), and thermogravimetric analysis (TGA). The results showed that the CMC-modified capsules had an average diameter of about 50nm and good uniformity. The phase change enthalpy of the capsules was increased and the cracking ratio decreased by incorporating a suitable amount of CMC. The optimum phase change enthalpy of the nanocapsules was 83.46J/g, and their paraffin content was 63.1%. The heat resistance of the capsule shells decreased after CMC modification. In addition, the nanocapsule cracking ratio of the nanocapsules was 11.0%, which is highly attractive for their application as nano phase change materials. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Radiation Synthesis of Super absorbent CMC Based Hydrogels For Agriculture Applications

    International Nuclear Information System (INIS)

    Raafat, A.I.; Eid, M.; El-Arnaouty, M.B.

    2010-01-01

    A good hydrogels of carboxy methyl cellulose (CMC) and poly vinyl pyrrolidone (PVP) were synthesized by gamma radiation at different doses and compositions. The prepared hydrogels were characterized by (FTIR) and (SEM). The hydrogels properties such as gelation (%), swelling and water retention capability were investigated. As the content of PVP in PVP/CMC hydrogels increased the gelation (%) increased. The swelling ratio of prepared hydrogel decreased with increasing of irradiation doses and the temperature. The (PVP/CMC) hydrogen of composition (40:60) prepared at 20 kGy showed the highest swelling ratio. The addition of sodium bicarbonate (NaHCO 3 ) to the PVP/CMC hydrogels during the irradiation process decreases the swelling ratio. The water retention reveals a similar behavior for the different compositions. The swelling characteristics in the presence of different cations and anions in a swelling medium were studied. The hydrogels were also loaded with urea solutions as a model agrochemical and their potential application for controlled release has been investigated. The improve properties of the prepared materials suggested that, the (PVP/CMC) hydrogels can be use in agriculture applications

  2. Development of the Virginia Tech Department of Geosciences MEDL-CMC

    Science.gov (United States)

    Glesener, G. B.

    2016-12-01

    In 2015 the Virginia Tech Department of Geosciences took a leading role in increasing the level of support for Geoscience instructors by investing in the development of the Geosciences Modeling and Educational Demonstrations Laboratory Curriculum Materials Center (MEDL-CMC). The MEDL-CMC is an innovative curriculum materials center designed to foster new collaborative teaching and learning environments by providing hands-on physical models combined with education technology for instructors and outreach coordinators. The mission of the MEDL-CMC is to provide advanced curriculum material resources for the purpose of increasing and sustaining high impact instructional capacity in STEM education for both formal and informal learning environments. This presentation describes the development methods being used to implement the MEDL-CMC. Major development methods include: (1) adopting a project management system to support collaborations with stakeholders, (2) using a diversified funding approach to achieve financial sustainability and the ability to evolve with the educational needs of the community, and (3) establishing a broad collection of systems-based physical analog models and data collection tools to support integrated sciences such as the geosciences. Discussion will focus on how these methods are used for achieving organizational capacity in the MEDL-CMC and on their intended role in reducing instructor workload in planning both classroom activities and research grant broader impacts.

  3. Structural investigations of sodium caseinate micelles in complex environments

    Energy Technology Data Exchange (ETDEWEB)

    Huck Iriart, C.; Herrera, M.L.; Candal, R. [Universidad de Buenos Aires, Buenos Aires (Argentina); Oliveira, C.L.P. [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil); Torriani, I. [Laboratorio Nacional de Luz Sincrotron (LNLS), Campinas, SP (Brazil)

    2012-07-01

    Full text: The most frequent destabilization mechanisms in Sodium Caseinate (NaCas) emulsions are creaming and flocculation. Coarse or fine emulsions with low protein con- tent destabilize mainly by creaming. If migration mechanism is suppressed, flocculation may become the main mechanism of destabilization. Small Angle X-Ray Scattering (SAXS) technique was applied to investigate sodium caseinate micelles structure in different environments. As many natural products, Sodium Caseinate samples have large polydisperse size distribution. The experimental data was analyzed using advanced modeling approaches. The Form Factor for the Caseinate micelle subunits was described by an ellipsoidal core shell model and the structure factor was split into two contributions, one corresponding to the particle-particle interactions and another one for the long range correlation of the subunits in the supramolecular structure. For the first term the hard sphere structure factor using the Percus-Yevick approximation for closure relation was used and for the second term a fractal model was applied. Three concentrations of sodium Caseinate (2, 5 and 7.5 %wt.) were measured in pure water, sugar solutions (20 %wt.) and in three different lipid phase emulsions containing 10 %wt. sunflower seed, olive and fish oils. Data analysis provided an average casein subunit radius of 4 nm, an average distance between the subunits of around 20nm and a fractal dimension value of around 3 for all samples. As indicated by the values of the correlation lengths for the set of studied samples, the casein aggregation is strongly affected by simple sugar additions and it is enhanced by emulsion droplets hydrophobic interaction. As will be presented, these nanoscale structural results provided by scattering experiments is consistent with macroscopic results obtained from several techniques, providing a new understanding of NaCas emulsions. (author)

  4. Structural investigations of sodium caseinate micelles in complex environments

    International Nuclear Information System (INIS)

    Huck Iriart, C.; Herrera, M.L.; Candal, R.; Oliveira, C.L.P.; Torriani, I.

    2012-01-01

    Full text: The most frequent destabilization mechanisms in Sodium Caseinate (NaCas) emulsions are creaming and flocculation. Coarse or fine emulsions with low protein con- tent destabilize mainly by creaming. If migration mechanism is suppressed, flocculation may become the main mechanism of destabilization. Small Angle X-Ray Scattering (SAXS) technique was applied to investigate sodium caseinate micelles structure in different environments. As many natural products, Sodium Caseinate samples have large polydisperse size distribution. The experimental data was analyzed using advanced modeling approaches. The Form Factor for the Caseinate micelle subunits was described by an ellipsoidal core shell model and the structure factor was split into two contributions, one corresponding to the particle-particle interactions and another one for the long range correlation of the subunits in the supramolecular structure. For the first term the hard sphere structure factor using the Percus-Yevick approximation for closure relation was used and for the second term a fractal model was applied. Three concentrations of sodium Caseinate (2, 5 and 7.5 %wt.) were measured in pure water, sugar solutions (20 %wt.) and in three different lipid phase emulsions containing 10 %wt. sunflower seed, olive and fish oils. Data analysis provided an average casein subunit radius of 4 nm, an average distance between the subunits of around 20nm and a fractal dimension value of around 3 for all samples. As indicated by the values of the correlation lengths for the set of studied samples, the casein aggregation is strongly affected by simple sugar additions and it is enhanced by emulsion droplets hydrophobic interaction. As will be presented, these nanoscale structural results provided by scattering experiments is consistent with macroscopic results obtained from several techniques, providing a new understanding of NaCas emulsions. (author)

  5. Lactoferrin binding to transglutaminase cross-linked casein micelles

    NARCIS (Netherlands)

    Anema, S.G.; de Kruif, C.G.|info:eu-repo/dai/nl/073609609

    2012-01-01

    Casein micelles in skim milk were either untreated (untreated milk) or were cross-linked using transglutaminase (TGA-milk). Added lactoferrin (LF) bound to the casein micelles and followed Langmuir adsorption isotherms. The adsorption level was the same in both milks and decreased the micellar zeta

  6. Structure and Stability of Complex Coacervate Core Micelles with Lysozyme

    NARCIS (Netherlands)

    Lindhoud, Saskia; de Vries, Renko; Norde, Willem; Cohen Stuart, Martinus Abraham

    2007-01-01

    Encapsulation of enzymes by polymers is a promising method to influence their activity and stability. Here, we explore the use of complex coacervate core micelles for encapsulation of enzymes. The core of the micelles consists of negatively charged blocks of the diblock copolymer PAA42PAAm417 and

  7. Structure and stability of complex coacervate core micelles with lysozyme

    NARCIS (Netherlands)

    Lindhoud, Saskia; de Vries, Renko; Norde, Willem; Cohen Stuart, Martien A.

    Encapsulation of enzymes by polymers is a promising method to influence their activity and stability. Here, we explore the use of complex coacervate core micelles for encapsulation of enzymes. The core of the micelles consists of negatively charged blocks of the diblock copolymer PAA(42)PAAm(417)

  8. Stimuli-responsive biodegradable polymeric micelles for targeted cancer therapy

    NARCIS (Netherlands)

    Talelli, M.A.

    2011-01-01

    Thermosensitive and biodegradable polymeric micelles based on mPEG-b-pHPMAmLacn have shown very promising results during the past years. The results presented in this thesis illustrate the high potential of these micelles for anticancer therapy and imaging and fully justify further pharmaceutical

  9. TNYL peptide functional chitosan-g-stearate conjugate micelles for tumor specific targeting

    Directory of Open Access Journals (Sweden)

    Chen FY

    2014-09-01

    Full Text Available Feng-Ying Chen,1 Jing-Jing Yan,1 Han-Xi Yi,2 Fu-Qiang Hu,2 Yong-Zhong Du,2 Hong Yuan,2 Jian You,2 Meng-Dan Zhao1 1Women’s Hospital, School of Medicine, Zhejiang University, Hangzhou, People’s Republic of China; 2College of Pharmaceutical Science, Zhejiang University, Hangzhou, People’s Republic of China Abstract: Nowadays, a real challenge in cancer therapy is to design drug delivery systems that can achieve high concentrations of drugs at the target site for improved therapeutic effect with reduced side effects. In this research, we designed and synthesized a homing peptide-(TNYLFSPNGPIA, TNYL modified chitosan-g-stearate (CS polymer micelle (named T-CS for targeting delivery. The peptide displayed specific binding affinity to EphB4 which is a member of the Eph family of receptor tyrosine protein kinases. The amphiphilic polymer T-CS can gather into micelles by themselves in an aqueous environment with a low critical micelle concentration value (91.2 µg/L and nano-scaled size (82.1±2.8 nm. The drug encapsulation efficiency reached 86.43% after loading the hydrophobic drug doxorubicin (DOX. The cytotoxicity of T-CS/DOX against SKOV3 cells was enhanced by approximately 2.3-fold when compared with CS/DOX. The quantitative and qualitative analysis for cellular uptake indicated that TNYL modification can markedly increase cellular internalization in the EphB4-overexpressing SKOV3 cell line, especially with a short incubation time. It is interesting that relatively higher uptake of the T-CS/DOX micelles by SKOV3 cells (positive-EphB4 than A549 cells (negative-EphB4 was observed when the two cells were co-incubated. Furthermore, in vivo distribution experiment using a bilateral-tumor model showed that there was more fluorescence accumulation in the SKOV3 tumor than in the A549 tumor over the whole experiment. These results suggest that TNYL-modified CS micelles may be promising drug carriers as targeting therapy for the EphB4-overexpressing

  10. The α-chymotrypsin and its hydrophobic derivatives in inverse micelles; L'α-chymotrypsine et ses derives hydrophobes en micelles inverses

    Energy Technology Data Exchange (ETDEWEB)

    Pitre, Franck

    1993-01-29

    concentrations en α-chymotrypsine proche de sa solubilisation maximale. Ceci est du au fait que l'α-chymotrypsine est une enzyme hydrosoluble et que dans les conditions ou elle est catalytiquement active, elle ne possede qu'une faible densite de charge en surface. L'absence de modifications de la structure du systeme ternaire apres incorporation de l'α-chymotrypsine est ideal pour les applications biotechnologiques. Dans le but de transformer l'α-chymotrypsine en une enzyme membranaire, quel que soit l'etat electrostatique des tetes polaires des molecules tensioactives, nous avons fixe, de maniere covalente, a la surface de l'α-chymotrypsine des molecules hydrophobes: un derive du fluorene et un groupement cholesteryle. Nous n'avons pas observe de changements du potentiel d'interaction intermicellaire apres avoir solubilise les α-chymotrypsines modifiees. Malgre des localisations differentes a l'interieur des micelles inverses, l'etude de l'activite enzymatique de l'α-chymotrypsine modifiee par le 9-fluorenyl methyl chloroformiate n'a pas non plus montre de changements de comportement en micelles inverses par rapport a l'α-chymotrypsine native. Ces resultats sont totalement differents de ceux obtenus apres solubilisation d'une proteine peripherique membranaire, le cytochrome c, ou un deplacement du seuil de percolation vers les plus faibles fractions volumiques correle avec une augmentation de la partie attractive du potentiel d'interaction intermicellaire ont ete observe. La difference des interactions AOT-enzyme en est vraisemblablement la cause. Dans les conditions d'etudes, le cytochrome c est fortement charge positivement et cette distribution est non uniforme. Il en resulte de fortes attractions entre les tetes polaires du tensioactif AOT et la proteine. Au contraire, les interactions entre les α-chymotrypsines modifiees et les molecules d'AOT sont beaucoup moins intenses, entrainant une deformation beaucoup plus faible de la surface intermicellaire.

  11. pH dependent polymeric micelle adsorption

    Energy Technology Data Exchange (ETDEWEB)

    McLean, S C; Gee, M L [The University of Melbourne, VIC (Australia). School of Chemistry

    2003-07-01

    Full text: Poly(2-vinylpyridine)-poly(ethylene oxide) (P2VP-PEO) shows potential as a possible drug delivery system for anti-tumour drugs since it forms pH dependent polymeric micelles. Hence to better understand the adsorption behaviour of this polymer we have studied the interaction forces between layers of P2VP-PEO adsorbed onto silica as a function of solution pH using an Atomic Force Microscope (AFM). When P2VP-PEO is initially adsorbed above the pKa of the P2VP block, P2VP-PEO adsorbs from solution as micelles that exist as either partially collapsed- or a hemi-micelles at the silica surface. Below the pKa of P2VP, the P2VP-PEO adsorbs as unimers, forming a compact layer with little looping and tailing into solution. When initial adsorption of P2VP-PEO is in the form of unimers, any driving force to self-assembly of the now charge neutral polymer is kinetically hindered. Hence, after initial adsorption at pH 3.6, a subsequent increase in pH to 6.6 results in a slow surface restructuring towards self-assembly and equilibrium. When the pH is increased from pH 6.6 to 9.7 there is a continuation of the evolution of the system to its equilibrium position during which the adsorbed P2VP-PEO unimers continue to 'unravel' from the surface, extending away from it, towards eventual complete surface self-assembly.

  12. Overview of CMC (Ceramic Matrix Composite) Research at the NASA Glenn Research Center

    Science.gov (United States)

    Kiser, J. Douglas; Grady, Joseph E.; Bhatt, Ramakrishna T.; Wiesner, Valerie L.; Zhu, Dongming

    2016-01-01

    In support of NASAs Aeronautics Research Mission, the Glenn Research Center has developed and assessed various constituents for a high temperature (2700F) SiCSiC CMC system for turbine engine applications. Combinations of highly creep-resistant SiC fibers, advanced 3D weaves, durable environmental barrier coatings (EBCs), and a 2700F-capable hybrid SiC matrix are being developed evaluated. The resulting improvements in CMC mechanical properties and durability will be summarized. The development and validation of models for predicting the effects of the environment on the durability of CMCs and EBCs and other operating-environment challenges including the effect of CMAS (calcium magnesium aluminosilicate) degradation of EBCs will be discussed. Progress toward the development of CMC joining technology for 2400F joint applications will also be reviewed.

  13. Biodegradation of PVP-CMC hydrogel film: a useful food packaging material.

    Science.gov (United States)

    Roy, Niladri; Saha, Nabanita; Kitano, Takeshi; Saha, Petr

    2012-06-20

    Hydrogels can offer new opportunities for the design of efficient packaging materials with desirable properties (i.e. durability, biodegradability and mechanical strength). It is a promising and emerging concept, as most of the biopolymer based hydrogels are supposed to be biodegradable, they can be considered as alternative eco-friendly packaging materials. This article reports about synthetic (polyvinylpyrrolidone (PVP)) and biopolymer (carboxymethyl cellulose (CMC)) based a novel hydrogel film and its nature of biodegradability under controlled environmental condition. The dry hydrogel films were prepared by solution casting method and designated as 'PVP-CMC hydrogel films'. The hydrogel film containing PVP and CMC in a ratio of 20:80 shows best mechanical properties among all the test samples (i.e. 10:90, 20:80, 50:50, 80:20 and 90:10). Thus, PVP-CMC hydrogel film of 20:80 was considered as a useful food packaging material and further experiments were carried out with this particular hydrogel film. Biodegradation of the PVP-CMC hydrogel films were studied in liquid state (Czapec-Dox liquid medium+soil extracts) until 8 weeks. Variation in mechanical, viscoelastic properties and weight loss of the hydrogel films with time provide the direct evidence of biodegradation of the hydrogels. About 38% weight loss was observed within 8 weeks. FTIR spectra of the hydrogel films (before and after biodegradation) show shifts of the peaks and also change in the peak intensities, which refer to the physico-chemical change in the hydrogel structure and SEM views of the hydrogels show how internal structure of the PVP-CMC film changes in the course of biodegradation. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. It's Just a Game, Right? Types of Play in Foreign Language CMC

    OpenAIRE

    Chantelle N. Warner

    2004-01-01

    This study focuses on the various playful uses of language that occurred during a semester-long study of two German language courses using one type of synchronous network-based medium, the MOO. Research and use of synchronous computer-mediated communication (CMC) have flourished in the study of second-language acquisition (SLA) since the late 1990s; however, the primary focus has been on the potential benefits of using CMC to increase the amount of communication (Beauvois, 1997; Kern, 1995; W...

  15. Effect of sodium azide addition and aging storage on casein micelle size

    Science.gov (United States)

    Sinaga, H.; Deeth, H.; Bhandari, B.

    2018-02-01

    Casein micelles affected most of milk properties, therefore the use sodium azide as milk preservation is not expected to alter milk properties during storage, including the casein micelle size. The aim of this study was to analyse casein micelle size after the addition of sodium azide during storage. The experiment was performed as a complete block randomised design with three replications. The addition of 0.02-0.10% Na-azide do not lead to any noticeable differences in average casein size at the same day and show similar trend after 14 day-storage. At concentration of 0.02% sodium azide (Na-azide), the size of pasteurised milk did not change up to 12 days, while the size of raw skim milk slightly increased by ageing time at day 5. The treated concentration did not affect the size distribution, except for milk with 0.02% Na-azide which had narrower distribution compared to other treated and control milk. The finding from this study suggests that the role of Na-azide in this experiments during storage at 4°C is only for preventing the microbial growth.

  16. Phase separation in solution of worm-like micelles: a dilute ? spin-vector model

    Science.gov (United States)

    Panizza, Pascal; Cristobal, Galder; Curély, Jacques

    1998-12-01

    We show how the dilute 0953-8984/10/50/006/img2 spin vector model introduced originally by Wheeler and co-workers for describing the polymerization phenomenon in solutions of liquid sulphur and of living polymers may be conveniently adapted for studying phase separation in systems containing long flexible micelles. We draw an isomorphism between the coupling constant appearing in the exchange Hamiltonian and the surfactant energies in the micellar problem. We solve this problem within the mean-field approximation and compare the main results we have obtained with respect to polymer theory and previous theories of phase separation in micellar solutions. We show that the attractive interaction term 0953-8984/10/50/006/img3 between monomers renormalizes the aggregation energy and subsequently the corresponding size distribution. Under these conditions, we observe that the general aspect of the phase diagram in the 0953-8984/10/50/006/img4 plane (where 0953-8984/10/50/006/img5 is the surfactant concentration) is different from previous results. The spinodal line shows a re-entrant behaviour and, at low concentrations, we point out the possibility of specific nucleation phenomena related to the existence of a metastable transition line between a region composed of spherical micelles and another one corresponding to a dilute solution of long flexible micelles.

  17. Simultaneous tuning of chemical composition and topography of copolymer surfaces: micelles as building blocks.

    Science.gov (United States)

    Zhao, Ning; Zhang, Xiaoyan; Zhang, Xiaoli; Xu, Jian

    2007-05-14

    A simple method is described for controlling the surface chemical composition and topography of the diblock copolymer poly(styrene)-b-poly(dimethylsiloxane)(PS-b-PDMS) by casting the copolymer solutions from solvents with different selectivities. The surface morphology and chemical composition were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), respectively, and the wetting behavior was studied by water contact angle (CA) and sliding angle (SA) and by CA hysteresis. Chemical composition and morphology of the surface depend on solvent properties, humidity of the air, solution concentration, and block lengths. If the copolymer is cast from a common solvent, the resultant surface is hydrophobic, with a flat morphology, and dominated by PDMS on the air side. From a PDMS-selective solvent, the surface topography depends on the morphology of the micelles. Starlike micelles give rise to a featureless surface nearly completely covered by PDMS, while crew-cut-like micelles lead to a rough surface with a hierarchical structure that consists partly of PDMS. From a PS-selective solvent, however, surface segregation of PDMS was restricted, and the surface morphology can be controlled by vapor-induced phase separation. On the basis of the tunable surface roughness and PDMS concentration on the air side, water repellency of the copolymer surface could be tailored from hydrophobic to superhydrophobic. In addition, reversible switching behavior between hydrophobic and superhydrophobic can be achieved by exposing the surface to solvents with different selectivities.

  18. Stepwise-activable multifunctional peptide-guided prodrug micelles for cancerous cells intracellular drug release

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jing, E-mail: zhangjing@zjut.edu.cn; Li, Mengfei [Zhejiang University of Technology, College of Materials Science and Engineering (China); Yuan, Zhefan [Zhejiang University, Key Laboratory of Biomass Chemical Engineering of Ministry of Education, Department of Chemical and Biological Engineering (China); Wu, Dan; Chen, Jia-da; Feng, Jie, E-mail: fengjie@zjut.edu.cn [Zhejiang University of Technology, College of Materials Science and Engineering (China)

    2016-10-15

    be activated by charge reversal of the prodrug micelles via hydrolysis of acid-labile β-carboxylic amides and regeneration of K{sub 10}. The cell-penetrating peptide, K{sub 10}, would enable efficient internalization of MPPM by tumor cells, and the drug would be rapidly released induced by concentrated glutathione and numerous proteases inside the cancerous cells, resulting in the inhibited effect of the cells.

  19. Glioma-targeting micelles for optical/magnetic resonance dual-mode imaging

    Directory of Open Access Journals (Sweden)

    Zhou Q

    2015-03-01

    , wherein the average fluorescence intensity of the tumor was about fourfold higher than that of normal brain tissue. Furthermore, 3-(4,5-dimethyl-2-thiazolyl-2,5-diphenyl-2-H-tetrazolium bromide assay results showed that the micelles were biocompatible at Fe concentrations of 0–100 µg/mL. In general, these optical/MRI bifunctional micelles can specifically target the glioma and provide guidance for surgical resection of the glioma before and during operation.Keywords: MRI, fluorescence image, micelles, lactoferrin, glioma

  20. Effects of Synchronous and Asynchronous Computer-Mediated Communication (CMC) Oral Conversations on English Language Learners' Discourse Functions

    Science.gov (United States)

    AbuSeileek, Ali Farhan; Qatawneh, Khaleel

    2013-01-01

    This study aimed to explore the effects of synchronous and asynchronous computer mediated communication (CMC) oral discussions on question types and strategies used by English as a Foreign Language (EFL) learners. The participants were randomly assigned to two treatment conditions/groups; the first group used synchronous CMC, while the second…

  1. Ni(0-CMC-Na Nickel Colloids in Sodium Carboxymethyl-Cellulose: Catalytic Evaluation in Hydrogenation Reactions

    Directory of Open Access Journals (Sweden)

    Abdallah Karim

    2011-01-01

    Full Text Available A recyclable catalyst, Ni(0-CMC-Na, composed of nickel colloids dispersed in a water soluble bioorganic polymer, sodium carboxymethylcellulose (CMC-Na, was synthesized by a simple procedure from readily available reagents. The catalyst thus obtained is stable and highly active in alkene hydrogenations.

  2. PEG-lipid micelles enable cholesterol efflux in Niemann-Pick Type C1 disease-based lysosomal storage disorder

    Science.gov (United States)

    Brown, Anna; Patel, Siddharth; Ward, Carl; Lorenz, Anna; Ortiz, Mauren; Duross, Allison; Wieghardt, Fabian; Esch, Amanda; Otten, Elsje G.; Heiser, Laura M.; Korolchuk, Viktor I.; Sun, Conroy; Sarkar, Sovan; Sahay, Gaurav

    2016-08-01

    2-Hydroxy-propyl-β-cyclodextrin (HPβCD), a cholesterol scavenger, is currently undergoing Phase 2b/3 clinical trial for treatment of Niemann Pick Type C-1 (NPC1), a fatal neurodegenerative disorder that stems from abnormal cholesterol accumulation in the endo/lysosomes. Unfortunately, the extremely high doses of HPβCD required to prevent progressive neurodegeneration exacerbates ototoxicity, pulmonary toxicity and autophagy-based cellular defects. We present unexpected evidence that a poly (ethylene glycol) (PEG)-lipid conjugate enables cholesterol clearance from endo/lysosomes of Npc1 mutant (Npc1-/-) cells. Herein, we show that distearyl-phosphatidylethanolamine-PEG (DSPE-PEG), which forms 12-nm micelles above the critical micelle concentration, accumulates heavily inside cholesterol-rich late endosomes in Npc1-/- cells. This potentially results in cholesterol solubilization and leakage from lysosomes. High-throughput screening revealed that DSPE-PEG, in combination with HPβCD, acts synergistically to efflux cholesterol without significantly aggravating autophagy defects. These well-known excipients can be used as admixtures to treat NPC1 disorder. Increasing PEG chain lengths from 350 Da-30 kDa in DSPE-PEG micelles, or increasing DSPE-PEG content in an array of liposomes packaged with HPβCD, improved cholesterol egress, while Pluronic block copolymers capable of micelle formation showed slight effects at high concentrations. We postulate that PEG-lipid based nanocarriers can serve as bioactive drug delivery systems for effective treatment of lysosomal storage disorders.

  3. Determination of Consciousness and Awareness of the Public in Lefka about the Cyprus Mining Corporation (CMC)

    Science.gov (United States)

    Gündüz, Serife; Erbulut, Can; Öznacar, Behcet; Bastas, Mert

    2016-01-01

    Supporting the increase of environmental consciousness with environmental education is always important in order to make healthy recommendations specific to the countries. Aim of this study is to determine the awareness and consciousness of the local community against the environmental pollution caused by the CMC mine by survey technique. 123…

  4. Language Learning Going Global: Linking Teachers and Learners via Commercial Skype-Based CMC

    Science.gov (United States)

    Terhune, N. M.

    2016-01-01

    This paper reports on students' use of face-to-face synchronous computer-mediated communication (CMC) for oral language learning. It describes a university English language class designed to prepare students for overseas study in which a Skype-based English conversation school was piloted. The study offers analysis of how students used the CMC…

  5. Compact, Lightweight, Ceramic Matrix Composite (CMC) Based Acoustic Liners for Reducing Subsonic Jet Aircraft Engine Noise

    Science.gov (United States)

    Kiser, J. Douglas; Grady, Joseph E.; Miller, Christopher J.; Hultgren, Lennart S.; Jones, Michael G.

    2016-01-01

    Recent developments have reduced fan and jet noise contributions to overall subsonic aircraft jet-engine noise. Now, aircraft designers are turning their attention toward reducing engine core noise. The NASA Glenn Research Center and NASA Langley Research Center have teamed to investigate the development of a compact, lightweight acoustic liner based on oxide/oxide ceramic matrix composite (CMC) materials. The NASA team has built upon an existing oxide/oxide CMC sandwich structure concept that provides monotonal noise reduction. Oxide/oxide composites have good high temperature strength and oxidation resistance, which could allow them to perform as core liners at temperatures up to 1000C (1832F), and even higher depending on the selection of the composite constituents. NASA has initiated the evaluation of CMC-based liners that use cells of different lengths (variable-depth channels) or effective lengths to achieve broadband noise reduction. Reducing the overall liner thickness is also a major goal, to minimize the volume occupied by the liner. As a first step toward demonstrating the feasibility of our concepts, an oxide/oxide CMC acoustic testing article with different channel lengths was tested. Our approach, summary of test results, current status, and goals for the future are reported.

  6. Persistence of oral coatings of CMC and starch-based custard desserts

    NARCIS (Netherlands)

    Wijk, de R.A.; Kapper, C.; Borsboom, P.; Prinz, J.F.

    2009-01-01

    Food coatings that remain after swallowing starch-based or CMC-based custard desserts were investigated for 19 subjects. Foods were orally processed for 5 s using a pre-defined protocol, after which the food was swallowed. The remaining food coating was assessed sensorially as well as instrumentally

  7. Communication Challenges Learners Face Online: Why Addressing CMC and Language Proficiency Will Not Solve Learners' Problems

    Science.gov (United States)

    Jung-Ivannikova, Liubov

    2016-01-01

    Computer-mediated communication (CMC) has been argued to cause (mis)communication issues. Research and practice suggest a range of tactics and strategies for educators focused on how to encourage and foster communication in a virtual learning environment (VLE) (eg, Salmon). However, while frameworks such as Salmon's support the effective…

  8. My First CMC Article Revisited: A Window on Spanish L2 Interlanguage

    Science.gov (United States)

    Blake, Robert

    2016-01-01

    The computer-assisted language learning (CALL) field seems to change overnight with new technological affordances. Blake revisits his 2000 "LLT" article on computer-mediation communication (CMC) in order to reflect on how the field has examined this topic over the past decade or so. While the Interaction Hypothesis continues to guide…

  9. CMC-coated Fe3O4 nanoparticles as new MRI probes for hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Sitthichai, Sudarat; Pilapong, Chalermchai; Thongtem, Titipun; Thongtem, Somchai

    2015-01-01

    Highlights: • Fe 3 O 4 nanoparticles (NPs) are superparamagnetic. • CMC is water-soluble and nontoxic cellulose-derivative polymer. • CMC-coated Fe 3 O 4 NPs were successfully prepared by co-precipitation method. • The promising NPs that can be used for magnetic resonance imaging application. - Abstract: Pure Fe 3 O 4 nanoparticles and Fe 3 O 4 magnetic nanoparticles (MNPs) coated with carboxymethyl cellulose (CMC) were successfully prepared by co-precipitating of FeCl 2 ·4H 2 O and FeCl 3 ·6H 2 O in the solutions containing ammonia at 80 °C for 3 h. Phase, morphology, particle-sized distribution, surface chemistry, and weight loss were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) including high-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED), thermogravimetric analysis (TGA), and Fourier transform infrared (FTIR) spectroscopy. In this research, CMC-coated Fe 3 O 4 MNPs consisting of Fe 2+ and Fe 3+ ions with 543.3-mM −1 s −1 high relaxivity were detected and were able to be used for magnetic resonance imaging (MRI) application with very good contrast for targeting hepatocellular carcinoma (HCC) without any further vectorization.

  10. CHARACTERIZATION OF CARBOXY METHYL CELLULOSE (CMC FROM Eichornia crassipes (Mart Solms

    Directory of Open Access Journals (Sweden)

    Arum Wijayani

    2010-06-01

    Full Text Available Carboxy Methyl Cellulose (CMC, a compound made made of eceng gondok has been implied for its characteristic by a constructive wet system, with media such as methanol, propanol and water. Four consecutive phases involving alkalization, carboxymethylization, neutralization and drainage were used in the making process of CMC. The first two process were prepared by reacting NaOH and ClCH2COONa with NaOH 22; 32.5; 39.2; 45.9 g and 20; 26; 32; 38 g ClCH2COONa respectively. Added acetic acid was used in the neutralization process, whilst drainage only involved heating in the oven. The overall result for each characteristic substitution degree, acidity; viscosity; contens of water consentration of NaCl and purity 0.4 - 0.85, 6.10 - 8.49, 3 - 10 cP, 3.57 - 19.4 %, 12.9 - 22.4 % and 77.96 - 87.09 % respectively. Based on the obtained characteristic, could be concluded that CMC is considered as a technical quality and can also be used as filler constituent in adhesive. Keywords: CMC, alkalization, carboxymethylization

  11. Enhanced solubility and targeted delivery of curcumin by lipopeptide micelles.

    Science.gov (United States)

    Liang, Ju; Wu, Wenlan; Lai, Danyu; Li, Junbo; Fang, Cailin

    2015-01-01

    A lipopeptide (LP)-containing KKGRGDS as the hydrophilic heads and lauric acid (C12) as the hydrophobic tails has been designed and prepared by standard solid-phase peptide synthesis technique. LP can self-assemble into spherical micelles with the size of ~30 nm in PBS (phosphate buffer saline) (pH 7.4). Curcumin-loaded LP micelles were prepared in order to increase the water solubility, sustain the releasing rate, and improve the tumor targeted delivery of curcumin. Water solubility, cytotoxicity, in vitro release behavior, and intracellular uptake of curcumin-loaded LP micelles were investigated. The results showed that LP micelles can increase the water solubility of curcumin 1.1 × 10(3) times and sustain the release of curcumin in a low rate. Curcumin-loaded LP micelles showed much higher cell inhibition than free curcumin on human cervix carcinoma (HeLa) and HepG2 cells. When incubating these curcumin-loaded micelles with HeLa and COS7 cells, due to the over-expression of integrins on cancer cells, the micelles can efficiently use the tumor-targeting function of RGD (functionalized peptide sequences: Arg-Gly-Asp) sequence to deliver the drug into HeLa cells, and better efficiency of the self-assembled LP micelles for curcumin delivery than crude curcumin was also confirmed by LCSM (laser confocal scanning microscope) assays. Combined with the enhanced solubility and higher cell inhibition, LP micelles reported in this study may be promising in clinical application for targeted curcumin delivery.

  12. Stereocomplex micelle from nonlinear enantiomeric copolymers efficiently transports antineoplastic drug

    Science.gov (United States)

    Wang, Jixue; Shen, Kexin; Xu, Weiguo; Ding, Jianxun; Wang, Xiaoqing; Liu, Tongjun; Wang, Chunxi; Chen, Xuesi

    2015-05-01

    Nanoscale polymeric micelles have attracted more and more attention as a promising nanocarrier for controlled delivery of antineoplastic drugs. Herein, the doxorubicin (DOX)-loaded poly(D-lactide)-based micelle (PDM/DOX), poly(L-lactide)-based micelle (PLM/DOX), and stereocomplex micelle (SCM/DOX) from the equimolar mixture of the enantiomeric four-armed poly(ethylene glycol)-polylactide (PEG-PLA) copolymers were successfully fabricated. In phosphate-buffered saline (PBS) at pH 7.4, SCM/DOX exhibited the smallest hydrodynamic diameter ( D h) of 90 ± 4.2 nm and the slowest DOX release compared with PDM/DOX and PLM/DOX. Moreover, PDM/DOX, PLM/DOX, and SCM/DOX exhibited almost stable D hs of around 115, 105, and 90 nm at above normal physiological condition, respectively, which endowed them with great potential in controlled drug delivery. The intracellular DOX fluorescence intensity after the incubation with the laden micelles was different degrees weaker than that incubated with free DOX · HCl within 12 h, probably due to the slow DOX release from micelles. As the incubation time reached to 24 h, all the cells incubated with the laden micelles, especially SCM/DOX, demonstrated a stronger intracellular DOX fluorescence intensity than free DOX · HCl-cultured ones. More importantly, all the DOX-loaded micelles, especially SCM/DOX, exhibited potent antineoplastic efficacy in vitro, excellent serum albumin-tolerance stability, and satisfactory hemocompatibility. These encouraging data indicated that the loading micelles from nonlinear enantiomeric copolymers, especially SCM/DOX, might be promising in clinical systemic chemotherapy through intravenous injection.

  13. Reverse micelles as a tool for probing solvent modulation of protein dynamics: Reverse micelle encapsulated hemoglobin

    Science.gov (United States)

    Roche, Camille J.; Dantsker, David; Heller, Elizabeth R.; Sabat, Joseph E.; Friedman, Joel M.

    2013-08-01

    Hydration waters impact protein dynamics. Dissecting the interplay between hydration waters and dynamics requires a protein that manifests a broad range of dynamics. Proteins in reverse micelles (RMs) have promise as tools to achieve this objective because the water content can be manipulated. Hemoglobin is an appropriate tool with which to probe hydration effects. We describe both a protocol for hemoglobin encapsulation in reverse micelles and a facile method using PEG and cosolvents to manipulate water content. Hydration properties are probed using the water-sensitive fluorescence from Hb bound pyranine and covalently attached Badan. Protein dynamics are probed through ligand recombination traces derived from photodissociated carbonmonoxy hemoglobin on a log scale that exposes the potential role of both α and β solvent fluctuations in modulating protein dynamics. The results open the possibility of probing hydration level phenomena in this system using a combination of NMR and optical probes.

  14. Effect of solvent and temperature on the size distribution of casein micelles measured by dynamic light scattering.

    Science.gov (United States)

    Beliciu, C M; Moraru, C I

    2009-05-01

    The objectives of this study were to investigate the effect of the solvent on the accuracy of casein micelle particle size determination by dynamic light scattering (DLS) at different temperatures and to establish a clear protocol for these measurements. Dynamic light scattering analyses were performed at 6, 20, and 50 degrees C using a 90Plus Nanoparticle Size Analyzer (Brookhaven Instruments, Holtsville, NY). Raw and pasteurized skim milk were used as sources of casein micelles. Simulated milk ultrafiltrate, ultrafiltered water, and permeate obtained by ultrafiltration of skim milk using a 10-kDa cutoff membrane were used as solvents. The pH, ionic concentration, refractive index, and viscosity of all solvents were determined. The solvents were evaluated by DLS to ensure that they did not have a significant influence on the results of the particle size measurements. Experimental protocols were developed for accurate measurement of particle sizes in all solvents and experimental conditions. All measurements had good reproducibility, with coefficients of variation below 5%. Both the solvent and the temperature had a significant effect on the measured effective diameter of the casein micelles. When ultrafiltered permeate was used as a solvent, the particle size and polydispersity of casein micelles decreased as temperature increased. The effective diameter of casein micelles from raw skim milk diluted with ultrafiltered permeate was 176.4 +/- 5.3 nm at 6 degrees C, 177.4 +/- 1.9 nm at 20 degrees C, and 137.3 +/- 2.7 nm at 50 degrees C. This trend was justified by the increased strength of hydrophobic bonds with increasing temperature. Overall, the results of this study suggest that the most suitable solvent for the DLS analyses of casein micelles was casein-depleted ultrafiltered permeate. Dilution with water led to micelle dissociation, which significantly affected the DLS measurements, especially at 6 and 20 degrees C. Simulated milk ultrafiltrate seemed to give

  15. Self-assembly of micelles into designed networks

    Directory of Open Access Journals (Sweden)

    Pyatenko Alexander

    2007-01-01

    Full Text Available AbstractThe EO20PO70EO20(molecular weight 5800 amphiphile as a template is to form dispersed micelle structures. Silver nanoparticles, as inorganic precursors synthesized by a laser ablation method in pure water, are able to produce the highly ordered vesicles detected by TEM micrography. The thickness of the outer layer of a micelle, formed by the silver nanoparticles interacting preferentially with the more hydrophilic EO20block, was around 3.5 nm. The vesicular structure ensembled from micelles is due to proceeding to the mixture of cubic and hexagonal phases.

  16. Enhancing fluorescence intensity of Ellagic acid in Borax-HCl-CTAB micelles

    Science.gov (United States)

    Wang, Feng; Huang, Wei; Zhang, Shuai; Liu, Guokui; Li, Kexiang; Tang, Bo

    2011-03-01

    Ellagic acid (C 14H 6O 8), a naturally occurring phytochemical, found mainly in berries and some nuts, has anticarcinogenic and antioxidant properties. It is found that fluorescence of Ellagic acid (EA) is greatly enhanced by micelle of cetyltrimethylammonium bromide (CTAB) surfactant. Based on this effect, a sensitive proposed fluorimetric method was applied for the determination of Ellagic acid in aqueous solution. In the Borax-HCl buffer, the fluorescence intensity of Ellagic acid in the presence of CTAB is proportional to the concentration of Ellagic acid in range from 8.0 × 10 -10 to 4.0 × 10 -5 mol L -1; and the detection limits are 3.2 × 10 -10 mol L -1 and 5.9 × 10 -10 mol L -1 excited at 266 nm and 388 nm, respectively. The actual samples of pomegranate rinds are simply manipulated and satisfactorily determined. The interaction mechanism studies argue that the negative EA-Borax complex is formed and solubilized in the cationic surfactant CTAB micelle in this system. The fluorescence intensity of EA enhances because the CTAB micelle provides a hydrophobic microenvironment for EA-Borax complex, which can prevent collision with water molecules and decrease the energy loss of EA-Borax complex.

  17. Star polymer-based unimolecular micelles and their application in bio-imaging and diagnosis.

    Science.gov (United States)

    Jin, Xin; Sun, Pei; Tong, Gangsheng; Zhu, Xinyuan

    2018-02-03

    As a novel kind of polymer with covalently linked core-shell structure, star polymers behave in nanostructure in aqueous medium at all concentration range, as unimolecular micelles at high dilution condition and multi-micelle aggregates in other situations. The unique morphologies endow star polymers with excellent stability and functions, making them a promising platform for bio-application. A variety of functions including imaging and therapeutics can be achieved through rational structure design of star polymers, and the existence of plentiful end-groups on shell offers the opportunity for further modification. In the last decades, star polymers have become an attracting platform on fabrication of novel nano-systems for bio-imaging and diagnosis. Focusing on the specific topology and physicochemical properties of star polymers, we have reviewed recent development of star polymer-based unimolecular micelles and their bio-application in imaging and diagnosis. The main content of this review summarizes the synthesis of integrated architecture of star polymers and their self-assembly behavior in aqueous medium, focusing especially on the recent advances on their bio-imaging application and diagnosis use. Finally, we conclude with remarks and give some outlooks for further exploration in this field. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Photophysical study of a charge transfer oxazole dye in micelles: Role of surfactant headgroups

    Energy Technology Data Exchange (ETDEWEB)

    Maiti, Jyotirmay [Department of Chemistry, West Bengal State University, Barasat, Kolkata 700126 (India); Sarkar, Yeasmin; Parui, Partha Pratim [Department of Chemistry, Jadavpur University, Kolkata 700032 (India); Chakraborty, Sandipan [Department of Microbiology, University of Calcutta, Kolkata 700019 (India); Biswas, Suman [Department of Chemistry, West Bengal State University, Barasat, Kolkata 700126 (India); Das, Ranjan, E-mail: ranjan.das68@gmail.com [Department of Chemistry, West Bengal State University, Barasat, Kolkata 700126 (India)

    2015-07-15

    Photophysics of 5-(4′′-dimethylaminophenyl)-2-(4′-sulfophenyl)oxazole, sodium salt (DMO) which undergoes intramolecular charge transfer in the excited state was studied in micelles. In the cationic and the nonionic micelles, significantly higher fluorescence quantum yield is observed in comparison to the anionic micelles, due to much lower accessibility of DMO to the water molecules in the former micelles than the latter. Time-resolved fluorescence decays were characterized by a fast (τ{sub 1}) and a slow (τ{sub 2}) component of decay in all the micelles. The fast decay component (τ{sub 1}) increases significantly in going from the anionic micelles to the cationic micelles, because of the poorly hydrated headgroup region of the latter micelles compared to the former. Furthermore, much higher value of the slow component of decay (τ{sub 2}) is observed for the cationic and the neutral micelles than the anionic micelles. This is attributed to the increased penetration of water molecules into the micellar core of the anionic micelles compared to the cationic and the neutral micelles. - Highlights: • Photophysics of the fluorophore are remarkably different in the cationic and the anionic micelles. • Differential hydration of the surfactant headgroups gives rise to significantly different fluorescence quantum yield and lifetime in oppositely charged micelles. • Electrostatic interactions fine tune location of the fluorophore in the micelle–water interface of ionic micelles.

  19. A LES-CMC formulation for premixed flames including differential diffusion

    Science.gov (United States)

    Farrace, Daniele; Chung, Kyoungseoun; Bolla, Michele; Wright, Yuri M.; Boulouchos, Konstantinos; Mastorakos, Epaminondas

    2018-05-01

    A finite volume large eddy simulation-conditional moment closure (LES-CMC) numerical framework for premixed combustion developed in a previous studyhas been extended to account for differential diffusion. The non-unity Lewis number CMC transport equation has an additional convective term in sample space proportional to the conditional diffusion of the progress variable, that in turn accounts for diffusion normal to the flame front and curvature-induced effects. Planar laminar simulations are first performed using a spatially homogeneous non-unity Lewis number CMC formulation and validated against physical-space fully resolved reference solutions. The same CMC formulation is subsequently used to numerically investigate the effects of curvature for laminar flames having different effective Lewis numbers: a lean methane-air flame with Leeff = 0.99 and a lean hydrogen-air flame with Leeff = 0.33. Results suggest that curvature does not affect the conditional heat release if the effective Lewis number tends to unity, so that curvature-induced transport may be neglected. Finally, the effect of turbulence on the flame structure is qualitatively analysed using LES-CMC simulations with and without differential diffusion for a turbulent premixed bluff body methane-air flame exhibiting local extinction behaviour. Overall, both the unity and the non-unity computations predict the characteristic M-shaped flame observed experimentally, although some minor differences are identified. The findings suggest that for the high Karlovitz number (from 1 to 10) flame considered, turbulent mixing within the flame weakens the differential transport contribution by reducing the conditional scalar dissipation rate and accordingly the conditional diffusion of the progress variable.

  20. pH-responsive polymer–drug conjugates as multifunctional micelles for cancer-drug delivery

    International Nuclear Information System (INIS)

    Kang, Yang; Ha, Wei; Ma, Yuan; Ding, Li-Sheng; Li, Bang-Jing; Liu, Ying-Qian; Fan, Min-Min; Zhang, Sheng

    2014-01-01

    We developed a novel linear pH-sensitive conjugate methoxy poly(ethylene glycol)-4β-aminopodophyllotoxin (mPEG-NPOD-I) by a covalently linked 4β-aminopodophyllotoxin (NPOD) and PEG via imine bond, which was amphiphilic and self-assembled to micelles in an aqueous solution. The mPEG-NPOD-I micelles simultaneously served as an anticancer drug conjugate and as drug carriers. As a drug conjugate, mPEG-NPOD-I showed a significantly faster NPOD release at a mildly acidic pH of 5.0 and 4.0 than a physiological pH of 7.4. Notably, it was confirmed that this drug conjugate could efficiently deliver NPOD to the nuclei of the tumor cells and led to much more cytotoxic effects to A549, Hela, and HepG2 cancer cells than the parent NPOD. The half maximal inhibitory concentration (IC 50 ) of mPEG-NPOD-I was about one order magnitude lower than that of the NPOD. In vivo, mPEG-NPOD-I reduced the size of the tumors significantly, and the biodistribution studies indicated that this drug conjugate could selectively accumulate in tumor tissues. As drug carriers, the mPEG-NPOD-I micelles encapsulated hydrophobic PTX with drug-loading efficiencies of 57% and drug-loading content of 16%. The loaded PTX also showed pH-triggered fast release behavior, and good additive cytotoxicity effect was observed for the PEG-NPOD-I/PTX. We are convinced that these multifunctional drug conjugate micelles have tremendous potential for targeted cancer therapy. (paper)

  1. Iron oxide nanoparticle-micelles (ION-micelles for sensitive (molecular magnetic particle imaging and magnetic resonance imaging.

    Directory of Open Access Journals (Sweden)

    Lucas W E Starmans

    Full Text Available BACKGROUND: Iron oxide nanoparticles (IONs are a promising nanoplatform for contrast-enhanced MRI. Recently, magnetic particle imaging (MPI was introduced as a new imaging modality, which is able to directly visualize magnetic particles and could serve as a more sensitive and quantitative alternative to MRI. However, MPI requires magnetic particles with specific magnetic properties for optimal use. Current commercially available iron oxide formulations perform suboptimal in MPI, which is triggering research into optimized synthesis strategies. Most synthesis procedures aim at size control of iron oxide nanoparticles rather than control over the magnetic properties. In this study, we report on the synthesis, characterization and application of a novel ION platform for sensitive MPI and MRI. METHODS AND RESULTS: IONs were synthesized using a thermal-decomposition method and subsequently phase-transferred by encapsulation into lipidic micelles (ION-Micelles. Next, the material and magnetic properties of the ION-Micelles were analyzed. Most notably, vibrating sample magnetometry measurements showed that the effective magnetic core size of the IONs is 16 nm. In addition, magnetic particle spectrometry (MPS measurements were performed. MPS is essentially zero-dimensional MPI and therefore allows to probe the potential of iron oxide formulations for MPI. ION-Micelles induced up to 200 times higher signal in MPS measurements than commercially available iron oxide formulations (Endorem, Resovist and Sinerem and thus likely allow for significantly more sensitive MPI. In addition, the potential of the ION-Micelle platform for molecular MPI and MRI was showcased by MPS and MRI measurements of fibrin-binding peptide functionalized ION-Micelles (FibPep-ION-Micelles bound to blood clots. CONCLUSIONS: The presented data underlines the potential of the ION-Micelle nanoplatform for sensitive (molecular MPI and warrants further investigation of the FibPep-ION-Micelle

  2. Logarithmic Exchange Kinetics in Monodisperse Copolymeric Micelles

    Science.gov (United States)

    García Daza, Fabián A.; Bonet Avalos, Josep; Mackie, Allan D.

    2017-06-01

    Experimental measurements of the relaxation kinetics of copolymeric surfactant exchange for micellar systems unexpectedly show a peculiar logarithmic decay. Several authors use polydispersity as an explanation for this behavior. However, in coarse-grained simulations that preserve microscopic details of the surfactants, we find evidence of the same logarithmic behavior. Since we use a strictly monodisperse distribution of chain lengths such a relaxation process cannot be attributed to polydispersity, but has to be caused by an inherent physical process characteristic of this type of system. This is supported by the fact that the decay is specifically logarithmic and not a power law with an exponent inherited from the particular polydispersity distribution of the sample. We suggest that the degeneracy of the energy states of the hydrophobic block in the core, which is broken on leaving the micelle, can qualitatively explain the broad distribution of energy barriers, which gives rise to the observed nonexponential relaxation.

  3. Studies on conductance of uranyl soaps

    International Nuclear Information System (INIS)

    Mehrotra, K.N.; Sharma, M.; Gahlaut, A.S.

    1987-01-01

    Specific conductance of uranyl soaps in dimethylformamide indicates two critical micelle concentrations CMC(I) and CMC(II). The value of CMC(II) decreases with the increase in chain length of the soap, whereas CMC(I) does not vary at all. The results show that the soaps behave as simple electrolyte. The major conductance at infinite dilution (μsub(o)) and dissociation constant (K) of these soaps have been evaluated. (author). 12 refs

  4. Structure and reactivity in amphiphile-water micelles

    International Nuclear Information System (INIS)

    Chevalier, Yves

    1985-01-01

    Following a review of the general properties of micelles, this report contains two parts: - A structural study of octylphosphate micelles. Important structural changes have been evidenced by mean of small angle neutron scattering as the electrical charge of the interface is varied. The NMR relaxation study of the conformation of the hydrocarbon chains has shown that the micellar core is disordered in contrast with the interface which is rather structured. The diffusion motions in the interface and the segmental motions of the chains are fast. - Studies on the reactivity in micelles have been carried out. A large micellar effect on the complexation of transition ions by amphiphilic ligands is evidenced. The problem of solute localization in micelles is developed with few examples. (author) [fr

  5. Influence of succinylation on physicochemical property of yak casein micelles.

    Science.gov (United States)

    Yang, Min; Yang, Jitao; Zhang, Yuan; Zhang, Weibing

    2016-01-01

    Succinylation is a chemical-modification method that affects the physicochemical characteristics and functional properties of proteins. This study assessed the influence of succinylation on the physicochemical properties of yak casein micelles. The results revealed that surface hydrophobicity indices decreased with succinylation. Additionally, denaturation temperature and denaturation enthalpy decreased with increasing succinylation level, except at 82%. The buffering properties of yak casein micelles were affected by succinylation. It was found that chemical modification contributed to a slight shift of the buffering peak towards a lower pH value and a markedly increase of the maximum buffering values of yak casein micelles at pH 4.5-6.0 and pH casein micellar hydration and whiteness values. The findings obtained from this study will provide the basic information on the physicochemical properties of native and succinylated yak casein micelles. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Interactions of casein micelles with calcium phosphate particles.

    Science.gov (United States)

    Tercinier, Lucile; Ye, Aiqian; Anema, Skelte G; Singh, Anne; Singh, Harjinder

    2014-06-25

    Insoluble calcium phosphate particles, such as hydroxyapatite (HA), are often used in calcium-fortified milks as they are considered to be chemically unreactive. However, this study showed that there was an interaction between the casein micelles in milk and HA particles. The caseins in milk were shown to bind to the HA particles, with the relative proportions of bound β-casein, αS-casein, and κ-casein different from the proportions of the individual caseins present in milk. Transmission electron microscopy showed no evidence of intact casein micelles on the surface of the HA particles, which suggested that the casein micelles dissociated either before or during binding. The HA particles behaved as ion chelators, with the ability to bind the ions contained in the milk serum phase. Consequently, the depletion of the serum minerals disrupted the milk mineral equilibrium, resulting in dissociation of the casein micelles in milk.

  7. Enzymatically triggered multifunctional delivery system based on hyaluronic acid micelles

    KAUST Repository

    Deng, Lin; Wang, Guangchao; Ren, Jian; Zhang, Bei; Yan, Jingjing; Li, Wengang; Khashab, Niveen M.

    2012-01-01

    (WI38). Higher Ch-HA micelles uptake was seen in cancer cells versus normal cells. Consequently, DOX release was elevated in cancer cells causing higher cytotoxicity and enhanced cell death. © 2012 The Royal Society of Chemistry.

  8. Synthesis and immobilization of polystyreneb-polyvinyltriethoxysilane micelles

    KAUST Repository

    Zhu, Saisai; Zhu, Hui; Xia, Ru; Feng, Xiaoshuang; Chen, Peng; Qian, Jiasheng; Cao, Ming; Yang, Bin; Miao, Jibin; Su, Lifen; Song, Changjiang

    2018-01-01

    Diblock copolymers polystyrene-block-polyvinyltriethoxysilane (PS-b-PVTES) were synthesized via atom transfer radical polymerization (ATRP), which self-assembled into spherical micelles in solvent of THF-methanol mixtures. The self

  9. Rennet-induced gelation of concentrated milk in the presence of sodium caseinate: differences between milk concentration using ultrafiltration and osmotic stressing.

    Science.gov (United States)

    Krishnankutty Nair, P; Corredig, M

    2015-01-01

    Concentrating milk is a common unit operation in the dairy industry. With the reduction of water, the particles interact more frequently with each other and the functionality of the casein micelles may depend on the interactions occurring during concentration. The objective of this research was to investigate the effect of concentration on the renneting properties of the casein micelles by comparing 2 concentration methods: ultrafiltration and osmotic stressing. Both methods selectively concentrate the protein fraction of milk, while the composition of the soluble phase is unaltered. To evaluate possible differences in the rearrangements of the casein micelles during concentration, renneting properties were evaluated with or without the addition of soluble caseins, added either before or after concentration. The results indicate that casein micelles undergo rearrangements during concentration and that shear during membrane filtration may play a role in affecting the final properties of the milk. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  10. Turbine Airfoil With CMC Leading-Edge Concept Tested Under Simulated Gas Turbine Conditions

    Science.gov (United States)

    Robinson, R. Craig; Hatton, Kenneth S.

    2000-01-01

    Silicon-based ceramics have been proposed as component materials for gas turbine engine hot-sections. When the Navy s Harrier fighter experienced engine (Pegasus F402) failure because of leading-edge durability problems on the second-stage high-pressure turbine vane, the Office of Naval Research came to the NASA Glenn Research Center at Lewis Field for test support in evaluating a concept for eliminating the vane-edge degradation. The High Pressure Burner Rig (HPBR) was selected for testing since it could provide temperature, pressure, velocity, and combustion gas compositions that closely simulate the engine environment. The study focused on equipping the stationary metal airfoil (Pegasus F402) with a ceramic matrix composite (CMC) leading-edge insert and evaluating the feasibility and benefits of such a configuration. The test exposed the component, with and without the CMC insert, to the harsh engine environment in an unloaded condition, with cooling to provide temperature relief to the metal blade underneath. The insert was made using an AlliedSignal Composites, Inc., enhanced HiNicalon (Nippon Carbon Co. LTD., Yokohama, Japan) fiber-reinforced silicon carbide composite (SiC/SiC CMC) material fabricated via chemical vapor infiltration. This insert was 45-mils thick and occupied a recessed area in the leading edge and shroud of the vane. It was designed to be free floating with an end cap design. The HPBR tests provided a comparative evaluation of the temperature response and leading-edge durability and included cycling the airfoils between simulated idle, lift, and cruise flight conditions. In addition, the airfoils were aircooled, uniquely instrumented, and exposed to the exact set of internal and external conditions, which included gas temperatures in excess of 1370 C (2500 F). In addition to documenting the temperature response of the metal vane for comparison with the CMC, a demonstration of improved leading-edge durability was a primary goal. First, the

  11. Polymeric micelles for potentiated antiulcer and anticancer activities of naringin

    Science.gov (United States)

    Mohamed, Elham Abdelmonem; Abu Hashim, Irhan Ibrahim; Yusif, Rehab Mohammad; Shaaban, Ahmed Abdel Aziz; El-Sheakh, Ahmed Ramadan; Hamed, Mohammed Fawzy; Badria, Farid Abd Elreheem

    2018-01-01

    Naringin is one of the most interesting phytopharmaceuticals that has been widely investigated for various biological actions. Yet, its low water solubility, limited permeability, and suboptimal bioavailability limited its use. Therefore, in this study, polymeric micelles of naringin based on pluronic F68 (PF68) were developed, fully characterized, and optimized. The optimized formula was investigated regarding in vitro release, storage stability, and in vitro cytotoxicity vs different cell lines. Also, cytoprotection against ethanol-induced ulcer in rats and antitumor activity against Ehrlich ascites carcinoma in mice were investigated. Nanoscopic and nearly spherical 1:50 micelles with the mean diameter of 74.80±6.56 nm and narrow size distribution were obtained. These micelles showed the highest entrapment efficiency (EE%; 96.14±2.29). The micelles exhibited prolonged release up to 48 vs 10 h for free naringin. The stability of micelles was confirmed by insignificant changes in drug entrapment, particle size, and retention (%) (91.99±3.24). At lower dose than free naringin, effective cytoprotection of 1:50 micelles against ethanol-induced ulcer in rat model has been indicated by significant reduction in mucosal damage, gastric level of malondialdehyde, gastric expression of tumor necrosis factor-alpha, caspase-3, nuclear factor kappa-light-chain-enhancer of activated B cells, and interleukin-6 with the elevation of gastric reduced glutathione and superoxide dismutase when compared with the positive control group. As well, these micelles provoked pronounced antitumor activity assessed by potentiated in vitro cytotoxicity particularly against colorectal carcinoma cells and tumor growth inhibition when compared with free naringin. In conclusion, 1:50 naringin–PF68 micelles can be represented as a potential stable nanodrug delivery system with prolonged release and enhanced antiulcer as well as antitumor activities. PMID:29497294

  12. New self-assembled nanocrystal micelles for biolabels and biosensors.

    Energy Technology Data Exchange (ETDEWEB)

    Tallant, David Robert; Wilson, Michael C. (University of New Mexico, Albuquerque, NM); Leve, Erik W. (University of New Mexico, Albuquerque, NM); Fan, Hongyou; Brinker, C. Jeffrey; Gabaldon, John (University of New Mexico, Albuquerque, NM); Scullin, Chessa (University of New Mexico, Albuquerque, NM)

    2005-12-01

    The ability of semiconductor nanocrystals (NCs) to display multiple (size-specific) colors simultaneously during a single, long term excitation holds great promise for their use in fluorescent bio-imaging. The main challenges of using nanocrystals as biolabels are achieving biocompatibility, low non-specific adsorption, and no aggregation. In addition, functional groups that can be used to further couple and conjugate with biospecies (proteins, DNAs, antibodies, etc.) are required. In this project, we invented a new route to the synthesis of water-soluble and biocompatible NCs. Our approach is to encapsulate as-synthesized, monosized, hydrophobic NCs within the hydrophobic cores of micelles composed of a mixture of surfactants and phospholipids containing head groups functionalized with polyethylene glycol (-PEG), -COOH, and NH{sub 2} groups. PEG provided biocompatibility and the other groups were used for further biofunctionalization. The resulting water-soluble metal and semiconductor NC-micelles preserve the optical properties of the original hydrophobic NCs. Semiconductor NCs emit the same color; they exhibit equal photoluminescence (PL) intensity under long-time laser irradiation (one week) ; and they exhibit the same PL lifetime (30-ns). The results from transmission electron microscopy and confocal fluorescent imaging indicate that water-soluble semiconductor NC-micelles are biocompatible and exhibit no aggregation in cells. We have extended the surfactant/lipid encapsulation techniques to synthesize water-soluble magnetic NC-micelles. Transmission electron microscopy results suggest that water-soluble magnetic NC-micelles exhibit no aggregation. The resulting NC-micelles preserve the magnetic properties of the original hydrophobic magnetic NCs. Viability studies conducted using yeast cells suggest that the magnetic nanocrystal-micelles are biocompatible. We have demonstrated, for the first time, that using external oscillating magnetic fields to manipulate

  13. Nanoscale elastic modulus variation in loaded polymeric micelle reactors.

    Science.gov (United States)

    Solmaz, Alim; Aytun, Taner; Deuschle, Julia K; Ow-Yang, Cleva W

    2012-07-17

    Tapping mode atomic force microscopy (TM-AFM) enables mapping of chemical composition at the nanoscale by taking advantage of the variation in phase angle shift arising from an embedded second phase. We demonstrate that phase contrast can be attributed to the variation in elastic modulus during the imaging of zinc acetate (ZnAc)-loaded reverse polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) diblock co-polymer micelles less than 100 nm in diameter. Three sample configurations were characterized: (i) a 31.6 μm thick polystyrene (PS) support film for eliminating the substrate contribution, (ii) an unfilled PS-b-P2VP micelle supported by the same PS film, and (iii) a ZnAc-loaded PS-b-P2VP micelle supported by the same PS film. Force-indentation (F-I) curves were measured over unloaded micelles on the PS film and over loaded micelles on the PS film, using standard tapping mode probes of three different spring constants, the same cantilevers used for imaging of the samples before and after loading. For calibration of the tip geometry, nanoindentation was performed on the bare PS film. The resulting elastic modulus values extracted by applying the Hertz model were 8.26 ± 3.43 GPa over the loaded micelles and 4.17 ± 1.65 GPa over the unloaded micelles, confirming that phase contrast images of a monolayer of loaded micelles represent maps of the nanoscale chemical and mechanical variation. By calibrating the tip geometry indirectly using a known soft material, we are able to use the same standard tapping mode cantilevers for both imaging and indentation.

  14. Structure of pure SDS and DTAB micelles in brine determined by small-angle neutron scattering (SANS)

    DEFF Research Database (Denmark)

    Bergström, M.; Pedersen, J.S.

    1999-01-01

    The geometrical structure of pure SDS and DTAB surfactant micelles in the absence of added salt as well as its dependence on the concentration of NaBr have been investigated at 40 degrees C using small-angle neutron scattering (SANS). In contrast to previous SANS measurements on the same systems we...... that ordinary surfactant micelles are shaped as circular or elongated bilayers (tablets). Both SDS and DTAB micelles appeared to be disk-like in pure D2O and the corresponding data were best fitted with a model for (monodisperse) oblate ellipsoids of revolution with half axes a=12.0 Angstrom, b=20.3 Angstrom...... ([SDS]=1.0 wt.%) and a=12.4 Angstrom, b=21.6 Angstrom ([DTAB]=1.0 wt.%). The half axis b related to the disk radius increases in both cases with an increasing amount of added salt to about 23 Angstrom (SDS) and 24 Angstrom (DTAB) at [NaBr]=0.1 M and at about [NaBr]=0.2 M the SDS micelles become tablet...

  15. A simple reduction-sensitive micelles co-delivery of paclitaxel and dasatinib to overcome tumor multidrug resistance

    Directory of Open Access Journals (Sweden)

    Li J

    2017-11-01

    Full Text Available Jun Li,1,* Ruitong Xu,2,* Xiao Lu,3 Jing He,1 Shidai Jin1 1Department of Medical Oncology, 2Department of General Practice, The First Affiliated Hospital with Nanjing Medical University, Nanjing, 3Department of Medical Oncology, Changshu No 1 People’s Hospital, Changshu, People’s Republic of China *These authors contributed equally to this work Abstract: Multidrug resistance (MDR is one of the major obstacles in successful chemotherapy. The combination of chemotherapy drugs and multidrug-resistant reversing agents for treating MDR tumor is a good strategy to overcome MDR. In this work, we prepared the simple redox-responsive micelles based on mPEG-SS-C18 as a co-delivery system to load the paclitaxel (PTX and dasatinib (DAS for treatment of MCF-7/ADR cells. The co-loaded micelles had a good dispersity and a spherical shape with a uniform size distribution, and they could quickly disassemble and rapidly release drugs under the reduction environment. Compared with MCF-7 cells, the DAS and PTX co-loaded redox-sensitive micelle (SS-PDNPs showed stronger cytotoxicity and a more improving intracellular drug concentration than other drug formulations in MCF-7/ADR cells. In summary, the results suggested that the simple co-delivery micelles of PTX and DAS possessed significant potential to overcome drug resistance in cancer therapy. Keywords: redox responsive, overcoming multidrug resistant, co-delivery, paclitaxel, dasatinib 

  16. Self-assembly of block copolymer micelles: synthesis via reversible addition-fragmentation chain transfer polymerization and aqueous solution properties.

    Science.gov (United States)

    Mya, Khine Y; Lin, Esther M J; Gudipati, Chakravarthy S; Gose, Halima B A S; He, Chaobin

    2010-07-22

    Poly(hexafluorobutyl methacrylate) (PHFBMA) homopolymer was synthesized by reversible addition-fragmentation chain transfer (RAFT)-mediated living radical polymerization in the presence of cyano-2-propyl dithiobenzoate (CPDB) RAFT agent. A block copolymer of PHFBMA-poly(propylene glycol acrylate) (PHFBMA-b-PPGA) with dangling poly(propylene glycol) (PPG) side chains was then synthesized by using CPDB-terminated PHFBMA as a macro-RAFT agent. The amphiphilic properties and self-assembly of PHFBMA-b-PPGA block copolymer in aqueous solution were investigated by dynamic and static light scattering (DLS and SLS) studies, in combination with fluorescence spectroscopy and transmission electron microscopy (TEM). Although PPG shows moderately hydrophilic character, the formation of nanosize polymeric micelles was confirmed by fluorescence and TEM studies. The low value of the critical aggregation concentration exhibited that the tendency for the formation of copolymer aggregates in aqueous solution was very high due to the strong hydrophobicity of the PHFBMA(145)-b-PPGA(33) block copolymer. The combination of DLS and SLS measurements revealed the existence of micellar aggregates in aqueous solution with an association number of approximately 40 +/- 7 for block copolymer micelles. It was also found in TEM observation that there are 40-50 micelles accumulated into one aggregate and these micelles are loosely packed inside the aggregate.

  17. Miscibility and interaction between 1-alkanol and short-chain phosphocholine in the adsorbed film and micelles.

    Science.gov (United States)

    Takajo, Yuichi; Matsuki, Hitoshi; Kaneshina, Shoji; Aratono, Makoto; Yamanaka, Michio

    2007-09-01

    The miscibility and interaction of 1-hexanol (C6OH) and 1-heptanol (C7OH) with 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC) in the adsorbed films and micelles were investigated by measuring the surface tension of aqueous C6OH-DHPC and aqueous C7OH-DHPC solutions. The surface density, the mean molecular area, the composition of the adsorbed film, and the excess Gibbs energy of adsorption g(H,E), were estimated. Further, the critical micelle concentration of the mixtures was determined from the surface tension versus molality curves; the micellar composition was calculated. The miscibility of the 1-alkanols and DHPC molecules in the adsorbed film and micelles was examined using the phase diagram of adsorption (PDA) and that of micellization (PDM). The PDA and the composition dependence of g(H,E) indicated the non-ideal mixing of the 1-alkanols and DHPC molecules due to the attractive interaction between the molecules in the adsorbed film, while the PDM indicated that the 1-alkanol molecules were not incorporated in the micelles within DHPC rich region. The dependence of the mean molecular area of the mixtures on the surface composition suggested that the packing property of the adsorbed film depends on the chain length of 1-alkanol: C6OH expands the DHPC adsorbed film more than C7OH.

  18. Presentation on the Modeling and Educational Demonstrations Laboratory Curriculum Materials Center (MEDL-CMC): A Working Model and Progress Report

    Science.gov (United States)

    Glesener, G. B.; Vican, L.

    2015-12-01

    Physical analog models and demonstrations can be effective educational tools for helping instructors teach abstract concepts in the Earth, planetary, and space sciences. Reducing the learning challenges for students using physical analog models and demonstrations, however, can often increase instructors' workload and budget because the cost and time needed to produce and maintain such curriculum materials is substantial. First, this presentation describes a working model for the Modeling and Educational Demonstrations Laboratory Curriculum Materials Center (MEDL-CMC) to support instructors' use of physical analog models and demonstrations in the science classroom. The working model is based on a combination of instructional resource models developed by the Association of College & Research Libraries and by the Physics Instructional Resource Association. The MEDL-CMC aims to make the curriculum materials available for all science courses and outreach programs within the institution where the MEDL-CMC resides. The sustainability and value of the MEDL-CMC comes from its ability to provide and maintain a variety of physical analog models and demonstrations in a wide range of science disciplines. Second, the presentation then reports on the development, progress, and future of the MEDL-CMC at the University of California Los Angeles (UCLA). Development of the UCLA MEDL-CMC was funded by a grant from UCLA's Office of Instructional Development and is supported by the Department of Earth, Planetary, and Space Sciences. Other UCLA science departments have recently shown interest in the UCLA MEDL-CMC services, and therefore, preparations are currently underway to increase our capacity for providing interdepartmental service. The presentation concludes with recommendations and suggestions for other institutions that wish to start their own MEDL-CMC in order to increase educational effectiveness and decrease instructor workload. We welcome an interuniversity collaboration to

  19. Micelle swelling agent derived cavities for increasing hydrophobic organic compound removal efficiency by mesoporous micelle@silica hybrid materials

    KAUST Repository

    Shi, Yifeng; Li, Bin; Wang, Peng; Dua, Rubal; Zhao, Dongyuan

    2012-01-01

    Mesoporous micelle@silica hybrid materials with 2D hexagonal mesostructures were synthesized as reusable sorbents for hydrophobic organic compounds (HOCs) removal by a facile one-step aqueous solution synthesis using 3-(trimethoxysily)propyl

  20. Thermosensitive mPEG-b-PA-g-PNIPAM comb block copolymer micelles: effect of hydrophilic chain length and camptothecin release behavior.

    Science.gov (United States)

    Yang, Xiao-Li; Luo, Yan-Ling; Xu, Feng; Chen, Ya-Shao

    2014-02-01

    Block copolymer micelles are extensively used as drug controlled release carriers, showing promising application prospects. The comb or brush copolymers are especially of great interest, whose densely-grafted side chains may be important for tuning the physicochemical properties and conformation in selective solvents, even in vitro drug release. The purpose of this work was to synthesize novel block copolymer combs via atom transfer radical polymerization, to evaluate its physicochemical features in solution, to improve drug release behavior and to enhance the bioavailablity, and to decrease cytotoxicity. The physicochemical properties of the copolymer micelles were examined by modulating the composition and the molecular weights of the building blocks. A dialysis method was used to load hydrophobic camptothecin (CPT), and the CPT release and stability were detected by UV-vis spectroscopy and high-performance liquid chromatography, and the cytotoxicity was evaluated by MTT assays. The copolymers could self-assemble into well-defined spherical core-shell micelle aggregates in aqueous solution, and showed thermo-induced micellization behavior, and the critical micelle concentration was 2.96-27.64 mg L(-1). The micelles were narrow-size-distribution, with hydrodynamic diameters about 128-193 nm, depending on the chain length of methoxy polyethylene glycol (mPEG) blocks and poly(N-isopropylacrylamide) (PNIPAM) graft chains or/and compositional ratios of mPEG to PNIPAM. The copolymer micelles could stably and effectively load CPT but avoid toxicity and side-effects, and exhibited thermo-dependent controlled and targeted drug release behavior. The copolymer micelles were safe, stable and effective, and could potentially be employed as CPT controlled release carriers.

  1. Synthesis and in vitro experiments of carcinoma vascular endothelial targeting polymeric nano-micelles combining small particle size and supermagnetic sensitivity.

    Science.gov (United States)

    Zhang, Yi; Pan, Jielin; Xu, Qilan; Li, Hao; Wang, Jianhao; Zhang, Chao; Hong, Guobin

    2018-01-01

    Objective: To construct carcinoma vascular endothelial-targeted polymeric nanomicelles with high magnetic resonance imaging (MRI) sensitivity and to evaluate their biological safety and in vitro tumor-targeting effect, and to monitor their feasibility using clinical MRI scanner. Method: Amphiphilic block copolymer, poly(ethylene glycol)- b -poly(ε-caprolactone) (PEG-PCL) was synthesized via the ring-opening polymerization of ε-caprolactone (CL) initiated by poly(ethylene glycol) (PEG), in which cyclic pentapeptide Arg-Gly-Asp (cRGD) was conjugated with the terminal of hydrophilic PEG block. During the self-assembly of PEG-PCL micelles, superparamagnetic γ-Fe 2 O 3 nanoparticles (11 nm) was loaded into the hydrophobic core. The cRGD-terminated γ-Fe 2 O 3 -loaded polymeric micelles targeting to carcinoma vascular endothelial cells, were characterized in particle size, morphology, loading efficiency and so on, especially high MRI sensitivity in vitro. Normal hepatic vascular endothelial cells (ED25) were incubated with the resulting micelles for assessing their safety. Human hepatic carcinoma vascular endothelial cells (T3A) were cultured with the resulting micelles to assess the micelle uptake using Prussian blue staining and the cell signal intensity using MRI. Results: All the polymeric micelles exhibited ultra-small particle sizes with approximately 50 nm, high relaxation rate, and low toxicity even at high iron concentrations. More blue-stained iron particles were present in the targeting group than the non-targeting and competitive inhibition groups. In vitro MRI showed T 2 WI and T 2 relaxation times were significantly lower in the targeting group than in the other two groups. Conclusion: γ-Fe 2 O 3 -loaded PEG-PCL micelles not only possess ultra-small size and high superparamagnetic sensitivity, also can be actively targeted to carcinoma vascular endothelial cells by tumor-targeted cRGD. It appears to be a promising contrast agent for tumor

  2. Mixed reverse micelles facilitated downstream processing of lipase involving water-oil-water liquid emulsion membrane.

    Science.gov (United States)

    Bhowal, Saibal; Priyanka, B S; Rastogi, Navin K

    2014-01-01

    Our earlier work for the first time demonstrated that liquid emulsion membrane (LEM) containing reverse micelles could be successfully used for the downstream processing of lipase from Aspergillus niger. In the present work, we have attempted to increase the extraction and purification fold of lipase by using mixed reverse micelles (MRM) consisting of cationic and nonionic surfactants in LEM. It was basically prepared by addition of the internal aqueous phase solution to the organic phase followed by the redispersion of the emulsion in the feed phase containing enzyme, which resulted in globules of water-oil-water (WOW) emulsion for the extraction of lipase. The optimum conditions for maximum lipase recovery (100%) and purification fold (17.0-fold) were CTAB concentration 0.075 M, Tween 80 concentration 0.012 M, at stirring speed of 500 rpm, contact time 15 min, internal aqueous phase pH 7, feed pH 9, KCl concentration 1 M, NaCl concentration 0.1 M, and ratio of membrane emulsion to feed volume 1:1. Incorporation of the nonionic surfactant (e.g., Tween 80) resulted in remarkable improvement in the purification fold (3.1-17.0) of the lipase. LEM containing a mixture of nonionic and cationic surfactants can be successfully used for the enhancement in the activity recovery and purification fold during downstream processing of enzymes/proteins. © 2014 American Institute of Chemical Engineers.

  3. Exploring the usefulness of comprehensive care plans for children with medical complexity (CMC: a qualitative study

    Directory of Open Access Journals (Sweden)

    Adams Sherri

    2013-01-01

    Full Text Available Abstract Background The Medical Home model recommends that Children with Special Health Care Needs (CSHCN receive a medical care plan, outlining the child’s major medical issues and care needs to assist with care coordination. While care plans are a primary component of effective care coordination, the creation and maintenance of care plans is time, labor, and cost intensive, and the desired content of the care plan has not been studied. The purpose of this qualitative study was to understand the usefulness and desired content of comprehensive care plans by exploring the perceptions of parents and health care providers (HCPs of children with medical complexity (CMC. Methods This qualitative study utilized in-depth semi-structured interviews and focus groups. HCPs (n = 15 and parents (n = 15 of CMC who had all used a comprehensive care plan were recruited from a tertiary pediatric academic health sciences center. Themes were identified through grounded theory analysis of interview and focus group data. Results A multi-dimensional model of perceived care plan usefulness emerged. The model highlights three integral aspects of the care plan: care plan characteristics, activating factors and perceived outcomes of using a care plan. Care plans were perceived as a useful tool that centralized and focused the care of the child. Care plans were reported to flatten the hierarchical relationship between HCPs and parents, resulting in enhanced reciprocal information exchange and strengthened relationships. Participants expressed that a standardized template that is family-centered and includes content relevant to both the medical and social needs of the child is beneficial when integrated into overall care planning and delivery for CMC. Conclusions Care plans are perceived to be a useful tool to both health care providers and parents of CMC. These findings inform the utility and development of a comprehensive care plan template as well as a model of how

  4. Mixed micelles of polyethylene glycol (23) lauryl ether with ionic surfactants studied by proton 1D and 2D NMR.

    Science.gov (United States)

    Gao, Hong-Chang; Zhao, Sui; Mao, Shi-Zhen; Yuan, Han-Zhen; Yu, Jia-Yong; Shen, Lian-Fang; Du, You-Ru

    2002-05-01

    (1)H NMR chemical shift, spin-lattice relaxation time, spin-spin relaxation time, self-diffusion coefficient, and two-dimensional nuclear Overhauser enhancement (2D NOESY) measurements have been used to study the nonionic-ionic surfactant mixed micelles. Cetyl trimethyl ammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) were used as the ionic surfactants and polyethylene glycol (23) lauryl ether (Brij-35) as the nonionic surfactant. The two systems are both with varying molar ratios of CTAB/Brij-35 (C/B) and SDS/Brij-35 (S/B) ranging from 0.5 to 2, respectively, at a constant concentration of 6 mM for Brij-35 in aqueous solutions. Results give information about the relative arrangement of the surfactant molecules in the mixed micelles. In the former system, the trimethyl groups attached to the polar heads of the CTAB molecules are located between the first oxy-ethylene groups next to the hydrophobic chains of Brij-35 molecules. These oxy-ethylene groups gradually move outward from the hydrophobic core of the mixed micelle with an increase in C/B in the mixed solution. In contrast to the case of the CTAB/Triton X-100 system, the long flexible hydrophilic poly oxy-ethylene chains, which are in the exterior part of the mixed micelles, remain coiled, but looser, surrounding the hydrophobic core. There is almost no variation in conformation of the hydrophilic chains of Brij-35 molecules in the mixed micelles of the SDS/Brij-35 system as the S/B increases. The hydrophobic chains of both CTAB and SDS are co-aggregated with Brij-35, respectively, in their mixed micellar cores.

  5. METHODOLOGICAL HURDLES IN CAPTURING CMC DATA: THE CASE OF THE MISSING SELF-REPAIR

    Directory of Open Access Journals (Sweden)

    Bryan Smith

    2008-02-01

    Full Text Available This paper reports on a study of the use of self-repair among learners of German in a task-based CMC environment. The purpose of the study was two-fold. The first goal sought to establish how potential interpretations of CMC data may be very different depending on the method of data collection and evaluation employed. The second goal was to explicitly examine the nature of CMC self-repair in the task-based foreign language CALL classroom. Paired participants (n=46 engaged in six jigsaw tasks over the course of one university semester via the chat function in Blackboard. Chat data were evaluated first by using only the chat log file and second by examining a video file of the screen capture of the entire interaction. Results show a fundamental difference in the interpretation of the chat interaction which varies as a function of the data collection and evaluation methods employed. The findings also suggest a possible difference in the nature of self-repair across face-to-face and SCMC environments. In view of the results, this paper calls for CALL researchers to abandon the reliance on printed chat log files when attempting to interpret SCMC interactional data.

  6. Amphipathic dextran-doxorubicin prodrug micelles for solid tumor therapy.

    Science.gov (United States)

    Jin, Rong; Guo, Xuelian; Dong, Lingli; Xie, Enyuan; Cao, Aoneng

    2017-10-01

    A group of micelles self-assembled from deoxycholic acid-doxorubicin-conjugated dextran (denoted as Dex-DCA-DOX) prodrugs were designed and prepared for pH-triggered drug release and cancer chemotherapy. These prodrugs could be successfully produced by chemically coupling hydrophobic deoxycholic acid (DCA) to dextran hydrazine (denoted as Dex-NHNH 2 ) and hydrazone linker formation between doxorubicin (DOX) and Dex-NHNH 2 . These Dex-DCA-DOX prodrugs self-assembled to form micelles under physiological conditions with varied particle sizes depending on molecular weight of dextran, degree of substitution (DS) of DCA and DOX. After optimization, Dex10k-DCA9-DOX5.5 conjugate comprising dextran of 10kDa, DCA of DS 9 and DOX loading content of 5.5wt%, formed the micelles with the smallest size (110nm). These prodrug micelles could slowly liberate DOX under physiological conditions but efficiently released the drug at an acidified endosomal pH by the hydrolysis of acid-labile hydrazone linker. In vitro cytotoxicity experiment indicated that Dex10k-DCA9-DOX5.5 micelles exerted marked antitumor activity against MCF-7 and SKOV-3 cancer cells. Besides, intravenous administration of the micelles afforded growth inhibition of SKOV-3 tumor bearing in nude mice at a dosage of 2.5mg per kg with anti-cancer efficacy comparable to free DOX-chemotherapy but low systemic toxicity. This study highlights the feasibility of bio-safe and efficient dextran-based prodrug micelles designed for cancer chemotherapy. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Microwave assisted in situ synthesis of Ag–NaCMC films and their reproducible surface-enhanced Raman scattering signals

    International Nuclear Information System (INIS)

    Jiang, Tao; Li, Junpeng; Zhang, Li; Wang, Binbing; Zhou, Jun

    2014-01-01

    Graphical abstract: Two kinds of Ag–NaCMC films for surface-enhanced Raman scattering (SERS) were prepared by conventional heating and microwave assisted in situ reduction methods without any additional capping or reducing agents. A relatively narrow and symmetric surface plasmon resonance band was observed in the absorption spectra of the films fabricated by the microwave assisted in situ reduction method. More uniform silver nanoparticles (NPs) implied by the symmetric absorption spectrum were further confirmed by the scanning electron microscopy images. After the simulation of the E-field intensity distribution around the silver NPs in NaCMC film, the Raman scattering enhancement factors (EFs) of these films were then investigated with 4-mercaptobenzoic acid molecule as a SERS reporter. Improved reproducibility of SERS signal was obtained in the microwave assisted synthesized Ag–NaCMC film, although it maintained an EF as only 1.11 × 10 8 . The reproducible SERS signal of the Ag–NaCMC film is particularly attractive and this microwave assisted in situ reduction method is suitable for the production of excellent substrate for biosensor application. - Highlights: • The synthesis of Ag–NaCMC films was successfully fulfilled by a low-cost microwave method. • More uniform silver nanoparticles were observed in Ag–NaCMC film synthesized by microwave. • Improved reproducibility of SERS signal was obtained in microwave synthesized Ag–NaCMC film. - Abstract: Two kinds of Ag–NaCMC films for surface-enhanced Raman scattering (SERS) were prepared by conventional heating and microwave assisted in situ reduction methods without any additional capping or reducing agents. A relatively narrow and symmetric surface plasmon resonance band was observed in the absorption spectra of the films fabricated by the microwave assisted in situ reduction method. More uniform silver nanoparticles (NPs) implied by the symmetric absorption spectrum were further confirmed by

  8. Optimization and anticancer activity in vitro and in vivo of baohuoside I incorporated into mixed micelles based on lecithin and Solutol HS 15.

    Science.gov (United States)

    Yan, Hong-Mei; Song, Jie; Zhang, Zhen-Hai; Jia, Xiao-Bin

    2016-10-01

    Baohuoside I, extracted from the Herba epimedii, is an effective but a poorly soluble antitumor drug. To improve its solubility, formulation of baohuoside I-loaded mixed micelles with lecithin and Solutol HS 15 (BLSM) has been performed in this study. We performed a systematic comparative evaluation of the antiproliferative effect, cellular uptake, antitumor efficacy, and in vivo tumor targeting of these micelles using non-small cell lung cancer (NSCLC) A549 cells. Results showed that the obtained micelles have a mean particle size of around 62.54 nm, and the size of micelles was narrowly distributed. With the improved cellular uptake, BLSM displayed a more potent antiproliferative action on A549 cell lines than baohuoside I; half-maximal inhibitory concentration (IC 50 ) was 6.31 versus 18.28 µg/mL, respectively. The antitumor efficacy test in nude mice showed that BLSM exhibited significantly higher antitumor activity against NSCLC with lesser toxic effects on normal tissues. The imaging study for in vivo targeting demonstrated that the mixed micelles formulation achieved effective and targeted drug delivery. Therefore, BLSM might be a potential antitumor formulation.

  9. Micelles as Soil and Water Decontamination Agents.

    Science.gov (United States)

    Shah, Afzal; Shahzad, Suniya; Munir, Azeema; Nadagouda, Mallikarjuna N; Khan, Gul Shahzada; Shams, Dilawar Farhan; Dionysiou, Dionysios D; Rana, Usman Ali

    2016-05-25

    Contaminated soil and water pose a serious threat to human health and ecosystem. For the treatment of industrial effluents or minimizing their detrimental effects, preventive and remedial approaches must be adopted prior to the occurrence of any severe environmental, health, or safety hazard. Conventional treatment methods of wastewater are insufficient, complicated, and expensive. Therefore, a method that could use environmentally friendly surfactants for the simultaneous removal of both organic and inorganic contaminants from wastewater is deemed a smart approach. Surfactants containing potential donor ligands can coordinate with metal ions, and thus such compounds can be used for the removal of toxic metals and organometallic compounds from aqueous systems. Surfactants form host-guest complexes with the hydrophobic contaminants of water and soil by a mechanism involving the encapsulation of hydrophobes into the self-assembled aggregates (micelles) of surfactants. However, because undefined amounts of surfactants may be released into the aqueous systems, attention must be paid to their own environmental risks as well. Moreover, surfactant remediation methods must be carefully analyzed in the laboratory before field implementation. The use of biosurfactants is the best choice for the removal of water toxins as such surfactants are associated with the characteristics of biodegradability, versatility, recovery, and reuse. This Review is focused on the currently employed surfactant-based soil and wastewater treatment technologies owing to their critical role in the implementation of certain solutions for controlling pollution level, which is necessary to protect human health and ensure the quality standard of the aquatic environment.

  10. Basic investigations on LCV micelle gel

    International Nuclear Information System (INIS)

    Ebenezer, S B; Rafic, M K; Ravindran, P B

    2013-01-01

    The aim of this study was to investigate the feasibility of using Leuco Crystal Violet (LCV) based micelle gel dosimeter as a quality assurance tool in radiotherapy applications. Basic properties such as absorption coefficient and diffusion of LCV gel phantom over time were evaluated. The gel formulation consisted of 25 mM Trichloroacetic acid, 1mM LCV, 4 mM Triton X-100, 4% gelatin by mass and distilled water. The advantages of using this gel are its tissue equivalence, easy and less preparation time, lower diffusion rate and it can be read with an optical scanner. We were able to reproduce some of the results of Babic et al. The peak absorption was found to be at 600 nm and hence a matrix of yellow LEDs was used as light source. The profiles obtained from projection images confirmed the diffusion of LCV gel after 6 hours of irradiation. Hence the LCV gel phantom should be read before 6 hours post irradiation to get accurate dose information as suggested previously.

  11. Oxide_Oxide Ceramic Matrix Composite (CMC) Exhaust Mixer Development in the NASA Environmentally Responsible Aviation (ERA) Project

    Science.gov (United States)

    Kiser, J. Douglas; Bansal, Narottam P.; Szelagowski, James; Sokhey, Jagdish; Heffernan, Tab; Clegg, Joseph; Pierluissi, Anthony; Riedell, Jim; Wyen, Travis; Atmur, Steven; hide

    2015-01-01

    LibertyWorks®, a subsidiary of Rolls-Royce Corporation, first studied CMC (ceramic matrix composite) exhaust mixers for potential weight benefits in 2008. Oxide CMC potentially offered weight reduction, higher temperature capability, and the ability to fabricate complex-shapes for increased mixing and noise suppression. In 2010, NASA was pursuing the reduction of NOx emissions, fuel burn, and noise from turbine engines in Phase I of the Environmentally Responsible Aviation (ERA) Project (within the Integrated Systems Research Program). ERA subtasks, including those focused on CMC components, were being formulated with the goal of maturing technology from Proof of Concept Validation (Technology Readiness Level 3 (TRL 3)) to System/Subsystem or Prototype Demonstration in a Relevant Environment (TRL 6). LibertyWorks®, a subsidiary of Rolls-Royce Corporation, first studied CMC (ceramic matrix composite) exhaust mixers for potential weight benefits in 2008. Oxide CMC potentially offered weight reduction, higher temperature capability, and the ability to fabricate complex-shapes for increased mixing and noise suppression. In 2010, NASA was pursuing the reduction of NOx emissions, fuel burn, and noise from turbine engines in Phase I of the Environmentally Responsible Aviation (ERA) Project (within the Integrated Systems Research Program). ERA subtasks, including those focused on CMC components, were being formulated with the goal of maturing technology from Proof of Concept Validation (Technology Readiness Level 3 (TRL 3)) to System/Subsystem or Prototype Demonstration in a Relevant Environment (TRL 6). Oxide CMC component at both room and elevated temperatures. A TRL˜5 (Component Validation in a Relevant Environment) was attained and the CMC mixer was cleared for ground testing on a Rolls-Royce AE3007 engine for performance evaluation to achieve TRL 6.

  12. Effect of counterions on properties of micelles formed by alkylpyridinium surfactants .1. Conductometry and H-1-NMR chemical shifts

    OpenAIRE

    Bijma, K; Engberts, J.B.F.N.

    1997-01-01

    This paper delineates the influence of counterions on the aggregation behavior of 1-methyl-4-n-dodecylpyridinium surfactants, using conductometry and H-1-NMR spectroscopy. Three types of counterions have been studied: (i) halides, (ii) alkanesulfonates, and (iii) aromatic counterions. The critical. micelle concentration is found to decrease with increasing counterion size and increasing counterion hydrophobicity, whereas the degree of counterion binding increases. The aggregation behavior of ...

  13. Improvement of Fish Sauce Quality by Strain CMC5-3-1: A Novel Species of Staphylococcus sp.

    Science.gov (United States)

    Udomsil, Natteewan; Rodtong, Sureelak; Tanasupawat, Somboon; Yongsawatdigul, Jirawat

    2015-09-01

    Staphylococcus sp. CMC5-3-1 and CMS5-7-5 isolated from fermented fish sauce at 3 to 7 mo, respectively, showed different characteristics on protein hydrolysis and volatile formation. These Gram-positive cocci were able to grow in up to 15% NaCl with the optimum at 0.5% to 5% NaCl in tryptic soy broth. Based on ribosomal 16S rRNA gene sequences, Staphylococcus sp. CMC5-3-1 and CMS5-7-5 showed 99.0% similarity to that of Staphylococcus piscifermentans JCM 6057(T) , but DNA-DNA relatedness was sauce inoculated with Staphylococcus sp. CMC5-3-1 was 740.5 mM, which was higher than that inoculated by the strain CMS5-7-5 (662.14 mM, P sauce inoculated with Staphylococcus sp. CMC5-3-1 showed the highest content of total glutamic acid (P sauce inoculated with Staphylococcus sp. CMC5-3-1 was 2-methypropanal, contributing to the desirable dark chocolate note. Staphylococcus sp. CMC5-3-1 could be applied as a starter culture to improve the umami and aroma of fish sauce. © 2015 Institute of Food Technologists®

  14. Synthesis of [Fe(Leq(Lax]n coordination polymer nanoparticles using blockcopolymer micelles

    Directory of Open Access Journals (Sweden)

    Christoph Göbel

    2017-06-01

    Full Text Available Spin-crossover compounds are a class of materials that can change their spin state from high spin (HS to low spin (LS by external stimuli such as light, pressure or temperature. Applications demand compounds with defined properties concerning the size and switchability that are maintained when the compound is integrated into composite materials. Here, we report the synthesis of [Fe(Leq(Lax]n coordination polymer (CP nanoparticles using self-assembled polystyrene-block-poly(4-vinylpyridine (PS-b-P4VP block copolymer (BCP micelles as template. Variation of the solvent (THF and toluene and the rigidity of the axial ligand Lax (Lax = 1,2-di(pyridin-4-ylethane (bpea, trans-1,2-di(pyridin-4-ylethene (bpee, and 1,2-di(pyridin-4-ylethyne (bpey; Leq = 1,2-phenylenebis(iminomethylidyne-bis(2,4-pentanedionato(2− allowed the determination of the preconditions for the selective formation of nanoparticles. A low solubility of the CP in the used solvent and a high stability of the Fe–L bond with regard to ligand exchange are necessary for the formation of composite nanoparticles where the BCP micelle is filled with the CP, as in the case of the [FeLeq(bpey]n@BCP. Otherwise, in the case of more flexible ligands or ligands that lead to high spin complexes, the formation of microcrystals next to the CP–BCP nanoparticles is observed above a certain concentration of [Fe(Leq(Lax]n. The core of the nanoparticles is about 45 nm in diameter due to the templating effect of the BCP micelle, independent of the used iron complex and [Fe(Leq(Lax]n concentration. The spin-crossover properties of the composite material are similar to those of the bulk for FeLeq(bpea]n@BCP while pronounced differences are observed in the case of [FeLeq(bpey]n@BCP nanoparticles.

  15. Stable and biocompatible genipin-inducing interlayer-crosslinked micelles for sustained drug release

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Yu; Zhang, Xiaojin, E-mail: zhangxj@cug.edu.cn [China University of Geosciences, Faculty of Materials Science and Chemistry (China)

    2017-05-15

    To develop the sustained drug release system, here we describe genipin-inducing interlayer-crosslinked micelles crosslinked via Schiff bases between the amines of amphiphilic linear-hyperbranched polymer poly(ethylene glycol)-branched polyethylenimine-poly(ε-caprolactone) (PEG-PEI-PCL) and genipin. The generation of Schiff bases was confirmed by the color changes and UV-Vis absorption spectra of polymeric micelles after adding genipin. The particle size, morphology, stability, in vitro cytotoxicity, drug loading capacity, and in vitro drug release behavior of crosslinked micelles as well as non-crosslinked micelles were characterized. The results indicated that genipin-inducing interlayer-crosslinked micelles had better stability and biocompatibility than non-crosslinked micelles and glutaraldehyde-inducing interlayer-crosslinked micelles. In addition, genipin-inducing interlayer-crosslinked micelles were able to improve drug loading capacity, reduce the initial burst release, and achieve sustained drug release.

  16. Lightweight, Ultra-High-Temperature, CMC-Lined Carbon/Carbon Structures

    Science.gov (United States)

    Wright, Matthew J.; Ramachandran, Gautham; Williams, Brian E.

    2011-01-01

    Carbon/carbon (C/C) is an established engineering material used extensively in aerospace. The beneficial properties of C/C include high strength, low density, and toughness. Its shortcoming is its limited usability at temperatures higher than the oxidation temperature of carbon . approximately 400 C. Ceramic matrix composites (CMCs) are used instead, but carry a weight penalty. Combining a thin laminate of CMC to a bulk structure of C/C retains all of the benefits of C/C with the high temperature oxidizing environment usability of CMCs. Ultramet demonstrated the feasibility of combining the light weight of C/C composites with the oxidation resistance of zirconium carbide (ZrC) and zirconium- silicon carbide (Zr-Si-C) CMCs in a unique system composed of a C/C primary structure with an integral CMC liner with temperature capability up to 4,200 F (.2,315 C). The system effectively bridged the gap in weight and performance between coated C/C and bulk CMCs. Fabrication was demonstrated through an innovative variant of Ultramet fs rapid, pressureless melt infiltration processing technology. The fully developed material system has strength that is comparable with that of C/C, lower density than Cf/SiC, and ultra-high-temperature oxidation stability. Application of the reinforced ceramic casing to a predominantly C/C structure creates a highly innovative material with the potential to achieve the long-sought goal of long-term, cyclic high-temperature use of C/C in an oxidizing environment. The C/C substructure provided most of the mechanical integrity, and the CMC strengths achieved appeared to be sufficient to allow the CMC to perform its primary function of protecting the C/C. Nozzle extension components were fabricated and successfully hot-fire tested. Test results showed good thermochemical and thermomechanical stability of the CMC, as well as excellent interfacial bonding between the CMC liner and the underlying C/C structure. In particular, hafnium-containing CMCs on

  17. SiC-CMC-Zircaloy-4 Nuclear Fuel Cladding Performance during 4-Point Tubular Bend Testing

    Energy Technology Data Exchange (ETDEWEB)

    IJ van Rooyen; WR Lloyd; TL Trowbridge; SR Novascone; KM Wendt; SM Bragg-Sitton

    2013-09-01

    The U.S. Department of Energy Office of Nuclear Energy (DOE NE) established the Light Water Reactor Sustainability (LWRS) program to develop technologies and other solutions to improve the reliability, sustain the safety, and extend the life of current reactors. The Advanced LWR Nuclear Fuel Development Pathway in the LWRS program encompasses strategic research focused on improving reactor core economics and safety margins through the development of an advanced fuel cladding system. Recent investigations of potential options for “accident tolerant” nuclear fuel systems point to the potential benefits of silicon carbide (SiC) cladding. One of the proposed SiC-based fuel cladding designs being investigated incorporates a SiC ceramic matrix composite (CMC) as a structural material supplementing an internal Zircaloy-4 (Zr-4) liner tube, referred to as the hybrid clad design. Characterization of the advanced cladding designs will include a number of out-of-pile (nonnuclear) tests, followed by in-pile irradiation testing of the most promising designs. One of the out-of-pile characterization tests provides measurement of the mechanical properties of the cladding tube using four point bend testing. Although the material properties of the different subsystems (materials) will be determined separately, in this paper we present results of 4-point bending tests performed on fully assembled hybrid cladding tube mock-ups, an assembled Zr-4 cladding tube mock-up as a standard and initial testing results on bare SiC-CMC sleeves to assist in defining design parameters. The hybrid mock-up samples incorporated SiC-CMC sleeves fabricated with 7 polymer impregnation and pyrolysis (PIP) cycles. To provide comparative information; both 1- and 2-ply braided SiC-CMC sleeves were used in this development study. Preliminary stress simulations were performed using the BISON nuclear fuel performance code to show the stress distribution differences for varying lengths between loading points

  18. Controlled Fab installation onto polymeric micelle nanoparticles for tuned bioactivity

    Science.gov (United States)

    Chen, Shaoyi; Florinas, Stelios; Teitgen, Abigail; Xu, Ze-Qi; Gao, Changshou; Wu, Herren; Kataoka, Kazunori; Cabral, Horacio; Christie, R. James

    2017-12-01

    Antibodies and antigen-binding fragments (Fabs) can be used to modify the surface of nanoparticles for enhanced target binding. In our previous work, site-specific conjugation of Fabs to polymeric micelles using conventional methods was limited to approximately 30% efficiency, possibly due to steric hindrance related to macromolecular reactants. Here, we report a new method that enables conjugation of Fabs onto a micelle surface in a controlled manner with up to quantitative conversion of nanoparticle reactive groups. Variation of (i) PEG spacer length in a heterofunctionalized cross-linker and (ii) Fab/polymer feed ratios resulted in production of nanoparticles with a range of Fab densities on the surface up to the theoretical maximum value. The biological impact of variable Fab density was evaluated in vitro with respect to cell uptake and cytotoxicity of a drug-loaded (SN38) targeted polymeric micelle bearing anti-EphA2 Fabs. Fab conjugation increased cell uptake and potency compared with non-targeted micelles, although a Fab density of 60% resulted in decreased uptake and potency of the targeted micelles. Altogether, our findings demonstrate that conjugation strategies can be optimized to allow control of Fab density on the surface of nanoparticles and also that Fab density may need to be optimized for a given cell-surface target to achieve the highest bioactivity.

  19. Effect of microfluidization on casein micelle size of bovine milk

    Science.gov (United States)

    Sinaga, H.; Deeth, H.; Bhandari, B.

    2018-02-01

    The properties of milk are likely to be dependent on the casein micelle size, and various processing technologies produce particular change in the average size of casein micelles. The main objective of this study was to manipulate casein micelle size by subjecting milk to microfluidizer. The experiment was performed as a complete block randomised design with three replications. The sample was passed through the microfluidizer at the set pressure of 83, 97, 112 and 126 MPa for one, two, three, four, five and six cycles, except for the 112 MPa. The results showed that microfluidized milk has smaller size by 3% with pressure up to 126 MPa. However, at each pressure, no further reduction was observed after increasing the passed up to 6 cycles. Although the average casein micelle size was similar, elevating pressure resulted in narrower size distribution. In contrast, increasing the number of cycles had little effect on casein micelle distribution. The finding from this study can be applied for future work to characterize the fundamental and functional properties of the treated milk.

  20. Preclinical safety evaluation of intravenously administered mixed micelles.

    Science.gov (United States)

    Teelmann, K; Schläppi, B; Schüpbach, M; Kistler, A

    1984-01-01

    Mixed micelles, with their main constituents lecithin and glycocholic acid, form a new principle for the parenteral administration of compounds which are poorly water-soluble. Their composition of mainly physiological substances as well as their comparatively good stability substantiate their attractivity in comparison to existing solvents. A decomposition due to physical influences such as heat or storage for several years will almost exclusively affect the lecithin component in the form of hydrolysis into free fatty acids and lysolecithin. Their toxicity was examined experimentally in various studies using both undecomposed and artificially decomposed mixed micelles. In these studies the mixed micelles were locally and systemically well tolerated and proved to be neither embryotoxic, teratogenic nor mutagenic. Only when comparatively high doses of the undecomposed mixed micelles were administered, corresponding to approximately 30 to 50 times the anticipated clinical injection volume (of e.g. diazepam mixed micelles), did some vomitus (dogs), slight liver enzyme elevation (rats and dogs), and slightly increased liver weights (dogs) occur. After repeated injections of the artificially decomposed formulation (approximately 25% of lecithin hydrolyzed to free fatty acids and lysolecithin) effects such as intravascular haemolysis, liver enzyme elevations and intrahepatic cholestasis (dogs only) were observed but only when doses exceeding a threshold of approximately 40 to 60 mg lysolecithin/kg body weight were administered. All alterations were reversible after cessation of treatment.

  1. Production and characterization of biosurfactant from Pseudomonas ...

    African Journals Online (AJOL)

    Further characterization of biosurfactant using Fourier transform infrared spectroscopy (FTIR) revealed it as a rhamnolipid. Keywords: Mangrove ecosystems, Pseudomonas aeruginosa, biosurfactant, critical micelle concentration (CMC), FT-IR fourier transform infrared spectroscopy (FTIR). African Journal of Biotechnology, ...

  2. A novel thiourea-based non-ionic surfacta

    Indian Academy of Sciences (India)

    millimolar critical micelle concentration (CMC) in ethanol and hexane, demonstrating that this is moderately amphiphobic. .... the compound in ethanol at room temperature is pre- sented in figure 1. .... nism for the electro-oxidation. The peak ...

  3. Injectable Thermoresponsive Hydrogel Formed by Alginate-g-Poly(N-isopropylacrylamide) That Releases Doxorubicin-Encapsulated Micelles as a Smart Drug Delivery System.

    Science.gov (United States)

    Liu, Min; Song, Xia; Wen, Yuting; Zhu, Jing-Ling; Li, Jun

    2017-10-18

    In this work, we have synthesized a thermoresponsive copolymer, alginate-g-poly(N-isopropylacrylamide) (alginate-g-PNIPAAm) by conjugating PNIPAAm to alginate, where PNIPAAm with different molecular weights and narrow molecular weight distribution was synthesized by atomic transfer radical polymerization. The copolymer dissolved in water or phosphate-buffered saline buffer solution at room temperature and formed self-assembled micelles with low critical micellization concentrations when the temperature increased to above their critical micellization temperatures. At higher concentration, that is, 7.4 wt % in water, the copolymer formed solutions at 25 °C and turned into thermosensitive hydrogels when temperature increased to the body temperature (37 °C). Herein, we hypothesized that the thermoresponsive hydrogels could produce self-assembled micelles with the dissolution of the alginate-g-PNIPAAm hydrogels in a biological fluid or drug release medium. If the drug was hydrophobic, the hydrogel eventually could release and produce drug-encapsulated micelles. In our experiments, we loaded the anticancer drug doxorubicin (DOX) into the alginate-g-PNIPAAm hydrogels and demonstrated that the hydrogels released DOX-encapsulated micelles in a sustained manner. The slowly released DOX-loaded micelles enhanced the cellular uptake of DOX in multidrug resistant AT3B-1 cells, showing the effect of overcoming the drug resistance and achieving better efficiency for killing the cancer cells. Therefore, the injectable thermoresponsive hydrogels formed by alginate-g-PNIPAAm and loaded with DOX turned into a smart drug delivery system, releasing DOX-encapsulated micelles in a sustained manner, showing great potential for overcoming the drug resistance in cancer therapy.

  4. Hydrolytic Degradation of Poly (ethylene oxide)-block-Polycaprolactone Worm Micelles

    OpenAIRE

    Geng, Yan; Discher, Dennis E.

    2005-01-01

    Spherical micelles and nanoparticles made with degradable polymers have been of great interest for therapeutic application, but degradation induced changes in a spherical morphology can be subtle and mechanism/kinetics appears poorly understood. Here, we report the first preparation of giant and flexible worm micelles self-assembled from degradable copolymer poly (ethylene oxide)-block-polycaprolactone. Such worm micelles spontaneously shorten to generate spherical micelles, triggered by poly...

  5. A new manganese-based oral contrast agent (CMC-001) for liver MRI. Pharmacological and pharmaceutical aspects

    International Nuclear Information System (INIS)

    Joergensen, Jan Troest; Rief, Matthias; Wagner, Moritz; Brismar, Torkel B.; Albiin, Nils

    2012-01-01

    Manganese is one of the most abundant metals on earth and is found as a component of more than 100 different minerals. Besides being an essential trace element in relation to the metabolic processes in the body, manganese is also a paramagnetic metal that possesses similar characteristics to gadolinium with regards to T1-weighted (T1-w) magnetic resonance imaging (MRI). Manganese, in the form of manganese (II) chloride tetrahydrate, is the active substance in a new targeted oral contrast agent, currently known as CMC-001, indicated for hepatobiliary MRI. Under physiological circumstances manganese is poorly absorbed from the intestine after oral intake, but by the use of specific absorption promoters, L-alanine and vitamin D3, it is possible to obtain a sufficiently high concentration in the liver in order to achieve a significant signal enhancing effect. In the liver manganese is exposed to a very high first-pass effect, up to 98 %, which prevents the metal from reaching the systemic circulation, thereby reducing the number of systemic side-effects. Manganese is one of the least toxic trace elements, and due to its favorable safety profile it may be an attractive alternative to gadolinium-based contrast agents for patients undergoing an MRI evaluation for liver metastases in the future. In this review the basic pharmacological and pharmaceutical aspects of this new targeted oral hepatobiliary specific contrast agent will be discussed

  6. Shear induced structures of soft colloids: Rheo-SANS experiments on kinetically frozen PEP-PEO diblock copolymer micelles

    International Nuclear Information System (INIS)

    Stellbrink, J; Lonetti, B; Rother, G; Willner, L; Richter, D

    2008-01-01

    We investigated the effect of external steady shear on dilute to concentrated solutions of PEP-PEO diblock copolymer micelles (soft colloids). The degree of softness in terms of particle interactions (intermolecular softness) and deformability of the individual particle (intramolecular softness) was varied by changing the ratio between hydrophobic and hydrophilic blocks from symmetric (1:1, hard sphere-like) to very asymmetric (1:20, star-like). We performed in situ rheology and small angle neutron scattering experiments (Rheo-SANS) to relate macroscopic flow properties to microscopic structural changes. The rheology data qualitatively show the same behavior for both types of micelles: (i) a divergence of the zero shear viscosity η 0 at a critical concentration φ c approximately following a Vogel-Fulcher-Tammann law and (ii) close to this liquid-solid transition a shear rate dependent viscosity which can be described by the Carreau function with an asymptotic power law η(γ-dot) ∼ γ-dot -0.4 starting at a critical shear rate γ-dot c . Rheo-SANS experiments in the liquid phase close to φ c were extended into the strong shear thinning region for both types of micelles at φ/φ c ∼0.8 and γ-dot red =γ-dot/γ-dot c approx. 10. In our Rheo-SANS data we observe a rather controversial influence of external shear on the structural properties of the two different micellar systems. With increasing shear rate the symmetric, hard sphere-like micelles show a decreasing structure factor S(Q) but a shear rate independent interparticle distance. The asymmetric, star-like micelles show an increase in S(Q) and an increase of the interparticle distance, both in the flow and vorticity direction. This unexpected behavior can be rationalized by a shear induced elongation and tilt of the star-like micelles along the flow direction as predicted by recent MD simulations (Ripoll et al 2006 Phys. Rev. Lett. 96 188302)

  7. Micelle fission through surface instability and formation of an interdigitating stalk

    NARCIS (Netherlands)

    Sammalkorpi, M.; Karttunen, M.E.J.; Haataja, M.

    2008-01-01

    We report on the first detailed atomic-scale studies of micelle fission in micellar systems consisting of anionic sodium dodecyl sulfate with explicit solvent. We demonstrate a new micelle fission pathway for ionic surfactants and show how micelle fission can be induced by varying the ionic

  8. Biomimetic oral mucin from polymer micelle networks

    Science.gov (United States)

    Authimoolam, Sundar Prasanth

    Mucin networks are formed by the complexation of bottlebrush-like mucin glycoprotein with other small molecule glycoproteins. These glycoproteins create nanoscale strands that then arrange into a nanoporous mesh. These networks play an important role in ensuring surface hydration, lubricity and barrier protection. In order to understand the functional behavior in mucin networks, it is important to decouple their chemical and physical effects responsible for generating the fundamental property-function relationship. To achieve this goal, we propose to develop a synthetic biomimetic mucin using a layer-by-layer (LBL) deposition approach. In this work, a hierarchical 3-dimensional structures resembling natural mucin networks was generated using affinity-based interactions on synthetic and biological surfaces. Unlike conventional polyelectrolyte-based LBL methods, pre-assembled biotin-functionalized filamentous (worm-like) micelles was utilized as the network building block, which from complementary additions of streptavidin generated synthetic networks of desired thickness. The biomimetic nature in those synthetic networks are studied by evaluating its structural and bio-functional properties. Structurally, synthetic networks formed a nanoporous mesh. The networks demonstrated excellent surface hydration property and were able capable of microbial capture. Those functional properties are akin to that of natural mucin networks. Further, the role of synthetic mucin as a drug delivery vehicle, capable of providing localized and tunable release was demonstrated. By incorporating antibacterial curcumin drug loading within synthetic networks, bacterial growth inhibition was also demonstrated. Thus, such bioactive interfaces can serve as a model for independently characterizing mucin network properties and through its role as a drug carrier vehicle it presents exciting future opportunities for localized drug delivery, in regenerative applications and as bio

  9. From micelle supramolecular assemblies in selective solvents to isoporous membranes

    KAUST Repository

    Nunes, Suzana Pereira

    2011-08-16

    The supramolecular assembly of PS-b-P4VP copolymer micelles induced by selective solvent mixtures was used to manufacture isoporous membranes. Micelle order in solution was confirmed by cryo-scanning electron microscopy in casting solutions, leading to ordered pore morphology. When dioxane, a solvent that interacts poorly with the micelle corona, was added to the solution, polymer-polymer segment contact was preferential, increasing the intermicelle contact. Immersion in water gave rise to asymmetric porous membranes with exceptional pore uniformity and high porosity. The introduction of a small number of carbon nanotubes to the casting solution improved the membrane stability and the reversibility of the gate response in the presence of different pH values. © 2011 American Chemical Society.

  10. Artificial Self-Sufficient P450 in Reversed Micelles

    Directory of Open Access Journals (Sweden)

    Teruyuki Nagamune

    2010-04-01

    Full Text Available Cytochrome P450s are heme-containing monooxygenases that require electron transfer proteins for their catalytic activities. They prefer hydrophobic compounds as substrates and it is, therefore, desirable to perform their reactions in non-aqueous media. Reversed micelles can stably encapsulate proteins in nano-scaled water pools in organic solvents. However, in the reversed micellar system, when multiple proteins are involved in a reaction they can be separated into different micelles and it is then difficult to transfer electrons between proteins. We show here that an artificial self-sufficient cytochrome P450, which is an enzymatically crosslinked fusion protein composed of P450 and electron transfer proteins, showed micelle-size dependent catalytic activity in a reversed micellar system. Furthermore, the presence of thermostable alcohol dehydrogenase promoted the P450-catalyzed reaction due to cofactor regeneration.

  11. From micelle supramolecular assemblies in selective solvents to isoporous membranes

    KAUST Repository

    Nunes, Suzana Pereira; Karunakaran, Madhavan; Neelakanda, Pradeep; Behzad, Ali Reza; Hooghan, Bobby; Sougrat, Rachid; He, Haoze; Peinemann, Klaus-Viktor

    2011-01-01

    The supramolecular assembly of PS-b-P4VP copolymer micelles induced by selective solvent mixtures was used to manufacture isoporous membranes. Micelle order in solution was confirmed by cryo-scanning electron microscopy in casting solutions, leading to ordered pore morphology. When dioxane, a solvent that interacts poorly with the micelle corona, was added to the solution, polymer-polymer segment contact was preferential, increasing the intermicelle contact. Immersion in water gave rise to asymmetric porous membranes with exceptional pore uniformity and high porosity. The introduction of a small number of carbon nanotubes to the casting solution improved the membrane stability and the reversibility of the gate response in the presence of different pH values. © 2011 American Chemical Society.

  12. Structural characterization of casein micelles: shape changes during film formation

    International Nuclear Information System (INIS)

    Gebhardt, R; Kulozik, U; Vendrely, C

    2011-01-01

    The objective of this study was to determine the effect of size-fractionation by centrifugation on the film structure of casein micelles. Fractionated casein micelles in solution were asymmetrically distributed with a small distribution width as measured by dynamic light scattering. Films prepared from the size-fractionated samples showed a smooth surface in optical microscopy images and a homogeneous microstructure in atomic force micrographs. The nano- and microstructure of casein films was probed by micro-beam grazing incidence small angle x-ray scattering (μGISAXS). Compared to the solution measurements, the sizes determined in the film were larger and broadly distributed. The measured GISAXS patterns clearly deviate from those simulated for a sphere and suggest a deformation of the casein micelles in the film. (paper)

  13. Charged triblock copolymer self-assembly into charged micelles

    Science.gov (United States)

    Chen, Yingchao; Zhang, Ke; Zhu, Jiahua; Wooley, Karen; Pochan, Darrin; Department of Material Science; Engineering University of Delaware Team; Department of Chemistry Texas A&M University Collaboration

    2011-03-01

    Micelles were formed through the self-assembly of amphiphlic block copolymer poly(acrylic acid)-block-poly(methyl acrylate)-block-polystyrene (PAA-PMA-PS). ~Importantly, the polymer is complexed with diamine molecules in pure THF solution prior to water titration solvent processing-a critical aspect in the control of final micelle geometry. The addition of diamine triggers acid-base complexation ~between the carboxylic acid PAA side chains and amines. ~Remarkably uniform spheres were found to form close-packed patterns when forced into dried films and thin, solvated films when an excess of amine was used in the polymer assembly process. Surface properties and structural features of these hexagonal-packed spherical micelles with charged corona have been explored by various characterization methods including Transmission Electron Microscopy (TEM), cryogenic TEM, z-potential analysis and Dynamic Light Scattering. The forming mechanism for this pattern and morphology changes against external stimulate such as salt will be discussed.

  14. Modification of encapsulation pressure of reverse micelles in liquid ethane.

    Science.gov (United States)

    Peterson, Ronald W; Nucci, Nathaniel V; Wand, A Joshua

    2011-09-01

    Encapsulation within reverse micelles dissolved in low viscosity fluids offers a potential solution to the slow tumbling problem presented by large soluble macromolecules to solution NMR spectroscopy. The reduction in effective macromolecular tumbling is directly dependent upon the viscosity of the solvent. Liquid ethane is of sufficiently low viscosity at pressures below 5000 psi to offer a significant advantage. Unfortunately, the viscosity of liquid ethane shows appreciable pressure dependence. Reverse micelle encapsulation in liquid ethane often requires significantly higher pressures, which obviates the potential advantages offered by liquid ethane over liquid propane. Addition of co-surfactants or co-solvents can be used to manipulate the minimum pressure required to obtain stable, well-behaved solutions of reverse micelles prepared in liquid ethane. A library of potential additives is examined and several candidates suitable for use with encapsulated proteins are described. Copyright © 2011 Elsevier Inc. All rights reserved.

  15. Enzymatically triggered multifunctional delivery system based on hyaluronic acid micelles

    KAUST Repository

    Deng, Lin

    2012-01-01

    Tumor targetability and stimuli responsivity of drug delivery systems (DDS) are key factors in cancer therapy. Implementation of multifunctional DDS can afford targetability and responsivity at the same time. Herein, cholesterol molecules (Ch) were coupled to hyaluronic acid (HA) backbones to afford amphiphilic conjugates that can self-assemble into stable micelles. Doxorubicin (DOX), an anticancer drug, and superparamagnetic iron oxide (SPIO) nanoparticles (NPs), magnetic resonance imaging (MRI) contrast agents, were encapsulated by Ch-HA micelles and were selectively released in the presence of hyaluronidase (Hyals) enzyme. Cytotoxicity and cell uptake studies were done using three cancer cell lines (HeLa, HepG2 and MCF7) and one normal cell line (WI38). Higher Ch-HA micelles uptake was seen in cancer cells versus normal cells. Consequently, DOX release was elevated in cancer cells causing higher cytotoxicity and enhanced cell death. © 2012 The Royal Society of Chemistry.

  16. Catalysis of the Oligomerization of O-Phospho-Serine, Aspartic Acid, or Glutamic Acid by Cationic Micelles

    Science.gov (United States)

    Bohler, Christof; Hill, Aubrey R., Jr.; Orgel, Leslie E.

    1996-01-01

    Treatment of relatively concentrated aqueous solutions of 0-phospho-serine (50 mM), aspartic acid (100 mM) or glutamic acid (100 mM) with carbonyldiimidazole leads to the formation of an activated intermediate that oligomerizes efficiently. When the concentration of amino acid is reduced tenfold, few long oligomers can be detected. Positively-charged cetyltrimethyl ammonium bromide micelles concentrate the negatively-charged activated intermediates of the amino acids at their surfaces and catalyze efficient oligomerization even from dilute solutions.

  17. Core-Shell-Corona Micelles with a Responsive Shell.

    Science.gov (United States)

    Gohy, Jean-François; Willet, Nicolas; Varshney, Sunil; Zhang, Jian-Xin; Jérôme, Robert

    2001-09-03

    A reactor for the synthesis of gold nanoparticles is one of the uses of a poly(styrene)-block-poly(2-vinylpyridine)-block-poly(ethylene oxide) triblock copolymer (PS-b-P2VP-b-PEO) which forms core-shell-corona micelles in water. Very low polydispersity spherical micelles are observed that consist of a PS core surrounded by a pH-sensitive P2VP shell and a corona of PEO chains end-capped by a hydroxyl group. The corona can act as a site for attaching responsive or sensing molecules. © 2001 WILEY-VCH Verlag GmbH, Weinheim, Fed. Rep. of Germany.

  18. Fluorescent supramolecular micelles for imaging-guided cancer therapy

    Science.gov (United States)

    Sun, Mengmeng; Yin, Wenyan; Dong, Xinghua; Yang, Wantai; Zhao, Yuliang; Yin, Meizhen

    2016-02-01

    A novel smart fluorescent drug delivery system composed of a perylene diimide (PDI) core and block copolymer poly(d,l-lactide)-b-poly(ethyl ethylene phosphate) is developed and named as PDI-star-(PLA-b-PEEP)8. The biodegradable PDI-star-(PLA-b-PEEP)8 is a unimolecular micelle and can self-assemble into supramolecular micelles, called as fluorescent supramolecular micelles (FSMs), in aqueous media. An insoluble drug camptothecin (CPT) can be effectively loaded into the FSMs and exhibits pH-responsive release. Moreover, the FSMs with good biocompatibility can also be employed as a remarkable fluorescent probe for cell labelling because the maximum emission of PDI is beneficial for bio-imaging. The flow cytometry and confocal laser scanning microscopy analysis demonstrate that the micelles are easily endocytosed by cancer cells. In vitro and in vivo tumor growth-inhibitory studies reveal a better therapeutic effect of FSMs after CPT encapsulation when compared with the free CPT drug. The multifunctional FSM nanomedicine platform as a nanovehicle has great potential for fluorescence imaging-guided cancer therapy.A novel smart fluorescent drug delivery system composed of a perylene diimide (PDI) core and block copolymer poly(d,l-lactide)-b-poly(ethyl ethylene phosphate) is developed and named as PDI-star-(PLA-b-PEEP)8. The biodegradable PDI-star-(PLA-b-PEEP)8 is a unimolecular micelle and can self-assemble into supramolecular micelles, called as fluorescent supramolecular micelles (FSMs), in aqueous media. An insoluble drug camptothecin (CPT) can be effectively loaded into the FSMs and exhibits pH-responsive release. Moreover, the FSMs with good biocompatibility can also be employed as a remarkable fluorescent probe for cell labelling because the maximum emission of PDI is beneficial for bio-imaging. The flow cytometry and confocal laser scanning microscopy analysis demonstrate that the micelles are easily endocytosed by cancer cells. In vitro and in vivo tumor growth

  19. Micelles and gels of oxyethylene-oxybutylene diblock copolymers in aqueous solution: The effect of oxyethylene-block length

    DEFF Research Database (Denmark)

    Derici, L.; Ledger, S.; Mai, S.M.

    1999-01-01

    and in aqueous 0.2 mol dm(-3) K(2)SO(4)), yielding the micellar association numbers, the hydrodynamic and thermodynamic radii, and related expansion factors. Micellar parameters were also obtained by small-angle neutron scattering (SANS) for solutions of a similar copolymer, E(86)B(10), in water, i......Block copolymer E(90)B(10) (E = oxyethylene, B = oxybutylene) was synthesised and characterised by gel permeation chromatography and (13)C NMR spectroscopy. Dynamic light scattering (DLS) and static light scattering (SLS) were used to characterise the micelles in solution (both in water...... of water in the micelle core. Moderately concentrated solutions of copolymer E(90)B(10) were studied in the gel state by small-angle X-ray scattering (SAXS) in tandem with rheology (oscillatory shear). Values for the dynamic elastic modulus (G') of the gels significantly exceeded 10(4) Pa across the range...

  20. Swell Gels to Dumbbell Micelles: Construction of Materials and Nanostructure with Self-assembly

    Science.gov (United States)

    Pochan, Darrin

    2007-03-01

    Bionanotechnology, the emerging field of using biomolecular and biotechnological tools for nanostructure or nanotecnology development, provides exceptional opportunity in the design of new materials. Self-assembly of molecules is an attractive materials construction strategy due to its simplicity in application. By considering peptidic or charged synthetic polymer molecules in the bottom-up materials self-assembly design process, one can take advantage of inherently biomolecular attributes; intramolecular folding events, secondary structure, and electrostatic interactions; in addition to more traditional self-assembling molecular attributes such as amphiphilicty, to define hierarchical material structure and consequent properties. Several molecular systems will be discussed. Synthetic block copolymers with charged corona blocks can be assembled in dilute solution containing multivalent organic counterions to produce micelle structures such as toroids. These ring-like micelles are similar to the toroidal bundling of charged semiflexible biopolymers like DNA in the presence of multivalent counterions. Micelle structure can be tuned between toroids, cylinders, and disks simply by using different concentrations or molecular volumes of organic counterion. In addition, these charged blocks can consist of amino acids as monomers producing block copolypeptides. In addition to the above attributes, block copolypeptides provide the control of block secondary structure to further control self-assembly. Design strategies based on small (less than 24 amino acids) beta-hairpin peptides will be discussed. Self-assembly of the peptides is predicated on an intramolecular folding event caused by desired solution properties. Importantly, the intramolecular folding event impart a molecular-level mechanism for environmental responsiveness at the material level (e.g. infinite change in viscosity of a solution to a gel with changes in pH, ionic strength, temperature).

  1. Binding of chloroquine to ionic micelles: Effect of pH and micellar surface charge

    Energy Technology Data Exchange (ETDEWEB)

    Souza Santos, Marcela de, E-mail: marcelafarmausp77@gmail.com [Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Avenida do Café, s/n, Ribeirão Preto, São Paulo 14040-903 (Brazil); Perpétua Freire de Morais Del Lama, Maria, E-mail: mpemdel@fcfrp.usp.br [Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Avenida do Café, s/n, Ribeirão Preto, São Paulo 14040-903 (Brazil); Instituto Nacional de Ciência e Tecnologia de Bioanalítica, Departamento de Química Analítica, Universidade Estadual de Campinas, Cidade Universitária Zeferino Vaz, s/n, Campinas, São Paulo 13083-970 (Brazil); Siuiti Ito, Amando, E-mail: amandosi@ffclrp.usp.br [Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes, 3900, Ribeirão Preto, São Paulo 14040-901 (Brazil); and others

    2014-03-15

    The pharmacological action of chloroquine relies on its ability to cross biological membranes in order to accumulate inside lysosomes. The present work aimed at understanding the basis for the interaction between different chloroquine species and ionic micelles of opposite charges, the latter used as a simple membrane model. The sensitivity of absorbance and fluorescence of chloroquine to changes in its local environment was used to probe its interaction with cetyltrimethylammonium micelles presenting bromide (CTAB) and sulfate (CTAS) as counterions, in addition to dodecyl sulfate micelles bearing sodium (SDS) and tetramethylammonium (TMADS) counterions. Counterion exchange was shown to have little effect on drug–micelle interaction. Chloroquine first dissociation constant (pKa{sub 1}) shifted to opposite directions when anionic and cationic micelles were compared. Chloroquine binding constants (K{sub b}) revealed that electrostatic forces mediate charged drug–micelle association, whereas hydrophobic interactions allowed neutral chloroquine to associate with anionic and cationic micelles. Fluorescence quenching studies indicated that monoprotonated chloroquine is inserted deeper into the micelle surface of anionic micelles than its neutral form, the latter being less exposed to the aqueous phase when associated with cationic over anionic assemblies. The findings provide further evidence that chloroquine–micelle interaction is driven by a tight interplay between the drug form and the micellar surface charge, which can have a major effect on the drug biological activity. -- Highlights: • Chloroquine (CQ) pKa{sub 1} increased for SDS micelles and decreased for CTAB micelles. • CQ is solubilized to the surface of both CTAB and SDS micelles. • Monoprotonated CQ is buried deeper into SDS micelles than neutral CQ. • Neutral CQ is less exposed to aqueous phase in CTAB over SDS micelles. • Local pH and micellar surface charge mediate interaction of CQ with

  2. Self-assembled micelles based on pH-sensitive PAE-g-MPEG-cholesterol block copolymer for anticancer drug delivery

    Directory of Open Access Journals (Sweden)

    Zhang CY

    2014-10-01

    Full Text Available Can Yang Zhang, Di Xiong, Yao Sun, Bin Zhao, Wen Jing Lin, Li Juan Zhang School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, Guangdong Province, People’s Republic of China Abstract: A novel amphiphilic triblock pH-sensitive poly(ß-amino ester-g-poly(ethylene glycol methyl ether-cholesterol (PAE-g-MPEG-Chol was designed and synthesized via the Michael-type step polymerization and esterification condensation method. The synthesized copolymer was determined with proton nuclear magnetic resonance and gel permeation chromatography. The grafting percentages of MPEG and cholesterol were determined as 10.93% and 62.02%, calculated from the area of the characteristic peaks, respectively. The amphiphilic copolymer was confirmed to self-assemble into core/shell micelles in aqueous solution at low concentrations. The critical micelle concentrations were 6.92 and 15.14 mg/L at pH of 7.4 and 6.0, respectively, obviously influenced by the changes of pH values. The solubility of pH-responsive PAE segment could be transformed depending on the different values of pH because of protonation–deprotonation of the amino groups, resulting in pH sensitivity of the copolymer. The average particle size of micelles increased from 125 nm to 165 nm with the pH decreasing, and the zeta potential was also significantly changed. Doxorubicin (DOX was entrapped into the polymeric micelles with a high drug loading level. The in vitro DOX release from the micelles was distinctly enhanced with the pH decreasing from 7.4 to 6.0. Toxicity testing proved that the DOX-loaded micelles exhibited high cytotoxicity in HepG2 cells, whereas the copolymer showed low toxicity. The results demonstrated how pH-sensitive PAE-g-MPEG-Chol micelles were proved to be a potential vector in hydrophobic drug delivery for tumor therapy. Keywords: micelle, pH-sensitive, cholesterol, poly(ß-amino ester, drug delivery

  3. PEG-lipid micelles enable cholesterol efflux in Niemann-Pick Type C1 disease-based lysosomal storage disorder

    Science.gov (United States)

    Brown, Anna; Patel, Siddharth; Ward, Carl; Lorenz, Anna; Ortiz, Mauren; DuRoss, Allison; Wieghardt, Fabian; Esch, Amanda; Otten, Elsje G.; Heiser, Laura M.; Korolchuk, Viktor I.; Sun, Conroy; Sarkar, Sovan; Sahay, Gaurav

    2016-01-01

    2-Hydroxy-propyl-β-cyclodextrin (HPβCD), a cholesterol scavenger, is currently undergoing Phase 2b/3 clinical trial for treatment of Niemann Pick Type C-1 (NPC1), a fatal neurodegenerative disorder that stems from abnormal cholesterol accumulation in the endo/lysosomes. Unfortunately, the extremely high doses of HPβCD required to prevent progressive neurodegeneration exacerbates ototoxicity, pulmonary toxicity and autophagy-based cellular defects. We present unexpected evidence that a poly (ethylene glycol) (PEG)-lipid conjugate enables cholesterol clearance from endo/lysosomes of Npc1 mutant (Npc1−/−) cells. Herein, we show that distearyl-phosphatidylethanolamine-PEG (DSPE-PEG), which forms 12-nm micelles above the critical micelle concentration, accumulates heavily inside cholesterol-rich late endosomes in Npc1−/− cells. This potentially results in cholesterol solubilization and leakage from lysosomes. High-throughput screening revealed that DSPE-PEG, in combination with HPβCD, acts synergistically to efflux cholesterol without significantly aggravating autophagy defects. These well-known excipients can be used as admixtures to treat NPC1 disorder. Increasing PEG chain lengths from 350 Da-30 kDa in DSPE-PEG micelles, or increasing DSPE-PEG content in an array of liposomes packaged with HPβCD, improved cholesterol egress, while Pluronic block copolymers capable of micelle formation showed slight effects at high concentrations. We postulate that PEG-lipid based nanocarriers can serve as bioactive drug delivery systems for effective treatment of lysosomal storage disorders. PMID:27572704

  4. A CMC database for use in the next generation launch vehicles (rockets)

    Science.gov (United States)

    Mahanta, Kamala

    1994-01-01

    Ceramic matrix composites (CMC's) are being envisioned as the state-of-the-art material capable of handling the tough structural and thermal demands of advanced high temperature structures for programs such as the SSTO (Single Stage to Orbit), HSCT (High Speed Civil Transport), etc. as well as for evolution of the industrial heating systems. Particulate, whisker and continuous fiber ceramic matrix (CFCC) composites have been designed to provide fracture toughness to the advanced ceramic materials which have a high degree of wear resistance, hardness, stiffness, and heat and corrosion resistance but are notorious for their brittleness and sensitivity to microscopic flaws such as cracks, voids and impurity.

  5. Non-CMC Solutions of the Einstein Constraint Equations on Compact Manifolds with Apparent Horizon Boundaries

    Science.gov (United States)

    Holst, Michael; Meier, Caleb; Tsogtgerel, G.

    2018-01-01

    In this article we continue our effort to do a systematic development of the solution theory for conformal formulations of the Einstein constraint equations on compact manifolds with boundary. By building in a natural way on our recent work in Holst and Tsogtgerel (Class Quantum Gravity 30:205011, 2013), and Holst et al. (Phys Rev Lett 100(16):161101, 2008, Commun Math Phys 288(2):547-613, 2009), and also on the work of Maxwell (J Hyperbolic Differ Eqs 2(2):521-546, 2005a, Commun Math Phys 253(3):561-583, 2005b, Math Res Lett 16(4):627-645, 2009) and Dain (Class Quantum Gravity 21(2):555-573, 2004), under reasonable assumptions on the data we prove existence of both near- and far-from-constant mean curvature (CMC) solutions for a class of Robin boundary conditions commonly used in the literature for modeling black holes, with a third existence result for CMC appearing as a special case. Dain and Maxwell addressed initial data engineering for space-times that evolve to contain black holes, determining solutions to the conformal formulation on an asymptotically Euclidean manifold in the CMC setting, with interior boundary conditions representing excised interior black hole regions. Holst and Tsogtgerel compiled the interior boundary results covered by Dain and Maxwell, and then developed general interior conditions to model the apparent horizon boundary conditions of Dainand Maxwell for compact manifolds with boundary, and subsequently proved existence of solutions to the Lichnerowicz equation on compact manifolds with such boundary conditions. This paper picks up where Holst and Tsogtgerel left off, addressing the general non-CMC case for compact manifolds with boundary. As in our previous articles, our focus here is again on low regularity data and on the interaction between different types of boundary conditions. While our work here serves primarily to extend the solution theory for the compact with boundary case, we also develop several technical tools that have

  6. Static structure factor of polymerlike micelles: Overall dimension, flexibility, and local properties of lecithin reverse micelles in deuterated isooctane

    DEFF Research Database (Denmark)

    Jerke, G.; Pedersen, J.S.; Egelhaaf, S.U.

    1997-01-01

    We report a systematic investigation of the static structure factor S(q,c) of polymerlike reverse micelles formed by soybean lecithin and trace amounts of water in deuterated isooctane using small-angle neutron scattering and static light scattering. The experimental data for different concentrat......We report a systematic investigation of the static structure factor S(q,c) of polymerlike reverse micelles formed by soybean lecithin and trace amounts of water in deuterated isooctane using small-angle neutron scattering and static light scattering. The experimental data for different...

  7. Study on novel functional materials carboxymethyl cellulose lithium (CMC-Li) improve high-performance lithium-ion battery.

    Science.gov (United States)

    Qiu, Lei; Shao, Ziqiang; Xiang, Pan; Wang, Daxiong; Zhou, Zhenwen; Wang, Feijun; Wang, Wenjun; Wang, Jianquan

    2014-09-22

    Novel cellulose derivative CMC-Li was synthesized by cotton as raw material. The mechanism of the CMC-Li modified electrode materials by electrospinning was reported. CMC-Li/lithium iron phosphate (LiFePO4, LFP) composite fiber coated with LFP and CMC-Li nanofibers was successfully obtained by electrospinning. Then, CMC-Li/LFP nano-composite fiber was carbonized under nitrogen at a high temperature formed CNF/LFP/Li (CLL) composite nanofibers as cathode material. It can increase the contents of Li+, and improving the diffusion efficiency and specific capacity. The battery with CLL as cathode material retained close to 100% of initial reversible capacity after 200 cycles at 168 mAh g(-1), which was nearly the theoretical specific capacity of LFP. The cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), X-ray diffraction (XRD) and scanning electron microscope (SEM) were characterizing material performance. The batteries have good electrochemical property, outstanding pollution-free, excellent stability. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Influence of PVA and CMC on the Properties of Pigment Coating Colors and their Effects on Curtain Stability

    Directory of Open Access Journals (Sweden)

    Eun Heui Choi

    2015-09-01

    Full Text Available The influence of polyvinyl alcohol (PVA and carboxymethyl cellulose (CMC on the properties of ground calcium carbonate (GCC and clay coating colors, as well as its effect on curtain stability during the coating process was investigated. Based on the experimental results of the zeta potential, sediment porosity, rheological measurements, the floc formation mechanisms of the cobinders were proposed. The zeta potential decreased with an increase in the amount of added PVA, while it barely changed when CMC was added. This was attributed to the adsorption of PVA onto the pigment surface, while the adsorption of CMC was hindered by electrostatic repulsion. CMC cobinder increased the low-shear viscosity, but it resulted in relatively low viscosity under high-shear conditions, indicating the disruption of the formed flocs under high shear. The destabilization mechanism of the curtain coating differed depending on the type of cobinder. The PVA cobinder flocculates the coating color via a gelling mechanism, while the CMC cobinder flocculates the colors via a depletion flocculation mechanism.

  9. Development of a Hydrogen Uptake-Release Mg-Based Alloy by Adding a Polymer CMC (Carboxymethylcellulose, Sodium Salt) via Reaction-Accompanying Milling

    Science.gov (United States)

    Kwak, Young Jun; Choi, Eunho; Song, Myoung Youp

    2018-03-01

    The addition of carboxymethylcellulose, sodium salt (CMC) might improve the hydrogen uptake and release properties of Mg since it has a relatively low melting point and the melting of CMC during milling in hydrogen (reaction-accompanying milling) may make the milled samples be in good states to absorb and release hydrogen rapidly and to have a large hydrogen-storage capacity. Samples with compositions of 95 w/o Mg + 5 w/o CMC (named Mg-5CMC) and 90 w/o Mg + 10 w/o CMC (named Mg-10CMC) were prepared by adding CMC via reaction-accompanying milling. Activation of Mg-10CMC was completed after about 3 hydrogen uptake-release cycles. Mg-10CMC had a higher initial hydrogen uptake rate and a larger amount of hydrogen absorbed in 60 min, U (60 min), than Mg-5CMC before and after activation. At the cycle number of three (CN = 3), Mg-10CMC had a very high initial hydrogen uptake rate (1.56 w/o H/min) and a large U (60 min) (5.57 w/o H) at 593 K in hydrogen of 12 bar, showing that the activated Mg-10CMC has an effective hydrogen-storage capacity of about 5.6 w/o at 593 K in hydrogen of 12 bar at CN = 3. At CN = 2, Mg-10CMC released 1.00 w/o H in 2.5 min, 4.67 w/o H in 10 min, and 4.76 w/o H in 60 min at 648 K in hydrogen of 1.0 bar. The milling in hydrogen of Mg with CMC is believed to generate imperfections and cracks and reduce the particle size. The addition of 10 w/o CMC was more effective on the initial hydrogen uptake rate and U (60 min) compared with the 10 w/o additions of NbF5, TaF5, Fe2O3, and MnO, and the 10 w/o simultaneous addition of Ni, Fe, and Ti. To the best of our knowledge, this study is the first in which a polymer CMC is added to Mg by reaction-accompanying milling to improve the hydrogen storage properties of Mg.

  10. Micelles as delivery vehicles for oligofluorene for bioimaging.

    Science.gov (United States)

    Su, Fengyu; Alam, Ruhaniyah; Mei, Qian; Tian, Yanqing; Meldrum, Deirdre R

    2011-01-01

    With the successful development of organic/polymeric light emitting diodes, many organic and polymeric fluorophores with high quantum efficiencies and optical stability were synthesized. However, most of these materials which have excellent optical properties are insoluble in water, limiting their applications in biological fields. Herein, we used micelles formed from an amino-group-containing poly(ε-caprolactone)-block-poly(ethylene glycol) (PCL-b-PEG-NH(2)) to incorporate a hydrophobic blue emitter oligofluorene (OF) to enable its application in biological conditions. Although OF is completely insoluble in water, it was successfully transferred into aqueous solutions with a good retention of its photophysical properties. OF exhibited a high quantum efficiency of 0.84 in a typical organic solvent of tetrahydrofuran (THF). In addition, OF also showed a good quantum efficiency of 0.46 after being encapsulated into micelles. Two cells lines, human glioblastoma (U87MG) and esophagus premalignant (CP-A), were used to study the cellular internalization of the OF incorporated micelles. Results showed that the hydrophobic OF was located in the cytoplasm, which was confirmed by co-staining the cells with nucleic acid specific SYTO 9, lysosome specific LysoTracker Red®, and mitochondria specific MitoTracker Red. MTT assay indicated non-toxicity of the OF-incorporated micelles. This study will broaden the application of hydrophobic functional organic compounds, oligomers, and polymers with good optical properties to enable their applications in biological research fields.

  11. Micelles as delivery vehicles for oligofluorene for bioimaging.

    Directory of Open Access Journals (Sweden)

    Fengyu Su

    Full Text Available With the successful development of organic/polymeric light emitting diodes, many organic and polymeric fluorophores with high quantum efficiencies and optical stability were synthesized. However, most of these materials which have excellent optical properties are insoluble in water, limiting their applications in biological fields. Herein, we used micelles formed from an amino-group-containing poly(ε-caprolactone-block-poly(ethylene glycol (PCL-b-PEG-NH(2 to incorporate a hydrophobic blue emitter oligofluorene (OF to enable its application in biological conditions. Although OF is completely insoluble in water, it was successfully transferred into aqueous solutions with a good retention of its photophysical properties. OF exhibited a high quantum efficiency of 0.84 in a typical organic solvent of tetrahydrofuran (THF. In addition, OF also showed a good quantum efficiency of 0.46 after being encapsulated into micelles. Two cells lines, human glioblastoma (U87MG and esophagus premalignant (CP-A, were used to study the cellular internalization of the OF incorporated micelles. Results showed that the hydrophobic OF was located in the cytoplasm, which was confirmed by co-staining the cells with nucleic acid specific SYTO 9, lysosome specific LysoTracker Red®, and mitochondria specific MitoTracker Red. MTT assay indicated non-toxicity of the OF-incorporated micelles. This study will broaden the application of hydrophobic functional organic compounds, oligomers, and polymers with good optical properties to enable their applications in biological research fields.

  12. Small angle neutron scattering studies of mixed micelles of sodium

    Indian Academy of Sciences (India)

    The aqueous solutions of sodium cumene sulphonate (NaCS) and its mixtures with each of cetyl trimethylammonium bromide (CTAB) and sodium dodecyl sulphate (SDS) are characterized by small angle neutron scattering (SANS). NaCS when added to CTAB solution leads to the formation of long rod-shaped micelles with ...

  13. Applications of polymeric micelles with tumor targeted in chemotherapy

    International Nuclear Information System (INIS)

    Ding Hui; Wang Xiaojun; Zhang Song; Liu Xinli

    2012-01-01

    Polymeric micelles (PMs) have gained more progress as a carrier system with the quick development of biological and nanoparticle techniques. In particular, PMs with smart targeting can deliver anti-cancer drugs directly into tumor cells at a sustained rate. PMs with core–shell structure (with diameters of 10 ∼ 100 nm) have been prepared by a variety of biodegradable and biocompatible polymers via a self-assembly process. The preparation of polymeric micelles with stimuli-responsive block copolymers or modification of target molecules on polymeric micelles’ surface are able to significantly improve the efficiency of drug delivery. Polymeric micelles, which have been considered as a novel promising drug carrier for cancer therapeutics, are rapidly evolving and being introduced in an attempt to overcome several limitations of traditional chemotherapeutics, including water solubility, tumor-specific accumulation, anti-tumor efficacy, and non-specific toxicity. This review describes the preparation of polymeric micelles and the targeted modification which greatly enhance the effects of chemotherapeutic agents.

  14. Structure and flexibility of worm-like micelles

    DEFF Research Database (Denmark)

    Jerke, G.; Pedersen, J.S.; Egelhaaf, S.U.

    1997-01-01

    Small-angle neutron scattering and static light scattering experiments have been performed on worm-like micelles formed by soybean lecithin and trace amounts of water in deuterated iso-octane. The structure and flexibility of the aggregates have been investigated as a function of solution...

  15. Reversibility and Relaxation Behavior of Polyelectrolyte Complex Micelle Formation

    NARCIS (Netherlands)

    Lindhoud, Saskia; Norde, Willem; Stuart, Martien A. Cohen

    2009-01-01

    In this study, the formation and disintegration of polyelectrolyte complex micelles is studied by dynamic light scattering titrations with the aim to assess the extent to which these complexes equilibrate. Also, the time evolution of samples at fixed (electroneutral) composition was followed to

  16. Flow of wormlike micelles in an expansion-contraction geometry

    NARCIS (Netherlands)

    Stukan, Mikhail R.; Boek, Edo S.; Boek, E.S.; Padding, J.T.; Briels, Willem J.; Crawshaw, John P.

    2008-01-01

    Recently there has been a great deal of attention, from researchers both in academia and in industry, focused on the rheological properties of solutions of viscoelastic wormlike micelles formed by surfactants. It is particularly vital to understand the properties of these solutions with regard to

  17. Investigating Block-Copolymer Micelle Dynamics for Tunable Cargo Delivery

    Science.gov (United States)

    Li, Xiuli; Kidd, Bryce; Cooksey, Tyler; Robertson, Megan; Madsen, Louis

    Block-copolymer micelles (BCPMs) can carry molecular cargo in a nanoscopic package that is tunable using polymer structure in combination with cargo properties, as well as with external stimuli such as temperature or pH. For example, BCPMs can be used in targeted anticancer drug delivery due to their biocompatibility, in vivo degradability and prolonged circulation time. We are using NMR spectroscopy and diffusometry as well as SANS to investigate BCPMs. Here we study a diblock poly(ethylene oxide)-b-(caprolactone) (PEO-PCL) that forms spherical micelles at 1% (w/v) in the mixed solvent D2O/THF-d8. We quantify the populations and diffusion coefficients of coexisting micelles and free unimers over a range of temperatures and solvent compositions. We use temperature as a stimulus to enhance unimer exchange and hence trigger cargo release, in some cases at a few degrees above body temperature. We present evidence for dominance of the insertion-expulsion mechanism of unimer exchange in these systems, and we map phase diagrams versus temperature and solvent composition. This study sheds light on how intermolecular interactions fundamentally affect cargo release, unimer exchange, and overall micelle tunability.

  18. High-frequency ultrasound-responsive block copolymer micelle.

    Science.gov (United States)

    Wang, Jie; Pelletier, Maxime; Zhang, Hongji; Xia, Hesheng; Zhao, Yue

    2009-11-17

    Micelles of a diblock copolymer composed of poly(ethylene oxide) and poly(2-tetrahydropyranyl methacrylate) (PEO-b-PTHPMA) in aqueous solution could be disrupted by high-frequency ultrasound (1.1 MHz). It was found that, upon exposure to a high-intensity focused ultrasound (HIFU) beam at room temperature, the pH value of the micellar solution decreased over irradiation time. The infrared spectroscopic analysis of solid block copolymer samples collected from the ultrasound irradiated micellar solution revealed the formation of carboxylic acid dimers and hydroxyl groups. These characterization results suggest that the high-frequency HIFU beam could induce the hydrolysis reaction of THPMA at room temperature resulting in the cleavage of THP groups. The disruption of PEO-b-PTHPMA micelles by ultrasound was investigated by using dynamic light scattering, atomic force microscopy, and fluorescence spectroscopy. On the basis of the pH change, it was found that the disruption process was determined by a number of factors such as the ultrasound power, the micellar solution volume and the location of the focal spot of the ultrasound beam. This study shows the potential to develop ultrasound-sensitive block copolymer micelles by having labile chemical bonds in the polymer structure, and to use the high-frequency HIFU to trigger a chemical reaction for the disruption of micelles.

  19. Colorful packages : fluorescent proteins in complex coacervate core micelles

    NARCIS (Netherlands)

    Nolles, Antsje

    2018-01-01

    This thesis explores the encapsulation of fluorescent proteins (FPs) into complex coacervate core micelles (C3Ms) and features the impact of this encapsulation on the biophysical properties of the FPs. In total eight different FPs were investigated originating from two different classes

  20. Monitoring the aggregation of single casein micelles using fluorescence microscopy

    DEFF Research Database (Denmark)

    Bomholt, Julie; Moth-Poulsen, Kasper; Harboe, Marianne

    2011-01-01

    The aggregation of casein micelles (CMs) induced by milk-clotting enzymes is a process of fundamental importance in the dairy industry for cheese production; however, it is not well characterized on the nanoscale. Here we enabled the monitoring of the kinetics of aggregation between single CMs (30...

  1. Coupled Organoclay/Micelle Action for the Adsorption of Diclofenac.

    Science.gov (United States)

    De Oliveira, Tiago; Guégan, Régis

    2016-09-20

    A Na-smectite clay mineral (Na-Mt) was exchanged with various amounts of benzyldimethyltetradecyl ammonium chloride cationic surfactant (BDTAC) up to four times the cation exchange capacity (CEC). The adsorption properties of these organoclays as well as a coupled micelle/organoclay process were evaluated to remove an anionic pharmaceutical product, the diclofenac (DCF), recognized as a recalcitrant compound for conventional water treatments and to be poorly adsorbed onto untreated clay mineral. The DCF affinity appears to depend on the lipophilic character of organoclays in correlation to the density of intercalated BDTA and is particularly enhanced for sorbent systems with free surfactant or micelle in solution. The combination of both organclay and BDTA in excess or micelle as a one pot adsorption system appears to be the most efficient material for the sequestration of DCF and other pharmaceutical products (PPs) with a KF Freundlich constant of 1.7 L g(-1) and no restriction of the adsorbed DCF amount as the linear adsorption isotherm shows. A BDTA hydrophobic core micelle coupled with a positive electric charge forms an organic complex with DCF that is properly intercalated within the interlayer space of BDTA-Mt organoclays as both Fourier transform infrared (FTIR) and X-ray diffraction (XRD) data supported.

  2. Clinical application of polymeric micelles for the treatment of cancer

    NARCIS (Netherlands)

    Varela Moreira, A.A.; Shi, Y.; Fens, M.H.A.M.; Lammers, T.G.G.M.; Hennink, W.E.; Schiffelers, R.M.

    2017-01-01

    The in vivo administration of chemotherapeutic drugs is a challenge due to their poor pharmacokinetic (PK) and biodistribution profiles. For this reason, the development of delivery systems capable of targeting these compounds to pathological sites is of great importance. Polymeric micelles (PMs)

  3. Quenching mechanism of exciplex fluorescence by inverted micelles

    International Nuclear Information System (INIS)

    Sato, Chika; Kikuchi, Koichi

    1992-01-01

    Using an emission-absorption laser photolysis method, the quenching mechanism of the pyrene-N,N-dimethylaniline exciplex fluorscence by inverted micelles is studied. The rate of enhanced intersystem crossing depends upon water pool size and is reduced by external magnetic fields. 15 refs., 3 figs., 2 tabs

  4. Complex coacervate core micelles with a lysozyme-modified corona

    NARCIS (Netherlands)

    Danial, Maarten; Klok, Harm-Anton; Norde, Willem; Stuart, Martien A. Cohen

    2007-01-01

    This paper describes the preparation, characterization, and enzymatic activity of complex coacervate core micelles (C3Ms) composed of poly(acrylic acid) (PAA) and poly(N-methyl-2-vinyl pyridinium iodide)-b-poly(ethylene oxide) (PQ2VP-PEO) to which the antibacterial enzyme lysozyme is end-attached.

  5. In vivo toxicity of cationic micelles and liposomes

    DEFF Research Database (Denmark)

    Knudsen, Kristina Bram; Northeved, Helle; Ek, Pramod Kumar

    2015-01-01

    This study investigated toxicity of nanocarriers comprised of cationic polymer and lipid components often used in gene and drug delivery, formulated as cationic micelles and liposomes. Rats were injected intravenously with 10, 25 or 100 mg/kg and sacrificed after 24 or 48 h, or 24 h after the las...

  6. Development of chitosan oleate ionic micelles loaded with silver sulfadiazine to be associated with platelet lysate for application in wound healing.

    Science.gov (United States)

    Dellera, Eleonora; Bonferoni, Maria Cristina; Sandri, Giuseppina; Rossi, Silvia; Ferrari, Franca; Del Fante, Claudia; Perotti, Cesare; Grisoli, Pietro; Caramella, Carla

    2014-11-01

    In the treatment of chronic wounds, topical application of anti-infective drugs such as silver sulfadiazine (AgSD) is of primary importance to avoid infections and accelerate wound repair. AgSD is used in burns and chronic wounds for its wide antibacterial spectrum, but presents limitations due to poor solubility and cytotoxicity. In the present work polymeric micelles obtained by self-assembling of chitosan ionically modified by interaction with oleic acid were developed as carriers for AgSD to overcome the drawbacks of the drug. The AgSD loaded micelles were intended to be associated in wound healing with platelet lysate (PL), a hemoderivative rich in growth factors. Unloaded micelles demonstrated good compatibility with both fibroblasts and PL. The relevance of chitosan concentration and of the ratio between chitosan and oleic acid to the drug loading and the particle size of nanoparticles was studied. A marked increase (up to 100 times with respect to saturated solution) of AgSD concentration in micelle dispersion was obtained. Moreover, the encapsulation reduced the cytotoxic effect of the drug towards fibroblasts and the drug incompatibility with PDGF-AB (platelet derived growth factor), chosen as representative of platelet growth factors. Copyright © 2014. Published by Elsevier B.V.

  7. Reverse micelles as suitable microreactor for increased biohydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, Anjana [Nanotechnology and Molecular Biology Laboratory, Centre of Biotechnology, University of Allahabad, Allahabad 211002 (India); Pandey, Ashutosh [Centre of Energy Studies, MNNIT, Allahabad 211004 (India)

    2008-01-15

    Reverse micelles have been shown to act as efficient microreactors for enzymic reactions and whole cell entrapment in organic (non-aqueous) media wherein the reactants are protected from denaturation by the surrounding organic solvent. These micelles are thermodynamically stable, micrometer sized water droplets dispersed in an organic phase by a surfactant. It has been observed that when whole cells of photosynthetic bacteria (Rhodopseudomonas sphaeroides or Rhodobacter sphaeroides 2.4.1) are entrapped inside these reverse micelles, the H{sub 2} production enhanced from 25 to 35 folds. That is, 1.71mmol(mgprotein){sup -1}h{sup -1} in case of R. sphaeroides which is 25 fold higher in benzene-sodium lauryl sulfate reverse micelles. Whereas, in case of R. sphaeroides 2.4.1 the H{sub 2} production was increased by 35 fold within AOT-isooctane reverse micelles i.e. 11.5mmol(mgprotein){sup -1}h{sup -1}. The observations indicate that the entrapment of whole cells of microbes within reverse micelles provides a novel and efficient technique to produce hydrogen by the inexhaustible biological route. The two microorganisms R. sphaeroides 2.4.1 (a photosynthetic bacteria) and Citrobacter Y19 (a facultative anaerobic bacteria) together are also entrapped within AOT-isooctane and H{sub 2} production was measured i.e. 69mmol(mgprotein){sup -1}h{sup -1}. The nitrogenase enzyme responsible for hydrogen production by R. sphaeroides/R. sphaeroides 2.4.1 cells is oxygen sensitive, and very well protected within reverse micelles by the use of combined approach of two cells (R. sphaeroides 2.4.1 and Citrobacter Y19). In this case glucose present in the medium of Citrobacter Y19 serves double roles in enhancing the sustained production rate of hydrogen. Firstly, it quenches the free O{sub 2}liberated as a side product of reaction catalyzed by nitrogenase, which is O{sub 2} labile. Secondly, organic acid produced by this reaction is utilized by the Citrobacter Y19 as organic substrate in

  8. Casein polymorphism heterogeneity influences casein micelle size in milk of individual cows.

    Science.gov (United States)

    Day, L; Williams, R P W; Otter, D; Augustin, M A

    2015-06-01

    Milk samples from individual cows producing small (148-155 nm) or large (177-222 nm) casein micelles were selected to investigate the relationship between the individual casein proteins, specifically κ- and β-casein phenotypes, and casein micelle size. Only κ-casein AA and β-casein A1A1, A1A2 and A2A2 phenotypes were found in the large casein micelle group. Among the small micelle group, both κ-casein and β-casein phenotypes were more diverse. κ-Casein AB was the dominant phenotype, and 3 combinations (AA, AB, and BB) were present in the small casein micelle group. A considerable mix of β-casein phenotypes was found, including B and I variants, which were only found in the small casein micelle group. The relative amount of κ-casein to total casein was significantly higher in the small micelle group, and the nonglycosylated and glycosylated κ-casein contents were higher in the milks with small casein micelles (primarily with κ-casein AB and BB variants) compared with the large micelle group. The ratio of glycosylated to nonglycosylated κ-casein was higher in the milks with small casein micelles compared with the milks with large casein micelles. This suggests that although the amount of κ-casein (both glycosylated and nonglycosylated) is associated with micelle size, an increased proportion of glycosylated κ-casein could be a more important and favorable factor for small micelle size. This suggests that the increased spatial requirement due to addition of the glycosyl group with increasing extent of glycosylation of κ-casein is one mechanism that controls casein micelle assembly and growth. In addition, increased electrostatic repulsion due to the sialyl residues on the glycosyl group could be a contributory factor. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  9. CMC-coated Fe3O4 nanoparticles as new MRI probes for hepatocellular carcinoma

    Science.gov (United States)

    Sitthichai, Sudarat; Pilapong, Chalermchai; Thongtem, Titipun; Thongtem, Somchai

    2015-11-01

    Pure Fe3O4 nanoparticles and Fe3O4 magnetic nanoparticles (MNPs) coated with carboxymethyl cellulose (CMC) were successfully prepared by co-precipitating of FeCl2·4H2O and FeCl3·6H2O in the solutions containing ammonia at 80 °C for 3 h. Phase, morphology, particle-sized distribution, surface chemistry, and weight loss were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) including high-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED), thermogravimetric analysis (TGA), and Fourier transform infrared (FTIR) spectroscopy. In this research, CMC-coated Fe3O4 MNPs consisting of Fe2+ and Fe3+ ions with 543.3-mM-1 s-1 high relaxivity were detected and were able to be used for magnetic resonance imaging (MRI) application with very good contrast for targeting hepatocellular carcinoma (HCC) without any further vectorization.

  10. It's Just a Game, Right? Types of Play in Foreign Language CMC

    Directory of Open Access Journals (Sweden)

    Chantelle N. Warner

    2004-05-01

    Full Text Available This study focuses on the various playful uses of language that occurred during a semester-long study of two German language courses using one type of synchronous network-based medium, the MOO. Research and use of synchronous computer-mediated communication (CMC have flourished in the study of second-language acquisition (SLA since the late 1990s; however, the primary focus has been on the potential benefits of using CMC to increase the amount of communication (Beauvois, 1997; Kern, 1995; Warschauer, 1997, motivate students (Beauvois, 1997; Kern, 1995; Warschauer, 1997 and foster the exchange of ideas (Beauvois, 1997; Kern, 1995; von der Emde, Schneider, & Kötter, 2001; Warschauer, 1997. Only more recently has research within SLA begun to investigate the types of communication that occur online.1 An analysis of the transcripts from a second-semester German course and an upper-level German communication course reveal that a large portion of the language use online cannot be described using standard referential definitions of communication, but rather is playful in nature. Using research from SLA and theories on social interaction, this article investigates the different types of play that occurred within the online discussions and the possible implications of the presence of play in online discourse.

  11. Ceramic Matrix Composite (CMC) Thermal Protection Systems (TPS) and Hot Structures for Hypersonic Vehicles

    Science.gov (United States)

    Glass, David E.

    2008-01-01

    Thermal protection systems (TPS) and hot structures are required for a range of hypersonic vehicles ranging from ballistic reentry to hypersonic cruise vehicles, both within Earth's atmosphere and non-Earth atmospheres. The focus of this paper is on air breathing hypersonic vehicles in the Earth's atmosphere. This includes single-stage to orbit (SSTO), two-stage to orbit (TSTO) accelerators, access to space vehicles, and hypersonic cruise vehicles. This paper will start out with a brief discussion of aerodynamic heating and thermal management techniques to address the high heating, followed by an overview of TPS for rocket-launched and air-breathing vehicles. The argument is presented that as we move from rocket-based vehicles to air-breathing vehicles, we need to move away from the insulated airplane approach used on the Space Shuttle Orbiter to a wide range of TPS and hot structure approaches. The primary portion of the paper will discuss issues and design options for CMC TPS and hot structure components, including leading edges, acreage TPS, and control surfaces. The current state-of-the-art will be briefly discussed for some of the components. The two primary technical challenges impacting the use of CMC TPS and hot structures for hypersonic vehicles are environmental durability and fabrication, and will be discussed briefly.

  12. Spatially distributed damage detection in CMC thermal protection materials using thin-film piezoelectric sensors

    Science.gov (United States)

    Kuhr, Samuel J.; Blackshire, James L.; Na, Jeong K.

    2009-03-01

    Thermal protection systems (TPS) of aerospace vehicles are subjected to impacts during in-flight use and vehicle refurbishment. The damage resulting from such impacts can produce localized regions that are unable to resist extreme temperatures. Therefore it is essential to have a reliable method to detect, locate, and quantify the damage occurring from such impacts. The objective of this research is to demonstrate a capability that could lead to detecting, locating and quantifying impact events for ceramic matrix composite (CMC) wrapped tile TPS via sensors embedded in the TPS material. Previous research had shown a correlation between impact energies, material damage state, and polyvinylidene fluoride (PVDF) sensor response for impact energies between 0.07 - 1.00 Joules, where impact events were located directly over the sensor positions1. In this effort, the effectiveness of a sensor array is evaluated for detecting and locating low energy impacts on a CMC wrapped TPS. The sensor array, which is adhered to the internal surface of the TPS tile, is used to detect low energy impact events that occur at different locations. The analysis includes an evaluation of signal amplitude levels, time-of-flight measurements, and signal frequency content. Multiple impacts are performed at each location to study the repeatability of each measurement.

  13. Preparation and characterization of monomethoxy poly(ethylene glycol-poly(ε-caprolactone micelles for the solubilization and in vivo delivery of luteolin

    Directory of Open Access Journals (Sweden)

    Qiu JF

    2013-08-01

    Full Text Available Jin-Feng Qiu,1 Xiang Gao,1,2 Bi-Lan Wang,1 Xia-Wei Wei,1 Ma-Ling Gou,1 Ke Men,1 Xing-Yu Liu,1 Gang Guo,1 Zhi-Yong Qian,1 Mei-Juan Huang1 1Department of Thoracic Oncology, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital and Medical School, Sichuan University, Chengdu, People’s Republic of China; 2Medical School and Department of Pathophysiology, College of Preclinical and Forensic Medical Sciences, Sichuan University, Chengdu, People’s Republic of China Abstract: Luteolin (Lu is one of the flavonoids with anticancer activity, but its poor water solubility limits its use clinically. In this work, we used monomethoxy poly(ethylene glycol-poly(ε-caprolactone (MPEG-PCL micelles to encapsulate Lu by a self-assembly method, creating a water-soluble Lu/MPEG-PCL micelle. These micelles had a mean particle size of 38.6 ± 0.6 nm (polydispersity index = 0.16 ± 0.02, encapsulation efficiency of 98.32% ± 1.12%, and drug loading of 3.93% ± 0.25%. Lu/MPEG-PCL micelles could slowly release Lu in vitro. Encapsulation of Lu in MPEG-PCL micelles improved the half-life (t½; 152.25 ± 49.92 versus [vs] 7.16 ± 1.23 minutes, P = 0.007, area under the curve (0–t (2914.05 ± 445.17 vs 502.65 ± 140.12 mg/L/minute, P = 0.001, area under the curve (0–∞ (2989.03 ± 433.22 vs 503.81 ± 141.41 mg/L/minute, P = 0.001, and peak concentration (92.70 ± 11.61 vs 38.98 ± 7.73 mg/L, P = 0.003 of Lu when the drug was intravenously administered at a dose of 30 mg/kg in rats. Also, Lu/MPEG-PCL micelles maintained the cytotoxicity of Lu on 4T1 breast cancer cells (IC50 = 6.4 ± 2.30 µg/mL and C-26 colon carcinoma cells (IC50 = 12.62 ± 2.17 µg/mL in vitro. These data suggested that encapsulation of Lu into MPEG-PCL micelles created an aqueous formulation of Lu with potential anticancer effect. Keywords: luteolin, micelle, MPEG-PCL, cancer therapy

  14. Nuclear relaxation induced by diffusion in confined media; the case of inverted micelles

    International Nuclear Information System (INIS)

    Llor, Antoine

    1983-01-01

    This work emphasizes the specificities of molecular motions in restricted media observed by NMR. The observation of proton nuclear relaxation of small water pools in AOT reversed micelles has led to separation of dipolar contributions using substitution by deuterium. The water-water contributions to relaxation are easily explained by well-known models and show that water rotational movements are, at most, five times slower than in pure water. The other contributions display a strong frequency dependence with spectrometer frequency and, in order to explain them, a specific dipolar relaxation model was developed between two particles whose movements are restricted to the surface of a sphere and in a concentric sphere respectively. This model was generalized to all cases of diffusion movements of particles in a spherical symmetry environment. In the case of AOT micelles, this model can not explain the experimental results. An elementary discussion taking into account the polar heads specificities and their interactions with water lead to a qualitative interpretation of the experimental data. (author) [fr

  15. Investigation of extractive microbial transformation in nonionic surfactant micelle aqueous solution using response surface methodology.

    Science.gov (United States)

    Xue, Yingying; Qian, Chen; Wang, Zhilong; Xu, Jian-He; Yang, Rude; Qi, Hanshi

    2010-01-01

    Extractive microbial transformation of L-phenylacetylcarbinol (L-PAC) in nonionic surfactant Triton X-100 micelle aqueous solution was investigated by response surface methodology. Based on the Box-Behnken design, a mathematical model was developed for the predication of mutual interactions between benzaldehyde, Triton X-100, and glucose on L-PAC production. It indicated that the negative or positive effect of nonionic surfactant strongly depended on the substrate concentration. The model predicted that the optimal concentration of benzaldehyde, Triton X-100, and glucose was 1.2 ml, 15 g, and 2.76 g per 100 ml, respectively. Under the optimal condition, the maximum L-PAC production was 27.6 mM, which was verified by a time course of extractive microbial transformation. A discrete fed-batch process for verification of cell activity was also presented.

  16. Mixed Micelle System Produced by Interaction Between Transglycosylated Stevia and an Ionic Surfactant Improves Dissolution Profile of Mefenamic Acid.

    Science.gov (United States)

    Fujimori, Miki; Kadota, Kazunori; Tozuka, Yuichi

    2017-04-01

    Transglycosylated stevia (stevia-G) can effectively improve the dissolution and bioavailability of poorly water-soluble drugs. Furthermore, addition of an ionic surfactant to stevia-G solution has been shown to enhance the dissolution effect of stevia-G on flurbiprofen. Herein, 4 surfactants, namely sodium dodecyl sulfate, sodium N-dodecanoylsarcosinate, sodium monododecyl phosphate, and lauryltrimethylammonium chloride (LTAC) were screened to investigate their synergistic effect with stevia-G in enhancing the solubility of mefenamic acid (MFA). The ternary formulation containing LTAC produced the highest increase in solubility, whereas the binary MFA/LTAC formulation did not increase the solubility of MFA. Surface tension was evaluated to analyze the interaction between stevia-G and each ionic surfactant, wherein the Rubingh model was applied to predict mixed micelle formation between stevia-G and LTAC. Interaction parameters calculated by the Rubingh model reflected mixed micelle formation between stevia-G and LTAC relative to the self-interactions of the 2 individual surfactants. All interaction parameters in this system showed negative values, indicating a favorable interaction (e.g., hydrogen bond or electrostatic and dipole) between binary components in the mixed micelles. Spray-dried particles of ternary formulations (MFA/stevia-G/LTAC) were prepared to evaluate the dissolution profile and physicochemical properties. Dissolution profiling showed that the concentration of MFA released from spray-dried particles was significantly higher than untreated MFA. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  17. Unusual nanosized associates of carboxy-calix[4]resorcinarene and cetylpyridinium chloride: the macrocycle as a glue for surfactant micelles.

    Science.gov (United States)

    Morozova, Ju E; Syakaev, V V; Shalaeva, Ya V; Ermakova, A M; Nizameev, I R; Kadirov, M K; Voloshina, A D; Zobov, V V; Antipin, I S; Konovalov, A I

    2017-03-08

    The association of cetylpyridinium chloride (CPC) micelles in the presence of octaacetated tetraphenyleneoxymethylcalix[4]resorcinarene (CR) leads to the formation of unusual spherical supramolecular nanoparticles (SNPs). Within the range of CR/CPC molar ratios from 10/1 to 1/10 (except for 1/8), CR, acting as a counterion, decreases the critical micelle concentration of CPC by one order of magnitude and leads to the formation of SNPs with an average hydrodynamic radius of 164 nm and an average zeta potential of -60 mV. The formation of SNPs was studied by NMR FT-PGSE and 2D NOESY, DLS, TEM, fluorimetry, and UV-Vis methods. The stability of SNPs at different temperatures and pH values and in the presence of electrolytes was investigated. The specificity of the interactions of the SNPs with substrates that were preferentially bound by a macrocycle or CPC micelle was studied. The enhancement of cation dye binding in the presence of SNPs is shown. The presented supramolecular system may serve as a nanocapsule for water-soluble and water-insoluble compounds.

  18. Synthesis and Characterization of Cleavable Core-Cross-Linked Micelles Based on Amphiphilic Block Copolypeptoids as Smart Drug Carriers.

    Science.gov (United States)

    Li, Ang; Zhang, Donghui

    2016-03-14

    Amphiphilic block copolypeptoids consisting of a hydrophilic poly(N-ethyl glycine) segment and a hydrophobic poly[(N-propargyl glycine)-r-(N-decyl glycine)] random copolymer segment [PNEG-b-P(NPgG-r-NDG), EPgD] have been synthesized by sequential primary amine-initiated ring-opening polymerization (ROP) of the corresponding N-alkyl N-carboxyanhydride monomers. The block copolypeptoids form micelles in water and the micellar core can be cross-linked with a disulfide-containing diazide cross-linker by copper-mediated alkyne-azide cycloaddition (CuAAC) in aqueous solution. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis revealed the formation of spherical micelles with uniform size for both the core-cross-linked micelles (CCLMs) and non-cross-linked micelles (NCLMs) precursors for selective block copolypeptoid polymers. The CCLMs exhibited increased dimensional stability relative to the NCLMs in DMF, a nonselective solvent for the core and corona segments. Micellar dissociation of CCLMs can be induced upon addition of a reducing agent (e.g., dithiothreitol) in dilute aqueous solutions, as verified by a combination of fluorescence spectroscopy, size exclusion chromatography (SEC), and (1)H NMR spectroscopic measurement. Doxorubicin (DOX), an anticancer drug, can be loaded into the hydrophobic core of CCLMs with a maximal 23% drug loading capacity (DLC) and 37% drug loading efficiency (DLE). In vitro DOX release from the CCLMs can be triggered by DTT (10 mM), in contrast to significantly reduced DOX release in the absence of DTT, attesting to the reductively responsive characteristic of the CCLMs. While the CCLMs exhibited minimal cytotoxicity toward HepG2 cancer cells, DOX-loaded CCLMs inhibited the proliferation of the HepG2 cancer cells in a concentration and time dependent manner, suggesting the controlled release of DOX from the DOX-loaded CCLMS in the cellular environment.

  19. Critical Synergistic Concentration of Lecithin Phospholipids Improves the Antimicrobial Activity of Eugenol against Escherichia coli

    Science.gov (United States)

    Zhang, Haoshu; Dudley, Edward G.

    2017-01-01

    ABSTRACT In this study, the effect of individual lecithin phospholipids on the antimicrobial properties of eugenol against Escherichia coli C600 was investigated. We tested five major phospholipids common in soy or egg lecithin (1,2-dihexadecanoyl-sn-glycero-3-phosphocholine [DPPC], 1,2-dioctadecanoyl-sn-glycero-3-phosphocholine [DSPC], 1,2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine [DPPE], 1,2-dihexadecanoyl-sn-glycero-3-phosphate [sodium salt] [DPPA], and 1,2-dihexadecanoyl-sn-glycero-3-phospho-l-serine [DPPS]) and one synthetic cationic phospholipid (1,2-dioctadecanoyl-sn-glycero-3-ethylphosphocholine [18:0 EPC]). Among the six phospholipids, DPPC, DSPC, DPPE, DPPA, and the cationic 18:0 EPC showed critical synergistic concentrations that significantly improved the inactivation effect of eugenol against E. coli after 30 min of exposure. At the critical synergistic concentration, an additional ca. 0.4 to 1.9 log reduction (ca. 0.66 to 2.17 log CFU/ml reduction) in the microbial population was observed compared to eugenol-only (control) treatments (ca. 0.25 log reduction). In all cases, increasing the phospholipid amount above the critical synergistic concentration (which was different for each phospholipid) resulted in antimicrobial properties similar to those seen with the eugenol-only (control) treatments. DPPS did not affect the antimicrobial properties of eugenol at the tested concentrations. The critical synergistic concentration of phospholipids was correlated with their critical micelle concentrations (CMC). IMPORTANCE Essential oils (EOs) are naturally occurring antimicrobials, with limited use in food due to their hydrophobicity and strong aroma. Lecithin is used as a natural emulsifier to stabilize EOs in aqueous systems. We previously demonstrated that, within a narrow critical-concentration window, lecithin can synergistically enhance the antimicrobial properties of eugenol. Since lecithin is a mixture of different phospholipids, we aimed to

  20. Critical Synergistic Concentration of Lecithin Phospholipids Improves the Antimicrobial Activity of Eugenol against Escherichia coli.

    Science.gov (United States)

    Zhang, Haoshu; Dudley, Edward G; Harte, Federico

    2017-11-01

    In this study, the effect of individual lecithin phospholipids on the antimicrobial properties of eugenol against Escherichia coli C600 was investigated. We tested five major phospholipids common in soy or egg lecithin (1,2-dihexadecanoyl-sn-glycero-3-phosphocholine [DPPC], 1,2-dioctadecanoyl-sn-glycero-3-phosphocholine [DSPC], 1,2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine [DPPE], 1,2-dihexadecanoyl-sn-glycero-3-phosphate [sodium salt] [DPPA], and 1,2-dihexadecanoyl-sn-glycero-3-phospho-l-serine [DPPS]) and one synthetic cationic phospholipid (1,2-dioctadecanoyl-sn-glycero-3-ethylphosphocholine [18:0 EPC]). Among the six phospholipids, DPPC, DSPC, DPPE, DPPA, and the cationic 18:0 EPC showed critical synergistic concentrations that significantly improved the inactivation effect of eugenol against E. coli after 30 min of exposure. At the critical synergistic concentration, an additional ca. 0.4 to 1.9 log reduction (ca. 0.66 to 2.17 log CFU/ml reduction) in the microbial population was observed compared to eugenol-only (control) treatments (ca. 0.25 log reduction). In all cases, increasing the phospholipid amount above the critical synergistic concentration (which was different for each phospholipid) resulted in antimicrobial properties similar to those seen with the eugenol-only (control) treatments. DPPS did not affect the antimicrobial properties of eugenol at the tested concentrations. The critical synergistic concentration of phospholipids was correlated with their critical micelle concentrations (CMC). IMPORTANCE Essential oils (EOs) are naturally occurring antimicrobials, with limited use in food due to their hydrophobicity and strong aroma. Lecithin is used as a natural emulsifier to stabilize EOs in aqueous systems. We previously demonstrated that, within a narrow critical-concentration window, lecithin can synergistically enhance the antimicrobial properties of eugenol. Since lecithin is a mixture of different phospholipids, we aimed to identify

  1. Glycopolymer micelles with reducible ionic cores for hepatocytes-targeting delivery of DOX.

    Science.gov (United States)

    Wang, Yanxia; Zhang, Xinge; Yu, Peien; Li, Chaoxing

    2013-01-30

    A novel galactose-decorated cross-linked micelles (cl-micelles) with ionic cores using cystamine (Cys) as a biodegradable cross-linker was prepared by using block ionomer complexes of poly(ethylene glycol)-b-poly(2-acryloxyethyl-galactose)-b-poly(acrylic acid) (PEG-b-PAEG-b-PAA) and Ca(2+) (PEG-b-PAEG-b-PAA cl-micelles/Cys). Doxorubicin (DOX) was successfully incorporated into the ionic cores of such micelles via electrostatic interactions. Proton nuclear magnetic resonance spectrum and Fourier transform infrared spectrometer indicated galactose ligands were exposed at the micellar surface. The micelles were spherical in shape, with an average size of 100nm. The in vitro release studies confirmed that DOX-loaded PEG-b-PAEG-b-PAA cl-micelles/Cys accomplished rapid drug release under reducing condition. Remarkably, PEG-b-PAEG-b-PAA cl-micelles/Cys efficiently delivered and released DOX into the cell nucleus of HepG2 cells, and the intensity of fluorescence observed in HepG2 cells was stronger than that incubated with the micelles without galactose ligands. In contrast, little fluorescence was observed in NIH3T3 cells after incubation with PEG-b-PAEG-b-PAA cl-micelles/Cys. Interestingly, cytotoxicity assays showed that DOX-loaded PEG-b-PAEG-b-PAA cl-micelles/Cys retained higher cell inhibition efficiency in HepG2 cells as compared with NIH3T3 cells, and were more potent than the micelles without galactose ligands and the micelles with non degradable cross-links. These results indicate that PEG-b-PAEG-b-PAA cl-micelles/Cys have great potential in liver tumor-targeted chemotherapy. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. Synthesis, surface properties and oil solubilisation capacity of cationic gemini surfactants

    NARCIS (Netherlands)

    Dam, Th.; Engberts, J.B.F.N.; Karthäuser, J.; Karaborni, S.; Os, N.M. van

    1996-01-01

    The critical micelle concentration (CMC) and the surface tension at the CMC have been determined for the gemini surfactants alkanediyl-u,w-bis(dimethyla1kylammoniubmr omide) by means of dynamic surface tension measurements. For the same number of carbon atoms in the hydrophobic chain per hydrophilic

  3. Degradation of Triton X-100 surfactant/lipid regulator systems by ionizing radiation in water

    International Nuclear Information System (INIS)

    Racz, Gergely; Obuda-University, Budapest; Csay, Tamas; Takacs, Erzsebet; Wojnarovits, Laszlo

    2017-01-01

    The radiolytic degradation of Triton X-100 surfactant was investigated at concentrations below and above the critical micelle concentration (CMC, ∼ 0.23 mmol dm -3 ) in air saturated aqueous solutions. At low concentrations the degradation took place both on the aromatic head and on the polyethoxylates chain, while above CMC it was shifted towards the chain. The CMC was higher in irradiated solutions at 10 Gy by a factor of 2, at 20 kGy by a factor of 3 than in the un-irradiated solution. The degradation of clofibric acid in the presence of TX-100 was more effective outside the micelles than inside them. (author)

  4. Language, mobile phones and internet : a study of SMS texting, email, IM and SNS chats in computer mediated communication (CMC) in Kenya

    NARCIS (Netherlands)

    Barasa, Sandra Nekesa

    2010-01-01

    This book examines the use of language in Computer Mediated Communication (CMC) genres in Kenya. It focuses on Short Messaging Service (SMS), Email, Instant Messages (IM) and Social Network Sites (SNS) genres. It presents an overview of the use and characteristics of Kenyan languages in CMC texts

  5. pH-sensitive micelles self-assembled from polymer brush (PAE-g-cholesterol-b-PEG-b-(PAE-g-cholesterol for anticancer drug delivery and controlled release

    Directory of Open Access Journals (Sweden)

    Huang X

    2017-03-01

    Full Text Available Xiangxuan Huang,1 Wenbo Liao,1 Gang Zhang,1 Shimin Kang,1 Can Yang Zhang2 1School of Chemical Engineering and Energy Technology, Dongguan University of Technology, Dongguan, People’s Republic of China; 2Department of Pharmaceutical Sciences, College of Pharmacy, Washington State University, Spokane, WA, USA Abstract: A novel amphiphilic pH-sensitive triblock polymer brush (poly(β-amino esters-g-cholesterol-b-poly(ethylene glycol-b-(poly(β-amino esters-g-cholesterol ((PAE-g-Chol-b-PEG-b-(PAE-g-Chol was designed and synthesized successfully through a three-step reaction, and their self-assembled polymeric micelles were used as hydrophobic anticancer drug delivery carriers to realize effectively controlled release. The critical micelle concentrations were 6.8 µg/mL, 12.6 µg/mL, 17.4 µg/mL, and 26.6 µg/mL at pH values of 7.4, 6.5, 6.0, and 5.0, respectively. The trend of critical micelle concentrations indicated that the polymer had high stability that could prolong the circulation time in the body. The hydrodynamic diameter and zeta potential of the polymeric micelles were influenced significantly by the pH values. As pH decreased from 7.4 to 5.0, the particle size and zeta potential increased from 205.4 nm to 285.7 nm and from +12.7 mV to +47.0 mV, respectively. The pKb of the polymer was confirmed to be approximately 6.5 by the acid–base titration method. The results showed that the polymer had sharp pH-sensitivity because of the protonation of the amino groups, resulting in transformation of the PAE segment from hydrophobic to hydrophilic. Doxorubicin-loaded polymeric micelles were prepared with a high loading content (20% and entrapment efficiency (60% using the dialysis method. The in vitro results demonstrated that drug release rate and cumulative release were obviously dependent on pH values. Furthermore, the drug release mechanism was also controlled by the pH values. The polymer had barely any cytotoxicity, whereas the

  6. On the Problem of Determining Aggregation Numbers from Surface Tension Measurements.

    Science.gov (United States)

    Rusanov, Anatoly I

    2017-11-07

    In view of the recent discovery of variable aggregation numbers in the vicinity of the critical micelle concentration (CMC), the mass-action-law theory of the surface tension isotherm of a micellar solution with variable aggregation numbers is formulated both for nonionic and ionic surfactants. It is shown that the shape of the surface tension isotherm should be concave in the logarithmic scale above the CMC. Considering a change in the isotherm slope at the CMC apparent break point, the problems of determining the aggregation number for nonionic micelles and the degree of counterion binding for ionic micelles are discussed. In case of the aggregation number variability near the CMC, finding the aggregation number above the CMC apparent break point is considered and a computational scheme is elaborated, requiring a higher precision for experiment. Some experimental data from the literature are analyzed, and the method of estimating the degree of counterion binding is improved.

  7. Self-assembly of star micelle into vesicle in solvents of variable quality: the star micelle retains its core-shell nanostructure in the vesicle.

    Science.gov (United States)

    Liu, Nijuan; He, Qun; Bu, Weifeng

    2015-03-03

    Intra- and intermolecular interactions of star polymers in dilute solutions are of fundamental importance for both theoretical interest and hierarchical self-assembly into functional nanostructures. Here, star micelles with a polystyrene corona and a small ionic core bearing platinum(II) complexes have been regarded as a model of star polymers to mimic their intra- and interstar interactions and self-assembled behaviors in solvents of weakening quality. In the chloroform/methanol mixture solvents, the star micelles can self-assemble to form vesicles, in which the star micelles shrink significantly and are homogeneously distributed on the vesicle surface. Unlike the morphological evolution of conventional amphiphiles from micellar to vesicular, during which the amphiphilic molecules are commonly reorganized, the star micelles still retain their core-shell nanostructures in the vesicles and the coronal chains of the star micelle between the ionic cores are fully interpenetrated.

  8. Batch and continuous extraction of bromelain enzyme by reversed micelles

    Directory of Open Access Journals (Sweden)

    Ana Maria Frattini Fileti

    2009-10-01

    Full Text Available The main aim of this study was to optimize the conditions for bromelain extraction by reversed micelles from pineapple juice (Ananas comosus. The purification was carried out in batch extraction and a micro-column with pulsed caps for continuous extraction. The cationic micellar solution was made of BDBAC as a surfactant, isooctane as a solvent and hexanol as a co-solvent. For the batch process, a purification factor of 3 times at the best values of surfactant agent, co-solvent and salt concentrations, pH of the back and forward extractions were, 100 mM, 10% v/v, 1 M, 3.5 and 8, respectively. For the continuous operation, independent variables optimal point was determined: ratio between light phase flow rate and total flow rate equal to 0.67 and 1 second for the time interval between the pulses. This optimal point led to a productivity of 1.29 mL/min and a purification factor of 4.96.Este trabalho teve como objetivo principal otimizar as condições para extração da bromelina do suco do abacaxi (Ananas comosus por micelas reversas. A purificação foi feita usando o processo de extração em batelada e contínuo, este último em uma micro-coluna de campânulas pulsantes. A solução micelar catiônica foi preparada com o surfactante BDBAC, i-octano como solvente e hexanol como co-solvente. Na extração em batelada encontrou-se um fator de purificação de 3 vezes, e seus melhores valores de concentração do agente surfactante, co-solvente e sal, de pH da re-extração e extração, foram respectivamente iguais a: 100 mM, 10% v/v, 1 M, 3,5 e 8. Para a operação contínua, as variáveis independentes ótimas foram: 0,67 para a razão entre as taxas de fluxos da fase leve e a total e 1 s para o intervalo de tempo entre pulsos das campânulas. Este ponto ótimo leva a uma produtividade de 1,29 mL/min e a um fator de purificação igual a 4,96.

  9. An Update on Design Tools for Optimization of CMC 3D Fiber Architectures

    Science.gov (United States)

    Lang, J.; DiCarlo, J.

    2012-01-01

    Objective: Describe and up-date progress for NASA's efforts to develop 3D architectural design tools for CMC in general and for SIC/SiC composites in particular. Describe past and current sequential work efforts aimed at: Understanding key fiber and tow physical characteristics in conventional 2D and 3D woven architectures as revealed by microstructures in the literature. Developing an Excel program for down-selecting and predicting key geometric properties and resulting key fiber-controlled properties for various conventional 3D architectures. Developing a software tool for accurately visualizing all the key geometric details of conventional 3D architectures. Validating tools by visualizing and predicting the Internal geometry and key mechanical properties of a NASA SIC/SIC panel with a 3D orthogonal architecture. Applying the predictive and visualization tools toward advanced 3D orthogonal SiC/SIC composites, and combining them into a user-friendly software program.

  10. Characterization of LWRS Hybrid SiC-CMC-Zircaloy-4 Fuel Cladding after Gamma Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Isabella J van Rooyen

    2012-09-01

    The purpose of the gamma irradiation tests conducted at the Idaho National Laboratory (INL) was to obtain a better understanding of chemical interactions and potential changes in microstructural properties of a mock-up hybrid nuclear fuel cladding rodlet design (unfueled) in a simulated PWR water environment under irradiation conditions. The hybrid fuel rodlet design is being investigated under the Light Water Reactor Sustainability (LWRS) program for further development and testing of one of the possible advanced LWR nuclear fuel cladding designs. The gamma irradiation tests were performed in preparation for neutron irradiation tests planned for a silicon carbide (SiC) ceramic matrix composite (CMC) zircaloy-4 (Zr-4) hybrid fuel rodlet that may be tested in the INL Advanced Test Reactor (ATR) if the design is selected for further development and testing

  11. Mixed micelles of 7,12-dioxolithocholic acid and selected hydrophobic bile acids: interaction parameter, partition coefficient of nitrazepam and mixed micelles haemolytic potential.

    Science.gov (United States)

    Poša, Mihalj; Tepavčević, Vesna

    2011-09-01

    The formation of mixed micelles built of 7,12-dioxolithocholic and the following hydrophobic bile acids was examined by conductometric method: cholic (C), deoxycholic (D), chenodeoxycholic (CD), 12-oxolithocholic (12-oxoL), 7-oxolithocholic (7-oxoL), ursodeoxycholic (UD) and hiodeoxycholic (HD). Interaction parameter (β) in the studied binary mixed micelles had negative value, suggesting synergism between micelle building units. Based on β value, the hydrophobic bile acids formed two groups: group I (C, D and CD) and group II (12-oxoL, 7-oxoL, UD and HD). Bile acids from group II had more negative β values than bile acids from group I. Also, bile acids from group II formed intermolecular hydrogen bonds in aggregates with both smaller (2) and higher (4) aggregation numbers, according to the analysis of their stereochemical (conformational) structures and possible structures of mixed micelles built of these bile acids and 7,12-dioxolithocholic acid. Haemolytic potential and partition coefficient of nitrazepam were higher in mixed micelles built of the more hydrophobic bile acids (C, D, CD) and 7,12-dioxolithocholic acid than in micelles built only of 7,12-dioxolithocholic acid. On the other hand, these mixed micelles still had lower values of haemolytic potential than micelles built of C, D or CD. The mixed micelles that included bile acids: 12-oxoL, 7-oxoL, UD or HD did not significantly differ from the micelles of 7,12-dioxolithocholic acid, observing the values of their haemolytic potential. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Engineering single-polymer micelle shape using nonuniform spontaneous surface curvature

    Science.gov (United States)

    Moths, Brian; Witten, T. A.

    2018-03-01

    Conventional micelles, composed of simple amphiphiles, exhibit only a few standard morphologies, each characterized by its mean surface curvature set by the amphiphiles. Here we demonstrate a rational design scheme to construct micelles of more general shape from polymeric amphiphiles. We replace the many amphiphiles of a conventional micelle by a single flexible, linear, block copolymer chain containing two incompatible species arranged in multiple alternating segments. With suitable segment lengths, the chain exhibits a condensed spherical configuration in solution, similar to conventional micelles. Our design scheme posits that further shapes are attained by altering the segment lengths. As a first study of the power of this scheme, we demonstrate the capacity to produce long-lived micelles of horseshoe form using conventional bead-spring simulations in two dimensions. Modest changes in the segment lengths produce smooth changes in the micelle's shape and stability.

  13. The fabrication of nanopatterns with Au nanoparticles-embedded micelles via nanoimprint lithography

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jung-Pil; Kim, Eun-Uk; Koh, Haeng-Deog; Kang, Nam-Goo; Jung, Gun-Young; Lee, Jae-Suk, E-mail: gyjung@gist.ac.k, E-mail: jslee@gist.ac.k [Department of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), 261 Cheomdan-gwagiro (Oryong-dong), Buk-gu Gwangju 500-712 (Korea, Republic of)

    2009-09-09

    We fabricated nanopatterns with Au nanoparticles-embedded micelles (Au-micelles) by self-assembly of block copolymers via nanoimprint lithography. The micelle structure prepared by self-assembled block copolymers was used as a template for the synthesis of Au nanoparticles (Au NPs). Au NPs were synthesized in situ inside the micelles of polystyrene-block-poly(2-vinylpyridine) (PS- b-P2VP). Au-micelles were arranged on the trenches of the polymer template, which was imprinted by nanoimprint lithography. The fabrication of line-type and dot-type nanopatterns was carried out by the combined method. In addition, multilayer nanopatterns of the Au-micelles were also proposed.

  14. Radiolabeling of liposomes and polymeric micelles with PET-isotopes

    DEFF Research Database (Denmark)

    Jensen, Andreas Tue Ingemann

    as a revolution in modern therapeutics, especially in chemotherapy. A major reason is the ability of nanoparticles to accumulate in tumor tissue. Liposomes are the classic nanoparticle, consisting of a lipid membrane with an aqueous core. Polymeric micelles are made from amphiphilic detergent‐like copolymers......This thesis is divided into three separate chapters that can be read independently. Chapter 1 is a general introduction, touching upon liposomes and polymeric micelles and radiolabeling with 18F and 64Cu. Chapter 2 and 3 address two separate research projects, each described below. A complete......‐life only allowing up to 8 hours scans. 18F must be covalently attached to components of the liposome. By binding to a lipid, it can be stably lodged in the membrane. A glycerolipid and a cholesteryl ether were synthesized with free primary alcohols and a series of their sulphonates (Ms, Ts, Tf) were...

  15. Application of polymeric nanoparticles and micelles in insulin oral delivery

    Directory of Open Access Journals (Sweden)

    Milind Sadashiv Alai

    2015-09-01

    Full Text Available Diabetes mellitus is an endocrine disease in which the pancreas does not produce sufficient insulin or the body cannot effectively use the insulin it produces. Insulin therapy has been the best choice for the clinical management of diabetes mellitus. The current insulin therapy is via subcutaneous injection, which often fails to mimic the glucose homeostasis that occurs in normal individuals. This provokes numerous attempts to develop a safe and effective noninvasive route for insulin delivery. Oral delivery is the most convenient administration route. However, insulin cannot be well absorbed orally because of its rapid enzymatic degradation in the gastrointestinal tract. Therefore, nanoparticulate carriers such as polymeric nanoparticles and micelles are employed for the oral delivery of insulin. These nanocarriers protect insulin from degradation and facilitate insulin uptake via a transcellular and/or paracellular pathway. This review article focuses on the application of nanoparticles and micelles in insulin oral delivery. The recent advances in this topic are also reviewed.

  16. Establishing an Empirical Link between Computer-Mediated Communication (CMC) and SLA: A Meta-Analysis of the Research

    Science.gov (United States)

    Lin, Huifen

    2014-01-01

    Drawing on interactionist and socio-cultural theories, tools provided in computer-mediated communication (CMC) environments have long been considered able to create an environment that shares many communicative features with face-to-face communication. Over the past two decades, researchers have employed a variety of strategies to examine the…

  17. Influence of Polyethylene Glycol (PEG in CMC-NH4BR Based Polymer Electrolytes: Conductivity and Electrical Study

    Directory of Open Access Journals (Sweden)

    Nur Khalidah Zainuddin

    2017-04-01

    Full Text Available The present work was carried with new type and promising polymer electrolytes system by development of carboxylmethylcellulose (CMC doped NH4Br and plasticized with polyethylene glycol (PEG. The sample was successfullyprepared via solution casting with no separation phase and good mechanical properties. The electrical conductivity andthermal conductivity of CMC-NH4Br-PEG based PEs system have been measured by the electrical impedancespectroscopy method in the temperature range of 303–373 K. The highest ionic conductivity gained is 2.48 x 10-3 Scm-1at ambient temperature for sample contain with 8 wt. % PEG. It can be concluded that the plasticized is accountable forthe conductance and assist to enhancing the ionic conductivity of the CMC-NH4Br-PEG electrolyte system. The addition of PEG to the CMC-based electrolyte can enhance towards the cation mobility which is turn increases ionic conductivity. The conductivity-temperature of plasticized BdPEs system was found obeys the Arrhenius relation where the ionic conductivity increases with temperature and activation energy for the ions hopping of the highest conducting PEs system only required small value to migrate. The electrical studies show a non-Debye behaviour of BdPEs based on the analyzed data using complex permittivity, ε* and complex electrical modulus, M* of the sample at different temperature.

  18. Teasing apart the effect of visibility and physical co-presence to examine the effect of CMC on interpersonal attraction

    NARCIS (Netherlands)

    Croes, Emmelyn; Antheunis, Marjolijn; Schouten, Alexander; Krahmer, Emiel

    2016-01-01

    This study analyzed the possible difference in interpersonal attraction between communicators in cue-rich computer-mediated communication (CMC) and face-to-face (FtF) communication. The first aim was to determine whether physical co-presence and visibility may account for differences in

  19. Postoperative intra-abdominal collections using a sodium hyaluronate-carboxymethylcellulose (HA-CMC) barrier at the time of laparotomy for uterine or cervical cancers.

    Science.gov (United States)

    Leitao, Mario M; Byrum, Graham V; Abu-Rustum, Nadeem R; Brown, Carol L; Chi, Dennis S; Sonoda, Yukio; Levine, Douglas A; Gardner, Ginger J; Barakat, Richard R

    2010-11-01

    A prior analysis of patients undergoing laparotomy for ovarian malignancies at our institution revealed an increased rate of intra-abdominal collections using HA-CMC film during debulking surgery. The primary objective of the current study was to determine whether the use of HA-CMC is associated with the development of postoperative intra-abdominal collections in patients undergoing laparotomy for uterine or cervical malignancies. We retrospectively identified all laparotomies performed for these malignancies from 3/1/05 to 12/31/07. We identified cases involving the use of HA-CMC via billing records and operative reports. Intra-abdominal collections were defined as localized intraperitoneal fluid accumulations in the absence of re-accumulating ascites. We noted incidences of intra-abdominal collections, as well as other complications. Appropriate statistical tests were applied using SPSS 15.0. We identified 169 laparotomies in which HA-CMC was used and 347 in which HA-CMC was not used. The following were statistically similar in both cohorts: age, body mass index (BMI), primary site, surgery for recurrent disease, prior intraperitoneal surgery, and extent of current surgery. Intra-abdominal collections were seen in 6 (3.6%) of 169 HA-CMC cases compared to 10 (2.9%) of 347 non-HA-CMC cases (p=0.7). The rate of infected collections was similar in both groups (1.2% vs. 1.4%). In the subgroup that underwent tumor debulking, intra-abdominal collections were seen in 3 (11.5%) of 26 HA-CMC cases compared to 2 (5.4%) of 37 non-HA-CMC cases (p=0.6). HA-CMC use does not appear to be associated with postoperative intra-abdominal collections in patients undergoing laparotomy for uterine or cervical cancer. Copyright © 2010 Elsevier Inc. All rights reserved.

  20. Micelle-stabilized room-temperature phosphorescence with synchronous scanning

    International Nuclear Information System (INIS)

    Femia, R.A.; Love, L.J.C.

    1984-01-01

    The experimental requirements for synchronous wavelength scanning micelle-stabilized room temperature phosphorescence and the factors affecting peak resolution are presented and compared with those for synchronous wavelength scanning fluorescence. Identification of individual compounds in a four-component mixture is illustrated, and criteria to identify and minimize triplet state energy transfer are given. Considerable improvement in resolution of the synchronous peaks is obtained via second derivative spectra. 20 references, 7 figures, 2 tables

  1. Block copolymer micelles as switchable templates for nanofabrication

    OpenAIRE

    Krishnamoorthy, S; Pugin, R; Brugger, J; Heinzelmann, H; Hoogerwerf, A C; Hinderling, C

    2006-01-01

    Block copolymer inverse micelles from polystyrene-block-poly-2-vinylpyridine (PS-b-P2VP) deposited as monolayer films onto surfaces show responsive behavior and are reversibly switchable between two states of different topography and surface chemistry. The as-coated films are in the form of arrays of nanoscale bumps, which can be transformed into arrays of nanoscale holes by switching through exposure to methanol. The use of these micellar films to act as switchable etch masks for the structu...

  2. Liquid crystalline states of surfactant solutions of isotropic micelles

    International Nuclear Information System (INIS)

    Bagdassarian, C.; Gelbart, W.M.; Ben-Shaul, A.

    1988-01-01

    We consider micellar solutions whose surfactant molecules prefer strongly to form small, globular aggregates in the absence of intermicellar interactions. At sufficiently high volume fraction of surfactant, the isotropic phase of essentially spherical micelles is shown to be unstable with respect to an orientationally ordered (nematic) state of rodlike aggregates. This behavior is relevant to the phase diagrams reported for important classes of aqueous amphiphilic solutions

  3. In vitro evaluation of antioxidant and neuroprotective effects of curcumin loaded in Pluronic micelles

    OpenAIRE

    Cvetelina Gorinova; Denitsa Aluani; Yordan Yordanov; Magdalena Kondeva-Burdina; Virginia Tzankova; Cvetelina Popova; Krassimira Yoncheva

    2016-01-01

    Curcumin is a polyphenolic substance with attractive pharmacological activities (e.g. antioxidant, anti-inflammatory, anticancer). Incorporation of curcumin in polymeric micelles could overcome the problems associated with its instability and low aqueous solubility. The aim of this study was to load curcumin in polymeric micelles based on Pluronic® P 123 or Pluronic® F 127 triblock copolymers and evaluate the antioxidant and neuroprotective effects after micellization. The micelles were prepa...

  4. Gadolinium DTPA-monoamide complexes incorporated into mixed micelles as possible MRI contrast agents

    OpenAIRE

    Parac-Vogt, Tatjana; Kimpe, Kristof; Laurent, Sophie; Pierart, Corinne; Vander Elst, Luce; Muller, Robert N.; Binnemans, Koen

    2004-01-01

    Four monoamide derivatives of Gd-DTPA with alkyl chains consisting of 12, 14, 16, or 18 carbon atoms were synthesized. The gadolinium(III) complexes with chain lengths of 14, 16 or 18 carbon atoms were efficiently incorporated into mixed micelles whereas the complex with a chain length of 12 carbon atoms was not incorporated into a micellar structure. The size distribution of the micelles was measured by photon correlation spectroscopy. The mean sizes of the micelles for all the complexes lay...

  5. Predicting proton titration in cationic micelle and bilayer environments

    Science.gov (United States)

    Morrow, Brian H.; Eike, David M.; Murch, Bruce P.; Koenig, Peter H.; Shen, Jana K.

    2014-08-01

    Knowledge of the protonation behavior of pH-sensitive molecules in micelles and bilayers has significant implications in consumer product development and biomedical applications. However, the calculation of pKa's in such environments proves challenging using traditional structure-based calculations. Here we apply all-atom constant pH molecular dynamics with explicit ions and titratable water to calculate the pKa of a fatty acid molecule in a micelle of dodecyl trimethylammonium chloride and liquid as well as gel-phase bilayers of diethyl ester dimethylammonium chloride. Interestingly, the pKa of the fatty acid in the gel bilayer is 5.4, 0.4 units lower than that in the analogous liquid bilayer or micelle, despite the fact that the protonated carboxylic group is significantly more desolvated in the gel bilayer. This work illustrates the capability of all-atom constant pH molecular dynamics in capturing the delicate balance in the free energies of desolvation and Coulombic interactions. It also shows the importance of the explicit treatment of ions in sampling the protonation states. The ability to model dynamics of pH-responsive substrates in a bilayer environment is useful for improving fabric care products as well as our understanding of the side effects of anti-inflammatory drugs.

  6. Complexation of Polyelectrolyte Micelles with Oppositely Charged Linear Chains.

    Science.gov (United States)

    Kalogirou, Andreas; Gergidis, Leonidas N; Miliou, Kalliopi; Vlahos, Costas

    2017-03-02

    The formation of interpolyelectrolyte complexes (IPECs) from linear AB diblock copolymer precursor micelles and oppositely charged linear homopolymers is studied by means of molecular dynamics simulations. All beads of the linear polyelectrolyte (C) are charged with elementary quenched charge +1e, whereas in the diblock copolymer only the solvophilic (A) type beads have quenched charge -1e. For the same Bjerrum length, the ratio of positive to negative charges, Z +/- , of the mixture and the relative length of charged moieties r determine the size of IPECs. We found a nonmonotonic variation of the size of the IPECs with Z +/- . For small Z +/- values, the IPECs retain the size of the precursor micelle, whereas at larger Z +/- values the IPECs decrease in size due to the contraction of the corona and then increase as the aggregation number of the micelle increases. The minimum size of the IPECs is obtained at lower Z +/- values when the length of the hydrophilic block of the linear diblock copolymer decreases. The aforementioned findings are in agreement with experimental results. At a smaller Bjerrum length, we obtain the same trends but at even smaller Z +/- values. The linear homopolymer charged units are distributed throughout the corona.

  7. Nanoparticle Contrast Agents for Computed Tomography: A Focus on Micelles

    Science.gov (United States)

    Cormode, David P.; Naha, Pratap C.; Fayad, Zahi A.

    2014-01-01

    Computed tomography (CT) is an X-ray based whole body imaging technique that is widely used in medicine. Clinically approved contrast agents for CT are iodinated small molecules or barium suspensions. Over the past seven years there has been a great increase in the development of nanoparticles as CT contrast agents. Nanoparticles have several advantages over small molecule CT contrast agents, such as long blood-pool residence times, and the potential for cell tracking and targeted imaging applications. Furthermore, there is a need for novel CT contrast agents, due to the growing population of renally impaired patients and patients hypersensitive to iodinated contrast. Micelles and lipoproteins, a micelle-related class of nanoparticle, have notably been adapted as CT contrast agents. In this review we discuss the principles of CT image formation and the generation of CT contrast. We discuss the progress in developing non-targeted, targeted and cell tracking nanoparticle CT contrast agents. We feature agents based on micelles and used in conjunction with spectral CT. The large contrast agent doses needed will necessitate careful toxicology studies prior to clinical translation. However, the field has seen tremendous advances in the past decade and we expect many more advances to come in the next decade. PMID:24470293

  8. Predicting proton titration in cationic micelle and bilayer environments

    Energy Technology Data Exchange (ETDEWEB)

    Morrow, Brian H.; Shen, Jana K. [Department of Pharmaceutical Sciences, University of Maryland, Baltimore, Maryland 21201 (United States); Eike, David M.; Murch, Bruce P.; Koenig, Peter H. [Computational Chemistry, Modeling and Simulation GCO, Procter and Gamble, Cincinnati, Ohio 45201 (United States)

    2014-08-28

    Knowledge of the protonation behavior of pH-sensitive molecules in micelles and bilayers has significant implications in consumer product development and biomedical applications. However, the calculation of pK{sub a}’s in such environments proves challenging using traditional structure-based calculations. Here we apply all-atom constant pH molecular dynamics with explicit ions and titratable water to calculate the pK{sub a} of a fatty acid molecule in a micelle of dodecyl trimethylammonium chloride and liquid as well as gel-phase bilayers of diethyl ester dimethylammonium chloride. Interestingly, the pK{sub a} of the fatty acid in the gel bilayer is 5.4, 0.4 units lower than that in the analogous liquid bilayer or micelle, despite the fact that the protonated carboxylic group is significantly more desolvated in the gel bilayer. This work illustrates the capability of all-atom constant pH molecular dynamics in capturing the delicate balance in the free energies of desolvation and Coulombic interactions. It also shows the importance of the explicit treatment of ions in sampling the protonation states. The ability to model dynamics of pH-responsive substrates in a bilayer environment is useful for improving fabric care products as well as our understanding of the side effects of anti-inflammatory drugs.

  9. Relationship between structure and reactivity in AOT inverse micelles

    International Nuclear Information System (INIS)

    Petit, Christophe

    1988-01-01

    As inverse micelles can be considered as chemical micro-reactors, the objective of this research thesis is to show that reaction rates can be modified, either by varying the size of micro-reactors, or by modifying the location of one of the reactants. After a brief overview of noticeable results obtained on AOT inverse micelles about the structure and reactivity, the author reports the study of structural modifications induced by an addition of small molecules or proteins. Two complementary models are proposed on this purpose: a geometrical model which reports the medium microscopic evolution and a kinetic model which could report the system microscopic evolution as well reactivity changes with respect to probe location. The next part reports the study of in situ synthesis of semi-conductor particles in AOT inverse micelles. The author then reports that a surprising aspect of macromolecule solubilization has been noticed: the solubilization of a polypeptide, gelatine, allows the whole system to be gelled whereas gelatine is essentially polar [fr

  10. Polypyrrole nanoparticles fabricated via Triton X-100 micelles template approach and their acetone gas sensing property

    Energy Technology Data Exchange (ETDEWEB)

    Li, Fake; Li, Hang [Department of Clinical Laboratory Medcine, Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing 400042 (China); Jiang, Hongmin [26th Research Institute, Chinese Electronics Scientific and Technical Group Company, Chongqing 400060 (China); Zhang, Kejun; Chang, Kai; Jia, Shuangrong; Jiang, Wenbin; Shang, Ya; Lu, Weiping [Department of Clinical Laboratory Medcine, Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing 400042 (China); Deng, Shaoli, E-mail: dengsl072@yahoo.com.cn [Department of Clinical Laboratory Medcine, Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing 400042 (China); Chen, Ming, E-mail: chenming1971@yahoo.com [Department of Clinical Laboratory Medcine, Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing 400042 (China)

    2013-09-01

    Nano-scaled polypyrrole (PPy) particles have been successfully synthesized with the help of Triton X-100 micelles via soft template approach. The polypyrrole nanoparticles have been spin-coated on surface acoustic wave (SAW) transducers to demonstrate their sensing capability toward acetone gas exposure. Field Emission Scanning Electron Microscopes (FE-SEM) and Fourier transform infrared (FT-IR) spectroscopy have been utilized to characterize these PPy nanoparticles. The PPy nanoparticles have an average diameter of 95 nm. The responses of the sensors are linearly associated with the acetone concentrations in the range from 5.5 ppm to 80 ppm. In response to 5.5 ppm acetone exposure, the response and recovery time are 9 s and 8.3 s, respectively. SAW sensors coated with PPy nanoparticles were potentially useful to detect acetone.

  11. Transesterification of oil mixtures catalyzed by microencapsulated cutinase in reversed micelles.

    Science.gov (United States)

    Badenes, Sara M; Lemos, Francisco; Cabral, Joaquim M S

    2010-03-01

    Recombinant cutinase from Fusarium solani pisi was used to catalyze the transesterification reaction between a mixture of triglycerides (oils) and methanol in reversed micelles of bis(2-ethylhexyl) sodium sulfosuccinate (AOT) in isooctane for the purposes of producing biodiesel. The use of a bi-phase lipase-catalyzed system brings advantages in terms of catalyst re-use and the control of water activity in the medium and around the enzyme micro-environment. Small-scale batch studies were performed to study the influence of the initial enzyme and alcohol concentrations, and the substrates molar ratio. Conversions in excess of 75 were obtained with reaction times under 24 h, which makes this enzymatic process highly competitive when compared to similar lipase catalyzed reactions for biodiesel production using methanol.

  12. Polypyrrole nanoparticles fabricated via Triton X-100 micelles template approach and their acetone gas sensing property

    International Nuclear Information System (INIS)

    Li, Fake; Li, Hang; Jiang, Hongmin; Zhang, Kejun; Chang, Kai; Jia, Shuangrong; Jiang, Wenbin; Shang, Ya; Lu, Weiping; Deng, Shaoli; Chen, Ming

    2013-01-01

    Nano-scaled polypyrrole (PPy) particles have been successfully synthesized with the help of Triton X-100 micelles via soft template approach. The polypyrrole nanoparticles have been spin-coated on surface acoustic wave (SAW) transducers to demonstrate their sensing capability toward acetone gas exposure. Field Emission Scanning Electron Microscopes (FE-SEM) and Fourier transform infrared (FT-IR) spectroscopy have been utilized to characterize these PPy nanoparticles. The PPy nanoparticles have an average diameter of 95 nm. The responses of the sensors are linearly associated with the acetone concentrations in the range from 5.5 ppm to 80 ppm. In response to 5.5 ppm acetone exposure, the response and recovery time are 9 s and 8.3 s, respectively. SAW sensors coated with PPy nanoparticles were potentially useful to detect acetone.

  13. Self-assembly behavior of well-defined polymethylene-block-poly(ethylene glycol) copolymers in aqueous solution

    KAUST Repository

    Alkayal, Nazeeha; Zapsas, George; Bilalis, Panayiotis; Hadjichristidis, Nikolaos

    2016-01-01

    procedure was confirmed by size-exclusion chromatography (SEC) and 1H NMR spectroscopy. These block copolymers self-assembled into spherical micelles in aqueous solutions and exhibit low critical micelle concentration (CMC) of 2–4 mg/mL, as determined

  14. Hydrolytic degradation of poly(ethylene oxide)-block-polycaprolactone worm micelles.

    Science.gov (United States)

    Geng, Yan; Discher, Dennis E

    2005-09-21

    Spherical micelles and nanoparticles made with degradable polymers have been of great interest for therapeutic application, but degradation-induced changes in a spherical morphology can be subtle and mechanism/kinetics appears poorly understood. Here, we report the first preparation of giant and flexible worm micelles self-assembled from degradable copolymer poly(ethylene oxide)-block-polycaprolactone. Such worm micelles spontaneously shorten to generate spherical micelles, triggered by polycaprolactone hydrolysis, with distinct mechanism and kinetics from that which occurs in bulk material.

  15. Small angle neutron scattering study of the micelle structure of amphiphilic block copolymers

    International Nuclear Information System (INIS)

    Yamaoka, H.; Matsuoka, H.; Sumaru, K.; Hanada, S.

    1994-01-01

    The amphiphilic block copolymers of vinyl ether were prepared by living cationic polymerization. The partially deuterated copolymers for SANS experiments were especially synthesized by introducing deuterated phenyl units in the hydrophobic chain. SANS measurements were performed for aqueous solutions of these copolymers by changing H 2 O/D 2 O ratios. The SANS profiles indicate that the micelles in the present system exhibit a core-shell structure and that the size and shape of micelles are largely dependent on the length of hydrophobic chain. The micelle of shorter hydrophobic chain was found to be nearly spherical, whereas the micelle of longer hydrophobic chain was confirmed to have an ellipsoidal shape

  16. Near-Infrared Squaraine Dye Encapsulated Micelles for in Vivo Fluorescence and Photoacoustic Bimodal Imaging.

    Science.gov (United States)

    Sreejith, Sivaramapanicker; Joseph, James; Lin, Manjing; Menon, Nishanth Venugopal; Borah, Parijat; Ng, Hao Jun; Loong, Yun Xian; Kang, Yuejun; Yu, Sidney Wing-Kwong; Zhao, Yanli

    2015-06-23

    Combined near-infrared (NIR) fluorescence and photoacoustic imaging techniques present promising capabilities for noninvasive visualization of biological structures. Development of bimodal noninvasive optical imaging approaches by combining NIR fluorescence and photoacoustic tomography demands suitable NIR-active exogenous contrast agents. If the aggregation and photobleaching are prevented, squaraine dyes are ideal candidates for fluorescence and photoacoustic imaging. Herein, we report rational selection, preparation, and micelle encapsulation of an NIR-absorbing squaraine dye (D1) for in vivo fluorescence and photoacoustic bimodal imaging. D1 was encapsulated inside micelles constructed from a biocompatible nonionic surfactant (Pluoronic F-127) to obtain D1-encapsulated micelles (D1(micelle)) in aqueous conditions. The micelle encapsulation retains both the photophysical features and chemical stability of D1. D1(micelle) exhibits high photostability and low cytotoxicity in biological conditions. Unique properties of D1(micelle) in the NIR window of 800-900 nm enable the development of a squaraine-based exogenous contrast agent for fluorescence and photoacoustic bimodal imaging above 820 nm. In vivo imaging using D1(micelle), as demonstrated by fluorescence and photoacoustic tomography experiments in live mice, shows contrast-enhanced deep tissue imaging capability. The usage of D1(micelle) proven by preclinical experiments in rodents reveals its excellent applicability for NIR fluorescence and photoacoustic bimodal imaging.

  17. Building a Better Microreactor: Enzyme Catalysis in AOT/Bile Salt Reversed Micelles

    National Research Council Canada - National Science Library

    McGown, Linda

    2001-01-01

    .... We have shown that trihydroxy bile salts modify the interfacial properties of AOT reversed micelles, thereby affecting the reversed micellar structure, the biological activity of entrapped enzymes...

  18. Micelle swelling agent derived cavities for increasing hydrophobic organic compound removal efficiency by mesoporous micelle@silica hybrid materials

    KAUST Repository

    Shi, Yifeng

    2012-06-01

    Mesoporous micelle@silica hybrid materials with 2D hexagonal mesostructures were synthesized as reusable sorbents for hydrophobic organic compounds (HOCs) removal by a facile one-step aqueous solution synthesis using 3-(trimethoxysily)propyl-octadecyldimethyl-ammonium chloride (TPODAC) as a structure directing agent. The mesopores were generated by adding micelle swelling agent, 1,3,5-trimethyl benzene, during the synthesis and removing it afterward, which was demonstrated to greatly increase the HOC removal efficiency. In this material, TPODAC surfactant is directly anchored on the pore surface of mesoporous silica via SiOSi covalent bond after the synthesis due to its reactive Si(OCH 3) 3 head group, and thus makes the synthesized materials can be easily regenerated for reuse. The obtained materials show great potential in water treatment as pollutants sorbents. © 2011 Elsevier Inc. All rights reserved.

  19. Internal and overall motions of the translation factor eIF4E: Cap binding and insertion in a CHAPS detergent micelle

    International Nuclear Information System (INIS)

    McGuire, Abigail Manson; Matsuo, Hiroshi; Wagner, Gerhard

    1998-01-01

    The mRNA cap-binding protein eIF4E is the limiting factor in the eIF4F translation initiation complex, which mediates the binding of the 40S ribosome to the mRNA. 15 N relaxation studies have been used to characterize the backbone dynamics of deuterated eIF4E in a CHAPS micelle for the apoprotein, the m 7 GDP-bound form, and the dinucleotide (m 7 GpppA)-bound form, as well as for CHAPS-free eIF4E. Large differences in overall correlation time between the CHAPS-free form (11.8 ns) and samples containing different concentrations of CHAPS (15.9-19.4 ns) indicate that eIF4E is embedded in a large micelle in the presence of CHAPS, with a total molecular weight in the range of 40-60 kDa. CHAPS seems to restrict the mobility of the a2-b3 and a4-b5 loops which are thought to be embedded in the micelle. No significant changes in overall mobility were seen between the m 7 GDP-bound form, the m 7 GpppA-bound form, and the apoprotein. Amide hydrogen exchange data indicate the presence of slowly exchanging amides in two surface-exposed helices (a2 and a4), as well as the a4-b5 loop, indicating protection by the CHAPS micelle. The micelle covers the convex side of the protein away from the cap-binding site

  20. Doxorubicin-Loaded PEG-PCL-PEG Micelle Using Xenograft Model of Nude Mice: Effect of Multiple Administration of Micelle on the Suppression of Human Breast Cancer

    Directory of Open Access Journals (Sweden)

    Ming-Fa Hsieh

    2010-12-01

    Full Text Available The triblock copolymer is composed of two identical hydrophilic segments: Monomethoxy poly(ethylene glycol (mPEG and one hydrophobic segment poly(ε‑caprolactone (PCL; which is synthesized by coupling of mPEG-PCL-OH and mPEG‑COOH in a mild condition using dicyclohexylcarbodiimide and 4-dimethylamino pyridine. The amphiphilic block copolymer can self-assemble into nanoscopic micelles to accommodate doxorubixin (DOX in the hydrophobic core. The physicochemical properties and in vitro tests, including cytotoxicity of the micelles, have been characterized in our previous study. In this study, DOX was encapsulated into micelles with a drug loading content of 8.5%. Confocal microscopy indicated that DOX was internalized into the cytoplasm via endocystosis. A dose-finding scheme of the polymeric micelle (placebo showed a safe dose of PEG-PCL-PEG micelles was 71.4 mg/kg in mice. Importantly, the circulation time of DOX-loaded micelles in the plasma significantly increased compared to that of free DOX in rats. A biodistribution study displayed that plasma extravasation of DOX in liver and spleen occurred in the first four hours. Lastly, the tumor growth of human breast cancer cells in nude mice was suppressed by multiple injections (5 mg/kg, three times daily on day 0, 7 and 14 of DOX-loaded micelles as compared to multiple administrations of free DOX.

  1. Doxorubicin-Loaded PEG-PCL-PEG Micelle Using Xenograft Model of Nude Mice: Effect of Multiple Administration of Micelle on the Suppression of Human Breast Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Cuong, Nguyen-Van [Department of Biomedical Engineering, Chung Yuan Christian University, 200, Chung Pei Rd., Chung Li, Taiwan (China); Department of Chemical Engineering, Ho Chi Minh City University of Industry, 12 Nguyen Van Bao St, Ho Chi Minh (Viet Nam); Jiang, Jian-Lin; Li, Yu-Lun [Department of Biomedical Engineering, Chung Yuan Christian University, 200, Chung Pei Rd., Chung Li, Taiwan (China); Chen, Jim-Ray [Department of Pathology, Chang Gung Memorial Hospital at Keelung, Taiwan and Chang Gung University, College of Medicine, Taoyuan, Taiwan (China); Jwo, Shyh-Chuan [Division of General Surgery, Chang Gung Memorial Hospital at Keelung, Taiwan and Chang Gung University, College of Medicine, Taoyuan, Taiwan (China); Hsieh, Ming-Fa, E-mail: mfhsieh@cycu.edu.tw [Department of Biomedical Engineering, Chung Yuan Christian University, 200, Chung Pei Rd., Chung Li, Taiwan (China)

    2010-12-28

    The triblock copolymer is composed of two identical hydrophilic segments Monomethoxy poly(ethylene glycol) (mPEG) and one hydrophobic segment poly(ε-caprolactone) (PCL); which is synthesized by coupling of mPEG-PCL-OH and mPEG-COOH in a mild condition using dicyclohexylcarbodiimide and 4-dimethylamino pyridine. The amphiphilic block copolymer can self-assemble into nanoscopic micelles to accommodate doxorubixin (DOX) in the hydrophobic core. The physicochemical properties and in vitro tests, including cytotoxicity of the micelles, have been characterized in our previous study. In this study, DOX was encapsulated into micelles with a drug loading content of 8.5%. Confocal microscopy indicated that DOX was internalized into the cytoplasm via endocystosis. A dose-finding scheme of the polymeric micelle (placebo) showed a safe dose of PEG-PCL-PEG micelles was 71.4 mg/kg in mice. Importantly, the circulation time of DOX-loaded micelles in the plasma significantly increased compared to that of free DOX in rats. A biodistribution study displayed that plasma extravasation of DOX in liver and spleen occurred in the first four hours. Lastly, the tumor growth of human breast cancer cells in nude mice was suppressed by multiple injections (5 mg/kg, three times daily on day 0, 7 and 14) of DOX-loaded micelles as compared to multiple administrations of free DOX.

  2. Doxorubicin-Loaded PEG-PCL-PEG Micelle Using Xenograft Model of Nude Mice: Effect of Multiple Administration of Micelle on the Suppression of Human Breast Cancer

    International Nuclear Information System (INIS)

    Cuong, Nguyen-Van; Jiang, Jian-Lin; Li, Yu-Lun; Chen, Jim-Ray; Jwo, Shyh-Chuan; Hsieh, Ming-Fa

    2010-01-01

    The triblock copolymer is composed of two identical hydrophilic segments Monomethoxy poly(ethylene glycol) (mPEG) and one hydrophobic segment poly(ε-caprolactone) (PCL); which is synthesized by coupling of mPEG-PCL-OH and mPEG-COOH in a mild condition using dicyclohexylcarbodiimide and 4-dimethylamino pyridine. The amphiphilic block copolymer can self-assemble into nanoscopic micelles to accommodate doxorubixin (DOX) in the hydrophobic core. The physicochemical properties and in vitro tests, including cytotoxicity of the micelles, have been characterized in our previous study. In this study, DOX was encapsulated into micelles with a drug loading content of 8.5%. Confocal microscopy indicated that DOX was internalized into the cytoplasm via endocystosis. A dose-finding scheme of the polymeric micelle (placebo) showed a safe dose of PEG-PCL-PEG micelles was 71.4 mg/kg in mice. Importantly, the circulation time of DOX-loaded micelles in the plasma significantly increased compared to that of free DOX in rats. A biodistribution study displayed that plasma extravasation of DOX in liver and spleen occurred in the first four hours. Lastly, the tumor growth of human breast cancer cells in nude mice was suppressed by multiple injections (5 mg/kg, three times daily on day 0, 7 and 14) of DOX-loaded micelles as compared to multiple administrations of free DOX

  3. Micelle-like nanoassemblies based on polymer-drug conjugates as an emerging platform for drug delivery.

    Science.gov (United States)

    Liu, Zhihong; Wang, Yutao; Zhang, Na

    2012-07-01

    During the past decades, polymer-drug conjugates are one of the hottest topics in novel drug development fields. Amphiphilic polymer-drug conjugates in aqueous solution could form micelles or micelle-like nanoassemblies. Compared with polymer-drug conjugates and the micelles into which drugs are physically entrapped, micelles or micelle-like nanoassemblies based on polymer-drug conjugates bring several additional advantages, including increased drug-loading capacity, enhanced intracellular uptake, reduced systemic toxicity, and improved therapeutic efficacy. This review focuses on recent progress achieved in the research field of micelles or micelle-like nanoassemblies based on polymer-drug conjugates. Firstly, properties of polymers, drugs, and linkers which could be used to build polymer-drug conjugate micelles or micelle-like nanoassemblies are summarized. Then, the characterization methods are described. Finally, the drug-targeting mechanisms are discussed. Micelles or micelle-like nanoassemblies based on polymer-drug conjugates as an emerging platform have the potential to achieve medical treatments with enhanced therapeutic effect. The application of micelles or micelle-like nanoassemblies based on polymer-drug conjugates may give new life to old active compounds abandoned due to their low solubility problems. For clinical application, there is a need to further optimize the properties of the polymer, drug, and linker.

  4. d-α-Tocopheryl polyethylene glycol succinate/Solutol HS 15 mixed micelles for the delivery of baohuoside I against non-small-cell lung cancer: optimization and in vitro, in vivo evaluation.

    Science.gov (United States)

    Yan, Hongmei; Zhang, Zhenhai; Jia, Xiaobin; Song, Jie

    Baohuoside I, extracted from the Herba epimedii, is an effective but a poorly soluble antitumor drug. To improve its solubility, formulation of baohuoside I-loaded mixed micelles with d-α-tocopheryl polyethylene glycol succinate and Solutol HS 15 (BTSM) has been developed in this study. We performed a systematic comparative evaluation of the antiproliferative effect, cellular uptake, antitumor efficacy, and in vivo tumor targeting of these micelles using non-small-cell lung cancer (NSCLC) A549 cells. Results showed that the obtained micelles have a mean particle size of ~62.54 nm, and the size of micelles was narrowly distributed. With the improved cellular uptake, BTSM displayed a more potent anti-proliferative action on A549 cell lines than baohuoside I; half-maximal inhibitory concentration was 7.83 vs 20.37 µg/mL, respectively. The antitumor efficacy test in nude mice showed that BTSM exhibited significantly higher antitumor activity against NSCLC with lesser toxic effects on normal tissues. The imaging study for in vivo targeting demonstrated that the mixed micelles formulation achieved effective and targeted drug delivery. Therefore, BTSM might be a potential antitumor formulation.

  5. On the binding of calcium by micelles composed of carboxy-modified pluronics measured by means of differential potentiometric titration and modeled with a self-consistent-field theory.

    Science.gov (United States)

    Lauw, Y; Leermakers, F A M; Cohen Stuart, M A; Pinheiro, J P; Custers, J P A; van den Broeke, L J P; Keurentjes, J T F

    2006-12-19

    We perform differential potentiometric titration measurements for the binding of Ca2+ ions to micelles composed of the carboxylic acid end-standing Pluronic P85 block copolymer (i.e., CAE-85 (COOH-(EO)26-(PO)39-(EO)26-COOH)). Two different ion-selective electrodes (ISEs) are used to detect the free calcium concentration; the first ISE is an indicator electrode, and the second is a reference electrode. The titration is done by adding the block copolymers to a known solution of Ca2+ at neutral pH and high enough temperature (above the critical micellization temperature CMT) and various amount of added monovalent salt. By measuring the difference in the electromotive force between the two ISEs, the amount of Ca2+ that is bound by the micelles is calculated. This is then used to determine the binding constant of Ca2+ with the micelles, which is a missing parameter needed to perform molecular realistic self-consistent-field (SCF) calculations. It turns out that the micelles from block copolymer CAE-85 bind Ca2+ ions both electrostatically and specifically. The specific binding between Ca2+ and carboxylic groups in the corona of the micelles is modeled through the reaction equilibrium -COOCa+ -COO- + Ca2+ with pKCa = 1.7 +/- 0.06.

  6. Multifunctional theranostic Pluronic mixed micelles improve targeted photoactivity of Verteporfin in cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Silva Pellosi, Diogo [Laboratory of Phobiology and photomdicine, Department of Chemistry (FFCLRP), University of São Paulo, Av. dos Bandeirantes 3900, 14040-901, Vila Monte Alegre, Ribeirão Preto (Brazil); Calori, Italo Rodrigo [Research Nucleus of Photodynamic Therapy, Department of Chemistry, State University of Maringá, Av. Colombo 5790, 97020-900 Maringá (Brazil); Barcelos de Paula, Leonardo [Laboratory of Phobiology and photomdicine, Department of Chemistry (FFCLRP), University of São Paulo, Av. dos Bandeirantes 3900, 14040-901, Vila Monte Alegre, Ribeirão Preto (Brazil); Hioka, Noboru [Research Nucleus of Photodynamic Therapy, Department of Chemistry, State University of Maringá, Av. Colombo 5790, 97020-900 Maringá (Brazil); Quaglia, Fabiana [Laboratory of Drug Delivery, Department of Pharmacy, University of Napoli Federico II, Via Domenico Montesanto 49, 80131 Napoli (Italy); Tedesco, Antonio Claudio, E-mail: atedesco@usp.br [Laboratory of Phobiology and photomdicine, Department of Chemistry (FFCLRP), University of São Paulo, Av. dos Bandeirantes 3900, 14040-901, Vila Monte Alegre, Ribeirão Preto (Brazil)

    2017-02-01

    Nanotechnology development provides new strategies to treat cancer by integration of different treatment modalities in a single multifunctional nanoparticle. In this scenario, we applied the multifunctional Pluronic P123/F127 mixed micelles for Verteporfin-mediated photodynamic therapy in PC3 and MCF-7 cancer cells. Micelles functionalization aimed the targeted delivery by the insertion of biotin moiety on micelle surface and fluorescence image-based through rhodamine-B dye conjugation in the polymer chains. Multifunctional Pluronics formed spherical nanoparticulated micelles that efficiently encapsulated the photosensitizer Verteporfin maintaining its favorable photophysical properties. Lyophilized formulations were stable at least for 6 months and readily reconstituted in aqueous media. The multifunctional micelles were stable in protein-rich media due to the dual Pluronic mixed micelles characteristic: high drug loading capacity provided by its micellar core and high kinetic stability due its biocompatible shell. Biotin surface functionalized micelles showed higher internalization rates due biotin-mediated endocytosis, as demonstrated by competitive cellular uptake studies. Rhodamine B-tagged micelles allowed monitoring cellular uptake and intracellular distribution of the formulations. Confocal microscopy studies demonstrated a larger intracellular distribution of the formulation and photosensitizer, which could drive Verteporfin to act on multiple cell sites. Formulations were not toxic in the dark condition, but showed high Verteporfin-induced phototoxicity against both cancer cell lines at low drug and light doses. These results point Verteporfin-loaded multifunctional micelles as a promising tool to further developments in photodynamic therapy of cancer. - Highlights: • We optimized the theranostic mixed micelles – verteporfin formulations. • Multifunctional Pluronic micelles formed nano-sized spherical nanoparticles. • Biotin surface conjugation

  7. Glutathione-responsive core cross-linked micelles for controlled cabazitaxel delivery

    Science.gov (United States)

    Han, Xiaoxiong; Gong, Feirong; Sun, Jing; Li, Yueqi; Liu, XiaoFei; Chen, Dan; Liu, Jianwen; Shen, Yaling

    2018-02-01

    Stimulus-responsive polymeric micelles (PMs) have recently received attention due to the controlled delivery of drug or gene for application in cancer diagnosis and treatment. In this work, novel glutathione-responsive PMs were prepared to encapsulate hydrophobic antineoplastic drug, cabazitaxel (CTX), to improve its solubility and toxicity. These CTX-loaded micelles core cross-linked by disulfide bonds (DCL-CTX micelles) were prepared by a novel copolymer, lipoic acid grafted mPEG-PLA. These micelles had regular spherical shape, homogeneous diameter of 18.97 ± 0.23 nm, and a narrow size distribution. The DCL-CTX micelles showed high encapsulation efficiency of 98.65 ± 1.77%, and the aqueous solubility of CTX was improved by a factor of 1:1200. In vitro release investigation showed that DCL-CTX micelles were stable in the medium without glutathione (GSH), whereas the micelles had burst CTX release in the medium with 10 mM GSH. Cell uptake results implied that DCL-CTX micelles were internalized into MCF-7 cells through clathrin-mediated endocytosis and released cargo more effectively than Jevtana (commercially available CTX) owing to GSH-stimulated degradation. In MTT assay against MCF-7 cells, these micelles inhibited tumor cell proliferation more effectively than Jevtana due to their GSH-responsive CTX release. All results revealed the potency of GSH-responsive DCL-CTX micelles for stable delivery in blood circulation and for intracellular GSH-trigged release of CTX. Therefore, DCL-CTX micelles show potential as safe and effective CTX delivery carriers and as a cancer chemotherapy formulation.

  8. Structure of sodium alkyl sulphate micelles

    International Nuclear Information System (INIS)

    Vass, Sz.

    1990-05-01

    Micellar aggregation numbers of aggregated sodium octyl, decyl, dodecyl and tetradecyl sulphate molecules obtained from small-angle neutron scattering (SANS) measurements are reported. The surfactant concentration and solution temperature were varied systematically. A survey of the physical models and evaluation algorithms applied for SANS are presented. By utilizing a new least square fitting algorithm, the formation and annihilation parameters of orthopositronium in the micellar pseudophase and in the aqueous solvent is deduced by evaluating positron lifetime spectra measured by conventional technqiues. (R.P.) 157 refs.; 10 figs

  9. Reduction-responsive interlayer-crosslinked micelles prepared from star-shaped copolymer via click chemistry for drug controlled release

    Science.gov (United States)

    Dai, Yu; Wang, Hongquan; Zhang, Xiaojin

    2017-12-01

    To improve the stability of polymeric micelles, here we describe interlayer-crosslinked micelles prepared from star-shaped copolymer via click chemistry. The formation of interlayer-crosslinked micelles was investigated and confirmed by proton nuclear magnetic resonance, Fourier-transform infrared spectroscopy, and fluorescence spectroscopy. The morphology of un-crosslinked micelles and crosslinked micelles observed by transmission electron microscope is both uniform nano-sized spheres (approximately 20 nm). The crosslinking enhances the stability of polymeric micelles and improves the drug loading capacity of polymeric micelles. The interlayer-crosslinked micelles prepared from star-shaped copolymer and a crosslinker containing a disulfide bond are reduction-responsive and can release the drug quickly in the presence of the reducing agents such as glutathione (GSH).

  10. "The refer less resolve more" initiative: A five-year experience from CMC Vellore, India

    Directory of Open Access Journals (Sweden)

    Jachin Velavan

    2012-01-01

    Full Text Available India′s one billion plus strong population presents huge health care needs. Presently, approximately 250,000 general practitioners and 30,000 Government doctors are a part of the Indian healthcare workforce, but 80% of them are based in urban India. Problems which plague healthcare delivery and attributed to physician practice may be enumerated as - physicians (1 lack competencies, (2 lack updating, (3 prescribe irrationally (pressures from pharmaceutical companies and patients, (4 practice unethically, (5 refer excessively to specialists and other clinical professionals, and (6 investigate for diseases without justification. A multi-competent Family Physician who could provide a single-window, ethical, and holistic healthcare to patients and families is the need of the hour. Therefore, training, equipping, and empowering these 250,000 doctors to become such physicians will reduce health costs considerably. Distance medical education using all the andragogic methods can be used to train large number of individuals without displacing them from their work-places. Distance learning provides a useful interface for rapidly developing a specialized pool of doctors practicing and advocating family medicine as most-needed discipline. This motivated CMC Vellore, a premier institution for medical education in India, to start a the "refer less resolve more initiative" by offering "two year family medicine diploma course" by distance mode. This is an innovatively-written program consisting of problem-based self-learning modules, video-lectures, video-conferencing, and face-to-face contact programs. Ten secondary level hospitals, across the country, under the supervision of national and international family medicine faculty form the pillars of this program. This distance learning program offered by CMC Vellore has become the platform for change as there is special focus is on ethics, rational prescribing, consultation skills, application of family medicine

  11. "The Refer Less Resolve More" Initiative: A Five-year Experience from CMC Vellore, India.

    Science.gov (United States)

    Velavan, Jachin

    2012-01-01

    India's one billion plus strong population presents huge health care needs. Presently, approximately 250,000 general practitioners and 30,000 Government doctors are a part of the Indian healthcare workforce, but 80% of them are based in urban India. Problems which plague healthcare delivery and attributed to physician practice may be enumerated as - physicians (1) lack competencies, (2) lack updating, (3) prescribe irrationally (pressures from pharmaceutical companies and patients), (4) practice unethically, (5) refer excessively to specialists and other clinical professionals, and (6) investigate for diseases without justification. A multi-competent Family Physician who could provide a single-window, ethical, and holistic healthcare to patients and families is the need of the hour. Therefore, training, equipping, and empowering these 250,000 doctors to become such physicians will reduce health costs considerably. Distance medical education using all the andragogic methods can be used to train large number of individuals without displacing them from their work-places. Distance learning provides a useful interface for rapidly developing a specialized pool of doctors practicing and advocating family medicine as most-needed discipline. This motivated CMC Vellore, a premier institution for medical education in India, to start a the "refer less resolve more initiative" by offering "two year family medicine diploma course" by distance mode. This is an innovatively-written program consisting of problem-based self-learning modules, video-lectures, video-conferencing, and face-to-face contact programs. Ten secondary level hospitals, across the country, under the supervision of national and international family medicine faculty form the pillars of this program. This distance learning program offered by CMC Vellore has become the platform for change as there is special focus is on ethics, rational prescribing, consultation skills, application of family medicine principles

  12. Polysarcosine-Based Lipids: From Lipopolypeptoid Micelles to Stealth-Like Lipids in Langmuir Blodgett Monolayers

    Directory of Open Access Journals (Sweden)

    Benjamin Weber

    2016-12-01

    Full Text Available Amphiphiles and, in particular, PEGylated lipids or alkyl ethers represent an important class of non-ionic surfactants and have become key ingredients for long-circulating (“stealth” liposomes. While poly-(ethylene glycol (PEG can be considered the gold standard for stealth-like materials, it is known to be neither a bio-based nor biodegradable material. In contrast to PEG, polysarcosine (PSar is based on the endogenous amino acid sarcosine (N-methylated glycine, but has also demonstrated stealth-like properties in vitro, as well as in vivo. In this respect, we report on the synthesis and characterization of polysarcosine based lipids with C14 and C18 hydrocarbon chains and their end group functionalization. Size exclusion chromatography (SEC and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS analysis reveals that lipopeptoids with a degree of polymerization between 10 and 100, dispersity indices around 1.1, and the absence of detectable side products are directly accessible by nucleophilic ring opening polymerization (ROP. The values for the critical micelle concentration for these lipopolymers are between 27 and 1181 mg/L for the ones with C18 hydrocarbon chain or even higher for the C14 counterparts. The lipopolypeptoid based micelles have hydrodynamic diameters between 10 and 25 nm, in which the size scales with the length of the PSar block. In addition, C18PSar50 can be incorporated in 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC monolayers up to a polymer content of 3%. Cyclic compression and expansion of the monolayer showed no significant loss of polymer, indicating a stable monolayer. Therefore, lipopolypeptoids can not only be synthesized under living conditions, but my also provide a platform to substitute PEG-based lipopolymers as excipients and/or in lipid formulations.

  13. Solubility enhancement of dioxins and PCBs by surfactant monomers and micelles quantified with polymer depletion techniques.

    Science.gov (United States)

    Schacht, Veronika J; Grant, Sharon C; Escher, Beate I; Hawker, Darryl W; Gaus, Caroline

    2016-06-01

    Partitioning of super-hydrophobic organic contaminants (SHOCs) to dissolved or colloidal materials such as surfactants can alter their behaviour by enhancing apparent aqueous solubility. Relevant partition constants are, however, challenging to quantify with reasonable accuracy. Partition constants to colloidal surfactants can be measured by introducing a polymer (PDMS) as third phase with known PDMS-water partition constant in combination with the mass balance approach. We quantified partition constants of PCBs and PCDDs (log KOW 5.8-8.3) between water and sodium dodecyl sulphate monomers (KMO) and micelles (KMI). A refined, recently introduced swelling-based polymer loading technique allowed highly precise (4.5-10% RSD) and fast (KMO. SHOC losses to experimental surfaces were substantial (8-26%) in monomer solutions, but had a low impact on KMO (0.10-0.16 log units). Log KMO for PCDDs (4.0-5.2) were approximately 2.6 log units lower than respective log KMI, which ranged from 5.2 to 7.0 for PCDDs and 6.6-7.5 for PCBs. The linear relationship between log KMI and log KOW was consistent with more polar and moderately hydrophobic compounds. Apparent solubility increased with increasing hydrophobicity and was highest in micelle solutions. However, this solubility enhancement was also considerable in monomer solutions, up to 200 times for OCDD. Given the pervasive presence of surfactant monomers in typical field scenarios, these data suggest that low surfactant concentrations may be effective long-term facilitators for subsurface transport of SHOCs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Effect of carboxymethyl cellulose concentration on physical properties of biodegradable cassava starch-based films

    Directory of Open Access Journals (Sweden)

    Sriburi Pensiri

    2011-02-01

    Full Text Available Abstract Background Cassava starch, the economically important agricultural commodity in Thailand, can readily be cast into films. However, the cassava starch film is brittle and weak, leading to inadequate mechanical properties. The properties of starch film can be improved by adding plasticizers and blending with the other biopolymers. Results Cassava starch (5%w/v based films plasticized with glycerol (30 g/100 g starch were characterized with respect to the effect of carboxymethyl cellulose (CMC concentrations (0, 10, 20, 30 and 40%w/w total solid and relative humidity (34 and 54%RH on the mechanical properties of the films. Additionally, intermolecular interactions were determined by Fourier transform infrared spectroscopy (FT-IR, melting temperature by differential scanning calorimetry (DSC, and morphology by scanning electron microscopy (SEM. Water solubility of the films was also determined. Increasing concentration of CMC increased tensile strength, reduced elongation at break, and decreased water solubility of the blended films. FT-IR spectra indicated intermolecular interactions between cassava starch and CMC in blended films by shifting of carboxyl (C = O and OH groups. DSC thermograms and SEM micrographs confirmed homogeneity of cassava starch-CMC films. Conclusion The addition of CMC to the cassava starch films increased tensile strength and reduced elongation at break of the blended films. This was ascribed to the good interaction between cassava starch and CMC. Cassava starch-CMC composite films have the potential to replace conventional packaging, and the films developed in this work are suggested to be suitable for low moisture food and pharmaceutical products.

  15. Versatile polyion complex micelles for peptide and siRNA vectorization to engineer tolerogenic dendritic cells.

    Science.gov (United States)

    Mebarek, Naila; Vicente, Rita; Aubert-Pouëssel, Anne; Quentin, Julie; Mausset-Bonnefont, Anne-Laure; Devoisselle, Jean-Marie; Jorgensen, Christian; Bégu, Sylvie; Louis-Plence, Pascale

    2015-05-01

    Dendritic cells (DCs) are professional antigen-presenting cells that play a critical role in maintaining the balance between immunity and tolerance and, as such are a promising immunotherapy tool to induce immunity or to restore tolerance. The main challenge to harness the tolerogenic properties of DCs is to preserve their immature phenotype. We recently developed polyion complex micelles, formulated with double hydrophilic block copolymers of poly(methacrylic acid) and poly(ethylene oxide) blocks and able to entrap therapeutic molecules, which did not induce DC maturation. In the current study, the intrinsic destabilizing membrane properties of the polymers were used to optimize endosomal escape property of the micelles in order to propose various strategies to restore tolerance. On the first hand, we showed that high molecular weight (Mw) copolymer-based micelles were efficient to favor the release of the micelle-entrapped peptide into the endosomes, and thus to improve peptide presentation by immature (i) DCs. On the second hand, we put in evidence that low Mw copolymer-based micelles were able to favor the cytosolic release of micelle-entrapped small interfering RNAs, dampening the DCs immunogenicity. Therefore, we demonstrate the versatile use of polyionic complex micelles to preserve tolerogenic properties of DCs. Altogether, our results underscored the potential of such micelle-loaded iDCs as a therapeutic tool to restore tolerance in autoimmune diseases. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Self-consistent-field calculations of proteinlike incorporations in polyelectrolyte complex micelles

    NARCIS (Netherlands)

    Lindhoud, S.; Cohen Stuart, M.A.; Norde, W.; Leermakers, F.A.M.

    2009-01-01

    Self-consistent field theory is applied to model the structure and stability of polyelectrolyte complex micelles with incorporated protein (molten globule) molecules in the core. The electrostatic interactions that drive the micelle formation are mimicked by nearest-neighbor interactions using

  17. Controlled thermoreversible transfer of poly(oxazoline) micelles between an ionic liquid and water

    NARCIS (Netherlands)

    Guerrero Sanchez, C.A.; Gohy, J.M.W.; D'Haese, C.; Thijs, H.M.L.; Hoogenboom, R.; Schubert, U.S.

    2008-01-01

    Poly(2-nonyl-2-oxazoline-block-2-ethyl-2-oxazoline) block copolymer micelles were investigated as an alternative system to the approach proposed by He and Lodge (Y. He and T. P. Lodge, J. Am. Chem. Soc., 2006, 128, 12666) for the thermoreversible transfer of micelles between a hydrophobic ionic

  18. Peptide-conjugated micelles as a targeting nanocarrier for gene delivery

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Wen Jen, E-mail: wjlin@ntu.edu.tw; Chien, Wei Hsuan [National Taiwan University, School of Pharmacy, Graduate Institute of Pharmaceutical Sciences (China)

    2015-09-15

    The aim of this study was to develop peptide-conjugated micelles possessing epidermal growth factor receptor (EGFR) targeting ability for gene delivery. A sequence-modified dodecylpeptide, GE11(2R), with enhancing EGF receptor binding affinity, was applied in this study as a targeting ligand. The active targeting micelles were composed of poly(d,l-lactide-co-glycolide)-poly(ethylene glycol) (PLGA-PEG) copolymer conjugated with GE11(2R)-peptide. The particle sizes of peptide-free and peptide-conjugated micelles were 277.0 ± 5.1 and 308.7 ± 14.5 nm, respectively. The peptide-conjugated micelles demonstrated the cellular uptake significantly higher than peptide-free micelles in EGFR high-expressed MDA-MB-231 and MDA-MB-468 cells due to GE11(2R)-peptide specificity. Furthermore, the peptide-conjugated micelles were able to encapsulate plasmid DNA and expressed cellular transfection higher than peptide-free micelles in EGFR high-expressed cells. The EGFR-targeting delivery micelles enhanced DNA internalized into cells and achieved higher cellular transfection in EGFR high-expressed cells.

  19. Improving anticancer activity and reducing systemic toxicity of doxorubicin by self-assembled polymeric micelles

    International Nuclear Information System (INIS)

    Gou Maling; Shi Huashan; Guo Gang; Men Ke; Zhang Juan; Li Zhiyong; Luo Feng; Qian Zhiyong; Wei Yuquan; Zheng Lan; Zhao Xia

    2011-01-01

    In an attempt to improve anticancer activity and reduce systemic toxicity of doxorubicin (Dox), we encapsulated Dox in monomethoxy poly(ethylene glycol)-poly(ε-caprolactone) (MPEG-PCL) micelles by a novel self-assembly procedure without using surfactants, organic solvents or vigorous stirring. These Dox encapsulated MPEG-PCL (Dox/MPEG-PCL) micelles with drug loading of 4.2% were monodisperse and ∼ 20 nm in diameter. The Dox can be released from the Dox/MPEG-PCL micelles; the Dox-release at pH 5.5 was faster than that at pH 7.0. Encapsulation of Dox in MPEG-PCL micelles enhanced the cellular uptake and cytotoxicity of Dox on the C-26 colon carcinoma cell in vitro, and slowed the extravasation of Dox in the transgenic zebrafish model. Compared to free Dox, Dox/MPEG-PCL micelles were more effective in inhibiting tumor growth in the subcutaneous C-26 colon carcinoma and Lewis lung carcinoma models, and prolonging survival of mice bearing these tumors. Dox/MPEG-PCL micelles also induced lower systemic toxicity than free Dox. In conclusion, incorporation of Dox in MPEG-PCL micelles enhanced the anticancer activity and decreased the systemic toxicity of Dox; these Dox/MPEG-PCL micelles are an interesting formulation of Dox and may have potential clinical applications in cancer therapy.

  20. Role of Synthetic and Dimensional Synthetic Organic Chemistry in Block Copolymer Micelle Nanosensor Engineering

    DEFF Research Database (Denmark)

    Ek, Pramod Kumar

    This thesis investigated the role of amphiphilic triblock copolymer micelle nanomaterials in nanosensors, with emphasis on the synthesis of micelle particle sensors. The thesis is focused on the role of synthetic and dimensional synthetic organic chemistry in amphiphilic triblock core-shellcorona...

  1. Preparation and evaluation of novel mixed micelles as nanocarriers for intravenous delivery of propofol

    Directory of Open Access Journals (Sweden)

    Li Xinru

    2011-01-01

    Full Text Available Abstract Novel mixed polymeric micelles formed from biocompatible polymers, poly(ethylene glycol-poly(lactide (mPEG-PLA and polyoxyethylene-660-12-hydroxy stearate (Solutol HS15, were fabricated and used as a nanocarrier for solubilizing poorly soluble anesthetic drug propofol. The solubilization of propofol by the mixed micelles was more efficient than those made of mPEG-PLA alone. Micelles with the optimized composition of mPEG-PLA/Solutol HS15/propofol = 10/1/5 by weight had particle size of about 101 nm with narrow distribution (polydispersity index of about 0.12. Stability analysis of the mixed micelles in bovine serum albumin (BSA solution indicated that the diblock copolymer mPEG efficiently protected the BSA adsorption on the mixed micelles because the hydrophobic groups of the copolymer were efficiently screened by mPEG, and propofol-loaded mixed micelles were stable upon storage for at least 6 months. The content of free propofol in the aqueous phase for mixed micelles was lower by 74% than that for the commercial lipid emulsion. No significant differences in times to unconsciousness and recovery of righting reflex were observed between mixed micelles and commercial lipid formulation. The pharmacological effect may serve as pharmaceutical nanocarriers with improved solubilization capacity for poorly soluble drugs.

  2. Effects of gamma-irradiation on some properties of bovine casein micelles

    International Nuclear Information System (INIS)

    Saito, Zenichi

    1974-01-01

    Sedimentation studies and electron microscopic observations revealed that an association between casein micelles dispersed in water or milk serum was not induced significantly by gamma-irradiation of exposure up to 3 x 10 6 R, whereas a release of nonprotein nitrogen was observed to a certain extent. It was concluded from the results of turbidi-metry and gel filtration using 3 size groups of casein micelles, namely large, medium and small, that an irradiation-induced polymerization or association occurred within individual casein micelles, and strengthend the micelle structure. Thus the irradiated casein micelles resisted, more or less, to the solubilizing effect of NaCl, EDTA, pyrophosphate and urea. Stabilities of casein micelles for ethanol and for acidification to an isoelectric point were decreased and increased, respectively, after irradiation. Gamma irradiation also caused the decrease of glycomacropeptide released from casein micelles by the action of rennin, and this resulted in the delay of rennin-coagulation of casein. There were no essential differences among the 3 size groups of casein micelles concerning the above described tendencies. (auth.)

  3. Preparation and evaluation of novel mixed micelles as nanocarriers for intravenous delivery of propofol

    Science.gov (United States)

    Li, Xinru; Zhang, Yanhui; Fan, Yating; Zhou, Yanxia; Wang, Xiaoning; Fan, Chao; Liu, Yan; Zhang, Qiang

    2011-12-01

    Novel mixed polymeric micelles formed from biocompatible polymers, poly(ethylene glycol)-poly(lactide) (mPEG-PLA) and polyoxyethylene-660-12-hydroxy stearate (Solutol HS15), were fabricated and used as a nanocarrier for solubilizing poorly soluble anesthetic drug propofol. The solubilization of propofol by the mixed micelles was more efficient than those made of mPEG-PLA alone. Micelles with the optimized composition of mPEG-PLA/Solutol HS15/propofol = 10/1/5 by weight had particle size of about 101 nm with narrow distribution (polydispersity index of about 0.12). Stability analysis of the mixed micelles in bovine serum albumin (BSA) solution indicated that the diblock copolymer mPEG efficiently protected the BSA adsorption on the mixed micelles because the hydrophobic groups of the copolymer were efficiently screened by mPEG, and propofol-loaded mixed micelles were stable upon storage for at least 6 months. The content of free propofol in the aqueous phase for mixed micelles was lower by 74% than that for the commercial lipid emulsion. No significant differences in times to unconsciousness and recovery of righting reflex were observed between mixed micelles and commercial lipid formulation. The pharmacological effect may serve as pharmaceutical nanocarriers with improved solubilization capacity for poorly soluble drugs.

  4. Improving anticancer activity and reducing systemic toxicity of doxorubicin by self-assembled polymeric micelles

    Energy Technology Data Exchange (ETDEWEB)

    Gou Maling; Shi Huashan; Guo Gang; Men Ke; Zhang Juan; Li Zhiyong; Luo Feng; Qian Zhiyong; Wei Yuquan [State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041 (China); Zheng Lan; Zhao Xia, E-mail: anderson-qian@163.com [West China Second University Hospital, West China Women' s and Children' s Hospital, Sichuan University, Chengdu 610041 (China)

    2011-03-04

    In an attempt to improve anticancer activity and reduce systemic toxicity of doxorubicin (Dox), we encapsulated Dox in monomethoxy poly(ethylene glycol)-poly({epsilon}-caprolactone) (MPEG-PCL) micelles by a novel self-assembly procedure without using surfactants, organic solvents or vigorous stirring. These Dox encapsulated MPEG-PCL (Dox/MPEG-PCL) micelles with drug loading of 4.2% were monodisperse and {approx} 20 nm in diameter. The Dox can be released from the Dox/MPEG-PCL micelles; the Dox-release at pH 5.5 was faster than that at pH 7.0. Encapsulation of Dox in MPEG-PCL micelles enhanced the cellular uptake and cytotoxicity of Dox on the C-26 colon carcinoma cell in vitro, and slowed the extravasation of Dox in the transgenic zebrafish model. Compared to free Dox, Dox/MPEG-PCL micelles were more effective in inhibiting tumor growth in the subcutaneous C-26 colon carcinoma and Lewis lung carcinoma models, and prolonging survival of mice bearing these tumors. Dox/MPEG-PCL micelles also induced lower systemic toxicity than free Dox. In conclusion, incorporation of Dox in MPEG-PCL micelles enhanced the anticancer activity and decreased the systemic toxicity of Dox; these Dox/MPEG-PCL micelles are an interesting formulation of Dox and may have potential clinical applications in cancer therapy.

  5. Novel oral administrated paclitaxel micelles with enhanced bioavailability and antitumor efficacy for resistant breast cancer.

    Science.gov (United States)

    Zhang, Ting; Luo, Jingwen; Fu, Yao; Li, Hanmei; Ding, Rui; Gong, Tao; Zhang, Zhirong

    2017-02-01

    Paclitaxel (PTX) is a widely used antineoplastic drug in clinic. Due to poor aqueous solubility, it is administrated by intravenous infusion of cremophor EL containing formulation with serious adverse effects. The low oral bioavailability is a great challenge for oral formulation development. In addition, P-gp mediated multidrug resistance limit its clinical use in various resistant cancers. In this study, a novel super-antiresistant PTX micelle formulation for oral administration was developed. A P-gp inhibitor, bromotetrandrine (W198) was co-encapsulated in the micelle. The micelles were composed of Solutol HS 15 and d-a-tocopheryl polyethylene glycol succinate to avoid Cremophor EL induced toxicity. The micelles were round with a mean particle size of ∼13nm and an encapsulation efficiency of ∼90%. A series of in vitro evaluations were performed in non-resistant MCF-7 cells and resistant MCF-7/Adr cells. The super-antiresistant PTX micelles showed higher cell uptake efficiency, significantly increased cytotoxicity and antimitotic effect in drug resistant MCF-7/Adr cells when compared with Taxol and other PTX micelle formulations. Compared with Taxol, the super-antiresistant PTX micelles significantly improved bioavailability after oral administration in rats, and inhibited tumor growth in multidrug resistance xenografted MCF-7/Adr nude mice. In summary, the noval super-antiresistant PTX micelles showed a great potential for oral delivery of PTX against resistant breast cancer. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Preparation and evaluation of novel mixed micelles as nanocarriers for intravenous delivery of propofol.

    Science.gov (United States)

    Li, Xinru; Zhang, Yanhui; Fan, Yating; Zhou, Yanxia; Wang, Xiaoning; Fan, Chao; Liu, Yan; Zhang, Qiang

    2011-03-31

    Novel mixed polymeric micelles formed from biocompatible polymers, poly(ethylene glycol)-poly(lactide) (mPEG-PLA) and polyoxyethylene-660-12-hydroxy stearate (Solutol HS15), were fabricated and used as a nanocarrier for solubilizing poorly soluble anesthetic drug propofol. The solubilization of propofol by the mixed micelles was more efficient than those made of mPEG-PLA alone. Micelles with the optimized composition of mPEG-PLA/Solutol HS15/propofol = 10/1/5 by weight had particle size of about 101 nm with narrow distribution (polydispersity index of about 0.12). Stability analysis of the mixed micelles in bovine serum albumin (BSA) solution indicated that the diblock copolymer mPEG efficiently protected the BSA adsorption on the mixed micelles because the hydrophobic groups of the copolymer were efficiently screened by mPEG, and propofol-loaded mixed micelles were stable upon storage for at least 6 months. The content of free propofol in the aqueous phase for mixed micelles was lower by 74% than that for the commercial lipid emulsion. No significant differences in times to unconsciousness and recovery of righting reflex were observed between mixed micelles and commercial lipid formulation. The pharmacological effect may serve as pharmaceutical nanocarriers with improved solubilization capacity for poorly soluble drugs.

  7. Design of block-copolymer-based micelles for active and passive targeting

    NARCIS (Netherlands)

    Lebouille, Jérôme G J L; Leermakers, Frans A M; Cohen Stuart, Martien A.; Tuinier, Remco

    2016-01-01

    A self-consistent field study is presented on the design of active and passive targeting block-copolymeric micelles. These micelles form in water by self-assembly of triblock copolymers with a hydrophilic middle block and two hydrophobic outer blocks. A minority amount of diblock copolymers with the

  8. Design of block-copolymer-based micelles for active and passive targeting

    NARCIS (Netherlands)

    Lebouille, Jérôme G.J.L.; Leermakers, Frans A.M.; Cohen Stuart, Martien A.; Tuinier, Remco

    2016-01-01

    A self-consistent field study is presented on the design of active and passive targeting block-copolymeric micelles. These micelles form in water by self-assembly of triblock copolymers with a hydrophilic middle block and two hydrophobic outer blocks. A minority amount of diblock copolymers with

  9. Evaluation of iron oxide nanoparticle micelles for Magnetic Particle Imaging (MPI) of thrombosis

    NARCIS (Netherlands)

    Starmans, L.W.E.; Moonen, R.P.M.; Aussems-Custers, E.; Daemen, M.J.A.P.; Strijkers, G. J.; Nicolay, K.; Grüll, H.

    2015-01-01

    Magnetic particle imaging (MPI) is an emerging medical imaging modality that directly visualizes magnetic particles in a hot-spot like fashion. We recently developed an iron oxide nanoparticle-micelle (ION-Micelle) platform that allows highly sensitive MPI. The goal of this study was to assess the

  10. Factors influencing casein micelle size in milk of individual cows: Genetic variants and glycosylation of k-casein

    NARCIS (Netherlands)

    Bijl, E.; Vries, de R.F.M.; Valenberg, van H.J.F.; Huppertz, T.; Hooijdonk, van A.C.M.

    2014-01-01

    The average casein micelle size varies widely between milk samples of individual cows. The factors that cause this variation in size are not known but could provide more insight into casein micelle structure and into the physiology of casein micelle formation. The objective of this research was

  11. Determination of thermodynamic potentials and the aggregation number for micelles with the mass-action model by isothermal titration calorimetry

    DEFF Research Database (Denmark)

    Olesen, Niels Erik; Westh, Peter; Holm, René

    2015-01-01

    of micelles with ITC were compared to a mass-action model (MAM) of reaction type: n⋅S⇌Mn. This analysis can provide guidelines for future ITC studies of systems behaving in accordance with this model such as micelles and proteins that undergo self-association to oligomers. Micelles with small aggregation...

  12. Effects of salinity, P H and temperature on CMC polymer and X C polymer performance

    International Nuclear Information System (INIS)

    Ghassem Alaskari, M. K.; Nickdel Teymoori, Reza

    2007-01-01

    The rheological and filtration properties of drilling mud under down-hole conditions may be very different from those measured at ambient pressures and temperatures at the surface. This paper presents the results of an experimental investigation into the temperature and salinity and p H effects on drilling mud rheological and filtration properties. Results are given from tests on water base mud containing CMC polymer and X C polymer. Drilling fluid was investigated at three different temperatures (21.1 d eg C , 48.9 d eg C , 80 d eg C ) containing 8.165 kg/b bl bentonite. The drilling mud salinities in this study were fresh water (Ahwaz water: ppm: 400, Hardness: 120). 2000 ppm, 4000 ppm, 8000 ppm and 40000 ppm. It was found that p H of drilling mud should be kept at range of 8-10, because increasing p H of drilling mud will increase its rheological properties. The salinity and temperature effects show that as the salinity and temperature of drilling mud are increased the effectiveness of polymers in drilling mud will decreased. Moreover, they have a negative effect on filtration properties of drilling mud. In suspensions of sodium montmorillonite that are well dispersed and have low gel strength, both plastic viscosity and yield point decrease with increasing temperature

  13. Complex and hierarchical micelle architectures from diblock copolymers using living, crystallization-driven polymerizations.

    Science.gov (United States)

    Gädt, Torben; Ieong, Nga Sze; Cambridge, Graeme; Winnik, Mitchell A; Manners, Ian

    2009-02-01

    Block copolymers consist of two or more chemically distinct polymer segments, or blocks, connected by a covalent link. In a selective solvent for one of the blocks, core-corona micelle structures are formed. We demonstrate that living polymerizations driven by the epitaxial crystallization of a core-forming metalloblock represent a synthetic tool that can be used to generate complex and hierarchical micelle architectures from diblock copolymers. The use of platelet micelles as initiators enables the formation of scarf-like architectures in which cylindrical micelle tassels of controlled length are grown from specific crystal faces. A similar process enables the fabrication of brushes of cylindrical micelles on a crystalline homopolymer substrate. Living polymerizations driven by heteroepitaxial growth can also be accomplished and are illustrated by the formation of tri- and pentablock and scarf architectures with cylinder-cylinder and platelet-cylinder connections, respectively, that involve different core-forming metalloblocks.

  14. Micelles from lipid derivatives of water-soluble polymers as delivery systems for poorly soluble drugs.

    Science.gov (United States)

    Lukyanov, Anatoly N; Torchilin, Vladimir P

    2004-05-07

    Polymeric micelles have a whole set of unique characteristics, which make them very promising drug carriers, in particular, for poorly soluble drugs. Our review article focuses on micelles prepared from conjugates of water-soluble polymers, such as polyethylene glycol (PEG) or polyvinyl pyrrolidone (PVP), with phospholipids or long-chain fatty acids. The preparation of micelles from certain polymer-lipid conjugates and the loading of these micelles with various poorly soluble anticancer agents are discussed. The data on the characterization of micellar preparations in terms of their morphology, stability, longevity in circulation, and ability to spontaneously accumulate in experimental tumors via the enhanced permeability and retention (EPR) effect are presented. The review also considers the preparation of targeted immunomicelles with specific antibodies attached to their surface. Available in vivo results on the efficiency of anticancer drugs incorporated into plain micelles and immunomicelles in animal models are also discussed.

  15. Synthesis of Cross-Linked Polymeric Micelle pH Nanosensors

    DEFF Research Database (Denmark)

    Ek, Pramod Kumar; Jølck, Rasmus Irming; Andresen, Thomas Lars

    2015-01-01

    The design flexibility that polymeric micelles offer in the fabrication of optical nanosensors for ratiometric pH measurements is investigated. pH nanosensors based on polymeric micelles are synthesized either by a mixed-micellization approach or by a postmicelle modification strategy. In the mixed......-micellization approach, self-assembly of functionalized unimers followed by shell cross-linking by copper-catalyzed azide-alkyne cycloaddition (CuAAC) results in stabilized cRGD-functionalized micelle pH nanosensors. In the postmicelle modification strategy, simultaneous cross-linking and fluorophore conjugation...... at the micelle shell using CuAAC results in a stabilized micelle pH nanosensor. Compared to the postmicelle modification strategy, the mixed-micellization approach increases the control of the overall composition of the nanosensors.Both approaches provide stable nanosensors with similar pKa profiles and thereby...

  16. Polyion complex micelles prepared by self-assembly of block-graft polycation and hyperbranched polyanion

    Science.gov (United States)

    Dai, Yu; Wang, Hongquan; Zhang, Xiaojin

    2017-09-01

    Polyion complex (PIC) micelles were prepared by self-assembly of block-graft polycation monomethoxy poly(ethylene glycol)- block-(poly(ɛ-caprolactone)- graft-polyethylenimine) (PEG- b-(PCL- g-PEI)) and hyperbranched polyanion sodium carboxyl-modified hyperbranched polyesters (Hx-COONa, x = 20, 30, 40). The results from commonly used MTT assay indicated that PIC micelles had good biocompatibility. PIC micelles with N/COO- of 8/3 had appropriate size (sub-110 nm) and moderate zeta potential ( 3 mV). PIC micelles were nano-sized spheres, and the average size was about 50 nm. PIC micelles had high drug loading capacity for hydrophilic drugs such as doxorubicin (DOX) hydrochloride and released the drugs under the influence of pH and ionic strength.

  17. Folding of DsbB in mixed micelles

    DEFF Research Database (Denmark)

    Otzen, Daniel

    2003-01-01

    state and an unfolding intermediate that accumulates only under unfolding conditions at high mole fractions of SDS. The stability of DsbB is around 4.4 kcal/mol in DM, and this is halved upon reduction of the two periplasmic disulfide bonds, and is sensitive to mutagenesis. With the caveat that kinetic...... is sensitive to changes in lipid and detergent composition. As an attempt to overcome this problem, I present a kinetic analysis of the folding of a membrane protein, disulfide bond reducing protein B (DsbB), in a mixed micelle system consisting of varying molar ratios of sodium dodecyl sulfate (SDS...

  18. Block copolymer micelles as switchable templates for nanofabrication.

    Science.gov (United States)

    Krishnamoorthy, Sivashankar; Pugin, Raphaël; Brugger, Juergen; Heinzelmann, Harry; Hoogerwerf, Arno C; Hinderling, Christian

    2006-04-11

    Block copolymer inverse micelles from polystyrene-block-poly-2-vinylpyridine (PS-b-P2VP) deposited as monolayer films onto surfaces show responsive behavior and are reversibly switchable between two states of different topography and surface chemistry. The as-coated films are in the form of arrays of nanoscale bumps, which can be transformed into arrays of nanoscale holes by switching through exposure to methanol. The use of these micellar films to act as switchable etch masks for the structuring of the underlying material to form either pillars or holes depending on the switching state is demonstrated.

  19. CMC-coated Fe{sub 3}O{sub 4} nanoparticles as new MRI probes for hepatocellular carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Sitthichai, Sudarat [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Pilapong, Chalermchai, E-mail: chalermchai.pilapong@cmu.ac.th [Center of Excellence for Molecular Imaging (CEMI), Department of Radiologic Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongtem, Titipun [Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongtem, Somchai, E-mail: schthongtem@yahoo.com [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

    2015-11-30

    Highlights: • Fe{sub 3}O{sub 4} nanoparticles (NPs) are superparamagnetic. • CMC is water-soluble and nontoxic cellulose-derivative polymer. • CMC-coated Fe{sub 3}O{sub 4} NPs were successfully prepared by co-precipitation method. • The promising NPs that can be used for magnetic resonance imaging application. - Abstract: Pure Fe{sub 3}O{sub 4} nanoparticles and Fe{sub 3}O{sub 4} magnetic nanoparticles (MNPs) coated with carboxymethyl cellulose (CMC) were successfully prepared by co-precipitating of FeCl{sub 2}·4H{sub 2}O and FeCl{sub 3}·6H{sub 2}O in the solutions containing ammonia at 80 °C for 3 h. Phase, morphology, particle-sized distribution, surface chemistry, and weight loss were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) including high-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED), thermogravimetric analysis (TGA), and Fourier transform infrared (FTIR) spectroscopy. In this research, CMC-coated Fe{sub 3}O{sub 4} MNPs consisting of Fe{sup 2+} and Fe{sup 3+} ions with 543.3-mM{sup −1} s{sup −1} high relaxivity were detected and were able to be used for magnetic resonance imaging (MRI) application with very good contrast for targeting hepatocellular carcinoma (HCC) without any further vectorization.

  20. Extraction protocol and liquid chromatography/tandem mass spectrometry method for determining micelle-entrapped paclitaxel at the cellular and subcellular levels: Application to a cellular uptake and distribution study.

    Science.gov (United States)

    Zheng, Nan; Lian, Bin; Du, Wenwen; Xu, Guobing; Ji, Jiafu

    2018-01-01

    Paclitaxel-loaded polymeric micelles (PTX-PM) are commonly used as tumor-targeted nanocarriers and display outstanding antitumor features in clinic, but its accumulation and distribution in vitro are lack of investigation. It is probably due to the complex micellar system and its low concentration at the cellular or subcellular levels. In this study, we developed an improved extraction method, which was a combination of mechanical disruption and liquid-liquid extraction (LLE), to extract the total PTX from micelles in the cell lysate and subcellular compartments. An ultra-performance liquid chromatography tandem mass spectroscopy (UPLC-MS/MS) method was optimized to detect the low concentration of PTX at cellular and subcellular levels simultaneously, using docetaxel as internal standard (IS). The method was proved to release PTX totally from micelles (≥95.93%) with a consistent and reproducible extraction recovery (≥75.04%). Good linearity was obtained at concentrations ranging from 0.2 to 20ng/mL. The relative error (RE%) for accuracy varied from 0.68 to 7.56%, and the intra- and inter-precision (relative standard deviation, RSD%) was less than 8.64% and 13.14%, respectively. This method was fully validated and successfully applied to the cellular uptake and distribution study of PTX-loaded PLGA-PEG micelles in human breast cancer cells (MCF-7). Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Effect of micellar collisions and polyvinylpyrrolidone confinement on the electrical conductivity percolation parameters of water/AOT/isooctane reverse micelles

    Science.gov (United States)

    Guettari, Moez; Aferni, Ahmed E. L.; Tajouri, Tahar

    2017-12-01

    The main aim of this paper is the analysis of micellar collisions and polymer confinement effects on the electrical conductivity percolative behavior of water/sodium bis(2-ethylhexyl) sulfosuccinate (AOT)/isooctane reverse micelles. Firstly, we have performed conductance measurements of the system for three AOT to isooctane volume ratio, φm = 0.1 , 0.15 and 0.2 to examine the influence of micellar collisions on the percolation parameters. All the measurements were carried out over the 298.15 K-333.15 K temperature range at a fixed water to AOT molar ratio, W0 = 45 . We have assessed that the rise of micellar collisions frequency enhances the conductance percolation. Secondly, the confinement effect of a water-soluble polymer, polyvinylpyrrolidone (PVP), on the reverse micelles conductance behavior was investigated. Temperature-induced percolation, Tp , have shown a dependence on the polymer concentration, CPVP . It was also observed that for various PVP concentrations, the activation energy of percolation decreases. Finally, the values of the critical exponents determined in the presence and absence of PVP prove that the polymer affects the dynamic of percolation.

  2. Curcumin-loaded biodegradable polymeric micelles for colon cancer therapy in vitro and in vivo

    Science.gov (United States)

    Gou, Maling; Men, Ke; Shi, Huashan; Xiang, Mingli; Zhang, Juan; Song, Jia; Long, Jianlin; Wan, Yang; Luo, Feng; Zhao, Xia; Qian, Zhiyong

    2011-04-01

    Curcumin is an effective and safe anticancer agent, but its hydrophobicity inhibits its clinical application. Nanotechnology provides an effective method to improve the water solubility of hydrophobic drug. In this work, curcumin was encapsulated into monomethoxy poly(ethylene glycol)-poly(ε-caprolactone) (MPEG-PCL) micelles through a single-step nano-precipitation method, creating curcumin-loaded MPEG-PCL (Cur/MPEG-PCL) micelles. These Cur/MPEG-PCL micelles were monodisperse (PDI = 0.097 +/- 0.011) with a mean particle size of 27.3 +/- 1.3 nm, good re-solubility after freeze-drying, an encapsulation efficiency of 99.16 +/- 1.02%, and drug loading of 12.95 +/- 0.15%. Moreover, these micelles were prepared by a simple and reproducible procedure, making them potentially suitable for scale-up. Curcumin was molecularly dispersed in the PCL core of MPEG-PCL micelles, and could be slow-released in vitro. Encapsulation of curcumin in MPEG-PCL micelles improved the t1/2 and AUC of curcuminin vivo. As well as free curcumin, Cur/MPEG-PCL micelles efficiently inhibited the angiogenesis on transgenic zebrafish model. In an alginate-encapsulated cancer cell assay, intravenous application of Cur/MPEG-PCL micelles more efficiently inhibited the tumor cell-induced angiogenesisin vivo than that of free curcumin. MPEG-PCL micelle-encapsulated curcumin maintained the cytotoxicity of curcumin on C-26 colon carcinoma cellsin vitro. Intravenous application of Cur/MPEG-PCL micelle (25 mg kg-1curcumin) inhibited the growth of subcutaneous C-26 colon carcinoma in vivo (p curcumin (p curcumin; this formulation can inhibit the growth of colon carcinoma through inhibiting angiogenesis and directly killing cancer cells.

  3. The effect of CMC and arabic gum stabilizer combination on the characteristics of soursop velva (Annona muricata L.)

    Science.gov (United States)

    Parnanto, N. H. R.; Yudhistira, B.; Pertiwi, S. R.; Pangestika, A.

    2018-03-01

    The aims of this study were to determine the effect of the combination of CMC and Arabic Gum stabilizer toward the soursop velva characteristics and to determine the best stabilizer combination of soursop velva. This study was performed using Completely Randomized Design (CRD) with one factor: combination of CMC and Arabic Gum stabilizer using two sample replications and the analysis was repeated three times. The result showed that the use of the combination of CMC and Arabic Gum stabilizer gave a significant effect on the overrun value, melting power, total dissolved solids, moisture content, dietary fiber, taste, texture and overalls. Moreover, there were no significant effect on color and flavor of the soursop velva. The experiment showed that soursop velva F4 (3:1) was the best formula with overrun value 9.93%, the melting power was 22 minutes 52 seconds, the total dissolved solids 19,10°Brix, the moisture content 71.508%, dietary fiber 3.301% and it has sensory values of color, taste, flavor, texture, overall at 3.66, 3.267, 3.33, 4.06, 3.10 respectively.

  4. Preparation and antitumor evaluation of self-assembling oleanolic acid-loaded Pluronic P105/D-α-tocopheryl polyethylene glycol succinate mixed micelles for non-small-cell lung cancer treatment

    Directory of Open Access Journals (Sweden)

    Wu H

    2016-11-01

    lines (A549 and PC-9. Cytotoxicity evaluations showed that the half-maximal inhibitory concentrations of free OA and OA-micelles were 36.8±4.8 and 20.9±3.7 µM, respectively, in A549 cells and 82.7±7.8 and 56.7±4.7 µM, respectively, in PC-9 cells. Apoptosis assays revealed that the apoptotic rate of OA-micelle-treated A549 and PC-9 cells was higher than that of cells treated with the same concentration of free OA. Wound healing and transwell assays showed that migration and invasion were significantly suppressed in OA-micelle-treated cells. Immunofluorescence and Western blot analyses confirmed that the epithelial–mesenchymal transition was reversed in OA-micelle-treated cells. Mixed micelles are a promising nano-drug delivery system for lung cancer treatment. Keywords: oleanolic acid, Pluronic P105, vitamin E-TPGS, polymer–drug conjugate, NSCLC

  5. Efficient simultaneous removal of U(VI) and Cu(II) from aqueous solution using core-shell nZVI@SA/CMC-Ca beads

    International Nuclear Information System (INIS)

    Shuhong Hu; Xiaoyan Lin; Wenhui Zhao; Ministry of Education, Sichuan; Xuegang Luo

    2018-01-01

    Core-shell nanoscale zero-valent iron@alginate/carboxymethyl cellulose sodium composite loaded with calcium (nZVI@SA/CMC-Ca) beads were synthesized in this study using coaxial electronic injection method. The adsorbent structure was characterized via FT-IR, SEM, EDX and XPS. The adsorption behavior of U(VI) and Cu(II) on core-shell nZVI@SA/CMC-Ca beads was studied under various experimental parameters like pH, contact time and temperature. The isotherm and the kinetic data, pertaining to the adsorption of U(VI) and Cu(II) by core-shell nZVI@SA/CMC-Ca beads obeyed both the Langmuir and Freundlich isotherms model and the pseudo-second-order kinetics model, respectively. The thermodynamic parameters revealed the spontaneous and endothermic nature of the adsorption. The experiment of regeneration and reusability suggested core-shell nZVI@SA/CMC-Ca bead was a regenerated material. (author)

  6. D-α-Tocopheryl polyethylene glycol succinate/Solutol HS 15 mixed micelles for the delivery of baohuoside I against non-small-cell lung cancer: optimization and in vitro, in vivo evaluation

    Directory of Open Access Journals (Sweden)

    Yan H

    2016-09-01

    Full Text Available Hongmei Yan,1,2 Zhenhai Zhang,2 Xiaobin Jia,1,2 Jie Song1,2 1College of Pharmacy, Nanjing University of Chinese Medicine, 2Key Laboratory of New Drug Delivery System of Chinese Materia Medica, Third School of Clinical Medical of Nanjing University of Chinese Medicine, Nanjing, People’s Republic of China Abstract: Baohuoside I, extracted from the Herba epimedii, is an effective but a poorly soluble antitumor drug. To improve its solubility, formulation of baohuoside I-loaded mixed micelles with d-α-tocopheryl polyethylene glycol succinate and Solutol HS 15 (BTSM has been developed in this study. We performed a systematic comparative evaluation of the antiproliferative effect, cellular uptake, antitumor efficacy, and in vivo tumor targeting of these micelles using non-small-cell lung cancer (NSCLC A549 cells. Results showed that the obtained micelles have a mean particle size of ~62.54 nm, and the size of micelles was narrowly distributed. With the improved cellular uptake, BTSM displayed a more potent antiproliferative action on A549 cell lines than baohuoside I; half-maximal inhibitory concentration was 7.83 vs 20.37 µg/mL, respectively. The antitumor efficacy test in nude mice showed that BTSM exhibited significantly higher antitumor activity against NSCLC with lesser toxic effects on normal tissues. The imaging study for in vivo targeting demonstrated that the mixed micelles formulation achieved effective and targeted drug delivery. Therefore, BTSM might be a potential antitumor formulation. Keywords: baohuoside I-loaded mixed micelles, TPGS, Solutol HS 15, antitumor

  7. Fluctuations of wormlike micelle fluids in capillary flow

    Science.gov (United States)

    Salipante, Paul; Meek, Stephen; Hudson, Steven; Polymers; Complex Fluids Group Team

    2017-11-01

    We investigate the effect of entrance geometry on the flow stability of wormlike micelles solutions in capillary flow. These solutions exhibit strong shear thinning behavior resulting from micelle breakage and have been observed to undergo large flow rate fluctuations. We investigate these fluctuations using simultaneous measurements of flow rate and pressure drop across a capillary, and we adjust entrance geometry. With a tapered constriction, we observe large persistent fluctuations above a critical flow rate, characterized by rapid decreases in the pressure drop with corresponding increase in flow rate followed by a period of recovery where pressure increases and flow rate decreases. Flow field observations in the tapered entrance show large flow circulations. An abrupt contraction produces smaller transient fluidized jets forming upstream of the constriction and the magnitude of the fluctuations are significantly diminished. The effect of fluid properties is studied by comparing the magnitude and timescales of the fluctuations for surfactant systems with different relaxation times. The onset of fluctuations is compared to a criterion for the onset of elastic instabilities and the magnitude is compared to estimates for changes in channel resistance. NIST on a Chip.

  8. Enhanced electrochemical properties of LiFePO4 (LFP) cathode using the carboxymethyl cellulose lithium (CMC-Li) as novel binder in lithium-ion battery.

    Science.gov (United States)

    Qiu, Lei; Shao, Ziqiang; Wang, Daxiong; Wang, Wenjun; Wang, Feijun; Wang, Jianquan

    2014-10-13

    Novel water-based binder CMC-Li is synthesized using cotton as raw material. The mechanism of the CMC-Li as a binder is reported. Electrochemical properties of batteries cathodes based on commercially available lithium iron phosphate (LiFePO4, LFP) and CMC-Li as a water-soluble binder are investigated. CMC-Li is a novel lithium-ion binder. Compare with conventional poly(vinylidene fluoride) (PVDF) binder, and the battery with CMC-Li as the binder retained 97.8% of initial reversible capacity after 200 cycles at 176 mAh g(-1), which is beyond the theoretical specific capacity of LFP. Constant current charge-discharge test results demonstrate that the LFP electrode using CMC-Li as the binder has the highest rate capability, follow closely by that using PVDF binder. The batteries have good electrochemical property, outstanding pollution-free and excellent stability. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Seasonal evolution of anionic, cationic and non-ionic surfactant concentrations in coastal aerosols from Askö, Sweden

    Science.gov (United States)

    Gérard, Violaine; Nozière, Barbara; Baduel, Christine

    2015-04-01

    Surfactants present in atmospheric aerosols are expected to enhance the activation into cloud droplets by acting on one of the two key parameters of the Köhler equation: the surface tension, σ. But because the magnitude of this effect and its regional and temporal variability are still highly uncertain [1,2], various approaches have been developed to evidence it directly in the atmosphere. This work presents the analysis of surfactants present in PM2.5 aerosol fractions collected at the coastal site of Askö, Sweden (58° 49.5' N, 17° 39' E) from July to October 2010. The total surfactant fraction was extracted from the samples using an improved double extraction technique. Surface tension measurements performed with the pendant drop technique [3] indicated the presence of very strong surfactants (σ ~ 30 - 35 mN/m) in these aerosols. In addition, these extractions were combined with colorimetric methods to determine the anionic, cationic and non-ionic surfactant concentrations [4,5], and provided for the first time interference-free surfactant concentrations in atmospheric aerosols. At this site, the total surfactant concentration in the PM2.5 samples varied between 7 to 150 mM and was dominated by anionic and non-ionic ones. The absolute surface tension curves obtained for total surfactant fraction displayed Critical Micelle Concentrations (CMC) in the range 50 - 400 uM, strongly suggesting a biological origin for the surfactants. The seasonal evolution of these concentrations and their relationships with environmental or meteorological parameters at the site will be discussed. [1] Ekström, S., Nozière, B. et al., Biogeosciences, 2010, 7, 387 [2] Baduel, C., Nozière, B., Jaffrezo, J.-L., Atmos. Environ., 2012, 47, 413 [3] Nozière, B., Baduel, C., Jaffrezo, J.-L., Nat. Commun., 2014, 5, 1 [4] Latif, M. T.; Brimblecombe, P. Environ. Sci. Technol., 2004, 38, 6501 [5] Pacheco e Silva et al., Method to measure surfactant in fluid, 2013, US 2013/0337568 A1

  10. A Novel Solubility-Enhanced Rubusoside-Based Micelles for Increased Cancer Therapy

    Science.gov (United States)

    Zhang, Meiying; Dai, Tongcheng; Feng, Nianping

    2017-04-01

    Many anti-cancer drugs have a common problem of poor solubility. Increasing the solubility of the drugs is very important for its clinical applications. In the present study, we revealed that the solubility of insoluble drugs was significantly enhanced by adding rubusoside (RUB). Further, it was demonstrated that RUB could form micelles, which was well characterized by Langmuir monolayer investigation, transmission electron microscopy, atomic-force microscopy, and cryogenic transmission electron microscopy. The RUB micelles were ellipsoid with the horizontal distance of 25 nm and vertical distance of 1.2 nm. Insoluble synergistic anti-cancer drugs including curcumin and resveratrol were loaded in RUB to form anti-cancer micelles RUB/CUR + RES. MTT assay showed that RUB/CUR + RES micelles had more significant toxicity on MCF-7 cells compared to RUB/CUR micelles + RUB/RES micelles. More importantly, it was confirmed that RUB could load other two insoluble drugs together for remarkably enhanced anti-cancer effect compared to that of RUB/one drug + RUB/another drug. Overall, we concluded that RUB-based micelles could efficiently load insoluble drugs for enhanced anti-cancer effect.

  11. HPMA-based polymeric micelles for curcumin solubilization and inhibition of cancer cell growth.

    Science.gov (United States)

    Naksuriya, Ornchuma; Shi, Yang; van Nostrum, Cornelus F; Anuchapreeda, Songyot; Hennink, Wim E; Okonogi, Siriporn

    2015-08-01

    Curcumin (CM) has been reported as a potential anticancer agent. However, its pharmaceutical applications as therapeutic agent are hampered because of its poor aqueous solubility. The present study explores the advantages of polymeric micelles composed of block copolymers of methoxypoly(ethylene glycol) (mPEG) and N-(2-hydroxypropyl) methacrylamide (HPMA) modified with monolactate, dilactate and benzoyl side groups to enhance CM solubility and inhibitory activity against cancer cells. Amphiphilic block copolymers, ω-methoxypoly(ethylene glycol)-b-(N-(2-benzoyloxypropyl) methacrylamide) (PEG-HPMA-Bz) were synthesized and characterized by (1)H NMR and GPC. One polymer with a molecular weight of 28,000Da was used to formulate CM and compared with other aromatic substituted polymers. CM was loaded by a fast heating method (PEG-HPMA-DL and PEG-HPMA-Bz-L) and a nanoprecipitation method (PEG-HPMA-Bz). Physicochemical characteristics and cytotoxicity/cytocompatibility of the CM loaded polymeric micelles were evaluated. It was found that HPMA-based polymeric micelles significantly enhanced the solubility of CM. The PEG-HPMA-Bz micelles showed the best solubilization properties. CM loaded polymeric micelles showed sustained release of the loading CM for more than 20days. All of CM loaded polymeric micelles formulations showed a significantly potent cytotoxic effect against three cancer cell lines. HPMA-based polymeric micelles are therefore promising nanodelivery systems of CM for cancer therapy. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Production of Fluconazole-Loaded Polymeric Micelles Using Membrane and Microfluidic Dispersion Devices

    Directory of Open Access Journals (Sweden)

    Yu Lu

    2016-05-01

    Full Text Available Polymeric micelles with a controlled size in the range between 41 and 80 nm were prepared by injecting the organic phase through a microengineered nickel membrane or a tapered-end glass capillary into an aqueous phase. The organic phase was composed of 1 mg·mL−1 of PEG-b-PCL diblock copolymers with variable molecular weights, dissolved in tetrahydrofuran (THF or acetone. The pore size of the membrane was 20 μm and the aqueous/organic phase volumetric flow rate ratio ranged from 1.5 to 10. Block copolymers were successfully synthesized with Mn ranging from ~9700 to 16,000 g·mol−1 and polymeric micelles were successfully produced from both devices. Micelles produced from the membrane device were smaller than those produced from the microfluidic device, due to the much smaller pore size compared with the orifice size in a co-flow device. The micelles were found to be relatively stable in terms of their size with an initial decrease in size attributed to evaporation of residual solvent rather than their structural disintegration. Fluconazole was loaded into the cores of micelles by injecting the organic phase composed of 0.5–2.5 mg·mL−1 fluconazole and 1.5 mg·mL−1 copolymer. The size of the drug-loaded micelles was found to be significantly larger than the size of empty micelles.

  13. Green Tea Catechin-Based Complex Micelles Combined with Doxorubicin to Overcome Cardiotoxicity and Multidrug Resistance

    Science.gov (United States)

    Cheng, Tangjian; Liu, Jinjian; Ren, Jie; Huang, Fan; Ou, Hanlin; Ding, Yuxun; Zhang, Yumin; Ma, Rujiang; An, Yingli; Liu, Jianfeng; Shi, Linqi

    2016-01-01

    Chemotherapy for cancer treatment has been demonstrated to cause some side effects on healthy tissues and multidrug resistance of the tumor cells, which greatly limits therapeutic efficacy. To address these limitations and achieve better therapeutic efficacy, combination therapy based on nanoparticle platforms provides a promising approach through delivering different agents simultaneously to the same destination with synergistic effect. In this study, a novel green tea catechin-based polyion complex (PIC) micelle loaded with doxorubicin (DOX) and (-)-Epigallocatechin-3-O-gallate (EGCG) was constructed through electrostatic interaction and phenylboronic acid-catechol interaction between poly(ethylene glycol)-block-poly(lysine-co-lysine-phenylboronic acid) (PEG-PLys/PBA) and EGCG. DOX was co-loaded in the PIC micelles through π-π stacking interaction with EGCG. The phenylboronic acid-catechol interaction endowed the PIC micelles with high stability under physiological condition. Moreover, acid cleavability of phenylboronic acid-catechol interaction in the micelle core has significant benefits for delivering EGCG and DOX to same destination with synergistic effects. In addition, benefiting from the oxygen free radicals scavenging activity of EGCG, combination therapy with EGCG and DOX in the micelle core could protect the cardiomyocytes from DOX-mediated cardiotoxicity according to the histopathologic analysis of hearts. Attributed to modulation of EGCG on P-glycoprotein (P-gp) activity, this kind of PIC micelles could effectively reverse multidrug resistance of cancer cells. These results suggested that EGCG based PIC micelles could effectively overcome DOX induced cardiotoxicity and multidrug resistance. PMID:27375779

  14. In vitro evaluation of antioxidant and neuroprotective effects of curcumin loaded in Pluronic micelles

    Directory of Open Access Journals (Sweden)

    Cvetelina Gorinova

    2016-09-01

    Full Text Available Curcumin is a polyphenolic substance with attractive pharmacological activities (e.g. antioxidant, anti-inflammatory, anticancer. Incorporation of curcumin in polymeric micelles could overcome the problems associated with its instability and low aqueous solubility. The aim of this study was to load curcumin in polymeric micelles based on Pluronic® P 123 or Pluronic® F 127 triblock copolymers and evaluate the antioxidant and neuroprotective effects after micellization. The micelles were prepared and loaded with curcumin by applying the dissolution method. Higher encapsulation efficiency was observed in the micelles formulated with Pluronic® P 123. These micelles were characterized with small size and narrow size distribution. The effects of micellar curcumin were investigated in two in vitro models. First, the capacity of micellar curcumin to inhibit iron/ascorbic acid-induced lipid peroxidation in rat liver microsomes was evaluated. Micellar curcumin and free drug showed similar inhibition of lipid peroxidation. Second, micellar curcumin and free curcumin showed protective potential in a model of 6-hydroxydopamine induced neurotoxicity in rat brain synaptosomes. The results from both methods indicated preservation of antioxidant and neuroprotective activity of curcumin in micelles. The small micellar size, high loading capacity and preservation of antioxidant activity of curcumin into Pluronic micelles, suggested their further evaluation as a curcumin delivery system.

  15. pH-Responsive Micelle-Based Cytoplasmic Delivery System for Induction of Cellular Immunity

    Directory of Open Access Journals (Sweden)

    Eiji Yuba

    2017-11-01

    Full Text Available (1 Background: Cytoplasmic delivery of antigens is crucial for the induction of cellular immunity, which is an important immune response for the treatment of cancer and infectious diseases. To date, fusogenic protein-incorporated liposomes and pH-responsive polymer-modified liposomes have been used to achieve cytoplasmic delivery of antigen via membrane rupture or fusion with endosomes. However, a more versatile cytoplasmic delivery system is desired for practical use. For this study, we developed pH-responsive micelles composed of dilauroyl phosphatidylcholine (DLPC and deoxycholic acid and investigated their cytoplasmic delivery performance and immunity-inducing capability. (2 Methods: Interaction of micelles with fluorescence dye-loaded liposomes, intracellular distribution of micelles, and antigenic proteins were observed. Finally, antigen-specific cellular immune response was evaluated in vivo using ELIspot assay. (3 Results: Micelles induced leakage of contents from liposomes via lipid mixing at low pH. Micelles were taken up by dendritic cells mainly via macropinocytosis and delivered ovalbumin (OVA into the cytosol. After intradermal injection of micelles and OVA, OVA-specific cellular immunity was induced in the spleen. (4 Conclusions: pH-responsive micelles composed of DLPC and deoxycholic acid are promising as enhancers of cytosol delivery of antigens and the induction capability of cellular immunity for the treatment of cancer immunotherapy and infectious diseases.

  16. EPR spin probe and spin label studies of some low molecular and polymer micelles

    Science.gov (United States)

    Wasserman, A. M.; Kasaikin, V. A.; Timofeev, V. P.

    1998-12-01

    The rotational mobility of spin probes of different shape and size in low molecular and polymer micelles has been studied. Several probes having nitroxide fragment localized either in the vicinity of micelle interface or in the hydrocarbon core have been used. Upon increasing the number of carbon atoms in hydrocarbon chain of detergent from 7 to 13 (sodium alkyl sulfate micelles) or from 12 to 16 (alkyltrimethylammonium bromide micelles) the rotational mobility of spin probes is decreased by the factor 1.5-2.0. The spin probe rotational mobility in polymer micelles (the complexes of alkyltrimethylammonium bromides and polymethacrylic or polyacrylic acids) is less than mobility in free micelles of the same surfactants. The study of EPR-spectra of spin labeled polymethacrylic acid (PMA) indicated that formation of water soluble complexes of polymer and alkyltrimethylammonium bromides in alkaline solutions (pH 9) does not affect the polymer segmental mobility. On the other hand, the polymer complexes formation in slightly acidic water solution (pH 6) breaks down the compact PMA conformation, thus increasing the polymer segmental mobility. Possible structures of polymer micelles are discussed.

  17. Nanotoxicity comparison of four amphiphilic polymeric micelles with similar hydrophilic or hydrophobic structure.

    Science.gov (United States)

    Zhao, Bo; Wang, Xue-Qing; Wang, Xiao-You; Zhang, Hua; Dai, Wen-Bing; Wang, Jun; Zhong, Zhen-Lin; Wu, Hou-Nan; Zhang, Qiang

    2013-10-03

    Nanocarriers represent an attractive means of drug delivery, but their biosafety must be established before their use in clinical research. Four kinds of amphiphilic polymeric (PEG-PG-PCL, PEEP-PCL, PEG-PCL and PEG-DSPE) micelles with similar hydrophilic or hydrophobic structure were prepared and their in vitro and in vivo safety were evaluated and compared. In vitro nanotoxicity evaluations included assessments of cell morphology, cell volume, inflammatory effects, cytotoxicity, apoptosis and membrane fluidity. An umbilical vein cell line (Eahy.926) and a kind of macrophages (J774.A1) were used as cell models considering that intravenous route is dominant for micelle delivery systems. In vivo analyses included complete blood count, lymphocyte subset analysis, detection of plasma inflammatory factors and histological observations of major organs after intravenous administration to KM mice. All the micelles enhanced inflammatory molecules in J774.A1 cells, likely resulting from the increased ROS levels. PEG-PG-PCL and PEEP-PCL micelles were found to increase the J774.A1 cell volume. This likely correlated with the size of PEG-PG-PCL micelles and the polyphosphoester structure in PEEP-PCL. PEG-DSPE micelles inhibited the growth of Eahy.926 cells via inducing apoptosis. This might relate to the structure of DSPE, which is a type of phospholipid and has good affinity with cell membrane. No evidence was found for cell membrane changes after treatment with these micelles for 24 h. In the in vivo study, during 8 days of 4 time injection, each of the four nanocarriers altered the hematic phase differently without changes in inflammatory factors or pathological changes in target organs. These results demonstrate that the micelles investigated exhibit diverse nanotoxicity correlated with their structures, their biosafety is different in different cell model, and there is no in vitro and in vivo correlation found. We believe that this study will certainly provide more

  18. Backbone-hydrazone-containing biodegradable copolymeric micelles for anticancer drug delivery

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Jing; Luan, Shujuan; Qin, Benkai; Wang, Yingying; Wang, Kai; Qi, Peilan; Song, Shiyong, E-mail: pharmsong@henu.edu.cn [Henan University, Institute of Pharmacy (China)

    2016-11-15

    Well-defined biodegradable, pH-sensitive amphiphilic block polymers, poly(ethylene glycol)-Hyd-poly(lactic acid) (mPEG-Hyd-PLA) which have acid-cleavable linkages in their backbones, were synthesized via ring-opening polymerization initiated from hydrazone-containing macroinitiators. Introducing a hydrazone bond onto the backbone of an amphiphilic copolymer will find a broad-spectrum encapsulation of hydrophobic drugs. Dynamic light scattering (DLS) and transmission electron microscopy showed that the diblock copolymers self-assembled into stable micelles with average diameters of 100 nm. The mean diameters and size distribution of the hydrazone-containing micelles changed obviously in mildly acidic pH (multiple peaks from 1 to 202 nm appeared under a pH 4.0 condition) than in neutral, while there were no changes in the case of non-sensitive ones. Doxorubicin (DOX) and paclitaxel (PTX) were loaded with drug loading content ranging from 2.4 to 3.5 %, respectively. Interestingly, the anticancer drugs released from mPEG-Hyd-PLA micelles could also be promoted by the increased acidity. An in vitro cytotoxicity study showed that the DOX-loaded mPEG-Hyd-PLA micelles have significantly enhanced cytotoxicity against HepG2 cells compared with the non-sensitive poly(ethylene glycol)-block-poly(lactic acid) (mPEG-PLA) micelles. Confocal microscopy observation indicated that more DOX were delivered into the nuclei of cells following 6 or 12 h incubation with DOX-loaded mPEG-Hyd-PLA micelles. In vivo studies on H22-bearing Swiss mice demonstrated the superior anticancer activity of DOX-loaded mPEG-Hyd-PLA micelles over free DOX and DOX-loaded mPEG-PLA micelles. These hydrazone-containing pH-responsive degradable micelles provide a useful strategy for antitumor drug delivery.

  19. Backbone-hydrazone-containing biodegradable copolymeric micelles for anticancer drug delivery

    International Nuclear Information System (INIS)

    Xu, Jing; Luan, Shujuan; Qin, Benkai; Wang, Yingying; Wang, Kai; Qi, Peilan; Song, Shiyong

    2016-01-01

    Well-defined biodegradable, pH-sensitive amphiphilic block polymers, poly(ethylene glycol)-Hyd-poly(lactic acid) (mPEG-Hyd-PLA) which have acid-cleavable linkages in their backbones, were synthesized via ring-opening polymerization initiated from hydrazone-containing macroinitiators. Introducing a hydrazone bond onto the backbone of an amphiphilic copolymer will find a broad-spectrum encapsulation of hydrophobic drugs. Dynamic light scattering (DLS) and transmission electron microscopy showed that the diblock copolymers self-assembled into stable micelles with average diameters of 100 nm. The mean diameters and size distribution of the hydrazone-containing micelles changed obviously in mildly acidic pH (multiple peaks from 1 to 202 nm appeared under a pH 4.0 condition) than in neutral, while there were no changes in the case of non-sensitive ones. Doxorubicin (DOX) and paclitaxel (PTX) were loaded with drug loading content ranging from 2.4 to 3.5 %, respectively. Interestingly, the anticancer drugs released from mPEG-Hyd-PLA micelles could also be promoted by the increased acidity. An in vitro cytotoxicity study showed that the DOX-loaded mPEG-Hyd-PLA micelles have significantly enhanced cytotoxicity against HepG2 cells compared with the non-sensitive poly(ethylene glycol)-block-poly(lactic acid) (mPEG-PLA) micelles. Confocal microscopy observation indicated that more DOX were delivered into the nuclei of cells following 6 or 12 h incubation with DOX-loaded mPEG-Hyd-PLA micelles. In vivo studies on H22-bearing Swiss mice demonstrated the superior anticancer activity of DOX-loaded mPEG-Hyd-PLA micelles over free DOX and DOX-loaded mPEG-PLA micelles. These hydrazone-containing pH-responsive degradable micelles provide a useful strategy for antitumor drug delivery.

  20. Polymeric Micelles as Novel Carriers for Poorly Soluble Drugs--A Review.

    Science.gov (United States)

    Reddy, B Pavan Kumar; Yadav, Hemant K S; Nagesha, Dattatri K; Raizaday, Abhay; Karim, Abdul

    2015-06-01

    Polymeric micelles are used as 'smart drug carriers' for targeting certain areas of the body by making them stimuli-sensitive or by attachment of a specific ligand molecule onto their surface. The main aim of using polymeric micelles is to deliver the poorly water soluble drugs. Now-a-days they are used especially in the areas of cancer therapy also. In this article we have reviewed several aspects of polymeric micelles concerning their mechanism of formation, chemical nature, preparation and characterization techniques, and their applications in the areas of drug delivery.

  1. Dominant role of wormlike micelles in temperature-responsive viscoelastic properties of their mixtures with polymeric chains

    KAUST Repository

    Molchanov, Vyacheslav S.

    2013-03-01

    Temperature effects on the rheological properties of viscoelastic solutions containing entangled wormlike micelles of potassium oleate and hydrophobically modified polyacrylamide were studied in a wide range of polymer concentrations. A very pronounced drop of viscosity by four orders of magnitude was observed at heating from 20 to 78 °C both in the presence and in the absence of polymer indicating that the wormlike micelles are mainly responsible for this effect. The highly thermosensitive behavior was attributed to the shortening of micellar chains induced by heating. Although the decrease in viscosity is almost the same for both surfactant and surfactant/polymer systems, the absolute values of the viscosity in the presence of polymer are by few orders of magnitude higher, which is due to the formation of a common network of entangled polymer and micellar chains. As a result, the added polymer allows one to get highly temperature responsive system that keeps viscoelastic properties in a much wider range of temperatures, which makes it very promising for various practical applications. © 2012 Elsevier Inc.

  2. Pharmaceutical micelles featured with singlet oxygen-responsive cargo release and mitochondrial targeting for enhanced photodynamic therapy

    Science.gov (United States)

    Zhang, Xin; Yan, Qi; Naer Mulatihan, Di; Zhu, Jundong; Fan, Aiping; Wang, Zheng; Zhao, Yanjun

    2018-06-01

    The efficacy of nanoparticulate photodynamic therapy is often compromised by the short life time and limited diffusion radius of singlet oxygen as well as uncontrolled intracellular distribution of photosensitizer. It was hypothesized that rapid photosensitizer release upon nanoparticle internalization and its preferred accumulation in mitochondria would address the above problems. Hence, the aim of this study was to engineer a multifunctional micellar nanosystem featured with singlet oxygen-responsive cargo release and mitochondria-targeting. An imidazole-bearing amphiphilic copolymer was employed as the micelle building block to encapsulate triphenylphosphonium-pyropheophorbide a (TPP-PPa) conjugate or PPa. Upon laser irradiation, the singlet oxygen produced by TPP-PPa/PPa oxidized the imidazole moiety to produce hydrophilic urea, leading to micelle disassembly and rapid cargo release. The co-localization analysis showed that the TPP moiety significantly enhanced the photosensitizer uptake by mitochondria, improved mitochondria depolarization upon irradiation, and hence boosted the cytotoxicity in 4T1 cells. The targeting strategy also dramatically reduced the intracellular ATP concentration as a consequence of mitochondria injury. The mitochondria damage was accompanied with the activation of the apoptosis signals (caspase 3 and caspase 9), whose level was directly correlated to the apoptosis extent. The current work provides a facile and robust means to enhance the efficacy of photodynamic therapy.

  3. Synthesis of nanosilver particles by reverse micelle method and study of their bactericidal properties

    Energy Technology Data Exchange (ETDEWEB)

    Tran Thi Ngoc Dung; Ngo Quoc Buu; Dang Viet Quang; Le Anh Bang; Nguyen Hoai Chau; Nguyen Thi Ly [Institute of Environmental Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay Distr., Hanoi (Viet Nam); Huynh Thi Ha [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay Distr., Hanoi (Viet Nam); Nguyen Vu Trung [National Institute for Infectious and Tropical Diseases, 1 Ton That Tung, Dong Da Distr., Hanoi (Viet Nam)], E-mail: ttndzung@yahoo.com, E-mail: buu_nq@yahoo.com

    2009-09-01

    Nanosilver particles have been synthesized by the reverse micelle method, where AgNO{sub 3} was used as a silver ions source, NaBH{sub 4} and quercetin - as reducing agents, CTAB, SDOSS and AOT- as surfactants, while the stabilizer was Vietnamese chitosan. Studying the factors influencing the process of nanosilver particle formation, it was shown that the particle size of the nanosilver products depends on the concentration of the reaction components and their stoichiometric ratio. It was also shown that the reaction system using AOT surfactant is capable of producing nanosilver particles with smallest nanoparticles ({phi}{sub av} {approx} 5 nm) and good particle-size distribution. The study on bactericidal activity of the nanosilver products indicated that the disinfecting solution with a nanosilver concentration of 3 ppm was able to inhibit all E.coli and Coliforms, TPC and fungi at 15 ppm, while Vibrio cholerae cells were inactivated completely with 0.5 ppm of nanosilver after 30 minutes exposition.

  4. Spectrophotometric speciation of Fe(II) and Fe(III) using hydrazone-micelle systems and flow injections

    International Nuclear Information System (INIS)

    Khojali, Inas Osman

    1999-04-01

    Two hydrazones were synthesised, namely salicylhyrazone (SH) and trihydroxyacetophenone (THAPH) were synthesised with the objective of developing a method for determining of Fe(II) and Fe(III) in the presence of each other and hence the total iron.those hydrazones were selected so as to combine the ability of phenolic compounds to complex Fe(III) ions and the complexing characteristics of hydrazones. The complexes of Fe(II) S H and Fe(III) S H as well those of Fe(II)-THAPH and Fe(III)-THAPH had shown maximum absorbance at λ=412 nm which was not not modified by presence of micelles i.e. sodium n-dodecyl sulphate (SDS) and n-hexa dodecyl pyridinium bromide. The maximum absorbance for all complexes takes place around a neutral pH. Generally, in addition, of n-hexa dodecylpyridinium bromide to fe(II)-SH and Fe(III)-SH absorbance of the complexes increases with increasing the concentration of the micelle. The effects of the addition of sodium n-dodecyle sulphate (SDS) to Fe(III)-SH is also studied. Generally, increasing the concentration of the micelle decrease the absorbance of the complexes. To study the effect of the presence of Fe(II) and Fe(III) on the determination of each other,mixtures of Fe(II)-SH and Fe(III)-SH are studied. However, the use of ascorbic acid as a reducing reagent for Fe(III) did not produce the needed results but non reducible results, which may be due to the masking effect of ascorbic acid and thus making the metal not available to the ligand. However, conversion of Fe(II) to Fe(III) prior to the determination was avoided as this requires the use of oxidant, which will oxidise the ligand as well. To establish the condition for the maximum absorbance of THAPH complexes, the effect of the base was investigated by using sodium and ammonium hydroxide. Generally, increasing the concentration of the base decreases the abosrbance. as expected, ammonium hydroxide produced positive results than sodium hydroxide. After establishing the optimum Fi

  5. Micelles driven magnetite (Fe{sub 3}O{sub 4}) hollow spheres and a study on AC magnetic properties for hyperthermia application

    Energy Technology Data Exchange (ETDEWEB)

    Goswami, Madhuri Mandal, E-mail: madhuri@bose.res.in [Department of Condensed Matter Physics and Material Science, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700106 (India); Dey, Chaitali [Department of Condensed Matter Physics and Material Science, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700106 (India); CRNN, University of Calcutta, Block JD, Sector III, Salt Lake, Kolkata 700106 (India); Bandyopadhyay, Ayan [CRNN, University of Calcutta, Block JD, Sector III, Salt Lake, Kolkata 700106 (India); Sarkar, Debasish [Department of Condensed Matter Physics and Material Science, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700106 (India); Ahir, Manisha [CRNN, University of Calcutta, Block JD, Sector III, Salt Lake, Kolkata 700106 (India)

    2016-11-01

    Here we have discussed about designing the magnetic particles for hyperthermia therapy and done some studies in this direction. We have used oleylamine micelles as template to synthesize hollow–nanospheres (HNS) of magnetite by solvo-thermal technique. We have shown that oleylamine plays an important role to generate hollow particles. Structural analysis was done by XRD measurement and morphological measurements like SEM and TEM was performed to confirm the shape and size of hollow sphere particles. The detail magnetic measurements give an idea about the application of these HNS for magnetic heating in hyperthermia therapy. In vitro cytotoxicity studies reveal that tolerable dose rate for these particles can be significantly high and particles are non-toxic in nature. Being hollow in structure and magnetic in nature such materials will also be useful in other application fields like in drug delivery, drug release, arsenic and heavy metal removal by adsorption technique, magnetic separation etc. - Graphical abstract: Oleylamine micelles driven easy synthesis of hollow nanosphere (HNS) magnetite for hyperthermia therapy. - Highlights: • We have reported a new method of synthesis of hollow spheres of magnetite using micelles as model core and removal of micelles evolve the hollow like structure by relocating the core particles to the edge one. • Size can be controlled by varying the micellar concentration. • The detail magnetic measurements give an idea of applicability of these nano hollow spheres (NHS) in hyperthermia therapy. • Cyto-toxicity study reveals that these particles are highly biofriendly and dose rate can be increased upto a significant amount.

  6. Flavonoid glycosides from Persea caerulea. Unraveling their interactions with SDS-micelles through matrix-assisted DOSY, PGSE, mass spectrometry, and NOESY.

    Science.gov (United States)

    Álvarez, Juan M; Raya-Barón, Álvaro; Nieto, Pedro M; Cuca, Luis E; Carrasco-Pancorbo, Alegría; Fernández-Gutiérrez, Alberto; Fernández, Ignacio

    2016-04-13

    Two flavonoid glycosides derived from rhamnopyranoside (1) and arabinofuranoside (2) have been isolated from leaves of Persea caerulea for the first time. The structures of 1 and 2 have been established by 1 H NMR, 13 C NMR, and IR spectroscopy, together with LC-ESI-TOF and LC-ESI-IT MS spectrometry. From the MS and MS/MS data, the molecular weights of the intact molecules as well as those of quercetin and kaempferol together with their sugar moieties were deduced. The NMR data provided information on the identity of the compounds, as well as the α and β configurations and the position of the glycosides on quercetin and kaempferol. We have also explored the application of sodium dodecyl sulfate (SDS) normal micelles in binary aqueous solution, at a range of concentrations, to the diffusion resolution of these two glycosides, by the application of matrix-assisted diffusion ordered spectroscopy (DOSY) and pulse field gradient spin echo (PGSE) methodologies, showing that SDS micelles offer a significant resolution which can, in part, be rationalized in terms of differing degrees of hydrophobicity, amphiphilicity, and steric effects. In addition, intra-residue and inter-residue proton-proton distances using nuclear Overhauser effect build-up curves were used to elucidate the conformational preferences of these two flavonoid glycosides when interacting with the micelles. By the combination of both diffusion and nuclear Overhauser spectroscopy techniques, the average location site of kaempferol and quercetin glycosides has been postulated, with the former exhibiting a clear insertion into the interior of the SDS-micelle, whereas the latter is placed closer to the surface. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  7. Successful in vivo hyperthermal therapy toward breast cancer by Chinese medicine shikonin-loaded thermosensitive micelle

    Directory of Open Access Journals (Sweden)

    Su Y

    2017-05-01

    intravenous injection is administered to the BALB/c nude mice bearing breast cancer, the intra-tumor accumulation of STNs is significantly increased as T > VPTT, which is regulated by the in-house developed heating device. The in vivo antitumor assays against breast cancer further confirm the synergistically enhanced therapeutic efficiency. The findings of this study indicate that STN is a potential effective nanoformulation in clinical cancer therapy. Keywords: thermosensitive micelle, shikonin, breast cancer, intra-tumor accumulation, critical micelle concentration, hyperthermal therapy, in vivo

  8. Cooperative catalysis with block copolymer micelles: A combinatorial approach

    KAUST Repository

    Bukhryakov, Konstantin V.

    2015-02-09

    A rapid approach to identifying complementary catalytic groups using combinations of functional polymers is presented. Amphiphilic polymers with "clickable" hydrophobic blocks were used to create a library of functional polymers, each bearing a single functionality. The polymers were combined in water, yielding mixed micelles. As the functional groups were colocalized in the hydrophobic microphase, they could act cooperatively, giving rise to new modes of catalysis. The multipolymer "clumps" were screened for catalytic activity, both in the presence and absence of metal ions. A number of catalyst candidates were identified across a wide range of model reaction types. One of the catalytic systems discovered was used to perform a number of preparative-scale syntheses. Our approach provides easy access to a range of enzyme-inspired cooperative catalysts.

  9. Cooperative catalysis with block copolymer micelles: A combinatorial approach

    KAUST Repository

    Bukhryakov, Konstantin V.; Desyatkin, Victor G.; O'Shea, John Paul; Almahdali, Sarah; Solovyeva, Vera; Rodionov, Valentin

    2015-01-01

    A rapid approach to identifying complementary catalytic groups using combinations of functional polymers is presented. Amphiphilic polymers with "clickable" hydrophobic blocks were used to create a library of functional polymers, each bearing a single functionality. The polymers were combined in water, yielding mixed micelles. As the functional groups were colocalized in the hydrophobic microphase, they could act cooperatively, giving rise to new modes of catalysis. The multipolymer "clumps" were screened for catalytic activity, both in the presence and absence of metal ions. A number of catalyst candidates were identified across a wide range of model reaction types. One of the catalytic systems discovered was used to perform a number of preparative-scale syntheses. Our approach provides easy access to a range of enzyme-inspired cooperative catalysts.

  10. Solvation dynamics in triton-X-100 and triton-X-165 micelles: Effect of micellar size and hydration

    Science.gov (United States)

    Kumbhakar, Manoj; Nath, Sukhendu; Mukherjee, Tulsi; Pal, Haridas

    2004-09-01

    Dynamic Stokes' shift measurements using coumarin 153 as the fluorescence probe have been carried out to study solvation dynamics in two nonionic micelles, viz., triton-X-100 (TX-100) and triton-X-165 (TX-165). In both the micelles, the solvent relaxation dynamics is biexponential in nature. While the fast solvation time τs1 is seen to be almost similar for both the micelles, the slow solvation time τs2 is found to be appreciably smaller in TX-165 than in TX-100 micelle. Dynamic light scattering measurements indicate that the TX-165 micelles are substantially smaller in size than that of TX-100. Assuming similar core size for both the micelles, as expected from the similar chemical structures of the nonpolar ends for both the surfactants, the Palisade layer is also indicated to be substantially thinner for TX-165 micelles than that of TX-100. The aggregation number of TX-165 micelles is also found to be substantially smaller than that of TX-100 micelles. Fluorescence spectral studies of C153 dye in the two micelles indicate that the Palisade layer of TX-165 micelles is more polar than that of TX-100 micelles. Fluorescence anisotropy measurements indicate that the microviscosity in the Palisade layer of TX-165 micelles is also lower than that of TX-100 micelles. Based on these results it is inferred that the structure of the Palisade layer of TX-165 micelles is quite loose and have higher degree hydration in comparison to that of TX-100 micelles. Due to these structural differences in the Palisade layers of TX-165 and TX-100 micelles the solvation dynamics is faster in the former micelles than in the latter. It has been further inferred that in the present systems the collective response of the water molecules at somewhat away from the probes is responsible for the faster component of the solvation time, which does not reflect much of the structural changes of the micellar Palisade layer. On the contrary, the slower solvation time component, which is mainly due to

  11. Enhancement of bioavailability by formulating rhEPO ionic complex with lysine into PEG-PLA micelle

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Yanan; Sun, Fengying; Wang, Dan; Zhang, Renyu [Jilin University, College of Life Science (China); Dou, Changlin; Liu, Wanhui; Sun, Kaoxiang, E-mail: sunkx@ytu.edu.cn [Yantai University, School of Pharmacy (China); Li, Youxin, E-mail: liyouxin@jlu.edu.cn [Jilin University, College of Life Science (China)

    2013-10-15

    A composite micelle of ionic complex encapsulated into poly(ethylene glycol)-poly(d,l-lactide) (PEG-PLA) di-block copolymeric micelles was used for protein drug delivery to improve its pharmacokinetic performance. In this study, recombinant human erythropoietin (rhEPO, as a model protein) was formulated with lysine into composite micelles at a diameter of 71.5 nm with narrow polydispersity indices (PDIs < 0.3). Only a trace amount of protein was in aggregate form. The zeta potential of the spherical micelles was ranging from -0.54 to 1.39 mv, and encapsulation efficiency is high (80 %). The stability of rhEPO was improved significantly in composite micelles in vitro. Pharmacokinetic studies in rats showed significant, enhanced plasma retention of the composite micelles in comparison with native rhEPO. Areas under curve (AUCs) of the rhEPO released from the composite micelles were 4.5- and 2.3-folds higher than those of the native rhEPO and rhEPO-loaded PEG-PLA micelle, respectively. In addition, the composite micelles exhibited good biocompatibility using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay with human embryonic kidney (HEK293T) cells. All these features are preferable for utilizing the composite micelles as a novel protein delivery system.

  12. Enhancement of bioavailability by formulating rhEPO ionic complex with lysine into PEG-PLA micelle

    Science.gov (United States)

    Shi, Yanan; Sun, Fengying; Wang, Dan; Zhang, Renyu; Dou, Changlin; Liu, Wanhui; Sun, Kaoxiang; Li, Youxin

    2013-10-01

    A composite micelle of ionic complex encapsulated into poly(ethylene glycol)-poly( d, l-lactide) (PEG-PLA) di-block copolymeric micelles was used for protein drug delivery to improve its pharmacokinetic performance. In this study, recombinant human erythropoietin (rhEPO, as a model protein) was formulated with lysine into composite micelles at a diameter of 71.5 nm with narrow polydispersity indices (PDIs protein was in aggregate form. The zeta potential of the spherical micelles was ranging from -0.54 to 1.39 mv, and encapsulation efficiency is high (80 %). The stability of rhEPO was improved significantly in composite micelles in vitro. Pharmacokinetic studies in rats showed significant, enhanced plasma retention of the composite micelles in comparison with native rhEPO. Areas under curve (AUCs) of the rhEPO released from the composite micelles were 4.5- and 2.3-folds higher than those of the native rhEPO and rhEPO-loaded PEG-PLA micelle, respectively. In addition, the composite micelles exhibited good biocompatibility using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay with human embryonic kidney (HEK293T) cells. All these features are preferable for utilizing the composite micelles as a novel protein delivery system.

  13. Development and evaluation of N-naphthyl-N,O-succinyl chitosan micelles containing clotrimazole for oral candidiasis treatment.

    Science.gov (United States)

    Tonglairoum, Prasopchai; Woraphatphadung, Thisirak; Ngawhirunpat, Tanasait; Rojanarata, Theerasak; Akkaramongkolporn, Prasert; Sajomsang, Warayuth; Opanasopit, Praneet

    2017-03-01

    Clotrimazole (CZ)-loaded N-naphthyl-N,O-succinyl chitosan (NSCS) micelles have been developed as an alternative for oral candidiasis treatment. NSCS was synthesized by reductive N-amination and N,O-succinylation. CZ was incorporated into the micelles using various methods, including the dropping method, the dialysis method, and the O/W emulsion method. The size and morphology of the CZ-loaded micelles were characterized using dynamic light scattering measurements (DLS) and a transmission electron microscope (TEM), respectively. The drug entrapment efficiency, loading capacity, release characteristics, and antifungal activity against Candida albicans were also evaluated. The CZ-loaded micelles prepared using different methods differed in the size of micelles. The micelles ranged in size from 120 nm to 173 nm. The micelles prepared via the O/W emulsion method offered the highest percentage entrapment efficiency and loading capacity. The CZ released from the CZ-loaded micelles at much faster rate compared to CZ powder. The CZ-loaded NSCS micelles can significantly hinder the growth of Candida cells after contact. These CZ-loaded NSCS micelles offer great antifungal activity and might be further developed to be a promising candidate for oral candidiasis treatment.

  14. Use of Magnetic Folate-Dextran-Retinoic Acid Micelles for Dual Targeting of Doxorubicin in Breast Cancer

    Directory of Open Access Journals (Sweden)

    J. Varshosaz

    2013-01-01

    Full Text Available Amphiphilic copolymer of folate-conjugated dextran/retinoic acid (FA/DEX-RA was self-assembled into micelles by direct dissolution method. Magnetic iron oxide nanoparticles (MNPs coated with oleic acid (OA were prepared by hydrothermal method and encapsulated within the micelles. Doxorubicin HCl was loaded in the magnetic micelles. The characteristics of the magnetic micelles were determined by Fourier transform infrared (FT-IR spectroscopy, thermogravimetric analysis (TGA, transmission electron microscopy (TEM, and vibrating sample magnetometer (VSM. The crystalline state of OA-coated MNPs and their heat capacity were analyzed by X-ray diffraction (XRD and differential scanning calorimetry (DSC methods, respectively. The iron content of magnetic micelles was determined using inductively coupled plasma optical emission spectrometry (ICP-OES. Bovine serum albumin (BSA was used to test the protein binding of magnetic micelles. The cytotoxicity of doxorubicin loaded magnetic micelles was studied on MCF-7 and MDA-MB-468 cells using MTT assay and their quantitative cellular uptake by fluorimetry method. TEM results showed the MNPs in the hydrophobic core of the micelles. TGA results confirmed the presence of OA and FA/DEX-RA copolymer on the surface of MNPs and micelles, respectively. The magnetic micelles showed no significant protein bonding and reduced the IC50 of the drug to about 10 times lower than the free drug.

  15. Electron transfer reactions of ruthenium(II) complexes with polyphenolic acids in micelles

    Energy Technology Data Exchange (ETDEWEB)

    Rajeswari, Angusamy [School of Chemistry, Madurai Kamaraj University, Madurai 625 021 (India); Department of Chemistry, Fatima College, Madurai 625 018 (India); Ramdass, Arumugam [School of Chemistry, Madurai Kamaraj University, Madurai 625 021 (India); Research Department of Chemistry, Aditanar College of Arts and Science, Tiruchendur 628 216 (India); Muthu Mareeswaran, Paulpandian [School of Chemistry, Madurai Kamaraj University, Madurai 625 021 (India); Department of Industrial Chemistry, Alagappa University, Karaikudi 630 003 (India); Rajagopal, Seenivasan, E-mail: rajagopalseenivasan@yahoo.com [School of Chemistry, Madurai Kamaraj University, Madurai 625 021 (India)

    2016-02-15

    The electron transfer in a microhetrogeneous system is a perfect mimic of biological electron transfer. The electron transfer between biologically important phenolic acids and ruthenium (II) complexes is systematically studied in the presence of anionic and cationic micelles. The photophysical properties of these ruthenium (II) complexes with anionic and cationic micelles and their binding abilities with these two type of micelles are also studies using absorption, emission and excited state lifetime spectral techniques. Pseudophase Ion Exchange (PIE) Model is applied to derive mechanism of electron transfer in two types of micelles. - Highlights: • Effect of microhetrogeneous system is studied using ruthenium (II) complexes and gallic acid is studied. • Pseudophase Ion exchange model is applied to derive the mechanism. • Binding constants are in the range of 10{sup 2}–10{sup 4} M{sup −1}.

  16. HPMA-based polymeric micelles for curcumin solubilization and inhibition of cancer cell growth

    NARCIS (Netherlands)

    Naksuriya, Ornchuma; Shi, Yang; Van Nostrum, Cornelus F.|info:eu-repo/dai/nl/134498690; Anuchapreeda, Songyot; Hennink, Wim E.|info:eu-repo/dai/nl/070880409; Okonogi, Siriporn

    2015-01-01

    Abstract Curcumin (CM) has been reported as a potential anticancer agent. However, its pharmaceutical applications as therapeutic agent are hampered because of its poor aqueous solubility. The present study explores the advantages of polymeric micelles composed of block copolymers of

  17. The structure of the antimicrobial active center of lactoferricin B bound to sodium dodecyl sulfate micelles.

    Science.gov (United States)

    Schibli, D J; Hwang, P M; Vogel, H J

    1999-03-12

    Lactoferricin B (LfcinB) is a 25-residue antimicrobial peptide released from bovine lactoferrin upon pepsin digestion. The antimicrobial center of LfcinB consists of six residues (RRWQWR-NH2), and it possesses similar bactericidal activity to LfcinB. The structure of the six-residue peptide bound to sodium dodecyl sulfate (SDS) micelles has been determined by NMR spectroscopy and molecular dynamics refinement. The peptide adopts a well defined amphipathic structure when bound to SDS micelles with the Trp sidechains separated from the Arg residues. Additional evidence demonstrates that the peptide is oriented in the micelle such that the Trp residues are more deeply buried in the micelle than the Arg and Gln residues.

  18. Effect of water on the local electric potential of simulated ionic micelles

    Energy Technology Data Exchange (ETDEWEB)

    Brodskaya, Elena N.; Vanin, Alexander A., E-mail: alexvanin@yandex.ru [Institute of Chemistry, St. Petersburg State University, Universitetskiy pr. 26, Petrodvoretz, St. Petersburg 198504 (Russian Federation)

    2015-07-28

    Ionic micelles in an aqueous solution containing single-charged counter-ions have been simulated by molecular dynamics. For both cationic and anionic micelles, it has been demonstrated that explicit description of solvent has strong effect on the micelle’s electric field. The sign of the local charge alters in the immediate vicinity of the mice