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1
Alopaeus, Julia F., Ellen Hagesæther und Ingunn Tho. „Micellisation Mechanism and Behaviour of Soluplus®–Furosemide Micelles: Preformulation Studies of an Oral Nanocarrier-Based System“. Pharmaceuticals 12, Nr. 1 (19.01.2019): 15. http://dx.doi.org/10.3390/ph12010015.
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: In this study, self-assembling Soluplus® micelles were examined for inherent properties. Through calorimetric analysis, the critical micelle concentration (CMC) could be determined at 25 and 37 °C, and the influence of three media (Milli-Q water, phosphate-buffered saline (PBS) with a pH of 7.4 and 0.1 M HCl) on the lower critical solution temperature (LCST) was detected. Furthermore, the solubilisation of a poorly soluble drug, furosemide, into the Soluplus® micelles was studied. The concentration-dependent properties of the micellar system were assessed through an examination of the micellar size, polydispersity, morphology, viscosity and solubilising properties, which were all found to be affected by the concentration, but temperature, pH and the composition of the test medium were also found to have an effect. Homogeneity in the estimated micellar size and morphology was shown for monophasic micelle dispersions in lower concentrations and with a shift towards more complex structures or aggregates in higher concentrations. The micelles were further investigated in terms of drug release and biocompatibility with mucus-producing HT29-MTX cells, where no biocompatibility issues were found. In this research, the implications for oral drug delivery are discussed and valuable preformulation information is provided on the micellar properties of a Soluplus® drug system in a liquid or semi-solid form.
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Nguyen, Hau Thi, Wen-Shing Chang, Nguyen Cong Nguyen, Shiao-Shing Chen und Hau-Ming Chang. „Influence of micelle properties on micellar-enhanced ultrafiltration for chromium recovery“. Water Science and Technology 72, Nr. 11 (14.08.2015): 2045–51. http://dx.doi.org/10.2166/wst.2015.370.
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An investigation of micelle properties on the recovery of chromium for micellar enhanced ultrafiltration (MEUF) process was conducted using cationic surfactant of cetyltrimethylammonium bromide (CTAB). The relationship between degree of ionization, micellar sizes and chromium removal were determined in this study. The results showed that the complete ionization for CTA+ and Br− was observed for CTAB lower than 0.72 mM and aggregation initiated at concentration of CTAB higher than 0.72 mM to yield attraction of counterion. The micellar sizes increased with increase in concentration of CTAB (higher than 4.02 mM) to generate micron-sized micelles. The distribution of micellar sizes was used to estimate the molecular weight cutoff of membrane used in the MEUF process. As chromium was added into aqueous CTAB solution, the chromate was dominant and bound on the micellar surface instead of Br−. Moreover, the presence of micelle formed a gel-layer to slightly shrink the membrane pore, therefore, UF membrane of 30k Da molecular weight cutoff (pore size ≈ 7.9 nm) was selected in the MEUF process to achieve the removal efficiency of Cr(VI) higher than 95%.
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MacInnis, Judith A., Greg D. Boucher, R. Palepu und D. Gerrard Marangoni. „The properties of a family of two-headed surfactant systems: the 4-alkyl-3-sulfosuccinates 2. Surface properties of alkyl sulfosuccinate micelles“. Canadian Journal of Chemistry 77, Nr. 3 (01.03.1999): 340–47. http://dx.doi.org/10.1139/v99-008.
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The micellar properties of a family of two-headed surfactants, the alkyl sulfosuccinates, were investigated employing fluorescence, ultra-violet spectroscopy, and acid-base titrations, as a function of the chain length of the surfactant. Polarity of the micellar interior was investigated using pyrene and the ionic probe 8-anilino-1-naphthalensulfonic acid ammonium salt (ANS). Pyrene I1/I3 ratios were used to probe the microenvironment of the probe in the palisade layer of the micelle. The pKa values of both of the anionic head groups were determined using acid-base titrations. Surface potential measurements were obtained from the measurement of the pKa of the hydrophobic indicator, 7-hydroxycoumarin, at the sulfosuccinate micellar interface. All of these results were used to examine the surface properties of the alkyl sulfosuccinate micelles and the polarity of the micellar interior.Key words: micellization, pKa, surface potential, surface charge density, 7-hydroxycoumarin, pyrene.
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Wen, Shan-Ni, Chih-Hang Chu, Yu-Chao Wang, Hsin-Ying Huang, Yu-Jing Wang, Jia-Yi Lin, Hsiao-Ting Lu, Sin-Jie Wang und Chung-Shi Yang. „Polymer-Stabilized Micelles Reduce the Drug Rapid Clearance In Vivo“. Journal of Nanomaterials 2018 (2018): 1–7. http://dx.doi.org/10.1155/2018/5818592.
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Micelles are self-assembled nanoscaled aggregates from amphiphilic unimers and can be used to encapsulate hydrophobic drugs. However, the dynamic exchanging of unimers between micelles and bulk solution often leads to micelle destabilization and subsequent leaking of the encapsulated substances. Thus, we incorporated a hydrophobic polymer into the micellar core for interlacing the unimers and stabilizing the micelle structure. The polymer-stabilized and non-polymer-stabilized micelles have similar physicochemical properties including small sizes (~35 nm), negative surface charges (~−35 mV), and high drug contents (~15%). Drugs encapsulated in polymer-stabilized micelles are released in a slower rate than are non-polymer-stabilized micelles. From in vivo pharmacokinetic studies, drugs loaded in polymer-stabilized micelles have lower clearance and higher plasma concentration and lower volume distribution than non-polymer-stabilized micelles have. In conclusion, polymer-stabilized micelles can reduce rapid drug clearance via strengthening of the micellar structure and increase in the available drug amount in plasma, thus broadening pharmaceutical applications of micelles.
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Ezhilrani, V. C., Vigneshwari R und Sasmita Dash. „Comparison Between Interaction of Hydrophobic-anionic and Hydrophobic-cationic Mixed Micellar System with Drug Ciprofloxacin“. Oriental Journal Of Chemistry 37, Nr. 6 (30.12.2021): 1376–86. http://dx.doi.org/10.13005/ojc/370616.
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The interaction studies of drug ciprofloxacin with two mixed micellar systems are reported. The mixed micelles comprise a nonionic hydrophobic surfactant, pluronic L-81, an anionic surfactant, Ammonium dodecyl sulfate (ADS); and a cationic surfactant, Cetylpyridinium bromide (CPB). The various combinations chosen were L-81-ADS and L-81-CPB. The properties of both the mixed micelles were compared. Spectrophotometric, conductometric, co-solvent effect, and Infrared studies were used for the investigations. The studies were carried out in a wide range of mixed micellar concentrations in the post micellar region of the individual surfactants. The solubilization of drug CPX in the L-81-ADS was higher than that in L-81-CPB mixed micelle, as evidenced by UV studies. Ethanol and ethylene glycol were found to be effective co-solvents for both the mixed micellar systems. The conductivity studies of CPX with ADS and CPB surfactants, displayed a higher value of conductance for CPX and ADS, from 0.37µs-1 to 0.74µs-1 compared to CPX and CPB. The drug-mixed micelle displayed a higher molecular weight complex formation as seen from the IR spectra.
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Mullally, Maria K., und D. Gerrard Marangoni. „Micellar properties of zwitterionic surfactant - alkoxyethanol mixed micelles“. Canadian Journal of Chemistry 82, Nr. 7 (01.07.2004): 1223–29. http://dx.doi.org/10.1139/v04-022.
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The micelle formation process for a zwitterionic surfactant, N-dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (ZW3-12), has been investigated in a series of mixed solvents consisting of different concentrations of ethoxylated alcohols and polymers. The critical micelle concentrations (cmc values) of the aggregates were determined by fluorescence spectroscopy, and the surfactant aggregation numbers were obtained from luminescence probing experiments. The cmc values for ZW3-12 changed very little in the presence of increasing amounts of poly(ethyleneoxide) (PEO) in the mixed solvent. In the case of the ethoxylated alcohol ZW3-12 systems, the cmc values and aggregation numbers decreased systematically with increasing alcohol concentration. However, the cmc values of the mixed micelles showed little dependence on the number of ethylene oxide (EO) groups at constant alcohol concentration. These results are compared with the well-studied sodium dodecylsulfate ethoxylated alcohol, and dodecyltrimethylammonium bromide ethoxylated alcohol mixed micellar systems and to SDSPEO systems and are discussed in terms of the contribution of the EO groups to the hydrophobic interactions. Key words: zwitterionic surfactant, alcohols, mixed micelles, luminescence probing.
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Elistratova, Anastasiia A., Alexander S. Gubarev, Alexey A. Lezov, Petr S. Vlasov, Anastasia I. Solomatina, Yu-Chan Liao, Pi-Tai Chou, Sergey P. Tunik, Pavel S. Chelushkin und Nikolai V. Tsvetkov. „Amphiphilic Diblock Copolymers Bearing Poly(Ethylene Glycol) Block: Hydrodynamic Properties in Organic Solvents and Water Micellar Dispersions, Effect of Hydrophobic Block Chemistry on Dispersion Stability and Cytotoxicity“. Polymers 14, Nr. 20 (16.10.2022): 4361. http://dx.doi.org/10.3390/polym14204361.
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Despite the fact that amphiphilic block copolymers have been studied in detail by various methods both in common solvents and aqueous dispersions, their hydrodynamic description is still incomplete. In this paper, we present a detailed hydrodynamic study of six commercial diblock copolymers featuring the same hydrophilic block (poly(ethylene glycol), PEG; degree of polymerization is ca. 110 ± 25) and the following hydrophobic blocks: polystyrene, PS35-b-PEG115; poly(methyl methacrylate), PMMA55-b-PEG95; poly(1,4-butadyene), PBd90-b-PEG130; polyethylene PE40-b-PEG85; poly(dimethylsiloxane), PDMS15-b-PEG115; and poly(ɛ-caprolactone), PCL45-b-PEG115. The hydrodynamic properties of block copolymers are investigated in both an organic solvent (tetrahydrofuran) and in water micellar dispersions by the combination of static/dynamic light scattering, viscometry, and analytical ultracentrifugation. All the micellar dispersions demonstrate bimodal particle distributions: small compact (hydrodynamic redii, Rh ≤ 17 nm) spherical particles ascribed to “conventional” core–shell polymer micelles and larger particles ascribed to micellar clusters. Hydrodynamic invariants are (2.4 ± 0.4) × 10−10 g cm2 s−2 K−1 mol−1/3 for all types of micelles used in the study. For aqueous micellar dispersions, in view of their potential biomedical applications, their critical micelle concentration values and cytotoxicities are also reported. The investigated micelles are stable towards precipitation, possess low critical micelle concentration values (with the exception of PDMS15-b-PEG115), and demonstrate low toxicity towards Chinese Hamster Ovarian (CHO-K1) cells.
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Biasutti, M. A., und Juana J. Silber. „Interaction between tetracyanoethylene and naphthalene in reverse micelles of AOT in n-hexane. The electron-donor properties of AOT“. Canadian Journal of Chemistry 74, Nr. 9 (01.09.1996): 1603–8. http://dx.doi.org/10.1139/v96-177.
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The electron donor–acceptor (EDA) interaction between TCNE and naphthalene (Naph) in n-hexane and reverse micelles of AOT in n-hexane was studied by UV–visible spectroscopy with the aim of determining the influence of the micellar media on the EDA interaction. The spectra of the mixtures of TCNE–Naph in n-hexane show two typical maxima at 418 and 534 nm, assigned to the formation of a π–π EDA complex. In the micellar media a new band is observed at 398 nm. When the spectra of TCNE in n-hexane are studied in the presence of AOT two new bands at 398 and 418 nm are detected. These bands are consistent with an EDA interaction between TCNE and AOT as n-donor. The stability constants of this interaction were calculated for AOT concentrations below the CMC and in the micellar media at different W(W = [H2O]/[AOT]). The results give evidence of the tendency of AOT to interact very strongly with electron acceptors. Moreover, in the system TCNE–Naph in the micellar media it is shown that Naph and AOT compete to form a complex with TCNE. The formation constants of the complexes of AOT–Naph in the micelle system were determined at W = 0 and 5. Despite the competition of AOT for TCNE the stability constant for the complex TCNE–Naph is higher than in homogeneous media, probably due to the high local concentration of the acceptor in the micelle. Key words: reverse micelles, aerosol-OT, tetracyanoethylene, naphthalene, electron donor–acceptor complexes.
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Liu, Rui, WanFen Pu, Hu Jia, XiaoPei Shang, Yue Pan und ZhaoPeng Yan. „Rheological Properties of Hydrophobically Associative Copolymers Prepared in a Mixed Micellar Method Based on Methacryloxyethyl-dimethyl Cetyl Ammonium Chloride as Surfmer“. International Journal of Polymer Science 2014 (2014): 1–14. http://dx.doi.org/10.1155/2014/875637.
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A novel cationic surfmer, methacryloxyethyl-dimethyl cetyl ammonium chloride (DMDCC), is synthesized. The micellar properties, including critical micelle concentration and aggregation number, of DMDCC-SDS mixed micelle system are studied using conductivity measurement and a steady-state fluorescence technique. A series of water-soluble associative copolymers with acrylamide and DMDCC are prepared using the mixed micellar polymerization. Compared to conventional micellar polymerization, this new method could not only reasonably adjust the length of the hydrophobic microblock, that is,NH, but also sharply reduce the amount of surfactant. Their rheological properties related to hydrophobic microblock and stickers are studied by the combination of steady flow and linear viscoelasticity experiments. The results indicate that both the hydrophobic content and, especially the length of the hydrophobic microblock are the dominating factors effecting the intermolecular hydrophobic association. The presence of salt influences the dynamics of copolymers, resulting in the variation of solution characters. Viscosity measurement indicates that mixed micelles between the copolymer chain and SDS molecules serving as junction bridges for transitional network remarkably enhance the viscosity. Moreover, the microscopic structures of copolymers at different experimental conditions are conducted by ESEM. This method gives us an insight into the preparation of hydrophobically associative water-soluble copolymers by cationic surfmer-anionic surfactant mixed micellar polymerization with good performance.
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Munir, Muhammad, Arsani Salib, Lok Shu Hui und Ayse Turak. „Unusual Phase Behaviour for Organo-Halide Perovskite Nanoparticles Synthesized via Reverse Micelle Templating“. Chemistry 5, Nr. 4 (12.11.2023): 2490–512. http://dx.doi.org/10.3390/chemistry5040163.
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Micelle templating has emerged as a powerful method to produce monodisperse nanoparticles. Herein, we explore unconventional phase transformations in the synthesis of organo-halide perovskite nanoparticles utilizing reverse micelle templates. We employ diblock-copolymer reverse micelles to fabricate these nanoparticles, which confines ions within micellar nanoreactors, retarding reaction kinetics and facilitating perovskite cage manipulation. The confined micellar environment exerts pressure on both precursors and perovskite crystals formed inside, enabling stable phases not typically observed at room temperature in conventional synthesis. This provides access to perovskite structures that are otherwise challenging to produce. The hydrophobic shell of the micelle also enhances perovskite stability, particularly when combined with anionic exchange approaches or large aromatic cations. This synergy results in long-lasting stable optical properties despite environmental exposure. Reverse micelle templates offer a versatile platform for modulating perovskite structure and behavior across a broad spectrum of perovskite compositions, yielding unique phases with diverse emission characteristics. By manipulating the composition and properties of the reverse micelle template, it is possible to tune the characteristics of the resulting nanoparticles, opening up exciting opportunities for customizing optical properties to suit various applications.
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Banshoya, Kengo, Tetsuya Nakamura, Tetsuro Tanaka und Yoshiharu Kaneo. „Coenzyme Q10-Polyethylene Glycol Monostearate Nanoparticles: An Injectable Water-Soluble Formulation“. Antioxidants 9, Nr. 1 (19.01.2020): 86. http://dx.doi.org/10.3390/antiox9010086.
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Therapeutic applications of coenzyme Q10 (CoQ10) are greatly limited by its lack of solubility in aqueous media. In this study, polyethylene glycol monostearate (stPEG) was used to construct micelles containing CoQ10 as a new formulation. The micellar formulations (stPEG/CoQ10) were prepared using five types of stPEG with 10, 25, 40, 55, and 140 PEG repeat units, respectively. The micellar preparation was simple, consisting of only stPEG and CoQ10. Next, we compared the physical properties and blood circulation of these micelles. The CoQ10 load of this formulation was approximately 15 w/w%. Based on the dynamic light scattering method, the average molecular size of the stPEG/CoQ10 micelles was approximately 15 to 60 nm. The zeta potentials of these micelles were approximately −10 to −25 mV. The micelles using stPEG25, 40, and 55 demonstrated high solubility in water. Furthermore, these micelles had in vitro antioxidant activity. On comparing the blood circulation of micelles using stPEG25, 40, 55, and 140, micelles using stPEG55 had a significantly higher circulation in blood. The stPEG55/CoQ10 micelle demonstrated a protective effect against acetaminophen-induced liver injury in mice. In conclusion, these data indicate that the intravenous administration of the stPEG/CoQ10 micellar aqueous formulation is of great value against oxidant stress.
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Xiong, Di, Liyang Wen, Shiyuan Peng, Jianchang Xu und Lijuan Zhang. „Reversible Cross-Linked Mixed Micelles for pH Triggered Swelling and Redox Triggered Degradation for Enhanced and Controlled Drug Release“. Pharmaceutics 12, Nr. 3 (12.03.2020): 258. http://dx.doi.org/10.3390/pharmaceutics12030258.
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Good stability and controlled drug release are important properties of polymeric micelles for drug delivery. A good candidate for drug delivery must have outstanding stability in a normal physiological environment, followed with low drug leakage and side effects. Moreover, the chemotherapeutic drug in the micellar core should also be quickly and “on-demand” released in the intracellular microenvironment at the tumor site, which is in favor of overcoming multidrug resistance (MDR) effects of tumor cells. In this work, a mixed micelle was prepared by the simple mix of two amphiphilic copolymers, namely PCL-SS-P(PEGMA-co-MAEBA) and PCL-SS-PDMAEMA, in aqueous solution. In the mixed micelle’s core–shell structure, PCL blocks were used as the hydrophobic core, while the micellar hydrophilic shell consisted of two blocks, namely P(PEGMA-co-MAEBA) and PDMAEMA. In the micellar shell, PEGMA provided hydrophilicity and stability, while MAEBA introduced the aldehyde sites for reversible crosslinking. Meanwhile, the PDMAEMA blocks were also introduced in the micellar shell for pH-responding protonation and swelling of the micelle. The disulfide bonds between the hydrophobic core and hydrophilic shell had redox sensitive properties. Reversible cross-linked micelles (RCLMs) were obtained by crosslinking the micellar shell with an imine structure. RCLMs showed good stability and excellent ability against extensive dilution by aqueous solution. In addition, the stability in different conditions with various pH values and glutathione (GSH) concentrations was studied. Then, the anticancer drug doxorubicin (DOX) was selected as the model drug to evaluate drug entrapment and release capacity of mixed micelles. The in vitro release profiles indicated that this RCLM had controlled drug release. In the simulated normal physiological environment (pH 7.4), the drug release of the RCLMs was restrained obviously, and the cumulative drug release content was only 25.7 during 72 h. When it came to acidic conditions (pH 5.0), de-crosslinking of the micelles occurred, as well as protonation of PDMAEMA blocks and micellar swelling at the same time, which enhanced the drug release to a large extent (81.4%, 72 h). Moreover, the drug release content was promoted further in the presence of the reductant GSH. In the condition of pH 5.0 with 10 mM GSH, disulfide bonds broke-up between the micelle core and shell, followed by shedding of the shell from the inner core. Then, the micellar disassembly (degradation) happened based on the de-crosslinking and swelling, and the drug release was as high as 95.3%. The MTT assay indicated that the CLSMs showed low cytotoxicity and good biocompatibility against the HepG2 cells. In contrast, the DOX-loaded CLSMs could efficiently restrain the proliferation of tumor cells, and the cell viability after 48 h incubation was just 13.2%, which was close to that of free DOX. This reversible cross-linked mixed micelle with pH/redox responsive behaviors is a potential nanocarrier for chemotherapy.
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MacInnis, Judith A., R. Palepu und D. Gerrard Marangoni. „A nuclear magnetic resonance investigation of the micellar properties of a series of sodium cyclohexylalkanoates“. Canadian Journal of Chemistry 77, Nr. 11 (01.11.1999): 1994–2000. http://dx.doi.org/10.1139/v99-211.
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The micellar properties of a family of surfactants, the sodium cyclohexylalkanoates, have been investigated in aqueous solution using multinuclear NMR spectroscopy. C-13 chemical shift measurements have been used to determine both the cmc values and the micellar aggregation numbers (Ns values) of these surfactants. The cmc values and the degrees of counterion binding were estimated from 23Na chemical shift measurements. The critical micelle concentrations (cmc's) and the aggregation numbers determined from the NMR experiments indicate that these amphiphiles have high cmc's and low aggregation numbers when compared to other single-headed surfactants (most notably the sodium alkanoates). The conformational changes incurred by the carbon atoms upon micelle formation have been deduced from the 13C chemical shift differences (δsurf,mic - δsurf,aq). These results are used to discuss the formation of the aggregates of the sodium cyclohexylalkanoate surfactants as a function of the length of the alkanoate side chain.Key words: micelles, surfactants, NMR spectroscopy, chemical shifts, aggregation numbers, degree of counterion binding, conformational changes.
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Groult, Hugo, Isabel García-Álvarez, Lorenzo Romero-Ramírez, Manuel Nieto-Sampedro, Fernando Herranz, Alfonso Fernández-Mayoralas und Jesús Ruiz-Cabello. „Micellar Iron Oxide Nanoparticles Coated with Anti-Tumor Glycosides“. Nanomaterials 8, Nr. 8 (25.07.2018): 567. http://dx.doi.org/10.3390/nano8080567.
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The synthesis procedure of nanoparticles based on thermal degradation produces organic solvent dispersible iron oxide nanoparticles (OA-IONP) with oleic acid coating and unique physicochemical properties of the core. Some glycosides with hydrophilic sugar moieties bound to oleyl hydrophobic chains have antimitotic activity on cancer cells but reduced in vivo applications because of the intrinsic low solubility in physiological media, and are prone to enzymatic hydrolysis. In this manuscript, we have synthetized and characterized OA-IONP-based micelles encapsulated within amphiphilic bioactive glycosides. The glycoside-coated IONP micelles were tested as Magnetic Resonance Imaging (MRI) contrast agents as well as antimitotics on rat glioma (C6) and human lung carcinoma (A549) cell lines. Micelle antimitotic activity was compared with the activity of the corresponding free glycosides. In general, all OA-IONP-based micellar formulations of these glycosides maintained their anti-tumor effects, and, in one case, showed an unusual therapeutic improvement. Finally, the micelles presented optimal relaxometric properties for their use as T2-weighed MRI contrast agents. Our results suggest that these bioactive hydrophilic nano-formulations are theranostic agents with synergistic properties obtained from two entities, which separately are not ready for in vivo applications, and strengthen the possibility of using biomolecules as both a coating for OA-IONP micellar stabilization and as drugs for therapy.
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Klyachko, Natalia L., Natalia G. Bogdanova, Andrei V. Levashov und Karel Martinek. „Micellar Enzymology: Superactivity of Enzymes in Reversed Micelles of Surfactants Solvated by Water/Organic Cosolvent Mixtures“. Collection of Czechoslovak Chemical Communications 57, Nr. 3 (1992): 625–40. http://dx.doi.org/10.1135/cccc19920625.
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Catalytic properties of α-chymotrypsin, peroxidase and laccase, dissolved in water-immiscible organic solvents by entrapping them into the reversed micelles of surfactants solvated by water/organic cosolvent (glycerol or 1,4- or 2,3-butanediol or dimethyl sulfoxide) mixtures, are studied. As micelle-forming surfactants, sodium salt of bis(2-ethylhexyl)sulfosuccinate (Aerosol OT) in n-octane or cetyltrimethylammonium bromide in n-octane/chloroform (1 : 1 by volume) mixture are used. The dependences of the catalytic activity on the surfactant solvation degree are bell-shaped. Maxima of the catalytic activity of enzymes solubilized in the micellar systems are observed at such optimum values of the surfactant solvation degree at which the size of micellar inner cavity and of the entrapped protein molecule is approximately equal. With decreasing content of water in the micellar media studied, the catalytic activity of the solubilized enzymes increases considerably, and is much (10-100 times) higher than in bulk aqueous buffers. In conclusion, possible mechanisms of the micellar effects are suggested.
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Tănase, Maria Antonia, Adina Raducan, Petruţa Oancea, Lia Mara Diţu, Miruna Stan, Cristian Petcu, Cristina Scomoroşcenco, Claudia Mihaela Ninciuleanu, Cristina Lavinia Nistor und Ludmila Otilia Cinteza. „Mixed Pluronic—Cremophor Polymeric Micelles as Nanocarriers for Poorly Soluble Antibiotics—The Influence on the Antibacterial Activity“. Pharmaceutics 13, Nr. 4 (24.03.2021): 435. http://dx.doi.org/10.3390/pharmaceutics13040435.
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In this work, novel polymeric mixed micelles from Pluronic F127 and Cremophor EL were investigated as drug delivery systems for Norfloxacin as model antibiotic drug. The optimal molar ratio of surfactants was determined, in order to decrease critical micellar concentration (CMC) and prepare carriers with minimal surfactant concentrations. The particle size, zeta potential, and encapsulation efficiency were determined for both pure and mixed micelles with selected composition. In vitro release kinetics of Norfloxacin from micelles show that the composition of surfactant mixture generates tunable extended release. The mixed micelles exhibit good biocompatibility against normal fibroblasts MRC-5 cells, while some cytotoxicity was found in all micellar systems at high concentrations. The influence of the surfactant components in the carrier on the antibacterial properties of Norfloxacin was investigated. The drug loaded mixed micellar formulation exhibit good activity against clinical isolated strains, compared with the CLSI recommended standard strains (Staphylococcus aureus ATCC 25923, Enterococcus faecalis ATCC 29213, Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922). P. aeruginosa 5399 clinical strain shows low sensitivity to Norfloxacin in all tested micelle systems. The results suggest that Cremophor EL-Pluronic F127 mixed micelles can be considered as novel controlled release delivery systems for hydrophobic antimicrobial drugs.
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Li, Jian Ping, Lian Lai Cui, Xin Tan und Ling Zhang. „Preparation of Interface-Cross-Linked Micelles as Drug Delivery via RAFT Polymerization“. Advanced Materials Research 716 (Juli 2013): 147–52. http://dx.doi.org/10.4028/www.scientific.net/amr.716.147.
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Block copolymer PLA200-b-PPEGMEMA225 were prepared via ring-open polymerization and RAFT process. Further stabilization of the micellar system was performed in water using a dimethacrylate (EDGMA), and the RAFT to cross-link the interface. The interface-cross-linked micelle was found to present better properties than the uncross-linked block copolymer micelle during the drug loading and releasing experiment. Both block copolymers and cross-linked micelles show no toxicity on COS-7 cell line.
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Mirgorod, Yu A., N. A. Borsch, A. M. Storozhenko und L. S. Ageeva. „Emergent properties of magnetic ions and nanoparticles in micellar solutions of surfactants: Use in fine technologies“. Fine Chemical Technologies 18, Nr. 5 (27.11.2023): 471–81. http://dx.doi.org/10.32362/2410-6593-2023-18-5-471-481.
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Objectives. To establish expected emergent (unexpected) properties of magnetic materials when obtained in aqueous micellar solutions of surfactants (aqueous quantum materials), and their use in fine technologies.Methods. Chemical synthesis of magnetic nanoparticles in aqueous micellar solutions of surfactants of various nature. Characterization of magnetic solutions and nanoparticles by magnetic measurements, spectroscopy, diffractometry, small-angle X-ray diffraction, scanning probe microscopy, and others.Results. The term “water quantum material” refers to materials (micellar solutions) whose properties are mainly determined by the nuclear quantum effect on macroscopic scales (emergent property). Micellar solutions exhibit phenomena and functionality not always consistent with the classical theory of micellization. The article presents in detail the experimental results that suggest the manifestation of the emergent properties of magnetic materials obtained in aqueous micellar solutions of surfactants. In particular, Gd3+ ions in an aqueous micellar solution of sodium dodecyl sulfate exhibit paramagnetic properties, possibly indicating their random arrangement in solution contrary to the classical theory of micellization with an ordered adsorption layer on micelles. Hybrid Pt–Gd nanoparticles are formed in a quantum material with cetylpyridinium chloride as a matrix, although Gd3+ ions must be repelled by CP+ ions on micelles. Nanosized powders of cobalt ferrite and nickel ferrite obtained in a micellar solution of sodium dodecyl sulfate have superparamagnetic properties, although the presence of their precursor ions in the adsorption layer in classical micelles should lead to ferromagnetic properties.Conclusions. The synthesis of nanoparticles in a quantum material opens up the possibility of reducing ions of different signs in one stage during the processing of metallurgy waste, in order to obtain nanoparticles of various metals and their composites. Magnetic nanoparticles obtained in a quantum surfactant material self-assemble on various substrates, enabling the creation of materials whose residual magnetization and coercive field can be controlled at room temperatures.
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Greencorn, David J., Victoria M. Sandre, Emily K. Piggott, Michael R. Hillier, A. James Mitchell, Taryn M. Reid, Michael J. McAlduff, Kulbir Singh und D. Gerrard Marangoni. „Asymmetric cationic gemini surfactants: an improved synthetic procedure and the micellar and surface properties of a homologous series in the presence of simple salts“. Canadian Journal of Chemistry 96, Nr. 7 (Juli 2018): 672–80. http://dx.doi.org/10.1139/cjc-2017-0676.
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The micellar and morphological properties of symmetric, cationic gemini surfactants have been well studied in the literature as a function of nature and type of the spacer group and the length and type of hydrophobic chain. In this paper, we have examined the effects of tail asymmetry on the properties of a series of cationic surfactants, the N-alkyl-1-N′-alkyl-2-N,N,N′,N′-tetramethyldiammonium dibromide. A novel synthetic method is used to prepare a series of these surfactants and the consequences of asymmetry on micellar properties are presented. This new method has been shown to be more efficient, with higher yields of the asymmetric surfactants than the yields of the accepted literature method. The critical micelle concentration values and the micelle sizes of the asymmetric gemini surfactants, 12-4-12, 12-4-10, 12-4-8, and 12-4-6 gemini surfactants, were obtained from conductivity and dynamic light scattering. With increasing chain asymmetry, the size of the micelle increased due to the formation of loose micelles. The addition of NaCl and Na2SO4 to the surfactant solutions increased the aggregate size, and this effect was more pronounced with increasing salt concentrations. These results are interpreted in terms of the effect these ions have on the “compactness” of the micelle structure.
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Malkawi, Ahmad, Nasr Alrabadi und Ross Allan Kennedy. „Dual-Acting Zeta-Potential-Changing Micelles for Optimal Mucus Diffusion and Enhanced Cellular Uptake after Oral Delivery“. Pharmaceutics 13, Nr. 7 (27.06.2021): 974. http://dx.doi.org/10.3390/pharmaceutics13070974.
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Context: Overcoming the intestinal mucosal barrier can be a challenge in drug delivery. Nanoemulsions with negative zeta potentials can effectively permeate the mucus layer, but those with positive zeta potentials are better taken up by cells; a nanoemulsion with capricious zeta potential from negative to positive can achieve both good permeation and high uptake. Objective: This study aimed to develop dual-acting zeta-potential-amphoteric micelles enabling optimal muco-permeation and enhancement of cellular uptake. Methods: A micellar pre-concentrate was prepared from 15% Labrasol, 15% Kolliphor EL, 30% Kolliphor RH 40, and 40% dimethylsulfoxide. The micellar pre-concentrate was loaded with anionic stearic acid (SA), forming ionic complexes with cationic polymers at a ratio of 25:1 with Eudragit RS 100 and Eudragit RL 100. Blank micelles and those containing complexes were separately diluted in physiological buffers and examined for their droplet sizes, polydispersity indices (PDIs), zeta potentials, and cytotoxicity. The SA release from the micellar complexes was evaluated in 0.1 mM phosphate buffer (pH 6.8) containing 0.001% fluorescein, thereby enabling an instant decrease in fluorescence. Finally, the micelles were loaded with the model drug fluorescein diacetate (FDA) and evaluated for their muco-permeation behavior and cellular uptake. Results: The micellar dilutions formed micelles at the critical micelle concentration (CMC) of 312 µg/mL and showed a uniform average droplet size of 14.2 nm, with a PDI < 0.1. Micellar dilutions were non-cytotoxic when used at 1:100 in a physiological medium. Micelles loaded with ionic complexes achieved a sustained release of 95.5 ± 3.7% of the SA in 180 min. Moreover, the zeta potential of the complex-loaded micelles shifted from −5.4 to +1.8 mV, whereas the blank micelles showed a stabilized zeta potential of −10 mV. Furthermore, the negatively charged blank and complex-loaded micelles exhibited comparable muco-permeation, with an overall average of 58.2 ± 3.7% diffusion of FDA. The complex-loaded micellar droplets, however, provided a significantly higher cellular uptake of the model drug FDA (2.2-fold, p ≤ 0.01) Conclusion: Due to undergoing a shift in zeta potential, the modified micelles significantly enhanced cellular uptake while preserving mucus-permeating properties.
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Mwalupindi, Averrin G., Rezik A. Agbaria und Isiah M. Warner. „Synthesis and Characterization of the Surfactant Terbium 3-[[1,2-Bis-[[(2-Ethylhexyl)Oxy]Carbonyl]Ethyl]Thio]Succinate as a Reagent for Determining Organic Analytes“. Applied Spectroscopy 48, Nr. 9 (September 1994): 1132–37. http://dx.doi.org/10.1366/0003702944029497.
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The surfactant terbium 3-[[1,2-bis[[(2-ethylhexyl)oxy]carbonyl]ethyl]thio]succinate has been synthesized and characterized by use of its absorption, luminescence, and microviscosity properties. In the presence of small amounts of water, this surfactant aggregates in cyclohexane to form reversed micelles containing Tb(III) counterions. The critical reverse micelle concentration has been determined to be 5.7 × 10−5 M with the use of an optical probe. Organic analytes solubilized in reverse micelles have been detected indirectly with the use of the luminescence characteristics of Tb(III) counterions. The detection scheme is based on energy transfer from the solubilized organic donor to acceptor Tb(III) counterions. Analytical figures of merit for the micellar system in the presence of organic analytes are presented. The microviscosity of the reverse micellar core has been estimated with the use of a viscosity-sensitive luminescent probe.
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Lebedeva, Inna O., Ekaterina B. Zhulina und Oleg V. Borisov. „Self-Assembly of Bottlebrush Block Copolymers in Selective Solvent: Micellar Structures“. Polymers 13, Nr. 9 (21.04.2021): 1351. http://dx.doi.org/10.3390/polym13091351.
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Block copolymers comprising chemically different bottlebrush blocks can self-assemble in selective solvents giving rise to micellar-like solution nanostructures. The self-consistent field theoretical approach is used for predicting relation between architectural parameters of both bottlebrush blocks (polymerization degrees of the main and side chains, density of grafting of the side chains to the backbone) and structural properties of micelles as well as critical micelle concentration (CMC). As predicted by the theory, replacement of linear blocks by bottlebrush ones with the same degrees of polymerization results in a decrease in the micellar core size (in aggregation number) and extension of the corona, whereas the CMC increases. These theoretical findings are in good agreement with results of computer simulations.
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Tian, Maozhang, Xi Chen, Xinyuan Zou, Yuchen Qian, Zhang Liu und Yaxun Fan. „pH-Responsive Rheological Properties and Microstructure Transition in Mixture of Anionic Gemini/Cationic Monomeric Surfactants“. Molecules 26, Nr. 16 (19.08.2021): 5013. http://dx.doi.org/10.3390/molecules26165013.
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Surfactant aggregates have long been considered as a tool to improve drug delivery and have been widely used in medical products. The pH-responsive aggregation behavior in anionic gemini surfactant 1,3-bis(N-dodecyl-N-propanesulfonate sodium)-propane (C12C3C12(SO3)2) and its mixture with a cationic monomeric surfactant cetyltrimethylammonium bromide (CTAB) have been investigated. The spherical-to-wormlike micelle transition was successfully realized in C12C3C12(SO3)2 through decreasing the pH, while the rheological properties were perfectly enhanced for the formation of wormlike micelles. Especially at 140 mM and pH 6.7, the mixture showed high viscoelasticity, and the maximum of the zero-shear viscosity reached 1530 Pa·s. Acting as a sulfobetaine zwitterionic gemini surfactant, the electrostatic attraction, the hydrogen bond and the short spacer of C12C3C12(SO3)2 molecules were all responsible for the significant micellar growth. Upon adding CTAB, the similar transition could also be realized at a low pH, and the further transformation to branched micelles occurred by adjusting the total concentration. Although the mixtures did not approach the viscosity maximum appearing in the C12C3C12(SO3)2 solution, CTAB addition is more favorable for viscosity enhancement in the wormlike-micelle region. The weakened charges of the headgroups in a catanionic mixed system minimizes the micellar spontaneous curvature and enhances the intermolecular hydrogen-bonding interaction between C12C3C12(SO3)2, facilitating the formation of a viscous solution, which would greatly induce entanglement and even the fusion of wormlike micelles, thus resulting in branched microstructures and a decline of viscosity.
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Jeyarajan, Helen Ratna Monica. „PHOTOPHYSICAL ASPECTS OF POLARITY SENSITIVE FLUOROPHORE IN CATIONIC REVERSE MICELLES“. Journal of Advanced Scientific Research 13, Nr. 01 (10.02.2022): 340–47. http://dx.doi.org/10.55218/jasr.202213140.
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In recent years, the field of reverse micelles has witnessed a significant growth of interest, partly due to the finding that proteins, other biopolymers, and even bacterial cells can be solubilized in the reverse micellar systems. Among surfactants capable of forming water in oil microemulsion, the cationic surfactant cetyltrimethylammonium bromide (CTAB) has received particular attention because of its ability to solubilize relatively large amount of water in a variety of hydrophobic organic solvents. Due to versatile photochemical and photophysical properties of Ru(II) complexes, Ru(II)- phenanthroline and its derivatives were used in this present work to form CTAB cationic reverse micelles and studied to characterise their photophysical properties such as absorption, emission and excited state life time. The findings from the spectral data observed in the present study proves that the excited state properties of Ru(II)-phenanthroline complexes are dramatically altered in the presence of reverse micelle. Specifically reverse micelle encapsulation of [Ru(dpphen)3]2+ complex in restricted environment causes blue shift in the emission maximum as well as have longer radiative lifetime. The blue shift in the emission maximum in the case of [Ru(dpphen)3]2+ indicates that the probes are near the water in oil reverse micellar interface, tightly bound and are not displaced towards the water pool of the micelle even at the highest water loading W0=50, which reveals the increased hydrophobicity. This highest fluorescence lifetime can serve as an excellent indicator to point out the location of the probe in a microheterogeneous system/environment.
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Georges, Joseph, und Jean-Michel Mermet. „Investigation of Micellar Effects in Thermal Lens Spectrophotometry“. Applied Spectroscopy 44, Nr. 1 (Januar 1990): 122–27. http://dx.doi.org/10.1366/0003702904086010.
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The effect of micellar solutions in thermal lens spectrophotometry was investigated. Several aspects of the thermal lens signal including the formation rate and the relaxation of the thermal lens were compared in various neat solvents and in aqueous micellar solutions. The experiments were performed with a double-beam thermal lens apparatus based upon a pulsed-dye laser as the excitation beam and a He-Ne laser as the probe beam. The results show that, if micellar solutions can be used to solubilize hydrophilic species in solvents having better thermo-optical properties than water, they do not provide sensitive modifications of the thermo-optical properties of water. The absence of micellar effect in thermal lensing, in comparison to the well-known micellar enhanced fluorescence, is discussed with respect to the size of micelles and micellar dynamics, the photophysical processes associated with thermal lensing, and the time dependence of the thermal lens signal.
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Ferreira, William T., Huynh A. Hong, Mateusz Hess, James R. G. Adams, Hannah Wood, Karolina Bakun, Sisareuth Tan et al. „Micellar Antibiotics of Bacillus“. Pharmaceutics 13, Nr. 8 (19.08.2021): 1296. http://dx.doi.org/10.3390/pharmaceutics13081296.
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Members of the Bacillus genus, particularly the “Bacillus subtilis group”, are known to produce amphipathic lipopeptides with biosurfactant activity. This includes the surfactins, fengycins and iturins that have been associated with antibacterial, antifungal, and anti-viral properties. We have screened a large collection of Bacillus, isolated from human, animal, estuarine water and soil samples and found that the most potent lipopeptide producers are members of the species Bacillus velezensis. B. velezensis lipopeptides exhibited anti-bacterial activity which was localised on the surface of both vegetative cells and spores. Interestingly, lipopeptide micelles (6–10 nm diameter) were detectable in strains exhibiting the highest levels of activity. Micelles were stable (heat and gastric stable) and shown to entrap other antimicrobials produced by the host bacterium (exampled here was the dipeptide antibiotic chlorotetaine). Commercially acquired lipopeptides did not exhibit similar levels of inhibitory activity and we suspect that micelle formation may relate to the particular isomeric forms produced by individual bacteria. Using naturally produced micelle formulations we demonstrated that they could entrap antimicrobial compounds (e.g., clindamycin, vancomycin and resveratrol). Micellar incorporation of antibiotics increased activity. Bacillus is a prolific producer of antimicrobials, and this phenomenon could be exploited naturally to augment antimicrobial activity. From an applied perspective, the ability to readily produce Bacillus micelles and formulate with drugs enables a possible strategy for enhanced drug delivery.
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Albano, Juan, Damian Grillo, Julio Facelli, Marta Ferraro und Mónica Pickholz. „Study of the Lamellar and Micellar Phases of Pluronic F127: A Molecular Dynamics Approach“. Processes 7, Nr. 9 (07.09.2019): 606. http://dx.doi.org/10.3390/pr7090606.
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In this work, we analyzed the behavior of Pluronic F127 through molecular dynamics simulations at the coarse-grain level, focusing on the micellar and lamellar phases. To this aim, two initial polymer conformations were considered, S-shape and U-shape, for both simulated phases. Through the simulations, we were able to examine the structural and mechanical properties that are difficult to access through experiments. Since no transition between S and U shapes was observed in our simulations, we inferred that all single co-polymers had memory of their initial configuration. Nevertheless, most copolymers had a more complex amorphous structure, where hydrophilic beads were part of the lamellar-like core. Finally, an overall comparison of the micellar a lamellar phases showed that the lamellar thickness was in the same order of magnitude as the micelle diameter (approx. 30 nm). Therefore, high micelle concentration could lead to lamellar formation. With this new information, we could understand lamellae as orderly packed micelles.
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Janosevic-Lezaic, Aleksandra, Nikola Paunovic und Natasa Pejic. „Thermodynamics of micellization of hexadecyltrimethylammonium bromide in propylene glycol-water mixture: A conductivity study“. Facta universitatis - series: Physics, Chemistry and Technology 12, Nr. 1 (2014): 17–26. http://dx.doi.org/10.2298/fupct1401017j.
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Micellization of hexadecyltrimethylammonium bromide (syn. cetyltrimethylammonium bromide, CTAB) in propylene glycol-water (30% v/v) binary mixture, as well as the thermodynamic properties of the resulting micelles, were investigated by electrical conductivity measurements. The conductivity data were used to determine both the critical micellar concentration (CMC) and the micellar ionization degree (?) of CTin the temperature range 298.2-310.2 K. The equilibrium model of micelle formation was applied in order to obtain the thermodynamic parameters (the standard molar Gibbs free energy, ?Gm0, enthalpy, ?Hm0 and entropy, ?Sm0) of the micellization process. The values of DGm0 and DHm0 were found to be negative at all investigated temperatures, while the values of ?Sm0 were positive and became more positive as temperature increased. A linear dependence between ?Sm0 and ?Hm0, i.e. an enthalpy-entropy compensation effect, was observed.
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Wen, Xin, Lei Wang, Xiaojuan Lai, Guiru Liu, Wenwen Yang, Jinhao Gao, Yameng Liu und Wenyu Cui. „Polymerization Behavior and Rheological Properties of a Surfactant-Modified Reactive Hydrophobic Monomer“. Chemistry 5, Nr. 4 (14.11.2023): 2598–612. http://dx.doi.org/10.3390/chemistry5040168.
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The structures and properties of hydrophobic association polymers can be controlled using micelles. In this work, we synthesize a reactive hydrophobic surfactant monomer, KS-3, from oleic acid, N,N-dimethylpropylenediamine, and allyl chloride. A strong synergistic effect between KS-3 and cocamidopropyl betaine in aqueous solution enhances the hydrophilic dispersibility of KS-3, thereby transforming spherical micelles into cylindrical micelles. KS-3 was grafted onto a polyacrylamide chain via aqueous free-radical polymerization to obtain RES, a hydrophobic association polymer. Structural analysis revealed that the RES polymers assembled in wormlike micelles were more tightly arranged than those assembled in spherical micelles, resulting in a compact network structure in water, smooth surface, and high thermal stability. Rheological tests revealed that the synthesized polymers with wormlike and spherical micelles exhibited shear-thinning properties along with different structural strengths and viscoelasticities. Therefore, controlling the micellar state can effectively regulate the polymer properties. The polymers obtained through wormlike micelle polymerization have potential applications in fields with high demands, such as drug release, water purification, and oilfield development.
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Hussein A. Abdul Hussein und Nidhal K. Maraie. „Highlights on polymeric micelles as versatile nanocarriers for drug transporting“. Al Mustansiriyah Journal of Pharmaceutical Sciences 21, Nr. 2 (19.04.2022): 21–30. http://dx.doi.org/10.32947/ajps.v21i2.806.
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Polymeric micelles are nanoscale core-shell structures formed by amphiphilic (block or graft) copolymers, that can self-aggregate in an aqueous medium. PMs characterized by small size, spherical shape, lower critical micellar concentration, which gave higher
stability for PMs over conventional surfactant micelles. The core/shell structure permits polymeric micelle to entrap poor soluble drugs and can improve their solubility and permeability. The preparation of PMs tends to be relatively easy as compared to other novel drug delivery systems. This review focus on the general properties, types, types of copolymer utilized, formation mechanism, preparation methods, characterization techniques, and the applications on PMs.
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Liu, Haipeng, und Darrell Irvine. „Immunostimulatory properties of dynamic oligonucleotide micelles (53.9)“. Journal of Immunology 188, Nr. 1_Supplement (01.05.2012): 53.9. http://dx.doi.org/10.4049/jimmunol.188.supp.53.9.
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Abstract Synthetic immunostimulatory oligonucleotides such as double-stranded RNA or unmethylated cytosine-guanosine motifs (CpG-ODNs) mimic molecular signatures of pathogens and trigger an immunostimulatory cascade; as a result, these synthetic ODNs have been extensively studied as therapeutic agents for cancer and as vaccine adjuvants. Using a self-assembly approach, we designed lipo-CpG-ODN molecules composed of CpG oligos conjugated with diacyl lipid tails. These dynamic amphiphiles form compact micelles ~20 nm in diam. in water but can also disassemble and insert their acyl tails into the plasma membrane when incubated with cells. These two key elements of the CpG micelle-ultra-small physical size and cell membrane insertion capability- combine to greatly enhance the adjuvant properties of CpG or other co-associated TLR agonists. Injection of CpG micelles s.c. resulted in a 5-15-fold enhancement of draining lymph node (dLN) retention compared with free CpG or stabilized CpG-micelles incapable of inserting into membranes. Immunization with soluble antigen mixed with CpG micelles induced 10-fold increased frequencies of antigen-specific T-cells in blood and elicited higher antibody production than equivalent doses of soluble CpG, and also elicited stronger responses than CpG-micelles lacking membrane insertion potential. Thus, dynamic micellar TLR agonists may be of interest as novel vaccine adjuvants.
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Cid, Antonio, Oscar Moldes, Juan Mejuto und Jesus Simal-Gandara. „Interaction of Caffeic Acid with SDS Micellar Aggregates“. Molecules 24, Nr. 7 (27.03.2019): 1204. http://dx.doi.org/10.3390/molecules24071204.
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Micellar systems consisting of a surfactant and an additive such as an organic salt or an acid usually self-organize as a series of worm-like micelles that ultimately form a micellar network. The nature of the additive influences micellar structure and properties such as aggregate lifetime. For ionic surfactants such as sodium dodecyl sulfate (SDS), CMC decreases with increasing temperature to a minimum in the low-temperature region beyond which it exhibits the opposite trend. The presence of additives in a surfactant micellar system also modifies monomer interactions in aggregates, thereby altering CMC and conductance. Because the standard deviation of β was always lower than 10%, its slight decrease with increasing temperature was not significant. However, the absolute value of Gibbs free enthalpy, a thermodynamic potential that can be used to calculate the maximum of reversible work, increased with increasing temperature and caffeic acid concentration. Micellization in the presence of caffeic acid was an endothermic process, which was entropically controlled. The enthalpy and enthropy positive values resulted from melting of “icebergs” or “flickering clusters” around the surfactant, leading to increased packing of hydrocarbon chains within the micellar core in a non-random manner. This can be possibly explained by caffeic acid governing the 3D matrix structure of water around the micellar aggregates. The fact that both enthalpy and entropy were positive testifies to the importance of hydrophobic interactions as a major driving force for micellization. Micellar systems allow the service life of some products to be extended without the need to increase the amounts of post-harvest storage preservatives used. If a surfactant is not an allowed ingredient or food additive, carefully washing it off before the product is consumed can avoid any associated risks. In this work, we examined the influence of temperature and SDS concentration on the properties of SDS–caffeic acid micellar systems. Micellar properties can be modified with various additives to develop new uses for micelles. This allows smaller amounts of additives to be used without detracting from their benefits.
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Gracie, Kim, Dale Turner und R. Palepu. „Thermodynamic properties of micellization of sodium dodecyl sulfate in binary mixtures of ethylene glycol with water“. Canadian Journal of Chemistry 74, Nr. 9 (01.09.1996): 1616–25. http://dx.doi.org/10.1139/v96-179.
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Micellar properties of sodium dodecyl sulfate (SDS) in aqueous mixtures of ethylene glycol (EG) were determined using techniques such as conductivity, density, EMF, surface tension, viscosity, ultrasonic velocity, and spectroscopy (fluorescence). The effective degree of disssociation of micelles (α) was determined using three different methods. Thermodynamics of micellization were obtained from the temperature dependence of critical micelle concentrations (cmc) values. The difference in Gibbs energies of micellization [Formula: see text] of SDS, between water and mixed solvent systems, was calculated to evaluate the influence of cosolvent on the micellization process. Surfactant aggregation numbers (Ns) obtained from static fluorescence quenching methods indicated a decrease in the aggregation numbers with increasing concentration of ethylene glycol in the binary solvent mixtures. In addition, the micropolarity of the micellar interior was determined from the pyreneI1/I3 ratios. These values were consistent with a decrease in the micropolarity surrounding the probe molecule as the EG content in the solvent mixture was increased. Key words: thermodynamics, micellization, aggregation numbers, ultrasonic velocity, degree of dissociation.
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JAMES, Stephen R., Sheila SMITH, Andrew PATERSON, T. Kendall HARDEN und C. Peter DOWNES. „Time-dependent inhibition of phospholipase Cβ-catalysed phosphoinositide hydrolysis: a comparison of different assays“. Biochemical Journal 314, Nr. 3 (15.03.1996): 917–21. http://dx.doi.org/10.1042/bj3140917.
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The properties of three different β-isoforms of phospholipase C (PLC) were analysed using substrate lipids dispersed in phospholipid vesicles, phospholipid–detergent mixed micelles and phospholipid monolayers spread at an air–water interface. Phosphatidylinositol 4,5-bisphosphate hydrolysis went virtually to completion in monolayers, but inositol trisphosphate production was curtailed prematurely in vesicular and micellar assays. Assays were linear for less than 2 min with vesicles; the linear portion could be significantly extended in micelles by increasing the ratio of micelles to enzyme molecules. However, onset of a second lower rate of substrate hydrolysis always occurred when ⩽ 10% of PtdIns(4,5)P2 had been utilized. This was not due to enzyme inactivation in the micellar interface, determined by addition of fresh substrate or fresh enzyme after the slow phase of activity had started, nor was it due to overt product inhibition of PLC or apparent entrapment of PLC at the micelle surface. These results are similar to those seen in assays using bacterial PLC and we suggest that the biphasic kinetics may be due to product-dependent changes in the presentation of substrate lipid to PLC in lamellar assays, leading to reduced activity.
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Zlotnikov, Igor D., Dmitriy A. Streltsov, Natalya Georgievna Belogurova und Elena Vadimovna Kudryashova. „Chitosan or Cyclodextrin Grafted with Oleic Acid Self-Assemble into Stabilized Polymeric Micelles with Potential of Drug Carriers“. Life 13, Nr. 2 (04.02.2023): 446. http://dx.doi.org/10.3390/life13020446.
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Polymeric micelles combining the advantages of biocompatible poly- and oligosaccharides with classical micellar amphiphilic systems represent a promising class of drug carriers. In this work, micelles based on chitosan (or cyclodextrin) and oleic acid with various modification degrees were synthesized—the most optimal grafting degree is 15–30% in terms of CMC. According to NTA data, micelles have a hydrodynamic diameter of the main fraction of 60–100 nm. The inclusion of the antibacterial agents: moxifloxacin or rifampicin in micelles was studied by FTIR spectroscopy and fluorescence spectroscopy using a pyrene label (using monomer-excimer approach). When aromatic molecules are incorporated into micelles, the absorption bands of C-H bonds of the fatty tails of micelles shift towards smaller wavenumbers, indicating a stabilization of the micelles structure, and the microenvironment of the drug molecule changes according to the low frequencies shift and intensity changes in oscillation frequencies of 1450 cm−1 corresponding to aromatic fragment. Loading of moxifloxacin and rifampicin into micelles leads to a change in the fluorescent properties: a shift of the maximum of fluorescence emission to the long-wavelength region and an increase in the fluorescence anisotropy due to a drastic increase in the hydrodynamic volume of the fluorophore-containing rotating fragment. Using the pyrene label, the critical micelle concentrations were determined: from 4 to 30 nM depending on the polymer composition. Micellar systems enhance the effect of the antibiotic by increasing the penetration into bacterial cells and storing the drug in a protective coat. As а part of the supramolecular structure, the antibiotic remains active for more than four days, while in free form, the activity decreases after two days. In pharmacokinetic experiments, in vivo moxifloxacin in micellar systems show 1.7 times more efficiency compared to free form; moreover, two times higher maximal concentration in the blood is achieved. The advantage of polymer micellar systems in comparison with simple cyclodextrins and chitosan, which do not so significantly contribute to the antibacterial and pharmacokinetic parameters, was shown. Thus, polymeric micelles are one of the key approaches to improving the effectiveness of antibacterial drugs and solving the problems of resistant bacterial infections and multidrug resistance.
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Kahana, Amit, Doron Lancet und Zoltan Palmai. „Micellar Composition Affects Lipid Accretion Kinetics in Molecular Dynamics Simulations: Support for Lipid Network Reproduction“. Life 12, Nr. 7 (24.06.2022): 955. http://dx.doi.org/10.3390/life12070955.
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Mixed lipid micelles were proposed to facilitate life through their documented growth dynamics and catalytic properties. Our previous research predicted that micellar self-reproduction involves catalyzed accretion of lipid molecules by the residing lipids, leading to compositional homeostasis. Here, we employ atomistic Molecular Dynamics simulations, beginning with 54 lipid monomers, tracking an entire course of micellar accretion. This was done to examine the self-assembly of variegated lipid clusters, allowing us to measure entry and exit rates of monomeric lipids into pre-micelles with different compositions and sizes. We observe considerable rate-modifications that depend on the assembly composition and scrutinize the underlying mechanisms as well as the energy contributions. Lastly, we describe the measured potential for compositional homeostasis in our simulated mixed micelles. This affirms the basis for micellar self-reproduction, with implications for the study of the origin of life.
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Majumder, Nairrita, Nandita G Das und Sudip K. Das. „Polymeric micelles for anticancer drug delivery“. Therapeutic Delivery 11, Nr. 10 (Oktober 2020): 613–35. http://dx.doi.org/10.4155/tde-2020-0008.
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Polymeric micelles have gained interest as novel drug delivery systems for the treatment and diagnosis of cancer, as they offer several advantages over conventional drug therapies. This includes drug targeting to tumor tissue, in vivo biocompatibility and biodegradability, prolonged circulation time, enhanced accumulation, retention of the drug loaded micelle in the tumor and decreased side effects. This article provides an overview on the current state of micellar formulations as nanocarriers for anticancer drugs and their effectiveness in cancer therapeutics, including their clinical status. The type of copolymers used, their physicochemical properties and characterization as well as recent developments in the design of functional polymeric micelles are highlighted. The article also presents the design and outcomes of various types of stimuli-responsive polymeric micelles.
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Hils, Christian, Ian Manners, Judith Schöbel und Holger Schmalz. „Patchy Micelles with a Crystalline Core: Self-Assembly Concepts, Properties, and Applications“. Polymers 13, Nr. 9 (04.05.2021): 1481. http://dx.doi.org/10.3390/polym13091481.
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Crystallization-driven self-assembly (CDSA) of block copolymers bearing one crystallizable block has emerged to be a powerful and highly relevant method for the production of one- and two-dimensional micellar assemblies with controlled length, shape, and corona chemistries. This gives access to a multitude of potential applications, from hierarchical self-assembly to complex superstructures, catalysis, sensing, nanomedicine, nanoelectronics, and surface functionalization. Related to these applications, patchy crystalline-core micelles, with their unique, nanometer-sized, alternating corona segmentation, are highly interesting, as this feature provides striking advantages concerning interfacial activity, functionalization, and confinement effects. Hence, this review aims to provide an overview of the current state of the art with respect to self-assembly concepts, properties, and applications of patchy micelles with crystalline cores formed by CDSA. We have also included a more general discussion on the CDSA process and highlight block-type co-micelles as a special type of patchy micelle, due to similarities of the corona structure if the size of the blocks is well below 100 nm.
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Kumar, Naveen, Rashmi Tyagi und V. K. Tyagi. „Efficiency of single and mixed dimeric surfactants micelles on solubil-ization of polycyclic aromatic hydrocarbons“. Applied Chemical Engineering 3, Nr. 1 (16.03.2020): 8. http://dx.doi.org/10.24294/ace.v3i1.545.
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The solubilization of polycyclic aromatic hydrocarbons (PAHs) such as naphthalene, phenanthrene and pyrene by single and mixed anionic dimeric surfactants was investigated and correlated with micellar properties of these surfactants. The surface and micellar properties of single and binary mixed combinations of anionic dimeric surfactants have been studied through surface tension as well as conductivity measurements at 300 K. The associations between their micelle properties and solubilizing efficiency towards PAHs have been quantified and discussed in terms of the molar solubilization ratio (MSR), micelle-water partition coefficient (Km) and standard free energy of solubilization (ΔG0S).The negative value of ΔG0Sexhibits spontaneously the solubilization process. The MSR values increase with the order “pyrene < phenanthrene < naphthalene”. The current study provides significant information for the selection of mixed dimeric surfactants for solubilizing water-insoluble compounds.
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Hossain, M. A., M. A. Rahman und M. A. Subhan. „Diffusion Interactions of Some Biologically Important Transition Metal Complexes on Micellar Properties of Sodium Dodecyl Sulphate“. Journal of Scientific Research 4, Nr. 1 (26.12.2011): 135. http://dx.doi.org/10.3329/jsr.v4i1.7989.
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The specific conductance of aqueous solutions of sodium dodecyl sulphate (SDS) was measured from 20 to 35 ºC with an interval of 5 °C in the absence and presence of metal complexes such as [Cr(acac)2(H2O)2]Cl, K3[Fe(C2O4)3] and (NH4)4[Co(C6H5O7)2] at concentrations ranging from 2.0 × 10-4 to 8.0 x 10-4 M. The specific conductance rapidly increased at the pre-micellar region with increasing of temperature and concentration of SDS, but after critical micelle concentration (CMC) the rate of increase was slower. As the concentrations of metal complexes [Cr(acac)2(H2O)2]Cl, K3[Fe(C2O4)3] and (NH4)4[Co(C6H5O7)2] increased, the CMC of SDS decreased exponentially, which was sharp with increasing temperature. The CMC decreases due to the formation of pre-micellar aggregates of the positive counter ions of the complexes with dodecyl sulphate ions (DS-) and hydrophobic interaction between ligands of complexes and hydrophobic tail of SDS. The pre-micellar aggregate formation was essentially influenced by the counter ions binding abilities to the anionic micelle. The effect of metal complexes on lowering the CMC of SDS was found to follow the order [Cr(acac)2(H2O)2]Cl < K3[Fe(C2O4)3] < (NH4)4[Co(C6H5O7)2]. Thermodynamics of metal complexes with SDS and parameters of micellization ΔG°mic, ΔH°mic and TΔS°mic were calculated.Keywords: Surfactants; Sodium dodecyl sulphate; Critical micelle concentration; Pre-micellar aggregate; Hydrophobic interaction.© 2011 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi: http://dx.doi.org/10.3329/jsr.v4i1.7989J. Sci. Res. 4 (1), 135-141 (2012)
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Jurok, Radek, Eva Svobodová, Radek Cibulka und František Hampl. „Reactivity in Micelles - Are We Really Able to Design Micellar Catalysts?“ Collection of Czechoslovak Chemical Communications 73, Nr. 2 (2008): 127–46. http://dx.doi.org/10.1135/cccc20080127.
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Coordination of lipophilic alkyl pyridin-2-yl ketoximes 1 to Ni2+ ions, reduction of lipophilic 3-alkoxyacetophenones 2 with sodium borohydride, and alkaline hydrolysis of 4-nitrophenyl diphenyl phosphate (PNPDPP) were employed as probes in the investigation which factors may influence the reactivity of organic compounds in micellar systems. In all these reactions, a lipophilic substrate solubilized in micellar core was attacked by a hydrophilic reagent from the bulk aqueous phase. To evaluate the contribution of electrostatic interactions between the micellar surface charge and the reagent to the observed reactivity, we combined reactions involving the reagents with opposite polarity (Ni2+ cations and borohydride or hydroxide anions) with positively charged micelles of hexadecyltrimethylammonium chloride (CTAC) or bromide (CTAB) and negatively charged micelles of sodium dodecyl sulfate (SDS). Non-ionic micelles (Triton X-100 or Brij 35) served as a reference. The results of the kinetic studies give evidence that each of the investigated systems has unique properties going in particular aspects beyond the scope of the generally accepted concepts of reactivity in micelles.
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Gudelj, Martina, Paola Šurina, Lucija Jurko, Ante Prkić und Perica Bošković. „The Additive Influence of Propane-1,2-Diol on SDS Micellar Structure and Properties“. Molecules 26, Nr. 12 (21.06.2021): 3773. http://dx.doi.org/10.3390/molecules26123773.
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Micellar systems are colloids with significant properties for pharmaceutical and food applications. They can be used to formulate thermodynamically stable mixtures to solubilize hydrophobic food-related substances. Furthermore, micellar formation is a complex process in which a variety of intermolecular interactions determine the course of formation and most important are the hydrophobic and hydrophilic interactions between surfactant–solvent and solvent–solvent. Glycols are organic compounds that belong to the group of alcohols. Among them, propane-1,2-diol (PG) is a substance commonly used as a food additive or ingredient in many cosmetic and hygiene products. The nature of the additive influences the micellar structure and properties of sodium dodecyl sulfate (SDS). When increasing the mass fraction of propane-1,2-diol in binary mixtures, the c.m.c. values decrease because propane-1,2-diol is a polar solvent, which gives it the ability to form hydrogen bonds, decreasing the cohesivity of water and reducing the dielectric constant of the aqueous phase. The values of ΔGm0 are negative in all mixed solvents according to the reduction in solvophobic interactions and increase in electrostatic interaction. With the rising concentration of cosolvent, the equilibrium between cosolvent in bulk solution and in the formed micelles is on the side of micelles, leading to the formation of micelles at a lower concentration with a small change in micellar size. According to the 1H NMR, with the addition of propylene glycol, there is a slight shift of SDS peaks towards lower ppm regions in comparison to the D2O peak. The shift is more evident with the increase in the amount of added propane-1,2-diol in comparison to the NMR spectra of pure SDS. Addition of propane-1,2-diol causes the upfield shift of the protons associated with hydrophilic groups, causing the shielding effect. This signifies that the alcohol is linked with the polar head groups of SDS due to its proximity to the SDS molecules.
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Brito, Mariano E., Sofia E. Mikhtaniuk, Igor M. Neelov, Oleg V. Borisov und Christian Holm. „Implicit-Solvent Coarse-Grained Simulations of Linear–Dendritic Block Copolymer Micelles“. International Journal of Molecular Sciences 24, Nr. 3 (01.02.2023): 2763. http://dx.doi.org/10.3390/ijms24032763.
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The design of nanoassemblies can be conveniently achieved by tuning the strength of the hydrophobic interactions of block copolymers in selective solvents. These block copolymer micelles form supramolecular aggregates, which have attracted great attention in the area of drug delivery and imaging in biomedicine due to their easy-to-tune properties and straightforward large-scale production. In the present work, we have investigated the micellization process of linear–dendritic block copolymers in order to elucidate the effect of branching on the micellar properties. We focus on block copolymers formed by linear hydrophobic blocks attached to either dendritic neutral or charged hydrophilic blocks. We have implemented a simple protocol for determining the equilibrium micellar size, which permits the study of linear–dendritic block copolymers in a wide range of block morphologies in an efficient and parallelizable manner. We have explored the impact of different topological and charge properties of the hydrophilic blocks on the equilibrium micellar properties and compared them to predictions from self-consistent field theory and scaling theory. We have found that, at higher degrees of branching in the corona and for short polymer chains, excluded volume interactions strongly influence the micellar aggregation as well as their effective charge.
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Numin, Mohd Sofi, Khairulazhar Jumbri, Anita Ramli und Noorazlenawati Borhan. „Microemulsion Rheological Analysis of Alkaline, Surfactant, and Polymer in Oil-Water Interface“. Processes 8, Nr. 7 (29.06.2020): 762. http://dx.doi.org/10.3390/pr8070762.
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Injection of alkaline (A), polymer (P), and surfactant (S) chemicals in enhanced oil recovery (cEOR) processes increases output by changing the properties of the injected fluid. In this work, micellar fluid interactions were studied via microemulsion rheological analysis. Crude oil and stimulated brine with ASP or SP was used for bottle testing. The results revealed that no microemulsion was produced when ASP (Alkaline, Surfactant, and Polymer) or SP (Surfactant and Polymer) was left out during the bottle testing phase. The addition of ASP and SP led to the formation of microemulsions—up to 29% for 50% water cut (WC) ASP, and 36% for 40% WC SP. This shows that the addition of ASP and SP can be applied to flooding applications. The results of the rheological analysis show that the microemulsions behaved as a shear-thinning micellar fluid by decreasing viscosity with increase in shear rate. As per the power-law equation, the ASP micellar fluid viscoelastic behavior shows better shear-thinning compared to SP, suggesting more efficiency in fluid mobility and sweep efficiency. Most of the microemulsions exhibited viscoelastic fluid behavior (G’ = G”) at angular frequency of 10 to 60 rad s−1, and stable elastic fluid behavior (G’ > G’’) below 10 rad s−1 angular frequency. The viscosity of microemulsion fluids decreases as temperature increases; this indicates that the crude oil (i.e., alkanes) was solubilized in core micelles, leading to radial growth in the cylindrical part of the wormlike micelles, and resulting in a drop in end-cap energy and micelle length. No significant difference was found in the analysis of viscoelasticity evaluation and viscosity analysis for both ASP and SP microemulsions. The microemulsion tendency test and rheology test show that the addition of ASP and SP in the oil-water interface yields excellent viscoelastic properties.
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Ahmadi, Elaheh, Tatijana Markoska, Thom Huppertz und Todor Vasiljevic. „Structural Properties of Casein Micelles with Adjusted Micellar Calcium Phosphate Content“. Foods 13, Nr. 2 (19.01.2024): 322. http://dx.doi.org/10.3390/foods13020322.
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Micellar calcium phosphate (MCP) content of skim milk was modified by pH adjustment followed by dialysis. Turbidity, casein micelle size and partitioning of Ca and caseins between the colloidal and soluble phases of milk were determined. Protein structure was characterised by Fourier transform infrared (FTIR) spectroscopy and proton nuclear magnetic resonance (1H NMR), whereas organic and inorganic phosphorus were studied by phosphorus-31 nuclear magnetic resonance (31P NMR). The sample with the lowest MCP content (MCP7) exhibited the smallest particle size and turbidity, measuring 83 ± 8 nm and 0.08 ± 0.01 cm−1, respectively. Concentrations of soluble caseins increased with decreasing MCP levels. At ~60% MCP removal, FTIR analysis indicated a critical stage of structural rearrangement and 31P NMR analysis showed an increase in signal intensity for Ca-free Ser-P, which further increased as MCP concentration was further reduced. In conclusion, this study highlighted the importance of MCP in maintaining micellar structure and its impact on the integrity of casein micelle.
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Huppertz, Thom, Mathias R. Zobrist, Therese Uniacke, Vivekk Upadhyat, Patrick F. Fox und Alan L. Kelly. „Effects of high pressure on some constituents and properties of buffalo milk“. Journal of Dairy Research 72, Nr. 2 (23.03.2005): 226–33. http://dx.doi.org/10.1017/s0022029905000701.
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In this study, effects of high pressure (HP) on some constituents and properties of buffalo milk were examined. HP treatment at 100–600 MPa for 30 min affected casein micelle size only slightly, whereas treatment at 800 MPa increased it by ~35%. Levels of non-micellar αs1- and β-caseins were increased by treatment [ges ]250 MPa, and were highest after treatment at 400–800 MPa. The level of non-micellar calcium increased with increasing pressure up to 600 MPa. The L*-value of the milk decreased gradually with increasing pressure, from ~82 for untreated milk to ~65 for milk treated at 800 MPa. Milk pH was increased by ~0·07 units after treatment at 100–800 MPa, with no significant difference between treatment pressures. Denaturation of α-lactalbumin occurred at pressures [ges ]400 MPa, and reached >90% after treatment at 800 MPa, whereas β-lactoglobulin (β-lg) was denatured >100 MPa, reaching ~100% after treatment at 400 MPa; after treatment [ges ]400 MPa, all β-lg was associated with the casein micelles. The rennet coagulation time of buffalo milk increased with increasing pressure, whereas the strength of the coagulum formed decreased after treatment at 250–800 MPa. Overall, HP treatment affected many constituents and properties of buffalo milk; some of these effects have also been observed in the milk from other species, but the extent of the effects, and the pressure at which they occurred, differed considerably.
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Tang, Yiu Lun Alan, Shixin Jin, Cheng Hao Lee, Ho Shing Law, Jiali Yu, Yanming Wang und Chi-wai Kan. „Reverse Micellar Dyeing of Cotton Fabric with Reactive Dye Using Biodegradable Non-Ionic Surfactant as Nanoscale Carrier: An Optimisation Study by One-Factor-at-One-Time Approach“. Polymers 15, Nr. 20 (20.10.2023): 4175. http://dx.doi.org/10.3390/polym15204175.
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This study investigates the feasibility of using biodegradable secondary alcohol ethoxylate (SAE) non-ionic surfactant as a building block for the formation of reverse micelles, functioning as reactive dye carriers for the dyeing of cotton fabric in non-aqueous octane medium. Ten dyeing parameters were optimised, by a one-factor-at-a-time approach, namely: (i) effect of colour fixation agent; (ii) surfactant-to-water mole ratio; (iii) surfactant-to-co-surfactant mole ratio; (iv) volume of soda ash; (v) volume of dye; (vi) solvent-to-cotton ratio; (vii) dyeing temperature; (viii) dyeing time; (ix) fixation time; (x) soda-ash-to-cotton ratio. The colour properties, fastness properties and physical properties of SAE-dyed samples were experimentally compared with the conventional water-dyed samples. The optimised condition was found when SAE samples were dyed as follows: (a) 1:20 surfactant-to-water ratio; (b) 1:8 surfactant-to-co-surfactant ratio; (c) 10:1 solvent ratio; (d) 40 min dyeing time; (e) 60 min fixation time; and (f) 70 °C dyeing and fixation temperature. The results showed that SAE-dyed samples have better colour strength, lower reflectance percentage and comparable levelness, fastness and physical properties than that of water-dyed samples. SEM images revealed that the dyed cotton fibres had no severe surface damage caused by an SAE-based reverse micellar dyeing system. The TEM image depicts that the reverse micelle was of nanoscale, spherical-shaped and had a core–shell structure, validating the presence of reverse micelle as a reactive dye carrier and the potential of an SAE-based reverse micellar system for dyeing of cotton fabrics.
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Coppola, Luigi, Domenico Gabriele, Isabella Nicotera und Cesare Oliviero. „Rheological Properties of the Reverse Mesophases of the Pluronic L64/P-Xylene/Water System“. Applied Rheology 14, Nr. 6 (01.12.2004): 315–23. http://dx.doi.org/10.1515/arh-2004-0018.
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Abstract The behaviour of reverse micellar solution and reverse hexagonal and lamellar liquid crystal phases in pluronic L64/water/p-xylene ternary system was investigated by rheological techniques. Samples with an increasing water content along the amphiphilic copolymer-lean side of the ternary phase diagram were analysed at different temperatures and a different behaviour was evidenced by both dynamic and steady tests for each considered phase, depending on the morphology of structure (micellar, lamellar, hexagonal phases). It was observed that the reverse micelles size increases with increasing water concentration and decreases with increasing temperature, without any phase transition. On the contrary the normal micelles become anisometric on temperature, showing a transition to a liquid crystalline phase. The observed mechanical spectra of the liquid crystalline phases are typical of hexagonal and lamellar phases according to the literature [1, 2]. A phase transition with temperature was found for both liquid crystalline phase (lamellar and hexagonal) by rheological tests and was confirmed by ocular inspection.
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Choi, Young, Eun-sook Choi, Kwan Mun, Se Lee, Sung Lee, Sang Jeong, Seung Lee und Hyun-Chul Kim. „Dual-responsive Gemini Micelles for Efficient Delivery of Anticancer Therapeutics“. Polymers 11, Nr. 4 (02.04.2019): 604. http://dx.doi.org/10.3390/polym11040604.
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Polymeric micelles as drug delivery vehicles are popular owing to several advantages. In this study, a gemini amphiphile (gemini mPEG-Cys-PMT) consisting of hydrophilic poly(ethylene glycol) and hydrophobic poly(methionine) with cystine disulfide spacer was synthesized and its micellar properties for thiol- or reactive oxygen species (ROS)-dependent intracellular drug delivery were described. The cleavage of cystine linkage in a redox environment or the oxidation of methionine units in a ROS environment caused the destabilization of micelles. Such redox- or ROS-triggered micellar destabilization led to enhanced release of encapsulated doxorubicin (DOX) to induce cytotoxicity against cancer cells. Further, the therapeutic effects of the DOX-loaded micelles were demonstrated using the KB cell line. This study shows that thiol and ROS dual-responsive gemini micelles are promising platforms for nano-drug delivery in various cancer therapies.
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Molchanov, V. S., A. I. Kuklin, A. S. Orekhov, N. A. Arkharova, E. S. Khudoleeva und O. E. Philippova. „Networks of Micellar Chains with Nanoplates“. Polymer Science, Series C 63, Nr. 2 (September 2021): 170–80. http://dx.doi.org/10.1134/s1811238221020053.
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Abstract Nanocomposite networks of surfactant micellar chains and natural bentonite clay nanoplates are studied by rheometry, small-angle neutron scattering, and cryogenic transmission electron microscopy. It is shown that, in an aqueous medium in the presence of a small part of an anionic surfactant, sodium dodecyl sulfate, the molecules of a biodegradable zwitterionic surfactant, oleyl amidopropyl dimethyl carboxybetaine, form micron-length living micellar chains which entangle and form a network possessing well-defined viscoelastic properties. It is found that addition of negatively charged clay nanoplates leads to an increase in viscosity and relaxation time by an order of magnitude. This is explained by the incorporation of the nanoplates into the network as physical multifunctional crosslinks. The incorporation occurs via the attachment of semispherical end-caps of the micelles to the surface of the particles covered with a surfactant layer, as visualized by cryogenic transmission electron microscopy. As the amount of nanoplates is increased, the rheological properties reach plateau; this is associated with the attachment of all end parts of micelles to nanoplates. The developed nanocomposite soft networks based on safe and eco-friendly components are promising for various practical applications.