A novel means of investigating the polarity gradient in the micelle sodium lauryl sulphate using a series of n-(9-anthroyloxy) fatty acids as fluorescent probes

Blatt, Edward; Ghiggino, Kenneth P.; Sawyer, William H.

doi:10.1039/f19817702551

Cited by 33 publications

(24 citation statements)

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“…Fluorescence quenching can be described by the SternVolmer equation [19,20,21,22,23,24,25,26,27,28,29]: (6) where I 0 and I are, respectively, the corrected fluorescence intensity of the fluorophores (n-AS probe) in the absence and presence of the drug, [Q] is the quencher (nimesulide) concentration and K SV the Stern-Volmer constant. However, when the quencher is distributed between membrane and aqueous phase and only the total quencher concentration is known, Eq.…”

Section: Determination Of Partition Coefficients By Fluorescence Quenmentioning

confidence: 99%

Partition and location of nimesulide in EPC liposomes: a spectrophotometric and fluorescence study

et al. 2003

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Study of the mechanism of action of anti-inflammatory drugs (NSAIDs) and their side-effects may fall in the domain of membranology. In this work the extent of the interaction between an NSAID (nimesulide) and membrane phospholipids was quantified by the partition coefficient, K(p ), using egg phosphatidylcholine (EPC) liposomes as cell membrane models. The liposome/aqueous phase partition coefficients were determined under physiological conditions, by derivative spectrophotometry and fluorescence quenching. Derivative spectrophotometry allows elimination of background signal effects (light scattering) due to the presence of liposomes. Theoretical models, accounting for simple partition of the NSAID between two different media, were used to fit the experimental data, allowing the determination of K(p)in multilamellar vesicles (MLVs) and large unilamellar vesicles (LUVs). The location of nimesulide in MLVs and LUVs was evaluated by fluorescence quenching using spectroscopic probes located at different sites on the membrane. All n-AS probes were quenched and the relative quenching efficiencies were ordered as 2-AS<6-AS approximately 9-AS<12-AS; this suggests the drug is deeply buried in the membrane. Fluorescence quenching using the 12-AS probe was also used to determine the partition coefficient of the drug in MLVs and LUVs. The two techniques yield similar results. Finally, measurement of zeta-potential in the presence of different concentrations of nimesulide was performed to investigate possible changes in the zwitterionic phosphatidylcholine membranes. The membrane surface potential was not altered, which seems to be an indication that nimesulide binds to lipid bilayer mostly by hydrophobic interactions.

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Section: Determination Of Partition Coefficients By Fluorescence Quenmentioning

confidence: 99%

Partition and location of nimesulide in EPC liposomes: a spectrophotometric and fluorescence study

et al. 2003

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“…In homogeneous solvents of low viscosity, linear Stern-Volmer plots are obtained and the bimolecular rate constant may be calculated from a knowledge of the excited-state lifetime of the fluorophore. Upwardcurving Stern-Volmer plots have also been observed as the viscosity of the solvent increases, and can be attributed to a static quenching mechanism (3). Under the latter condition, a fluorophore within a spherical volume surrounding the quencher is quenched instantaneously, while fluorophores located outside an active sphere may be quenched by collisional interactions.…”

Section: Introductionmentioning

confidence: 97%

“…These quenching mechanisms (i.e., dynamic and/or static) have also been proposed to explain the shapes of Stern-Volmer plots in two-phase systems (3)(4)(5)(6)(7)(8). However, the nature of the distribution of quencher between aqueous and lipid compartments has not been examined in detail, and the effects of this distribution on the characteristics of Stern-Volmer plots have not been explored.…”

Section: Introductionmentioning

confidence: 99%

Effects of Quenching Mechanism and Type of Quencher Association on Stern-Volmer Plots in Compartmentalized Systems

Blatt¹,

Chatelier²,

Sawyer³

1986

Biophysical Journal

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Fluorescence quenching techniques have been used extensively in recent years to examine reaction rates and the compartmentalization of components in lipid micelles and membranes. Steady-state fluorescence methods are frequently employed in such studies but the interpretation of the resulting Stern-Volmer plots is often hampered by uncertainties regarding the mode of association of the quencher with the lipid structure and the nature of the quenching mechanism. This paper presents a method for simulating steady-state Stern-Volmer plots in two phase systems, and shows how the forms of such plots are influenced by the type of association of the quencher with the membrane or micelle (partition and/or binding) and by the type of quenching mechanism (dynamic and/or static). Comparisons of simulated plots with experimental data must take into account the possible combinations of quencher association(s) and quenching mechanism(s). The methods presented are applicable to synthetic and natural membranes and provide a basis for comparing the quenching of fluorescent molecules in biological membranes of differing composition.

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“…Methanol and n‐dodecane were chosen as the polar and nonpolar solvent, respectively. If the UV–Vis spectrum of paraffin oil solubilized in NAS solution resembles that in dodecane solvent but vary from that in methanol solvent, conclusions may be that the paraffin oil is positioned in the nonpolar core of NAS micelles (Blatt et al, 1981). If not, the paraffin oil should be located in the semipolar palisade region close to the head group, with a result that the UV–Vis spectrum of the paraffin oil solubilized in the NAS solution matches that in methanol solvent (Kim et al, 2001; Nagarajan et al, 1984).…”

Section: Resultsmentioning

confidence: 99%

Enhancing Oil Recovery by Low Concentration of Alkylaryl Sulfonate Surfactant without Ultralow Interfacial Tension

Zhan

Gong

Luan³

et al. 2021

J Surfact & Detergents

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Surfactant flooding plays a critical role in chemically enhanced oil recovery over the last half century, with the widely accepted mechanism of ultralow interfacial tension (IFT) by forming middle-phase microemulsions with high concentration of a lead surfactant and a cosurfactant. However, it is found practically from field trials that high oil recovery efficiency can be obtained from low concentration surfactant flooding without forming microemulsions, and the principle behind has not been clearly unraveled yet. Here the solubilization of paraffin oil by the micelles formed with a commercial enhanced oil recovery surfactant, raw naphthenic arylsulfonates (NAS), was investigated using ultraviolet-visible (UV-Vis) spectroscopy, dynamic light scattering (DLS), and transmission electron microscopy (TEM). It is found that paraffin oil can be well solubilized inside the NAS micelles, and mainly localized in the hydrophobic core of the micelles. The solubilization capacity of NAS micelles increases with increasing its concentration, and the size of micelles increases, but morphology of the micelles remains spherical with increasing the amount of paraffin oil, along with an appearance transition from transparent to opaque until the maximum solubilization capacity is reached. Core flooding results with crude oil indicate that in the presence of 0.24 wt.% polymer, addition of 0.1, 0.2, 0.5, and 1.0 wt.% NAS can get oil recovery factor of 24.1%, 27.0%, 30.5%, and 38.3%, which increases linearly with increasing NAS concentration though with the interfacial tension values only in the magnitude of 10 −2 mN m −1 level. These findings prove preliminarily micellar solubilization can help increasing oil recovery efficiency even without ultralow IFT.

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A novel means of investigating the polarity gradient in the micelle sodium lauryl sulphate using a series of n-(9-anthroyloxy) fatty acids as fluorescent probes

Cited by 33 publications

References 1 publication

Partition and location of nimesulide in EPC liposomes: a spectrophotometric and fluorescence study

Partition and location of nimesulide in EPC liposomes: a spectrophotometric and fluorescence study

Effects of Quenching Mechanism and Type of Quencher Association on Stern-Volmer Plots in Compartmentalized Systems

Enhancing Oil Recovery by Low Concentration of Alkylaryl Sulfonate Surfactant without Ultralow Interfacial Tension

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