Compounds In Micelles Research Articles

Solubilization of polycyclic aromatic compounds into supralong-chain surfactants with double quaternary ammonium micelles

The dissolution of poorly water-soluble compounds in micelles via hydrophobic interactions is termed solubilization. The solubilization of polycyclic aromatic compounds, namely, naphthalene, anthracene, and pyrene, was studied using supralong-chain surfactants with two consecutive cationic hydrophilic groups [CnH2n+1N+(CH3)2-(CH2)2-N+(CH3)3 2Br-: Cn-2Am (n = 18, 20, and 22)] and typical cationic surfactants [CnH2n+1N+(CH3)3 Br-: Cn-Am (n = 12, 14, and 16)]. Long alkyl chains in hydrophobic surfactants are advantageous for forming a large micellar core. The maximum quantity of solubilized polycyclic aromatic compounds increased as the alkyl chain length of the surfactant increased. Therefore, the molar solubilization ratio (MSR), which represents the solubilization ability of the surfactant, was maximized when the alkyl chain length was C22-2Am. Similarly, the Gibbs free energy (ΔG0) associated with the solubilization of polycyclic aromatic compounds was also lowest for C22-2Am. Surfactants with long alkyl chains functioned as excellent solubilizers. The solubilization sites of the polycyclic aromatic compounds were determined using two-dimensional NMR and small-angle X-ray scattering (SAXS) measurements. As the molecular size of the polycyclic aromatic compounds increased, the solubilization positions in the micelles shifted from the palisade layer to the vicinity of the hydrophilic groups. Extension of the alkyl chain length of the surfactant resulted in an increase in the palisade region of the micelles, which was advantageous for solubilization.

Exploring flavylium-based SWIR emitters: Design, synthesis and optical characterization of dyes derivatized with polar moieties

Imaging in the shortwave infrared (SWIR, 1000–1700 nm) region is gaining traction for biomedical applications, leading to an in-depth search for fluorophores emitting at these wavelengths. The development of SWIR emitters, to be used in vivo in biological media, is mostly hampered by the considerable lipophilicity of the structures, resulting from the highly conjugated scaffold required to shift the emission to this region, that limit their aqueous solubility. In this work, we have modulated a known SWIR emitter, named Flav7, by adding hydrophilic moieties to the flavylium scaffold and we developed a new series of Flav7-derivatives, which proved to be indeed more polar than the parent compound, but still not freely water-soluble. Optical characterization of these derivatives allowed us to select FlavMorpho, a new compound with improved emission properties compared to Flav7. Encapsulation of the two compounds in micelles resulted in water-soluble SWIR emitters, with FlavMorpho micelles being twice as emissive as Flav7 micelles. The SWIR emission extent of FlavMorpho micelles proved also superior to the tail-emission of Indocyanine Green (ICG), the FDA-approved reference cyanine, in the same region, by exciting the probes at their respective absorption maxima in phosphate buffered saline (PBS) solution. The availability of optical imaging devices equipped with lasers able to excite these dyes at their maximum of absorption in the SWIR region, could pave the way for implemented SWIR imaging results.

Transferring of red Monascus pigments from nonionic surfactant to hydrophobic ionic liquid by novel microemulsion extraction

Nonionic surfactant micelle aqueous solution as well as cloud point system is a potential separation/reaction medium. Downstream processing for recovery of product and regeneration of surfactant is indispensable. Adjustment of pH in the dilute phase of cloud point extraction is a common strategy for separation of ionizable organic compound from nonionic surfactant. However, this strategy is no longer suitable for recovery of ionizable organic compound with strong hydrophobicity due to the high solubilization of the ionic state of hydrophobic organic compound in micelles. Setting extractive fermentation of intracellular Monascus pigments in nonionic surfactant micelle aqueous solution to produce high color hue of red Monascus pigments as an example, transferring of hydrophobic Monascus pigments from nonionic surfactant to ionic liquid by novel hydrophobic ionic liquid–nonionic surfactant–water Winsor I microemulsion extraction and then back-extraction of the ionizable Monascus pigments from the ionic liquid by ionic liquid–water two-phase extraction were carried out. Nearly 80% yield was achieved in the complete process for recovery of Monascus pigments. It provides a novel strategy for stripping of hydrophobic ionizable organic compound from nonionic surfactant micelle aqueous solution.

ASAXS Study on Spatial Distribution of Hydrophobic Compounds in Polymer Micelles

In drug delivery system (DDS) using polymer micelles as drug carrier, DDS properties are related to spatial distribution of drug compounds in the micelles [1]. Because the spatial distribution of drug compounds should strongly depend on interactions and solubility of drug compounds in the micelles, elucidation of the relation between chemical structures of drug compounds and their spatial distribution in the micelle is much important. Thus, in this study, we examine to elucidate the relation between chemical features and spatial distribution of drug compounds in polymer micelles by using anomalous small-angle X-ray scattering (ASAXS). To apply the ASAXS near bromine K-edge for analysis [2] of spatial distribution of drug compounds in polymer micelles, we employ 4 different bromine-labeled hydrophobic compounds as model drug compounds and polymer micelles composed of poly(dimethylaminoethyl methacrylate)-block-poly(methyl methacrylate) (PDMAEMA-b-PMMA). Figure shows SAXS and resonant term obtained from ASAXS near bromine K-edge for the polymer micelles containing 9-bromofluorene (BrF). The domain size estimated from the resonant term is much smaller than that of hydrophobic PMMA core of the micelle. Therefore, When BrF, which is highly hydrophobic and scarcely dissolved in hydrophobic PMMA, is incorporated in the polymer micelle, BrF forms small droplet in the hydrophobic core composed of PMMA. For the micelles incorporating bromobenzene, which as similar properties of BrF, similar result is obtained. On the other hand, 4-bromobenzyl alcohol and ethyl 2-bromoethyl propionate, which are miscible with PMMA, are homogeneously dispersed in the PMMA core of the micelles. These results indicate that highly hydrophobic compounds forms small droplet in hydrophobic core, and introduction of polarity to the compounds causes expansion of the area existing the hydrophobic compounds in polymer micelle.

Spatial Orientation of Aromatics at Micellar Interface: Selectivity Enhancement in Oxychlorination

The regioselective oxychlorination of various activated and deactivated aromatic compounds in micellar media was studied. Favourable orientation of substituted aromatic compounds in micelles increased the selectivity toward ortho- chlorination. The selectivity toward ortho- product increased with the increasing order of micellar solubility of activated aromatic compounds from meta- and ortho- cresol to 3,5-xylenol. Significant enhancement toward ortho- selectivity and increase in the percentage conversion in chlorination of deactivated aromatic compounds were observed. Amongst deactivated aromatic compounds studied, benzoic acid, chlorobenzene and iodobenzene showed enhancement in the percentage conversion and selectivity toward ortho- product. The study of proton NMR spectra of aromatic compounds (3,5-xylenol and benzoic acid) in micellar media proved the spatial orientation of these aromatics at micellar interface and explained the mechanism of selectivity enhancement. ortho- selectivity in chlorination was also found to be dependent on the concentration of surfactant employed.

Assessing bioavailability of the solubilization of organic compound in nonionic surfactant micelles by dose–response analysis

It is uncertain in some extent that organic compounds solubilized in micelles of a nonionic surfactant aqueous solution are bioavailable directly by the microbes in an extractive microbial transformation or biodegradation process. In this work, a dose-response method, where a bioequivalence concept is introduced to evaluate the synergic toxicity of the nonionic surfactants and the organic compounds, was applied to analyze the inhibition effect of organic compounds (naphthalene, phenyl ether, 2-phenylethanol, and 1-butanol) in nonionic surfactant Triton X-100 micelle aqueous solutions and Triton X-114 in aqueous solutions forming cloud point systems. Based on the result, a mole solubilization ratio of organic compounds in micelle was also determined, which consisted very well with those of classic semi-equilibrium dialysis experiments. The results exhibit that bioavailability of organic compounds solubilized in micelles to microbial cells is negligible, which provides a guideline for application of nonionic surfactant micelle aqueous solutions or cloud point systems as novel media for microbial transformations or biodegradations.

PAH degradation by UV/H 2O 2 in perfluorinated surfactant solutions

Polycyclic aromatic hydrocarbons (PAHs) solubilized in perfluorinated surfactant (PFS) solutions were degraded by direct photolysis and UV/H 2O 2 process. The subsequent recovery and reuse of these surfactant solutions were also demonstrated. Phenanthrene and pyrene were selected as representative PAHs and an anionic PFS; ammonium perfluorooctanoate (APFO) was used. In our experiments, micellar APFO solutions retarded the phenanthrene photolysis and enhanced the pyrene photolysis. The results indicate that the photochemical reactivity of compound in micelles is strongly dependent on specific properties of the solubilizate, possibly due to the different excited state behaviors of compound. UV/H 2O 2 process exhibits a greatly enhanced rate of PAH photolysis in both water and APFO compared to direct photolysis, indicating that hydroxyl radicals may be generated or penetrated at the sites of PAHs solubilized in the micelles. Additionally, a smaller rate enhancement by UV/H 2O 2 in micelles than in water suggests that micelles provide some degree of protection from hydroxyl radical attack. The possibility of recovery and reuse of PFS has been demonstrated by measuring the solubilizing capacity of APFO after direct photolysis and UV/H 2O 2 process. Overall, this study demonstrates UV/H 2O 2 process can be an effective treatment method for not only PAH degradation but also surfactant recovery and reuse.

Protolytic photodissociation of hydroxyaromatic compounds in micelles and lipid bilayer membranes of vesicles

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTProtolytic photodissociation of hydroxyaromatic compounds in micelles and lipid bilayer membranes of vesiclesYu. V. Il'ichev, A. B. Demyashkevich, and M. G. KuzminCite this: J. Phys. Chem. 1991, 95, 8, 3438–3444Publication Date (Print):April 1, 1991Publication History Published online1 May 2002Published inissue 1 April 1991https://doi.org/10.1021/j100161a088RIGHTS & PERMISSIONSArticle Views114Altmetric-Citations31LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (759 KB) Get e-Alerts

Comparison between Intra- and Intermolecular Photoinduced Electron Transfer Reactions of Micelle-Solubilized Substances

Abstract The rate constants of intramolecular photoinduced electron-transfer reactions of a linked pyrene–viologen molecule A and a linked pyrene–ferrocene molecule B solubilized in micellar solutions of a hexadecyltrimethylammonium chloride were determined to be 9×108 and 4×108 s−1 respectively, from the stationary fluorescence intensity. However, the observed fluorescence decay curve of A suggests that a large fraction of the molecules have conformations for which the distances between two functional moieties are sufficiently small to permit direct electron transfer. The quasi-first-order rate constants of the intermolecular photoinduced electron-transfer reactions between 1-hexylpyrene (HPy) and dodecylviologen (DDV), and between HPy and butylferrocene (BFc) solubilized in a micellar solution, were also determined to be 9×106 and 2×107 s−1 respectively, from the fluorescence decay curves. It is shown that the rate constants of the intermolecular photoinduced electron-transfer reaction in micelles are determined by the diffusion of the reactants in a micelle. On the other hand, it is suggested that the rate constants of the intramolecular electron-transfer reactions are determined by the molecular conformations of the linked compounds in micelles.

Freeze-thaw effect on the solubilization of hydrophobic compounds in micelles and artificial bilayer membranes

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFreeze-thaw effect on the solubilization of hydrophobic compounds in micelles and artificial bilayer membranesKoji Kano, Yoshiyuki Ueno, Keisuke Umakoshi, Shizunobu Hashimoto, Tatsuo Ishibashi, and Teiichiro OgawaCite this: J. Phys. Chem. 1984, 88, 21, 5087–5092Publication Date (Print):October 1, 1984Publication History Published online1 May 2002Published inissue 1 October 1984https://doi.org/10.1021/j150665a058RIGHTS & PERMISSIONSArticle Views143Altmetric-Citations23LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (827 KB) Get e-Alerts

Laser-photolysis study of the external magnetic field effect upon the photochemical processes of carbonyl compounds in micelles

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLaser-photolysis study of the external magnetic field effect upon the photochemical processes of carbonyl compounds in micellesYoshio Sakaguchi, Hisaharu Hayashi, and Saburo NagakuraCite this: J. Phys. Chem. 1982, 86, 16, 3177–3184Publication Date (Print):August 1, 1982Publication History Published online1 May 2002Published inissue 1 August 1982https://doi.org/10.1021/j100213a023RIGHTS & PERMISSIONSArticle Views109Altmetric-Citations91LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1024 KB) Get e-Alerts

Laser-photolysis study of the photochemical processes of carbonyl compounds in micelles under high magnetic fields

The magnetic field effects of the photochemical reactions of benzophenone derivatives and dibenzylketone were studied. The decay rate of the 4.4 ′-difluorobenzophenone ketyl radical in a sodium dodecylsulfate micelle continued to decrease from 2.9 × 10 6 s −1 at 0 T to 3.0 × 10 5 s −1 at 1.34 T.

Spin label studies of structural and dynamical properties of detergent aggregates

Amphiphilic spin probes were used to investigate the structural and dynamical properties of ionic detergent aggregates. The analysis of the electron spin resonance spectra of the probes yielded information on the degree of motion and organization of molecules in micelles, on the effect of an ionic agent on the micellar structure, on the ability of detergents to form aggregates below their critical micelle concentration, and on the nonhomogeneous distribution of water-insoluble compounds in micelles. The results are analyzed in terms of the relevance of these phenomena to processes such as micellar catalysis, the mechanism of micelle formation, and the mechanism of solubilization of substrates by micelles. The possible effect of the rotational correlation time of the micelle on the observed spectral lineshapes is discussed.