Particles consisting of aggregates of molecules held loosely together by secondary bonds. The surface of micelles are usually comprised of amphiphatic compounds that are oriented in a way that minimizes the energy of interaction between the micelle and its environment. Liquids that contain large numbers of suspended micelles are referred to as EMULSIONS.
Two-phase systems in which one is uniformly dispersed in another as particles small enough so they cannot be filtered or will not settle out. The dispersing or continuous phase or medium envelops the particles of the discontinuous phase. All three states of matter can form colloids among each other.
Polymers of ETHYLENE OXIDE and water, and their ethers. They vary in consistency from liquid to solid depending on the molecular weight indicated by a number following the name. They are used as SURFACTANTS, dispersing agents, solvents, ointment and suppository bases, vehicles, and tablet excipients. Some specific groups are NONOXYNOLS, OCTOXYNOLS, and POLOXAMERS.
Forms to which substances are incorporated to improve the delivery and the effectiveness of drugs. Drug carriers are used in drug-delivery systems such as the controlled-release technology to prolong in vivo drug actions, decrease drug metabolism, and reduce drug toxicity. Carriers are also used in designs to increase the effectiveness of drug delivery to the target sites of pharmacological actions. Liposomes, albumin microspheres, soluble synthetic polymers, DNA complexes, protein-drug conjugates, and carrier erythrocytes among others have been employed as biodegradable drug carriers.
Agents that modify interfacial tension of water; usually substances that have one lipophilic and one hydrophilic group in the molecule; includes soaps, detergents, emulsifiers, dispersing and wetting agents, and several groups of antiseptics.
Eight-carbon saturated hydrocarbon group of the methane series. Include isomers and derivatives.
Purifying or cleansing agents, usually salts of long-chain aliphatic bases or acids, that exert cleansing (oil-dissolving) and antimicrobial effects through a surface action that depends on possessing both hydrophilic and hydrophobic properties.
Calcium and magnesium salts used therapeutically in hepatobiliary dysfunction.
An anionic surfactant, usually a mixture of sodium alkyl sulfates, mainly the lauryl; lowers surface tension of aqueous solutions; used as fat emulsifier, wetting agent, detergent in cosmetics, pharmaceuticals and toothpastes; also as research tool in protein biochemistry.
The ability of a substance to be dissolved, i.e. to form a solution with another substance. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Compounds formed by the joining of smaller, usually repeating, units linked by covalent bonds. These compounds often form large macromolecules (e.g., BIOPOLYMERS; PLASTICS).
Cetyltrimethylammonium compounds that have cationic detergent, antiseptic, and disinfectant activities. They are used in pharmaceuticals, foods, and cosmetics as preservatives; on skin, mucous membranes, etc., as antiseptics or cleansers, and also as emulsifiers. These compounds are toxic when used orally due to neuromuscular blockade.
Nonionic surfactant mixtures varying in the number of repeating ethoxy (oxy-1,2-ethanediyl) groups. They are used as detergents, emulsifiers, wetting agents, defoaming agents, etc. Octoxynol-9, the compound with 9 repeating ethoxy groups, is a spermatocide.
Polymers of organic acids and alcohols, with ester linkages--usually polyethylene terephthalate; can be cured into hard plastic, films or tapes, or fibers which can be woven into fabrics, meshes or velours.
Relating to the size of solids.
Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).
Systems for the delivery of drugs to target sites of pharmacological actions. Technologies employed include those concerning drug preparation, route of administration, site targeting, metabolism, and toxicity.
Nanometer-sized, hollow, spherically-shaped objects that can be utilized to encapsulate small amounts of pharmaceuticals, enzymes, or other catalysts (Glossary of Biotechnology and Nanobiotechnology, 4th ed).
A nonionic polyoxyethylene-polyoxypropylene block co-polymer with the general formula HO(C2H4O)a(-C3H6O)b(C2H4O)aH. It is available in different grades which vary from liquids to solids. It is used as an emulsifying agent, solubilizing agent, surfactant, and wetting agent for antibiotics. Poloxamer is also used in ointment and suppository bases and as a tablet binder or coater. (Martindale The Extra Pharmacopoeia, 31st ed)
A clear, odorless, tasteless liquid that is essential for most animal and plant life and is an excellent solvent for many substances. The chemical formula is hydrogen oxide (H2O). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
NMR spectroscopy on small- to medium-size biological macromolecules. This is often used for structural investigation of proteins and nucleic acids, and often involves more than one isotope.
A trihydroxy bile salt that is used as a digestive aid in dietary supplements. It is used in culture media and in conjunction with PAPAIN and PANCREATIN.
Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to a choline moiety. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid and choline and 2 moles of fatty acids.
A bile salt formed in the liver by conjugation of deoxycholate with taurine, usually as the sodium salt. It is used as a cholagogue and choleretic, also industrially as a fat emulsifier.
A change from planar to elliptic polarization when an initially plane-polarized light wave traverses an optically active medium. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
The homogeneous mixtures formed by the mixing of a solid, liquid, or gaseous substance (solute) with a liquid (the solvent), from which the dissolved substances can be recovered by physical processes. (From Grant & Hackh's Chemical Dictionary, 5th ed)
The diversion of RADIATION (thermal, electromagnetic, or nuclear) from its original path as a result of interactions or collisions with atoms, molecules, or larger particles in the atmosphere or other media. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
A copolymer of polyethylene and polypropylene ether glycol. It is a non-ionic polyol surface-active agent used medically as a fecal softener and in cattle for prevention of bloat.
The level of protein structure in which regular hydrogen-bond interactions within contiguous stretches of polypeptide chain give rise to alpha helices, beta strands (which align to form beta sheets) or other types of coils. This is the first folding level of protein conformation.
Measurement of the intensity and quality of fluorescence.
Lipids containing one or more phosphate groups, particularly those derived from either glycerol (phosphoglycerides see GLYCEROPHOSPHOLIPIDS) or sphingosine (SPHINGOLIPIDS). They are polar lipids that are of great importance for the structure and function of cell membranes and are the most abundant of membrane lipids, although not stored in large amounts in the system.
The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Liquids that dissolve other substances (solutes), generally solids, without any change in chemical composition, as, water containing sugar. (Grant & Hackh's Chemical Dictionary, 5th ed)
Colipase I and II, consisting of 94-95 and 84-85 amino acid residues, respectively, have been isolated from porcine pancreas. Their role is to prevent the inhibitory effect of bile salts on the lipase-catalyzed intraduodenal hydrolysis of dietary long-chain triglycerides.
Artificial, single or multilaminar vesicles (made from lecithins or other lipids) that are used for the delivery of a variety of biological molecules or molecular complexes to cells, for example, drug delivery and gene transfer. They are also used to study membranes and membrane proteins.
Layers of lipid molecules which are two molecules thick. Bilayer systems are frequently studied as models of biological membranes.
The thermodynamic interaction between a substance and WATER.
Derivatives of PHOSPHATIDYLCHOLINES obtained by their partial hydrolysis which removes one of the fatty acid moieties.
Nanometer-sized particles that are nanoscale in three dimensions. They include nanocrystaline materials; NANOCAPSULES; METAL NANOPARTICLES; DENDRIMERS, and QUANTUM DOTS. The uses of nanoparticles include DRUG DELIVERY SYSTEMS and cancer targeting and imaging.
Deacetylated CHITIN, a linear polysaccharide of deacetylated beta-1,4-D-glucosamine. It is used in HYDROGEL and to treat WOUNDS.
Chemistry dealing with the composition and preparation of agents having PHARMACOLOGIC ACTIONS or diagnostic use.
The rate dynamics in chemical or physical systems.
The product of conjugation of cholic acid with taurine. Its sodium salt is the chief ingredient of the bile of carnivorous animals. It acts as a detergent to solubilize fats for absorption and is itself absorbed. It is used as a cholagogue and cholerectic.
The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.
Spherical particles of nanometer dimensions.
Steroid acids and salts. The primary bile acids are derived from cholesterol in the liver and usually conjugated with glycine or taurine. The secondary bile acids are further modified by bacteria in the intestine. They play an important role in the digestion and absorption of fat. They have also been used pharmacologically, especially in the treatment of gallstones.
Artificially produced membranes, such as semipermeable membranes used in artificial kidney dialysis (RENAL DIALYSIS), monomolecular and bimolecular membranes used as models to simulate biological CELL MEMBRANES. These membranes are also used in the process of GUIDED TISSUE REGENERATION.
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
Exclusive legal rights or privileges applied to inventions, plants, etc.
Three individuals derived from three FETUSES that were fertilized at or about the same time, developed in the UTERUS simultaneously, and born to the same mother.
Expendable and nonexpendable equipment, supplies, apparatus, and instruments that are used in diagnostic, surgical, therapeutic, scientific, and experimental procedures.
Process that is gone through in order for a device to receive approval by a government regulatory agency. This includes any required preclinical or clinical testing, review, submission, and evaluation of the applications and test results, and post-marketing surveillance. It is not restricted to FDA.
Freedom of equipment from actual or potential hazards.
Number of fetal deaths with stated or presumed gestation of 20 weeks or more in a given population. Late fetal mortality is death after of 28 weeks or more.

Biophysical characterization of the structure of the amino-terminal region of gp41 of HIV-1. Implications on viral fusion mechanism. (1/2247)

A peptide of 51 amino acids corresponding to the NH2-terminal region (5-55) of the glycoprotein gp41 of human immunodeficiency virus type 1 was synthesized to study its conformation and assembly. Nuclear magnetic resonance experiments indicated the sequence NH2-terminal to the leucine zipper-like domain of gp41 was induced into helix in the micellar solution, in agreement with circular dichroism data. Light scattering experiment showed that the peptide molecules self-assembled in water into trimeric structure on average. That the peptide molecules oligomerize in aqueous solution was supported by gel filtration and diffusion coefficient experiments. Molecular dynamics simulation based on the NMR data revealed a flexible region adjacent to the hydrophobic NH2 terminus of gp41. The biological significance of the present findings on the conformational flexibility and the propensity of oligomerization of the peptide may be envisioned by a proposed model for the interaction of gp41 with membranes during fusion process.  (+info)

Further studies on the mechanism of adrenaline-induced lipolysis in lipid micelles. (2/2247)

Lipase [EC 3.1.1.3] depleted lipid micelles, in which lipolysis was not elicited by adrenaline, were prepared from lipid micelles. When these lipase-depleted lipid micelles incubated with adipose tissue extract containing lipase activity, adrenaline-induced lipolysis was restored to almost the same level as that of native lipid micelles. Adrenaline-induced lipolysis was not restored when the lipase-depleted lipid micelles were homogenized or sonicated. Various tissue extracts from kidney, lung, liver, and pancreas, and post-heparin plasma, which contained lipase activity, restored adrenaline-induced lipolysis in lipase-depleted lipid micelles.  (+info)

Folding of apocytochrome c induced by the interaction with negatively charged lipid micelles proceeds via a collapsed intermediate state. (3/2247)

Unfolded apocytochrome c acquires an alpha-helical conformation upon interaction with lipid. Folding kinetic results below and above the lipid's CMC, together with energy transfer measurements of lipid bound states, and salt-induced compact states in solution, show that the folding transition of apocytochrome c from the unfolded state in solution to a lipid-inserted helical conformation proceeds via a collapsed intermediate state (I(C)). This initial compact state is driven by a hydrophobic collapse of the polypeptide chain in the absence of the heme group and may represent a heme-free analogue of an early compact intermediate detected on the folding pathway of cytochrome c in solution. Insertion into the lipid phase occurs via an unfolding step of I(C) through a more extended state associated with the membrane surface (I(S)). While I(C) appears to be as compact as salt-induced compact states in solution with substantial alpha-helix content, the final lipid-inserted state (Hmic) is as compact as the unfolded state in solution at pH 5 and has an alpha-helix content which resembles that of native cytochrome c.  (+info)

Molecular dynamics study of substance P peptides in a biphasic membrane mimic. (4/2247)

Two neuropeptides, substance P (SP) and SP-tyrosine-8 (SP-Y8), have been studied by molecular dynamics (MD) simulation in a TIP3P water/CCl4 biphasic solvent system as a mimic for the water-membrane system. Initially, distance restraints derived from NMR nuclear Overhauser enhancements (NOE) were incorporated in the restrained MD (RMD) in the equilibration stage of the simulation. The starting orientation/position of the peptides for the MD simulation was either parallel to the water/CCl4 interface or in a perpendicular/insertion mode. In both cases the peptides equilibrated and adopted a near-parallel orientation within approximately 250 ps. After equilibration, the conformation and orientation of the peptides, the solvation of both the backbone and the side chain of the residues, hydrogen bonding, and the dynamics of the peptides were analyzed from trajectories obtained in the RMD or the subsequent free MD (where the NOE restraints were removed). These analyses showed that the peptide backbone of nearly all residues are either solvated by water or are hydrogen-bonded. This is seen to be an important factor against the insertion mode of interaction. Most of the interactions with the hydrophobic phase come from the hydrophobic interactions of the side chains of Pro-4, Phe-7, Phe-8, Leu-10, and Met-11 for SP, and Phe-7, Leu-10, Met-11 and, to a lesser extent, Tyr-8 in SP-Y8. Concerted conformational transitions took place in the time frame of hundreds of picoseconds. The concertedness of the transition was due to the tendency of the peptide to maintain the necessary secondary structure to position the peptide properly with respect to the water/CCl4 interface.  (+info)

Molecular dynamics study of substance P peptides partitioned in a sodium dodecylsulfate micelle. (5/2247)

Two neuropeptides, substance P (SP) and SP-tyrosine-8 (SP-Y8), have been studied by molecular dynamics (MD) simulation in an explicit sodium dodecylsulfate (SDS) micelle. Initially, distance restraints derived from NMR nuclear Overhauser enhancements (NOE) were incorporated in the restrained MD (RMD) during the equilibration stage of the simulation. It was shown that when SP-Y8 was initially placed in an insertion (perpendicular) configuration, the peptide equilibrated to a surface-bound (parallel) configuration in approximately 450 ps. After equilibration, the conformation and orientation of the peptides, the solvation of both the backbone and the side chain of the residues, hydrogen bonding, and the dynamics of the peptides were analyzed from trajectories obtained from the RMD or the subsequent free MD (where the NOE restraints were removed). These analyses showed that the peptide backbones of all residues are either solvated by water or are hydrogen-bonded. This is seen to be an important factor against the insertion mode of interaction. Most of the interactions come from the hydrophobic interaction between the side chains of Lys-3, Pro-4, Phe-7, Phe-8, Leu-10, and Met-11 for SP, from Lys-3, Phe-7, Leu-10, and Met-11 in SP-Y8, and the micellar interior. Significant interactions, electrostatic and hydrogen bonding, between the N-terminal residues, Arg-Pro-Lys, and the micellar headgroups were observed. These latter interactions served to affect both the structure and, especially, the flexibility, of the N-terminus. The results from simulation of the same peptides in a water/CCl4 biphasic cell were compared with the results of the present study, and the validity of using the biphasic system as an approximation for peptide-micelle or peptide-bilayer systems is discussed.  (+info)

Cryoelectron microscopy of a nucleating model bile in vitreous ice: formation of primordial vesicles. (6/2247)

Because gallstones form so frequently in human bile, pathophysiologically relevant supersaturated model biles are commonly employed to study cholesterol crystal formation. We used cryo-transmission electron microscopy, complemented by polarizing light microscopy, to investigate early stages of cholesterol nucleation in model bile. In the system studied, the proposed microscopic sequence involves the evolution of small unilamellar to multilamellar vesicles to lamellar liquid crystals and finally to cholesterol crystals. Small aliquots of a concentrated (total lipid concentration = 29.2 g/dl) model bile containing 8.5% cholesterol, 22.9% egg yolk lecithin, and 68.6% taurocholate (all mole %) were vitrified at 2 min to 20 days after fourfold dilution to induce supersaturation. Mixed micelles together with a category of vesicles denoted primordial, small unilamellar vesicles of two distinct morphologies (sphere/ellipsoid and cylinder/arachoid), large unilamellar vesicles, multilamellar vesicles, and cholesterol monohydrate crystals were imaged. No evidence of aggregation/fusion of small unilamellar vesicles to form multilamellar vesicles was detected. Low numbers of multilamellar vesicles were present, some of which were sufficiently large to be identified as liquid crystals by polarizing light microscopy. Dimensions, surface areas, and volumes of spherical/ellipsoidal and cylindrical/arachoidal vesicles were quantified. Early stages in the separation of vesicles from micelles, referred to as primordial vesicles, were imaged 23-31 min after dilution. Observed structures such as enlarged micelles in primordial vesicle interiors, segments of bilayer, and faceted edges at primordial vesicle peripheries are probably early stages of small unilamellar vesicle assembly. A decrease in the mean surface area of spherical/ellipsoidal vesicles was correlated with the increased production of cholesterol crystals at 10-20 days after supersaturation by dilution, supporting the role of small unilamellar vesicles as key players in cholesterol nucleation and as cholesterol donors to crystals. This is the first visualization of an intermediate structure that has been temporally linked to the development of small unilamellar vesicles in the separation of vesicles from micelles in a model bile and suggests a time-resolved system for further investigation.  (+info)

Lipid exchange between mixed micelles of phospholipid and triton X-100. (7/2247)

If phospholipase catalyzed hydrolysis of phospholipid dissolved in a detergent mixed micelle is limited to the phospholipid carried by a single micelle, then hydrolysis ceases upon exhaustion of that pool. However, if the rate of phospholipid exchange between micelles exceeds the catalytic rate then all of the phospholipid is available for hydrolysis. To determine phospholipid availability we studied the exchange of 1,2-dioleoyl-sn-glycero-3-phosphocholine between mixed micelles of phospholipid and non-ionic Triton detergents by both stopped-flow fluorescence-recovery and nuclear magnetic resonance-relaxation techniques. Stopped-flow analysis was performed by combining mixed micelles of Triton and phospholipid with mixed micelles that contained the fluorescent phospholipid 1-palmitoyl-2-(12-[{7-nitro-2-1, 3-benzoxadiazo-4-yl}amino]dodecanoyl)-sn-glycero-3-phosphocholine (P-2-NBD-PC). The concentration dependence of fluorescence recovery suggested a second-order exchange mechanism that was saturable. The true second-order rate constant depends on the specific mechanism for exchange, which was not determined in this study, but the rate constant will be on the order of 106 to 107 M-1s-1. Incorporation of 1-palmitoyl-2-(16-doxylstearoyl)phosphatidylcholine into micelles increased the rate of proton relaxation and gave a limiting relaxation time of 1.3 ms. The results demonstrate that phospholipid exchange was rapid and that the phospholipid content of a single micelle did not limit the rate of phospholipid hydrolysis by phospholipases.  (+info)

Protective effect of quinaprilat, an active metabolite of quinapril, on Ca2+-overload induced by lysophosphatidylcholine in isolated rat cardiomyocytes. (8/2247)

We examined the effects of quinaprilat, an active metabolite of quinapril (an angiotensin converting enzyme (ACE) inhibitor) on the increase in intracellular concentration of Ca2+ ([Ca2+]i) (Ca2+-overload) induced by lysophosphatidylcholine (LPC) in isolated rat cardiomyocytes. LPC (15 microM) produced Ca2+-overload with a change in cell-shape from rod to round. Quinaprilat but not quinapril at 20 or 50 microM attenuated the LPC-induced increase in [Ca2+]i and the change in cell-shape in a concentration-dependent manner. Since quinaprilat has an inhibitory action on ACE and quinapril has practically no inhibitory action on ACE, it is likely that the inhibitory action of quinaprilat on ACE is necessary for the protective effect of the drug against LPC-induced changes. We therefore examined the effects of enalapril (another ACE inhibitor with the weak inhibitory action on ACE) and enalaprilat (an active metabolite of enalapril with an inhibitory action on ACE) on the LPC-induced changes. Both enalapril and enalaprilat attenuated the LPC-induced Ca2+-overload, suggesting that the inhibitory action on ACE may not mainly contribute to the protective effect of ACE inhibitors against LPC-induced Ca2+-overload. This suggestion was supported by the fact that neither ACE (0.2 U/ml) nor angiotensin II (0.1-100 microM) increased [Ca2+]i in isolated cardiomyocytes. Furthermore, application of bradykinin (0.01-10 microM) did not enhance the protective effect of quinaprilat against LPC-induced changes. LPC also increased release of creatine kinase (CK) from the myocyte markedly, and quinaprilat but not quinapril attenuated the LPC-induced CK release. Unexpectedly, both enalapril and enalaprilat did not attenuate the LPC-induced CK release. Neither quinapril nor quinaprilat changed the critical micelle concentration of LPC, suggesting that these drugs do not directly bind to LPC. We conclude that quinaprilat attenuates the LPC-induced increase in [Ca2+]i, and that the protective effect of quinaprilat on the LPC-induced change may not be related to a decrease in angiotensin II production or an increase in bradykinin production.  (+info)

How is Critical Micellular Concentration (concentration at which a detergent spontaneously forms micelles) abbreviated? CMC stands for Critical Micellular Concentration (concentration at which a detergent spontaneously forms micelles). CMC is defined as Critical Micellular Concentration (concentration at which a detergent spontaneously forms micelles) rarely.
HYBRID BLOCK COPOLYMER MICELLES WITH MIXED STEREOCHEMISTRY FOR ENCAPSULATION OF HYDROPHOBIC AGENTS - diagram, schematic, and image 32 ...
Page contains details about PLA-PEO bottlebrush block copolymer micelles . It has composition images, properties, Characterization methods, synthesis, applications and reference articles : nano.nature.com
Gohy, Jean-François ; Willet, N. ; Varshney, S. K. ; Jérôme, R.. Responsive block copolymer micelles.Rolduc 11th Polymer Meeting (Kerkrade (The Netherlands), du 05/05/2002 au 08/05/2002 ...
Title:Polymeric Micelles of Modified Chitosan Block Copolymer as Nanocarrier for Delivery of Paclitaxel. VOLUME: 9 ISSUE: 1. Author(s):V. Lather, V. Saini and D. Pandita*. Affiliation:Department of Pharmaceutical Chemistry, JCDM College of Pharmacy, Sirsa-125055, Haryana, Department of Pharmaceutics, JCDM College of Pharmacy, Sirsa-125055, Haryana, Department of Pharmaceutics, JCDM College of Pharmacy, Sirsa-125055, Haryana. Keywords:Polymeric micelles, amphiphilic, self assembly, chitosan, paclitaxel, copolymer.. Abstract:Background: Polymeric micelles are being used as successful nanocarriers for the delivery of diverse drug molecules due to properties like solubilization, selective targeting, P-glycoprotein inhibition, altered drug internalization route and subcellular localization etc. Objective: The present investigation was planned to prepare and characterize novel polymeric micelles derived from self assembly of amphiphilic chitosan-bile salt derivative (CS-mPEG-DA) as nanocarrier and ...
An endovascular stent comprising an expandable framework including a plurality of interconnected segments, and a plurality of entangled cylindrical micelles disposed on the expandable framework. Each of the plurality of cylindrical micelles may be loaded with a therapeutic agent.
A combined model for the structures of the mixed micelles of taurocholate and 1,2-ethylene-di-N-n-propylcarbamate (1) has been proposed. Present model suggests that the structures of micelles of taurocholate are equally composed of these four dimeric fragments. Moreover, lipid molecules can only insert into back-to-back dimeric fragments but not into face-to-face dimeric fragments in the mixed micelles of taurocholate and lipid. To test this model, a short-chain analogue of glycerol lipid, 1,2-ethylene-di-N-n-propylcarbamate (1), was synthesized and was mixed with the micellar taurocholate to form the mixed micelle of taurocholate and compound 1. From the H-1 NMR spectra. the cc-methylene protons of compound I split after formation of the mixed micelle with taurocholate. Thus, half of compound I molecules insert into the anti-parallel back-to-back dimers in the mixed micelle and the other half of compound 1 molecules insert into the parallel back-to-back dimers in the mixed micelle ...
Polymeric micelles self-assembled from cholesterol-conjugated poly(ethylene glycol) (PEG) and anchored with transcriptional activator TAT peptide (TAT-PEG-b-Col) were fabricated for delivery of antibiotics across the blood-brain barrier (BBB). Ciprofloxacin, which demonstrated a high bactericidal effect, was efficiently loaded into the micelles by a membrane dialysis method. The ciprofloxacin-loaded micelles were characterized via dynamic light scattering and SEM. The micelles were spherical in nature, having an average diameter of smaller than 180 nm. Sustained release of ciprofloxacin was achieved over 6 h in phosphate-buffered saline (pH 7.4) at 37°C. Confocal laser scanning microscopy reveals that the uptake of Fluorescein 5-isothiocyanate (FITC)-loaded TAT-PEG-b-Col micelles by human astrocytes was much higher than that of free FITC. Animal studies proved that these micelles crossed the BBB and entered the brain. The TAT-conjugated micelles may be used to deliver antibiotics across the BBB ...
In this study we explore the preparation of core-crosslinked micelles of linear-dendritic methoxy-poly(ethylene glycol) (MPEG)-co-poly(ester-sulfide) (PES) polymers to improve the stability of such polymeric micelle systems against premature disintegration and drug release. A series of MPEG-PES copolymers were synthesised via stepwise reactions of acetylation and thiol-ene photoreaction. Surface tension measurement showed that the copolymers with ethenyl surface groups could self-associate in dilute aqueous solutions to form micelles. Crosslinking within the micelle cores in the presence of dithioerythritol (DTT) linker was initiated under UV radiation. The formation of core-crosslinked micelles was confirmed by HPLC in combination with charged aerosol detection (CAD). The copolymers were found to readily hydrolyse under acidic conditions due to the ester-containing dendrons. Drug solubilisation capacities of the micellar solutions were determined using griseofulvin as a poorly water-soluble ...
TY - JOUR. T1 - Fluid mechanical shear induces structural transitions in assembly of a peptide-lipid conjugate. AU - Shimada, Tomoko. AU - Megley, Katie. AU - Tirrell, Matthew. AU - Hotta, Atsushi. PY - 2011/10/7. Y1 - 2011/10/7. N2 - Peptide amphiphiles (PA) can self-assemble into both spherical micelles and worm-like micelles. The control of worm-like micelle formation of PA is an area of active research, most often accomplished by modulating the temperature, salt content, or pH of the environment. In this work, we demonstrate the shear-induced formation of worm-like micelles in our designed peptide amphiphile C 16-W3K. Before adding shear, the peptide amphiphiles form spherical micelles in solution and exhibit little to no viscoelasticity. As the solution is subjected to simple shear flow, with increasing shear rate, spherical micelles form rapidly into elongated worm-like micelles up to microns in length. Though it has been reported that some dilute surfactant solutions exhibit shear-induced ...
Polymeric micelles for encapsulation of hydrophobic molecules are provided. Methods and formulations for delivering hydrophobic molecules to a host via these micelles are also provided. Methods of stabilizing liposomes or lipid based formulations by addition of polymeric micelles are also provided.
A novel theory for the structural behavior of surfactant micelles is expounded. The micelles are considered to be generally shaped as triaxial tablets with distinct thickness width and length, respectively, and may become spherical, spherocylindrical or disk-shaped in the special cases where two or more of the dimensions are equal. It is demonstrated that the average width and length of a tablet-shaped micelle with a fixed thickness is mainly determined by two constants, k1 and k2, related to the first and second order correction in curvature of the micellar end caps. The size of the micelles is found to be mainly determined by k1, whereas k2 influences the shape, i.e., the length-to-width ratio, of the micelles so that the micellar size increases with increasing k1 and the length-to-width ratio decreases with increasing k2. Hence, large positive values of k2 promote the formation of tablets rather than very long spherocylinders. An additional parameter related to the curvature of the straight ...
Page contains details about supramolecularly engineered amphiphilic macromolecule spherical micelles . It has composition images, properties, Characterization methods, synthesis, applications and reference articles : nano.nature.com
Curcumin and Amphotericin B were successfully encapsulated in the novel block copolymer micelles via nanoprecipitation method. The results obtained from curcumin loading and release studies suggested that these novel PDL block copolymers could perform in similar fashion when compared with poly(caprolactone) (PCL) block copolymer micelles. However, in subsequent study micelle of mPEG-b-PDL gave high loading content compared to mPEG-b-PCL micelles when amphotericin B was used as a drug. Further, a preliminary in vitro degradation study of mPEG-b-PDL micelles was performed and the results proposed that the ester linkage of PDL chain were susceptible to hydrolytic degradation in physiological condition. Additionally, in vitro cytotoxicity studies performed on HCT-116 human colon cancer cells revealed that the novel mPEG-b-PDL micelles have similar toxicity profiles when compared to the well-established mPEG-b-PCL micelles ...
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We investigated the micellar behavior of a series of asymmetric polystyrene-block-poly (4-vinylpyridine) (PS-b-P4VP) block copolymers in different P4VP-selective alcoholic solvents. The micellar behavior was further correlated with the spectroscopic ellipsometry results obtained on swelling of PS and P4VP polymer films in the corresponding solvent vapors. The time-resolved (in situ) dynamic light scattering (DLS) measurements, in combination with (ex situ) electron microscopy imaging, revealed information about the aggregation state of PS-b-P4VP BCP in different alcohols and the effect of heat treatment. The ellipsometry measurements allowed us to estimate the difference in solvent selectivity toward PS/P4VP pair. Both DLS and ellipsometric studies suggested that less polar alcohols (i.e., 1-propanol, 1-butanol, and 1-pentanol) are likely to be close to each other in terms of their selectivity toward PS/P4VP pair, whereas more polar ethanol and methanol show the highest and the lowest affnity toward
The goals of this project are to fabricate, optimize and characterize a nano self-assembled micelle system for drug delivery of siRNA.
Author: Kubowicz, S. et al.; Genre: Journal Article; Published in Print: 2005-08-02; Title: Cylindrical micelles of alpha-fluorocarbon-omega-hydrocarbon end-capped poly(N-acylethylene imine)s
A micellar solution consists of a dispersion of micelles in a solvent (most usually water). Micelles consist of aggregated amphiphiles, and in a micellar solution these are in equilibrium with free, unaggregated amphiphiles. Micellar solutions form when the concentration of amphiphile exceeds the critical micellar concentration (CMC) or critical aggregation concentration - CAC, and persist until the amphiphile concentration becomes sufficiently high to form a lyotropic liquid crystal phase.[1][2][3][4] Although micelles are often depicted as being spherical, they can be cylindrical or oblate depending on the chemical structure of the amphiphile. Micellar solutions are isotropic phases. Micellar water has been used in France since 1913.[5] ...
The rapamycin analog, ridaforolimus, has demonstrated potent anti-proliferative effects in cancer treatment, and it currently is being evaluated in a range of clinical cancer studies. Ridaforolimus is an extremely lipophilic compound with limited aqueous solubility, which may benefit from formulation with polymeric micelles. Herein, we report the encapsulation of ridaforolimus in 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-methoxy-poly(ethylene glycol 2000) (DSPE-PEG2000) via a solvent extraction technique. Micelle loading greatly improved the solubility of ridaforolimus by approximately 40 times from 200 μg/mL to 8.9 mg/mL. The diameters of the drug-loaded micelles were 33 ± 15 nm indicating they are of appropriate size to accumulate within the tumor site via the enhanced permeability and retention (EPR) effect. The DSPE-PEG2000 micelle formulation was dosed intravenously to rats at 10 mg/kg and compared to a control of ridaforolimus in ethanol/PEG 400. The micelle significantly increased the
TY - JOUR. T1 - Chaotropic-anion-induced supramolecular self-assembly of ionic polymeric micelles. AU - Li, Yang. AU - Wang, Yiguang. AU - Huang, Gang. AU - Ma, Xinpeng. AU - Zhou, Kejin. AU - Gao, Jinming. PY - 2014/7/28. Y1 - 2014/7/28. N2 - Traditional micelle self-assembly is driven by the association of hydrophobic segments of amphiphilic molecules forming distinctive core-shell nanostructures in water. Here we report a surprising chaotropic-anion-induced micellization of cationic ammonium-containing block copolymers. The resulting micelle nanoparticle consists of a large number of ion pairs (≈60 000) in each hydrophobic core. Unlike chaotropic anions (e.g. ClO4 -), kosmotropic anions (e.g. SO42-) were not able to induce micelle formation. A positive cooperativity was observed during micellization, for which only a three-fold increase in ClO4 - concentration was necessary for micelle formation, similar to our previously reported ultra-pH-responsive behavior. This unique ...
We developed camptothecin (CPT)-conjugated, core-cross-linked (CCL) micelles that are subject to redox-responsive cleavage of the built-in disulfide bonds, resulting in disruption of the micellar structure and rapid release of CPT. CCL micelles were prepared via coprecipitation of disulfide-containing CPT-poly(tyrosine(alkynyl)-OCA) conjugate and monomethoxy poly(ethylene glycol)-b-poly(tyrosine(alkynyl)-OCA), followed by cross-linking of the micellar core via azide-alkyne click chemistry. CCL micelles exhibited excellent stability under physiological conditions, while they underwent rapid dissociation in reduction circumstance, resulting in burst release of CPT. These redox-responsive CCL micelles showed enhanced cytotoxicity against human breast cancer cells in vitro. Wang, Hua; Tang, Li; Tu, Chunlai; Song, Ziyuan; Yin, Qian; Yin, Lichen; Zhang, Zhonghai; Cheng, Jianjun
The determination of the critical micelle concentration (CMC) value of surfactants under different environmental conditions is important for a number of different biological and chemical processes. Because the CMC is not a constant value, shifting with different environmental conditions, it is important that a rapid, reliable and easy methodology be available to facilitate testing. This application note describes the rapid semi-automated determination of CMC values for surfactants in 384-well mi
Polymeric micelles, self-assemblies of block copolymers, are emerging as attractive drug delivery systems for hydrophobic photodynamic sensitizers. Recent advances in the formulation of photosensitizers for photodynamic therapy (PDT) with diblock copolymers are presented. This paper reviews the main characteristics of existing drug-loading micelles with diblock copolymers, including loading efficiency, particle size and morphology, stability, cellular uptake, subcellular distribution and therapeutic efficiency. The results indicate that diblock polymeric micelles are potentially useful for the delivery and release of hydrophobic photosensitizers in PDT. While significant progress has been achieved, many challenges remain in elucidating the detailed internalization mechanisms of the micelles and resulting mechanisms for enhanced photocytotoxicity. Some critical issues for diblock copolymers to deliver hydrophobic photosensitizers for PDT are highlighted ...
1G8C: Structure of the bovine antimicrobial peptide indolicidin bound to dodecylphosphocholine and sodium dodecyl sulfate micelles.
Using a very popular and commonly used surfactant sodium dodecylbenzene sulfonate (SDBS, C18H29SO3Na) for a case study, we report a new method of monitoring different forms of surfactant molecules in aqueous solution and measuring their critical micelle concentration (CMC) by ultraviolet-visible (UV-Vis) spectroscopy. The forms of SDBS micelles are also investigated by synthesizing and characterizing NiB nanoparticles using the micelles as molecular templates. In addition, the observed shifts of UV-Vis bands are analysed from the viewpoint of the electrons locations and distributions within the molecules and the possible overlap of their electronic orbitals between neighbouring molecules in each micelle ...
Polymeric nanoparticles formed by triblock copolymer polystyrene-block-poly(2-vinylpyridine)-block-poly(ethylene oxide), PS-PVP-PEO, in aqueous media were studied by a combination of fluorescence correlation spectroscopy with other fluorescence techniques, light scattering and atomic force microscopy. The studied polymeric nanoparticles exist in the form of (i) core/shell micelles in acid solution at pH lower than 4.8 and (ii) three-layer onion micelles at higher pH. Since water is a very strong precipitant for PS, both types of micelles have kinetically frozen spherical PS cores. The cores of micelles in acid media are surrounded by soluble shells formed by partly protonated PVP and PEO, while the cores of micelles in alkaline media are surrounded by compact insoluble layers of deprotonated PVP and soluble PEO shells. The micellization behavior of PS-PVP-PEO micelles is accompanied by secondary aggregation of micelles, which is provoked by stirring, shaking and also by filtration of micellar ...
The Krafft temperature (also known as Krafft point, or critical micelle temperature) is the minimum temperature at which surfactants form micelles. It is named after German chemist Friedrich Krafft. Below the Krafft temperature, there is no value for the critical micelle concentration (CMC), i.e., micelles cannot form. The Krafft temperature is a point of phase change below which the surfactant remains in crystalline form, even in aqueous solution. Visually the effect of going below the Krafft point is similar to that of going above the cloud point, with the solution becoming cloudy or opaque due to the surfactant molecules undergoing flocculation. Surfactants in such a crystalline state will only solubilize and form micelles if another surfactant assists it in overcoming the forces that keep it crystallized, or if the temperature increases, thus causing entropy to have a stronger force and encouraging the crystalline structure to break apart. Surfactants are usually composed of a hydrocarbon ...
DNA-based vaccines offer significant therapeutic potential but safe, efficacious delivery systems are still needed to enable clinical applications. Well-defined nonviral vectors, including those produced via reversible addition-fragmentation chain transfer (RAFT) polymerization, represent one approach for overcoming barriers to DNA delivery. Block copolymer micelles are an example of a complex architecture achievable by the RAFT process, adopting a core-shell morphology under physiological conditions. These polymeric nanoparticles consist of discrete segments capable of specific physicochemical and biological activities determined by their chemical composition. This thesis describes synthetic approaches focused on engineering the intra- and extracellular activity of this class of nanomaterials, with the goal of developing an in vivo DNA delivery platform. Chapter 1 focuses on how polymerization and carbohydrate chemistry techniques can be utilized to develop DNA-based cancer vaccines. Chapter 2 ...
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Polymeric micelles prepared from a series of poly(ethylene glycol)-poly(lactide) (PEG-PLA) diblock copolymers with various PLA chain lengths were designed as drug carriers for water insoluble drug amphotericin B (AmB). Physicochemical properties of AmB-loaded micelles were evaluated. Micelles were freeze-dried to obtain longtime stable formulations. The redispersibility of the freeze-dried samples was poor when the weight ratio of PLA block was bigger than the PEG block of the copolymer. Various types of lyoprotectants including saccharides and PEGs with different molecular weight were tested to improve the redispersion performance of the freeze-dried samples. PEG was proved to be more effective than saccharides on stabilizing the micelles during lyophilization when the weight ratio of PLA block was bigger than PEG block. The sustained release in vitro of AmB was evidenced. About 80% of AmB was released in 80 h. The in vitro release behavior could be best described by the first-order equation. ...
Since their discovery over a century ago, surfactant micelles have been a topic of intense interest in both academic and technological research [1]. Surfactant molecules consist of a hydrophilic head group covalently linked to a hydrophobic tail (hydrocarbon) group. In aqueous solution above a critical micellar concentration (cmc), they self-assemble into micelles consisting of a hydrophobic core of tail groups surrounded by a shell of hydrophilic head groups and water. The shape and size of these micelles depend on the type of surfactant and thermodynamic conditions such as temperature, solvent composition and salinity. Typically surfactant micelles aggregate into highly dynamic nanostructures consisting of either spherical or non-spherical shapes such as ellipsoidal, cylindrical and discoidal shapes. Detailed insight into their fundamental behaviour is important owing to their widespread applications ranging from detergents and additives in personal care and household cleaning products to ...
The synthesized mPEG-b-PεDL copolymer was investigated as a potential drug delivery vehicle for solubilization and controlled delivery of indomethacin. The indomethacin loading and release from mPEG-b-PεDL micelles (amorphous core) was compared against well-established mPEG-b-PCL micelles (semicrystalline core). The drug-polymer compatibility was also determined through a predictive computational approach to access the drug solubilisation (or drug loading) into hydrated micelles. The micelles were prepared by solvent evaporation method and characterized for size, morphology, indomethacin (IND) loading and release. Both of the micelle formulations showed a uniform distribution of spherical micelles with size ,60 nm. However, a significantly higher size of empty mPEG-b- PεDL micelle was observed compared to mPEG-b-PCL micelles. A higher compatibility of the drug was predicted with PCL core as determined by modified Flory-Huggins interaction parameters (sp) using the Hanson solubility ...
Senile plaques are well-known hallmarks of Alzheimers Diseases (AD). However, drugs targeting tangles of the protein tau and plaques of beta-amyloid have no significant effect on disease progression, and the studies on the underlying mechanism of AD remain in high demand. Growing evidence supports the protective role of senile plaques in local inflammation driven by S100A9. We herein demonstrate that oleic acid (OA) micelles interact with hen egg white lysozyme (HEWL) and promote its amyloid formation. Consequently, SH-SY5Y cell line and mouse neural stem cells are rescued from OA toxicity by co-aggregation of OA and HEWL. Using atomic force microscopy in combination with fluorescence microscopy, we revealed that HEWL forms round-shaped aggregates in the presence of OA micelles instead of protofibrils of HEWL alone. These HEWL amyloids act as a sink for toxic OA micelles and their co-aggregate form large clumps, suggesting a protective function in amyloid and OA cytotoxicity.. ...
The specific activity of Ca2+-ATPase reconstituted into diC18 : 1PC bilayers decreases at molar ratios C12NO : PC , 2where mixed rod-like (cylindrical) C12NO + diC18 : 1PC micelles (r , 1) are formed ). The geometry of the surfactant + phospholipid aggregates consisting of two compo- nents depends on the effective molecular packing parameter . The theory predicts that, depending on the packing parameter d, molecules form spherical micelles (d , 0.33),normal cylindrical micelles (0.33 , d , 0.5), curved bilayers (0.5 , d , 1), flat bilayers (d = 1) or inverted micelles (d , 1). We conclude that the inhibition of Ca2+-ATPase observed in diC18 : 1PC bilayers is most probably caused by C12NO:PC (mol:mol) a severe deformation of the bilayer resulting in the formation of Fig. 5. Dependences of the specific Ca2+-ATPase activity A at 37 normal tubular mixed C12NO + diC18 : 1PC micelles in isola- thickness (SANS parameter dg) of the diC18 : 1PC bilayer (?), SANS tion (d , 0.5). A decrease of the activity ...
Environmentally responsive nanoparticles synthesized from Elastin-Like Polypeptides (ELP) present a promising system for applications such as biosensors, drug delivery vehicles, and viscosity modifiers. These nanoparticles undergo a transition from a soluble state at Troom to micellar aggregates above the transition. The ELP micelles have been found to be sensitive to various outside stimuli including pH, salt concentration, and solvent. Dynamic and Static Light Scattering were used to study structure and dynamics of ELP nanoparticles below the transition and of formed ELP micelles above the transition. Micelles were found to generally depend strongly on solution pH, however, in the pH window of 10.1-10.4 their size stayed constant. The apparent radius and molecular weight of micelles in this pH range strongly depend on salt concentration with three apparent regimes. At low salt (0-15mM), largely spherical micelles were found with Rh=15nm, which corresponds to the size of folded ELP hydrophilic tail;
Water-based cleansers are all the rage right now. As more beauty bloggers started talking about them, the more I felt intrigued to try one out for myself. Its safe to say Im I glad I did. Ive been using Bioderma Sensibio H2O Micelle Solution for just over a month now, and Im happy to say that this is the best cleanser I have ever used. It retails for £9.99 for 250ml or £4.50 for 100ml at www.escentual.com. The formulation is specifically designed for people with normal-to-dry and sensitive skin. I have particularly sensitive areas in my cheeks and chin, and it doesnt irritate them at all. Its also fragrance free which is great for me as I avoid putting fragranced products on my face at all costs. I apply to my whole face, neck and eyes in upwards motions. Not only does it remove make-up, it also removes dirt and other nastiness from your face. Its amazing seeing the amount of stuff that comes off your face on the cotton pad. I use twice daily, morning and night, as the first step in my ...
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Supramolecular assemblies involving interaction of a small organic molecule, 2-hydroxy-6-Naphthoic acid (HNA), with poly(styrene)-block-poly(4-vinylpyridine) (PS-b-P4VP) diblock copolymers are utilized to obtain micellar structures in solution, nanostructured thin films on flat substrates and, finally, nanoporous thin films. The formation of hydrogen bonds between HNA and the poly(4-vinylpyridine) (P4VP) blocks is confirmed by spectroscopic measurements. The accordingly P4VP/HNA hydrogen-bonded complexes are poorly soluble in 1,4-dioxane, resulting in the formation of micellar structures with a P4VP/HNA core and a polystyrene (PS) corona. Those micelles have been spin-coated onto silicon wafers, resulting in nanostructured thin films consisting of P4VP/HNA dot-like features embedded in a PS matrix. The morphology of those films has been tuned by solvent annealing. Selective dissolution of HNA by methanol results in the formation of a nanoporous thin film. The P4VP/HNA nanodomains have been also
35 into Eq. 36, and rearranging leads to Çw Çw dNT 71 = kemms [R*w] = 7788 = 77241 dt 1 + (kep NT /kemms ) 1 + (eNT /Sm) (37) where kepNT/kemms denotes the ratio of the rate of radical entry into polymer particles to that into micelles and is rewritten as eNT/Sm, where e=(kep/kem)Mm and e is the one unknown parameter, which affects the number of polymer particles produced. Here, Sm is the total number of emulsifier molecules forming micelles, and Mm is the aggregation number of emulsifier molecules per micelle, defined by Mm=Sm/ms. Case A: The rate of radical entry into micelles that results in the formation of new particles is approximately equal to the rate of radical generation in the water phase (Çw), as long as emulsifier micelles are present; in other words, dNT 7 = Çw dt (28) Particle formation stops at the time tc, when the emulsifier micelles have just disappeared because all of the emulsifier molecules comprising the emulsifier micelles have been transferred to the surfaces of ...
More recently, Gianneschi et al. reported a one-pot ROMPISA procedure utilizing an oligo(ethylene glycol) (OEG)-based NB monomer for formation of the steric stabilizer block and a NB monomer functionalized with a short protected peptide sequence for the solvophobic core-forming component, using G3 under inert atmosphere in DMF/MeOH solvent mixtures.42 Importantly, when a longer brush-like corona block was used, morphological evolution was limited and only spherical micelles of varying size were developed, whereas a shorter corona block allowed for distinct higher-order nano-object morphologies of worm-like micelles and vesicles to also be accessed. Moreover, Delaittre and coworkers reported the fabrication of spherical micelles with tunable size (10-100 nm) bearing TEMPO units in their outer shell via an ultra-fast two-step ROMPISA methodology in organic milieu.43 A solvent-soluble random copolymer from OEG-NB and TEMPO-NB was first synthesized via ROMP using G1 in THF. This was then used as the ...
Current research has shown that polymers themselves are bioactive - they actively coordinate with binding domains on low density lipoproteins. In addition, the polymeric micelles can be slightly modified for complexation with oligonucleotides and plasmids. Second, PolymerDrugs are polymers that biodegrade into therapeutically useful molecules.
TY - JOUR. T1 - Micellization in aqueous solutions of monoalkyl phosphate salts. AU - Arakawa, Jun. AU - Pethica, Brian Anthony. PY - 1980/1/1. Y1 - 1980/1/1. N2 - The micellization of the mono-salts of octyl, decyl, and dodecyl phosphates and of the di-salts of dodecyl phosphate have been studied in aqueous solutions by conductivity methods. The effects of temperature, salt concentration, counterion type, and chain length have been examined. The mono-salts of the alkyl phosphates show properties similar to those of fatty acid soaps and alkyl sulfates. The di-salts show rather different counterion and temperature effects. The solubility diagrams for the mono-salts are anomalous and are explained in terms of the preferred precipitation of stable solid salts of the composition RPO4H2-RPO4HM where M is an alkali metal.. AB - The micellization of the mono-salts of octyl, decyl, and dodecyl phosphates and of the di-salts of dodecyl phosphate have been studied in aqueous solutions by conductivity ...
Aim: To investigate the preparation, in vitro release, in vivo pharmacokinetics and tissue distribution of a novel polymeric micellar formulation of paclitaxel (PTX) with Pluronic P123. Methods: The polymeric micelles of paclitaxel with Pluronic P123 were prepared by a solid dispersion method. The characteristics of micelles including particle size distribution, morphology and in vitro release of PTX from micelles were carried out. PTX-loaded micellar solutions were administered through the tail vein to healthy Sprague-Dawley rats and Kunming strain mice to assess the pharmacokinetics and tissue distribution of PTX, respectively. Taxol, the commercially available intravenous formulation of PTX, was also administered as control. Results: By using a dynamic light scattering sizer and a transmission electron microscopy, it was shown that the PTX-loaded micelles had a mean size of approximately 25 nm with narrow size distribution and a spherical shape. PTX was continuously released from Pluronic ...
A novel series of anionic fluorine-containing amphiphilic graft copolymers, poly(hexafluorobutyl methacrylate-co-sodium 4-vinylbenzenesulfonate)-g- poly(ethylene glycol) methyl ether methacrylate [poly(HFMA-co-NaSS)-g-PEG], were prepared via the free radical copolymerization. The micellization behavior of the copolymers was studied by critical micelle concentration (CMC), dynamic light scattering (DLS) and transmission electron microscopy (TEM). The results showed that poly(HFMA-co-NaSS)-g-PEG copolymers could self-assemble into core/shell structure micelles in aqueous solution. Afterward, the micelles stability was studied by zeta potential measurement, which demonstrated that the copolymer micelles had good stability in biological milieu. The interaction between the copolymer micelles and BSA was characterized by fluorescence spectroscopy, and the morphology of the micelles/BSA complexes was observed by TEM. The results demonstrated that the adsorption could be easily achieved between the ...
TY - PAT. T1 - Drug carriers comprising amphiphilic block copolymers. AU - Lewis, Andrew. AU - Armes, S.P.. AU - Lloyd, Andrew. AU - Salvage, Jonathan. PY - 2005/10/6. Y1 - 2005/10/6. N2 - An aqueous composition comprises an amphiphilic block copolymer, having a hydrophilic block comprising pendant zwitterionic groups and a hydrophobic block, and a biologically active compound associated with the polymer. The polymer is preferably in the form of micelles, and preferably the biological active is a hydrophobic drug, for instance having a calculated or experimentally determined logP of at least 1.0, where P is the octanol:water partition coefficient. The hydrophilic block is preferably formed from acrylic monomer including phosphoryicholine groups. The hydrophobic group is suitably formed from monomer which has groups which can be ionised at useful pHs, especially tertiary amine groups. Micelles may be formed by dissolving the block copolymer in aqueous solvent at a pH at which the amine groups ...
Supracolloidal chains of diblock copolymer micelles were functionalized with gold and silver nanoparticles (NPs). Both NPs were independently synthesized in situ in the core of spherical micelles which were then converted to patchy micelles. With these patchy micelles as colloidal monomers, supracolloidal chains were polymerized by combining the patches of neighboring micelles. Since all micelles contained NPs, NPs were incorporated in every repeat unit of chains. In addition, a single gold NP was synthesized in the micellar core in contrast to several silver NPs so that we differentiated the chains with Au NPs from those with Ag NPs by the number of NPs in the repeat unit as well as by plasmonic bands in UV-Vis spectra ...
L-Aspartic acid (L-Asp) was produced using Escherichia coli (ATCC 11303), and its recovery from the reaction mixture was studied using reverse micelle and gas hydrate methods. The effect of initial substrate concentration on L-Asp production was also investigated, and inhibition was shown to occur above 0.75 mol L-1. The values of the kinetic constants were determined as r(max) = 2.33 x 10(-4) mol L-1 min(-1), K-M = 0.19 mol L-1, and K-ss = 3.98 mol L-1. The reverse micelle phase used for extraction contained Aliquat-336, 1-decanol and isooctane, and a micro-injection technique was used for extraction of L-Asp. The reverse micelle system is a useful technique for obtaining small particle sizes, which can be used for the synthesis of nanoparticle biomolecules. Recovery of L-Asp from reverse micelles using CO2 hydrates was carried out, giving a recovery of 55%. The formation of CO2 hydrate from the reverse micelle solution breaks the micelle by reducing the amount of water in the micelle ...
The invention relates to micelles and emulsion preconcentrates comprising i) one or more active ingredients and ii) wood resin, optionally in combination with gum arabic, and iii) optionally additional adjuvants; products containing said micelles and/or emulsion preconcentrates, method for the production of micelles, emulsion preconcentrates, and products.
Noncovalently cross-linked networks are attractive hydrogel platforms because of their facile fabrication, dynamic behavior, and biocompatibility. The majority of noncovalently cross-linked hydrogels, however, exhibits poor mechanical properties, which significantly limit their utility in load bearing applications. To address this limitation, hydrogels are presented composed of micelles created from genetically engineered, amphiphilic, elastin-like polypeptides that contain a relatively large hydrophobic block and a hydrophilic terminus that can be cross-linked through metal ion coordination. To create the hydrogels, heat is firstly used to trigger the self-assembly of the polypeptides into monodisperse micelles that display transition metal coordination motifs on their coronae, and subsequently cross-link the micelles by adding zinc ions. These hydrogels exhibit hierarchical structure, are stable over a large temperature range, and exhibit tunable stiffness, self-healing, and fatigue ...
Moreover, the UHT treatment of milk causes structural changes in its protein system. The main change is the denaturation of whey proteins and their interaction with casein micelles. Consequently, it was expected that the behavior of the UHT milk would be similar to that of casein micelles, as observed with native casein. However, it has been shown that the interaction between casein micelles and whey proteins is also accompanied by a large increase in number of very small, soluble particles resulting from the desegregation of casein micelles. Consequently, by weakening the interaction forces between caseins, heat treatment provokes both a loss of the micelle framework and the formation of small aggregates. Correlatively, an increase in the amount of nonsedimentable casein has been observed in UHT milk following high-speed centrifugation (33). Two effects of these changes on milk properties may be softer coagulation and a higher susceptibility to enzymatic hydrolysis due to loosening of the ...
Two problems arising from the use of complex fluidic systems in the energy industry were studied: the behavior of worm-like surfactant micelles in porous media and the control and measurement of the hydration of hydraulic cement. The first problem arises when surfactant solutions are used as fracturing fluids in drilling operations. To influence the behavior of these surfactants, a hydrophobically modified chitosan was synthesized, and the interactions of the polymers synthesized with surfactant micelles was studied via rheology. The addition of polymer led to a increase in the elasticity and relaxation time of the system. A high-pressure microfluidic device was produced via lithographic techniques to study the in-situ behavior of the worm-like micelles, and was also utilized as a capillary rheometer to measure the behavior of the worm-like micelles at high shear rates. In the second problem, two tools were developed and validated to enable the accurate measurement of the setting of cement. The ...
Olson, D.W. and D. J. McMahon. 1991. Zeta-potential of casein micelles in UHT-treated ultrafiltered skim milk. 86th American Dairy Science Association Meeting, . Dairy Sci. 74(Supp. 1):D155. ...
Preparation of Two Types of Polymeric Micelles Based on Polyβ-L-Malic Acid for Antitumor Drug Delivery. . Biblioteca virtual para leer y descargar libros, documentos, trabajos y tesis universitarias en PDF. Material universiario, documentación y tareas realizadas por universitarios en nuestra biblioteca. Para descargar gratis y para leer online.
TY - JOUR. T1 - Photochemical enhancement of transgene expression by polymeric micelles incorporating plasmid DNA and dendrimer-based photosensitizer. AU - Nishiyama, Nobuhiro. AU - Arnida, AU - Jang, Woo Dong. AU - Date, Kotoe. AU - Miyata, Kanjiro. AU - Kataoka, Kazunori. N1 - Funding Information: The authors wish to express their gratefulness to the Health and Labor Sciences Research Grants in Research on Advanced Medical Technology in Nanomedicine Area from the Ministry of Health, Labor and Welfare (MHLW), Japan. Also, they wish to express their thanks for the Grant-in-Aid for Scientific Research, the Special Coordination Funds for Promoting Science and Technology and the Project on the Materials Development for Innovative Nano-Drug Delivery Systems from the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan.. PY - 2006/7. Y1 - 2006/7. N2 - The development of synthetic gene carriers has recently received much attention; however, they might lack the ability to ...
We have employed quasi-elastic light-scattering methods to characterize micellar aggregates and microprecipitates formed in aqueous solutions containing sodium taurocholate (TC), egg lecithin (L), and cholesterol (Ch). Particle size and polydispersity were studied as functions of Ch mole fraction (XCh = 0-15%), L/TC molar ratio (0-1.6), temperature (5-85 degrees C), and total lipid concentration (3 and 10 g/dL in 0.15 M NaCl). For XCh values below the established solubilization limits (XChmax) [Carey, M. C., & Small, D. M. (1978) J. Clin. Invest. 61, 998], added Ch has little influence on the size of simple TC micelles (type 1 systems), on the coexistence of simple and mixed TC-L micelles (type 2 systems), or on the growth of mixed disc TC-L micelles (type 3 systems). For supersaturated systems (XCh/XChmax greater than 1), 10 g/dL type 1 systems (L/TC = 0) exist as metastable micellar solutions even at XCh/XChmax = 5.3. Metastability is decreased in type 2 systems (0 less than L/TC less than 0.6), and
en] Novel nanostructured thermosetting materials have been prepared by modification of an epoxy resin with a semifluorinated diblock copolymer, poly(heptadecafluorodecyl acrylate)-b-poly(caprolactone), PaF-b-PCL. In a first step, the phase behavior and linear viscoelasticity of PaF-b-PCL were investigated. According to the segregation regime, no order-order transitions were detected, being the order-disorder transition temperature beyond the degradation temperature. Atomic force microscopy (AFM) images of the block copolymer after different thermal treatments revealed that self-assembly takes place into spherical nanodomains, which is consistent with the copolymer composition. This block copolymer was further used to prepare a nanostructured thermoset blend with an epoxy resin. DSC and DMA analysis reveals microphase separation of PaF block from the epoxy-rich phase after curing. The PaF block self-assembled into wormlike and spherical micelles in the thermoset system. This nanostructured blend ...
article{49dad94b-7449-4b26-a82e-492450a9362d, abstract = {A complex salt of cetyltrimethylammonium (CTA(+)) with short (30 repeating units) polyacrylate (PA(-)) counterions has been synthesized. The phase diagrams of its aqueous mixtures with either the surfactant cetyltrimethylammonium acetate (CTAAc), or the polyelectrolyte NaPA, have been studied by visual inspection through crossed polarizers and by small-angle X-ray scattering. Both of the ternary phase diagrams are strikingly simple, containing only micellar, cubic micellar, and hexagonal phases. In the CTAPA/CTAAc/water system, the surfactant forms essentially spherical micelles above ca. 50 wt % of water, regardless of the counterion composition, and the system may serve as a model for charged colloids with mixed monovalent/polymeric counterions. The interactions between micelles varies from repulsive to attractive as the fraction of monovalent counterions is dec,br/,,br, eased. This results, first, in a liquid-liquid phase separation ...
6-SHOGAOL RICH GINGER OLEORESIN LOADED MIXED MICELLES ENHANCES IN VITRO CYTOTOXICITY ON MCF-7 CELLS AND IN VIVO ANTICANCER ACTIVITY AGAINST DAL CELLS
p align=justify,GLV could be helpful to suggest using leafy vegetables as a part of daily meal. To achieve this goal, nutritional awareness on the importance of these GLV is warranted among various communities in the country. The present study clearly demonstrates that PC in mixed micelles suppresses the intestinal uptake, accumulation and conversion of newly absorbed β-carotene in to retinol, while lysoPC enhances β-carotene level and conversion efficiency of retinol by activating the dioxygenase. Thus, the present results suggest that the hydrolysis of PC to lysoPC is an important step for the intestinal uptake of β-carotene solubilized in mixed micelles and that dietary lysoPC modify the bioavailability of β-carotene. The mechanism of these effects of phospholipids in mixed micelles on the intestinal uptake of β-carotene and, in particular, its relationship to intestinal lipid metabolism deserves further study.,/p ...
Note: The molecular weights for some detergents are average values. Triton X-100, for example, can range between 600 and over 650 MW depending on synthesis. The exact molecular weight influences the CMC. Note: CMCs can vary with ionic strength and temperature. For ionic detergents the CMC is reduced by increasing the ionic strength of the solution, but is relatively unaffected by temperature. For non-ionic detergents the CMC is relatively unaffected by ionic strength, but increases significantly with higher temperature. Ranges refer to a 20-25ºC temperature range. Note: Saponin is a class of amphiphilic, natural metabolites with detergent properties often extracted from plants. CMC may vary. ...
Bile or gall acts to some extent as a surfactant, helping to emulsify the lipids in food. Bile salt anions are hydrophilic on one side and hydrophobic on the other side; consequently, they tend to aggregate around droplets of lipids (triglycerides and phospholipids) to form micelles, with the hydrophobic sides towards the fat and hydrophilic sides facing outwards. The hydrophilic sides are negatively charged, and this charge prevents fat droplets coated with bile from re-aggregating into larger fat particles. Ordinarily, the micelles in the duodenum have a diameter around 14-33 μm.[citation needed]. The dispersion of food fat into micelles provides a greatly increased surface area for the action of the enzyme pancreatic lipase, which actually digests the triglycerides, and is able to reach the fatty core through gaps between the bile salts. A triglyceride is broken down into two fatty acids and a monoglyceride, which are absorbed by the villi on the intestine walls. After being transferred ...
This pore refining solution, also known as the Sebium Pore Refiner, is part of the Sebium line. Its meant for skin with blemishes and its like a skincare treatment + primer hybrid. Its meant to be applied either all over the face, or on oily areas like the forehead, nose and chin. Although it does contain silicone (so common in many smoothing and mattifying products), it also has ingredients meant to regulate sebum production.. I like using this when I want to treat and prime my skin. I think it helps smooth blemishes a little so that my foundation applies more smoothly over top. Its just a nice skincare treatment that is nice to add to your arsenal if you have the occasional breakout. I like that I dont have to worry about it interfering with the rest of my makeup, as is the case with some acne treatments.. ...
The field of drug delivery has provided a solution to the limited efficacy and high toxicity of many drugs. Nano-sized drug carriers are popular because their size allows for selective accumulation in the diseased area. Polysaccharides are non-toxic and biodegradable natural polymers that can serve as the basis for these nano-sized carriers. Polysialic acid (PSA) is such a polysaccharide with strong hydrophilicity that may reduce uptake by the reticuloendothelial system and prolong drug circulation. In this study, we developed PSA-based nanocarriers, specifically micelles and nanoparticles, for improved drug delivery with improved efficacy and minimized toxicity. PSA-based micelle systems were developed via conjugation with two hydrophobic groups, decylamine (DA) and polycaprolactone (PCL). Nanoparticles were fabricated via ionic complexation of the negatively charged PSA with positively charged N, N, N-trimethyl chitosan (TMC). All three nanocarriers possessed sizes close to 100 nm with low
are also real and exist. Recent studies have shown a correlation between tea drinking and reduce cardiovascular disease events, such as acute myocardial infarction and stroke. A study conducted by Boston University in 2001 concluded that this effect was due to components in black tea reversing endothelial vasomotor dysfunction, reducing the possibility of dangerous cardiovascular events. In addition, a compound known as theaflavin-3-gallate has shown promise in reducing the incorporation of cholesterol into mixed micelles. These micelles are responsible for absorbing cholesterol into the body, and blocking such an event may help with cholesterol levels, even if in modest levels. However, to gain these benefits, black tea must be drunk without milk. A German study in 2006 showed that milk cancels out these health benefits. This is likely because the casein proteins in milk bind to the active components in tea that have the purported health benefits. Plus, a study conducted by the University ...
The sternal gland of primitive termites of the genus Zootermopsis (Z. nevadensis or Z. angusticollus) (Hagen) seems more organized than that of higher termites, in being comprised of three cell layers. It is also studded with about 200 campaniform sensilla. Below the meshwork cuticle of the gland lies a layer of columnar epithelial cells whose apical surfaces form a brush border, and whose basal surfaces are sculptured into a basketwork into which the second layer fits. Below the brush border are small microtubule-associated pits and coated vesicles. No channels can be seen either within or, except for the sensilla, between the cells. The second cell layer probably secretes the trail-following pheromone. Numerous electron-lucent droplets and large channels containing lipid micelles are found in the cytoplasm here, but the channels cannot be traced out of the secretory layer. The third layer consists of large pyriform cells. The campaniform sensilla are composed of three cells: the sensory cell ...
Self-assembly processes of polyelectrolyte block copolymers are ubiquitous in industrial and biological processes; understanding their physical properties can also provide insights into the design of polyelectrolyte materials with novel and tailored properties. Here, we report systematic analysis on how the
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The addition of a few percent of diblock copolymers to epoxy leads to a huge increase (some factor of 50) in the toughness of the cured epoxy. It is known, from transmission electron microscopy, that the diblock copolymers form spherical and cylindrical micelles with a radius of ~100 nanometers. It is surprising that these soft inclusions can increase the toughness of cross-linked epoxy so dramatically. There is currently no theoretical understanding of this behavior. In order to determine the origin of this effect, these researchers are simulating the toughness of simple elastic crosslinked networks with soft inclusions. In particular, they are modeling epoxy using large random elastic networks of stiff springs with soft inclusions modeled as domains of springs with reduced spring constants. This project involves the use of molecular dynamics and/or Monte Carlo simulation techniques to determine the toughness of these networks, and the effect of the shape and size of soft inclusions.. Another ...
New methods in nanoparticle development have aimed to develop customized carriers suited for specific purposes. Micelles, due to their highly tailorable nature, are prime candidates for this customizable methodology. In order to maximize drug loading and tailor release, groups of the micelle core should be carefully selected in order to exploit inherent interactions between the selected drug and the carrier core. Small variations within the composition of these groups can greatly affect micelle characteristics (e.g., size, stability, loading and release). While covalent bonding of drug-to-carrier has enhanced drug loading, drawbacks include inhibited release and altered drug properties. As a result, drug/carrier non-covalent interactions such as hydrophobic attraction, hydrogen bonding and π-π stacking have all garnered great interest, allowing for both enhanced loading as well as bond dissociation to aid in drug release. Just as important, external composition of these micelles should be suited for
Chitosan (CS), a nature-derived polysaccharide, is a promising nano-carrier material with good biocompatibility and biodegradability. However, the biomedical applications of CS are hindered because of its poor aqueous solubility. To circumvent this drawback, a series of Brij-grafted-chitosan copolymers (BCs) with various grafting degree of Brij-S20 were first developed and reported. The results indicated that the water solubility of BCs (from 9.13 to 9.54 mg/mL) were much higher than that of CS (0.32 mg/mL), due to the broken intra- and/or inter-molecular hydrogen bonds and the decreased initial crystallinity in BCs. The amphiphilic structure of BCs presented lower critical micelle concentration (0.116-0.376 mg/mL) thus facilitating its self-aggregation into micelles for drug encapsulation. Moreover, BCs markedly enhanced the intracellular uptake of rhodamine-123 in MDCK-MDR1 cells. This inhibition on Pgp-mediated efflux was also confirmed by confocal microscopy. In conclusion, BCs could be ...
The topical application of all- trans retinoic acid (ATRA) is an effective treatment for several skin disorders, including photo-aging. Unfortunately, ATRA is susceptible to light, heat, and oxidizing
Polymeric Reverse Micelles as Selective Extraction Agents and Related Methods of MALDI-MS Analysis - diagram, schematic, and image 01 ...
Correa DS, De Boni L, Parra GG, Misoguti L, Mendonça CR, Borissevitch I, Zílio SC, Barbosa Neto NM, Gonçalves PJ. Excited-state absorption of meso-tetrasulfonatophenyl porphyrin: effects of pH and micelles [Internet]. Optical Materials. 2015 ; 42 516-521.Available from: http://dx.doi.org/10.1016/j.optmat.2015.01. ...
Thesis, English, Experimental and theoretical studies of a photo active unsaturated compound in different solvents and micelles for El Nshar Tarek Eid Farag
Doxorubicin-loaded aromatic imine-contained amphiphilic branched star polymer micelles: synthesis, self-assembly, and drug delivery Liang Qiu, Chun-Yan Hong, Cai-Yuan Pan Chinese Academy of Sciences Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui, People’s Republic of China Abstract: Redox- and pH-sensitive branched star polymers (BSPs), BP(DMAEMA-co-MAEBA-co-DTDMA)(PMAIGP)ns, have been successively prepared by two steps of reversible addition–fragmentation chain transfer (RAFT) polymerization. The first step is RAFT polymerization of 2-(N,N-dimethylaminoethyl)methacrylate (DMAEMA) and p-(methacryloxyethoxy)benzaldehyde (MAEBA) in the presence of divinyl monomer, 2,2'-dithiodiethoxyl dimethacrylate (DTDMA). The resultant branched polymers were used as a macro-RAFT agent in the subsequent RAFT polymerization. After hydrolysis of the BSPs to form BP(DMAEMA-co-MAEBA-co-DTDMA)(PMAGP)ns (BSP
Casein micelle image from Dalgleish, D. G., P. Spagnuolo and H. D. Goff. 2004. A possible structure of the casein micelle based on high-resolution field-emission scanning electron microscopy. International Dairy Journal. 14: 1025-1031. This micelle is 120 nm in diameter.. There have been many models developed over the years to explain the structure of the casein micelle, based on all of the information available about its composition and reactivity. The casein sub-micelle model was prominent for many years, but there is sufficient evidence now to conclude that there is not a defined sub-micellar structure to the micelle at all. More recent models suggest a more open structure comprised of aggregates of protein around calcium phosphate nanoclusters. Each of the casein proteins has unique abilitites to either bind with CaP or with other caseins, which gie rise to the aggregates. The nanoclusters provide regions of more or less density. The structure is sufficiently porous to hold a considrable ...
The BOMN-158 God Micelles In An Angle! Tits Shaking Massage While Blow movie model Nishii Yuka, Kisaki Mikoto, Ootsuki Mayuka, Saegusa Chitose, Konno Mako, Amayoshi Shizuku, Shikine Maho, Aino Mahoro, Ichinose Natsuki, Ayana Rina production, with the key search is BOMN-158.
Casein phosphorylation is a posttranslational modification catalyzed by kinase enzymes that attach phosphate groups to specific AA in the protein sequence. This modification is one of the key factors responsible for the stabilization of calcium phosphate nanoclusters in casein micelles and for the internal structure of the casein micelles. aS1-Casein (as1-CN) is of special interest because it constitutes up to 40% of the total casein fraction in milk, and it has 2 common phosphorylation states, with 8 (aS1-CN-8P) and 9 (aS1-CN-9P) phosphorylated serine residues. Factors affecting this variation in the degree of phosphorylation are not currently known. The objective of this research was to determine the genetic background of aS1-CN-8P and aS1-CN-9P. The genetic and phenotypic correlation between aS1-CN-8P and aS1-CN-9P was low (0.18 and 0.19, respectively). This low genetic correlation suggests a different genetic background. These differences were further investigated by means of a genome-wide ...
The aqueous environment in the gastrointestinal tract frequently requires solubilization of hydrophobic drug molecules in appropriate drug delivery vehicles. An effective uptake/absorption and systemic exposure of a drug molecule entails many processes, one being transport properties of the vehicles through the mucus layer. The mucus layer is a complex mixture of biological molecules. Among them, mucin is responsible of the gel properties of this layer. In this study, we have investigated the diffusion of polyoxyethylene sorbitane monooleate (polysorbate 80), a commonly used nonionic surfactant, in aqueous solution, in mucin solutions at 0.25 and 5 wt %, and in mucus. These measurements were done by using the pulsed field gradient spin echo nuclear magnetic resonance (PGSE-NMR) technique. We conclude that polysorbate 80 is a mixture of non-surface-active molecules that can diffuse freely through all the systems investigated and of surface-active molecules that form micellar structures with transport
In generic terms, a drug delivery substrate (DDS) can be described as a vehicle to transport drug to the point of interest. A DDS that would ideally have the ca...
Newkome GR, Yao Z, Baker GR, Gupta VK (1985). "Micelles Part 1. Cascade molecules: a new approach to micelles, A-arborol". J. ... Newkome GR, Yao Z, Baker GR, Gupta VK (1985). "Micelles. Part 1. Cascade molecules: a new approach to micelles. A [27]-arborol ... The use of dendrimers as unimolecular micelles was proposed by Newkome in 1985. This analogy highlighted the utility of ... Liu M, Kono K, Fréchet JM (March 2000). "Water-soluble dendritic unimolecular micelles: their potential as drug delivery agents ...
Multicompartment polymer micelles. Attempts to Mimic Biomembrane Processes: Synthetic and natural receptors in molecular ...
The second type is noticeably larger than the first and has been termed 'super micelles'. Unfortunately, the structure of the ... In the case of spherical Janus micelles having hemispheres of polystyrene (PS) and poly(methyl methacrylate) (PMMA), ... "Janus Micelles" (PDF). Macromolecules. 34 (4): 1069-1075. Bibcode:2001MaMol..34.1069E. doi:10.1021/ma000670p.CS1 maint: ...
Bates, Frank S.; Davis, H. Ted; Won, You-Yeon (1999-02-12). "Giant Wormlike Rubber Micelles". Science. 283 (5404): 960-963. ... "Giant Wormlike Rubber Micelles", Science 283, 960 (1999). F.S. Bates, G.H. Fredrickson, D. Hucul, S.F. Hahn "PCHE-based ... "Toughening of Epoxies with Block Copolymer Micelles of Wormlike Morphology". Macromolecules. 43 (17): 7238-7243. Bibcode: ...
Reverse micelles as hosts for proteins and small molecules; P.P. Luisi, M. Giomini, M.P. Pileni, B. Robinson; Biochem. Biophys ... 947, 209-216, (1988). Reverse micelles : a microreactors; M.P. Pileni; J. Phys.Chem. 97, 6961-6974 (1993). Nanosized Particles ...
"Micelle". Google Scholar. 2006. Retrieved 18 October 2014. "TWAS". TWAS. 2015. Retrieved 23 January 2015. "APAM". APAM. 2014. ... Sood has also experimented with soft condensed matter like micelle composed viscoelastic gels which establish a deterministic ...
Micelles, Membranes, Microemulsions, and Monolayers. Springer. pp. 1-104. doi:10.1007/978-1-4613-8389-5_1. ISBN 978-1-4613-8391 ... and on the self-assembly theory of micelles, surfactant monolayers, and biological membranes. During a sabbatical year in 1998- ...
An aggregation number is a description of the number of molecules present in a micelle once the critical micelle concentration ... Micelles: theoretical and applied aspects. Springer Science & Business Media, 1992. N.E. Olesen. Journal of Colloid and ... In more detail, it has been defined as the average number of surfactant monomers in a spherical micelle. The aggregation number ... "What can isothermal titration microcalorimetry experiments tell us about the self‐organization of surfactants into micelles?." ...
"Glycation Reactions of Casein Micelles". Journal of Agricultural and Food Chemistry. 64 (14): 2953-2961. doi:10.1021/acs.jafc. ...
Micelle; Spaulding, Paul M.; Velazco, Marcelo; Weksler, John r.; Wible, Andrea L.; Cirranello, A. L. (8 February 2013). "The ...
"Micelle Edwards". University of Iowa Department of Intercollegiate Athletics. Retrieved 5 Jun 2014. "Michelle Edwards To Be ...
Haydel, Micelle; Scott, Dulebohn. "Blunt Head Trauma". StatPearls. PubMed. Retrieved 11 December 2018. Nickson, Chris. " ...
Micelle; Velazco, Paul M.; Weksler, Marcelo; Wible, John r.; Cirranello, Andrea L. (8 February 2013). "The Placental Mammal ...
Haydel, Micelle J.; Preston, Charles A.; Mills, Trevor J.; Luber, Samuel; Blaudeau, Erick; DeBlieux, Peter M.C. (2000). " ...
1990). "Amino acids in AOT reversed micelles. 2. The hydrophobic effect and hydrogen bonding as driving forces for interfacial ... measured the partitioning of 14 radiolabeled amino acids using sodium dodecyl sulfate (SDS) micelles. Also, amino acid side ...
... micelles} }} is number concentration of micelles (number of micelles per unit volume), and N A {\displaystyle N_{\mathrm {A ... Excess surfactant creates micelles in the water. Small amounts of monomer diffuse through the water to the micelle. A water- ... Monomer in the micelle quickly polymerizes and the growing chain terminates. At this point the monomer-swollen micelle has ... Those micelles that did not encounter a radical during the earlier stage of conversion begin to disappear, losing their monomer ...
Once solubilized by encapsulation in either a hydrophobic interior micelle or a hydrophilic exterior micelle, the QDs can be ... which will spontaneously form micellular structures at its critical micelle concentration (CMC). The critical micelle ... These micelles can be moved in a magnetic field to create concentration gradients that will influence a cell's processes. Gold ... However, if the PEG chain is too long the micelle will become unstable. It has been observed that a stable hydrogel can only be ...
Bandyopadhyaya, Rajdip; Kumar, R.; Gandhi, K. S. (2000). "Simulation of precipitation reactions in reverse micelles". Langmuir ...
Kaler is coeditor of the book Giant Micelles and is author or coauthor of more than 200 papers. He holds 10 U.S. patents. Kaler ... Examples are liquid crystals, microemulsions and micelles, some polymeric solutions, vesicles, emulsions, and protein solutions ... Kaler, Eric William (1982). Surfactant Microstructures (Microemulsions, Micelles) (Ph.D. thesis). University of Minnesota. OCLC ...
Merocyanine dyes in cationic and anionic micelles". Journal of Organic Chemistry, 44:3252, 1979. Amaresh Mishra, et al.: " ...
However, in sharp contrast to surfactant micelles, the interior of a casein micelle is highly hydrated. The caseins in the ... Any of several molecular models could account for the special conformation of casein in the micelles. One of them proposes the ... It is found in milk as a suspension of particles, called casein micelles, which show only limited resemblance with surfactant- ... Holt C (1992). "Structure and Stability of Bovine Casein Micelles". In Anfinsen CB, Richards FM, Edsall JT, et al. (eds.). ...
There are several models that account for the special conformation of casein in the micelles. One of them proposes that the ... Holt, C. (1992). "Structure and Stability of Bovine Casein Micelles". In Anfinsen, C.B.; Richards, Frederic M.; Edsall, John T ... All 3 models consider micelles as colloidal particles formed by casein aggregates wrapped up in soluble κ-casein molecules. ... Walstra, Pieter (1979). "The voluminosity of bovine casein micelles and some of its implications". Journal of Dairy Research. ...
Cates, M E; Candau, S J (20 August 1990). "Statics and dynamics of worm-like surfactant micelles". Journal of Physics: ...
... micelles, and vesicles, VII. Hexadecahydro-29H,31H-tetrabenzo[b,g,l,q]porphin and -octayl octaacetate". Liebigs Annalen der ...
Nishiyama N, Matsumura Y, Kataoka K (July 2016). "Development of polymeric micelles for targeting intractable cancers". Cancer ... "A first-in-human Phase 1 study of epirubicin-conjugated polymer micelles (K-912/NC-6300) in patients with advanced or recurrent ...
Using ABC miktoarm star polymers the first example of multicomponent block copolymer micelles was shown, driven by the mutual ... He, Yiyong; Li, Zhibo; Simone, Peter; Lodge, Timothy P. (2006). "Self-Assembly of Block Copolymer Micelles in an Ionic Liquid ... Li, Z.; Kesselman, E.; Talmon, Y.; Hillmyer, M. A.; Lodge, T. P. (2004-10-01). "Multicompartment Micelles from ABC Miktoarm ... In a subsequent paper the simultaneous, segregated storage of two different chromophores in the different micelle domains was ...
The addition of micelles to the mobile phase introduces a third phase into which the solutes may partition. Micelles are ... The solute will partition between the water and the stationary phase (KSW), the water and the micelles (KMW), and the micelles ... Many of the characteristics of micelles differ from those of bulk solvents. For example, the micelles are, by nature, spatially ... When the concentration of a surfactant in solution reaches its critical micelle concentration (CMC), it forms micelles which ...
ASMs behave as unimolecular micelles, where four polymer particles are covalently bound. AScMs consist of part of the star like ... Uhrich's second research line is on polymeric micelles. Like soap, these polymers have a hydrophilic 'head' and a hydrophobic ' ... Uhrich's research group investigates two general classes of nanoscale polymeric micelles: amphiphilic star-like macromolecules ...
... "micelles". Water could penetrate between the micelles, and new micelles could form in the interstices between old micelles. The ... The modern usage of 'micelle' refers strictly to lipids, but its original usage clearly extended to other types of biomolecule ... at the US Department of Agriculture developed a colloidal phase separation model for milk casein micelles that form within ... The formation of these structures involves phase separation to from colloidal micelles or liquid crystal bilayers, but they are ...
They serve as micelle-forming surfactants, which encapsulate nutrients, facilitating their absorption. These micelles are ... Bile acid-containing micelles aid lipases to digest lipids and bring them near the intestinal brush border membrane, which ... As a result, the concentration of bile acids/salts in the small intestine is high enough to form micelles and solubilize lipids ... Oct 1972). "Micelle formation by bile salts. Physical-chemical and thermodynamic considerations". Arch Intern Med. 130 (4): 506 ...
micelle* An aggregate of molecules in a colloid [1]. For example, phospholipids in aqueous solution form micelles - small ... micelle An aggregate of molecules in a colloid. For example, phospholipids in aqueous solution form micelles - small clusters ... micelles A Dictionary of Food and Nutrition © A Dictionary of Food and Nutrition 2005, originally published by Oxford ... micelle A Dictionary of Biology © A Dictionary of Biology 2004, originally published by Oxford University Press 2004. ...
This type of micelle is known as a normal-phase micelle (oil-in-water micelle). Inverse micelles have the head groups at the ... Micelles form only when the concentration of surfactant is greater than the critical micelle concentration (CMC), and the ... The formation of micelles can be understood using thermodynamics: Micelles can form spontaneously because of a balance between ... These can be achieved in two ways: when the unimers forming the micelles are not soluble in the solvent of the micelle solution ...
Micelles only form above critical micelle temperature. For example, the value of CMC for sodium dodecyl sulfate in water ( ... The CMC is the concentration of surfactants in the bulk at which micelles start forming. The word bulk is important because ... It is desired that the surfactant will work at the lowest interfacial tension (IFT). The formation of micelles take place only ... Upon reaching CMC, any further addition of surfactants will just increase the number of micelles (in the ideal case). There are ...
Each of the plurality of cylindrical micelles may be loaded with a therapeutic agent. ... and a plurality of entangled cylindrical micelles disposed on the expandable framework. ... The cylindrical micelles 50 are not illustrated in FIG. 1. for the sake of clarity). Cylindrical micelles are a class of self- ... The cylindrical micelles 50 and/or specific block components of the copolymers of the cylindrical micelles 50 may be biostable ...
NMR measurements revealed significant differences in DAGK-detergent interactions involving LMPC micelles versus micelles ... Lysophospholipid micelles sustain the stability and catalytic activity of diacylglycerol kinase in the absence of lipids. * ... Here, we report that near-optimal catalytic properties are observed for DAGK in micelles composed of ... in order to be catalytically viable in micelles. ... with significant activity also being observed in micelles ...
Silica-shelled single quantum dot micelles. BioPhotonics. Oct 2006 David Shenkenberg. Quantum dots might become more widely ... Before silica-shelling, they coated the quantum dots with detergent micelles, which enable the incorporation of other ... In addition, initial studies showed that PDT performed with silica micelles containing quantum dots and phthalocyanine could ...
Casein micelle image from Dalgleish, D. G., P. Spagnuolo and H. D. Goff. 2004. A possible structure of the casein micelle based ... Structure: The Casein Micelle. Most, but not all, of the casein proteins exist in a colloidal particle known as the casein ... This micelle is 120 nm in diameter.. There have been many models developed over the years to explain the structure of the ... The casein sub-micelle model was prominent for many years, but there is sufficient evidence now to conclude that there is not a ...
... Ali Mohammad Alizadeh,1 Majid Sadeghizadeh,2 ... Ali Mohammad Alizadeh, Majid Sadeghizadeh, Farhood Najafi, et al., "Encapsulation of Curcumin in Diblock Copolymer Micelles for ...
Reverse Micelle Active Charcoal Enzyme SOLUBILIZED Turnover Number Hydrocarbon Phase This is a preview of subscription content ... Luisi P., Meyer P., Wolf R. (1980) Properties of Enzymes Solubilized in Hydrocarbons Via Reversed Micelles. In: Weetall H.H., ...
Schematic of micelle stabilization. (A) Lipid monomers (1) form micelles above a critical micelle concentration (2), but this ... FRET assay to measure micelle stability. (A) FRET spectra of DSPE-PEG micelles and (B) diC18-UUUUU micelles show an increase in ... Micelle characterization. (A) TEM image of diC18-UGGGU micelles. (B) Experimental SAXS profiles of DSPE-PEG, diC18-UGGGU, and ... Overlay of NMR spectra for diC18-UGGGU micelles after D2O exchange. diC18-UGGGU micelles were incubated in D2O for 24 h (blue ...
Micelles. For micelles, instead of the simulation time, the number of configurations Nconf over which the atomic distribution ... The reason is that micelles sizes can fluctuate over the simulation and the averaging is done over all micelles of the same ... Molecular dynamics simulations of various micelles to predict micelle water partition equilibria with COSMOmic: Influence of ... TUHH > V8 > Links > Membranes/Micelles Data from molecular dynamics simulations for COSMOmic. Introduction. COSMOmic is an ...
Non-Centrosymmetric Cylindrical Micelles by Unidirectional Growth. By Paul A. Rupar, Laurent Chabanne, Mitchell A. Winnik, Ian ... Non-Centrosymmetric Cylindrical Micelles by Unidirectional Growth. By Paul A. Rupar, Laurent Chabanne, Mitchell A. Winnik, Ian ... Non-Centrosymmetric Cylindrical Micelles by Unidirectional Growth Message Subject. (Your Name) has forwarded a page to you from ... These nanostructures grow to form long, non-centrosymmetric cylindrical A-B and A-B-C block co-micelles upon the addition of ...
Results of dynamic light scattering showed micelle size ranging from 11 to 40 nm. Unimolecular micelles were also analyzed by ... pH-sensitive unimolecular polymeric micelles: synthesis of a novel drug carrier.. Jones MC1, Ranger M, Leroux JC. ... These new polymers present a core-shell structure similar to polymeric micelles, but are inherently stable to dilution and are ... However, in the intestine, the micelles will be more than 40% ionized. Fluorescence studies were conducted in order to evaluate ...
2LOU: Structural features of the apelin receptor N-terminal tail and first transmembrane segment implicated in ligand binding and receptor trafficking.
Micelle formation is described by thermodynamics, driven by entropy and enthalpy. Function and Usage[edit]. Micelles usually ... Micelles show up as vesicles in biology. Unlike a micelle, however, vesicles contain a lipid bilayer, which is composed of two ... Micelles are also at work in the human body. Micelles help the body absorb lipid and fat soluble vitamins. They help the small ... Sizes of micelles range from 2 nm (20 A) to 20 nm (200 A), depending on composition and concentration. The size of a micelle is ...
CLSM imaging revealed that mixed micelles were efficiently absorbed into the cytoplasm region of MCF-7 cells. Therefore, Cur- ... The objective of this study was to prepare curcumin-loaded mixed Soluplus/TPGS micelles (Cur-TPGS-PMs) for oral administration ... Mixed micelles can provide multiple functionality micelles by constituent copolymers. Therefore, a mixed micelle was developed ... Preparation of Micelles. Mixed micelles containing curcumin were prepared by an ameliorated film dispersion method [19]. ...
Ganglioside GM1 (GM1) micelles have been studied by means of water proton T1 NMRD experiment. The field dependent spin-lattice ... A Proton Water T1-NMRD Study of Ganglioside Micelles. Westlund, Per-Olof Umeå University, Faculty of Science and Technology, ... Theradiusoftheganglioside micelles has previously been determined as about 54 using fluorescence experiments and with Stoke- ... Proton T1.NMRD Profiels, Proton Spin-lattice Relaxation, Ganglioside Micelles National Category Chemical Sciences Identifiers. ...
... we show that by maintaining detergent micelles in solutions, well above the critical micelle concentration (CMC), it is ... Micelles Protect Membrane Complexes from Solution to Vacuum. By Nelson P. Barrera, Natalie Di Bartolo, Paula J. Booth, Carol V ... Micelles Protect Membrane Complexes from Solution to Vacuum. By Nelson P. Barrera, Natalie Di Bartolo, Paula J. Booth, Carol V ... Micelles Protect Membrane Complexes from Solution to Vacuum Message Subject. (Your Name) has forwarded a page to you from ...
In addition, the polymeric micelles can be slightly modified for complexation with oligonucleotides and plasmids. Second, ... In addition, the polymeric micelles can be slightly modified for complexation with oligonucleotides and plasmids. Second, ...
NMR Solution structure of GLP-2 in DHPC micelles. *DOI: 10.2210/pdb2L64/pdb ...
The micelles were subsequently crosslinked by UV illumination at 365 nm with a normal handheld UV lamp. The micelles showed ... which formed micelles by heating its aqueous solution above the lower critical solution temperature (LCST). ... The micelles were subsequently crosslinked by UV illumination at 365 nm with a normal handheld UV lamp. The micelles showed a ... Anthracene functionalized thermosensitive and UV-crosslinkable polymeric micelles Y. Shi, R. M. Cardoso, C. F. van Nostrum and ...
Methods and formulations for delivering hydrophobic molecules to a host via these micelles are also provided. Methods of ... stabilizing liposomes or lipid based formulations by addition of polymeric micelles are also provided. ... Polymeric micelles for encapsulation of hydrophobic molecules are provided. ... Thus, polymeric micelles do not have a CMC. Typical micelles can only encapsulate hydrophobic moieties when above the CMC and ...
These micelles can further grow only if other micelles dissolve by releasing unimers. This is particularly clear from the ... we obtained the mean radius of micelles and their aggregation number or the average number of block copolymers per micelle (P ... The broader distribution signifies micellar rearrangement processes where small micelles shrink and large micelles grow. At ... Figure 2. a) Time evolution of the mean aggregation number of micelles (Pmean) for different concentrations of the block ...
biodistribution brain tumors cell penetrating peptide intranasal brain delivery micelles Takanori Kanazawa and Hiroyuki Taki ... Yokoyama M, Opanasopit P, Okano T, Kawano K, Maitani Y. Polymer design and incorporation methods for polymeric micelle carrier ... We have demonstrated that utilization of nano-sized micelles modified with Tat can facilitate direct intranasal brain delivery. ... Cell-Penetrating Peptide-Modified Block Copolymer Micelles Promote Direct Brain Delivery via Intranasal Administration. ...
... wherein each worm-like micelle comprises one or more wholly synthetic, polymeric, super-amphiphilic molecules that s ... Provided are worm-like micelles, capable of encapsulating at least one encapsulant, ... Worm micelles were incubated with the cells, typically for 4 hours, after which, the media and unbound worm micelles were ... Therefore, the worm micelles of the present invention are free of organic solvents, distinguishing the worm micelles from the ...
... micelles from lipoamino acids; construction of block copolymer micelles and single-chain nanoparticles in non-selective ... Micelles: Structural Biochemistry, Formation and Functions and Usage. Danielle Bradburn (Editor). Tom Bittinger (Editor) ... Micelles from Lipoamino Acids. (Célia Faustino, António Calado, Luis Garcia-Rio, iMed.UL - Research Institute for Medicines and ... Thermodynamic Aspects of Micelles. (Hiroshi Maeda, Kyushu University, Hakozaki, Higashi Ward, Fukuoka, Fukuoka Prefecture, ...
... can be efficiently encapsulated in polymeric micelles (PM-MTH), based on Pluronic® block copolymers, by a new microfluidic ... Mithramycin encapsulated in polymeric micelles by microfluidic technology as novel therapeutic protocol for beta-thalassemia ... Mithramycin encapsulated in polymeric micelles by microfluidic technology as novel therapeutic protocol for beta-thalassemia. ... Abstract: This report shows that the DNA-binding drug, mithramycin, can be efficiently encapsulated in polymeric micelles (PM- ...
Combination therapy with EGCG and doxorubicin in the micelle core could protect the cardiomyocytes from DOX-mediated ... DOX was co-loaded in the PIC micelles throughπ-π stacking interaction with EGCG. The phenylboronic acid-catechol interaction ... Attributed to modulation of EGCG on P-glycoprotein (P-gp) activity, this kind of PIC micelles could effectively reverse ... In this study, a novel green tea catechin-based polyion complex (PIC) micelle loaded with doxorubicin (DOX) and (-)- ...
Figure 3. Schematic illustration of the transformation of spherical/ellipsoidal micelles to worm-like micelles at higher salt ... In conclusion, we have successfully followed the formation of worm-like/polymer-like micelles from globular micelles by ... micelles are formed by the fusion of globular and transient elongated micelles on a millisecond time scale in a similar fashion ... we have succeeded in following the complete kinetics of micelle formation from a pool of monomers to globular micelles using ...
These results strongly support the fact that the "inversed" surface micelles are formed on water via hybridization of PS-b-P4VP ... "Inversed" Surface Micelle Array Fabrication of an Amphiphilic Block Copolymer on Water Surface ...

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