Thermodynamic and elastic fluctuation analysis of langmuir mixed monolayers composed by dehydrocholic acid (HDHC) and didodecyldimethylammonium bromide (DDAB)

Messina, Paula V.; Prieto, Gerardo; Ruso, Juan M.; Fernández-Leyes, Marcos D.; Schulz, Pablo C.; Sarmiento, Félix

doi:10.1016/j.colsurfb.2009.08.008

Cited by 11 publications

(13 citation statements)

References 32 publications

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“…2). DDAB is an amphiphilic molecule that forms the stable monolayer at the air/water interface according to this study and other reports [25]. Furthermore, DDAB can form the micelles and vesicles [26,27].…”

Section: Characteristics Of the Nanoassembliesmentioning

confidence: 75%

Rational design of didodecyldimethylammonium bromide-based nanoassemblies for gene delivery

Jin

Wang

et al. 2015

Colloids and Surfaces B: Biointerfaces

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Section: Characteristics Of the Nanoassembliesmentioning

confidence: 75%

Rational design of didodecyldimethylammonium bromide-based nanoassemblies for gene delivery

Jin

Wang

et al. 2015

Colloids and Surfaces B: Biointerfaces

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“…At surface pressures lower than the minimum point, the C s –1 values are less than 60 mN m –1 , indicating that the monolayer exists in the liquid-expanded (LE) state. The C s –1 values increase to >200 mN m –1 at pressures higher than the minimum point, signifying that a densely packed gel state is formed . The film collapses at ∼72 mN m –1 for 24 °C and at ∼68 mN m –1 for 44 °C.…”

Section: Resultsmentioning

confidence: 97%

Spectroelectrochemical Characterization of 1,2-Dipalmitoyl-sn-glycero-3-cytidine Diphosphate Nucleolipid Monolayer Supported on Gold (111) Electrode

Álvarez-Malmagro

Leitch

et al. 2019

Langmuir

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The effect of the electrode potential on the orientation and conformation of the 1,2-dipalmitoyl-sn-glycero-3cytidine monolayer deposited on a gold (111) electrode surface was described. The potential of zero free charge (E pzc ) for the monolayer-covered electrode was determined to be −0.2 V vs SCE. The differential capacitance and charge density data indicated that the monolayer is stable at the electrode surface when (E − E pzc ) > 0.0 V. At negative rational potentials, a progressive detachment (electrodewetting) of the monolayer occurs. The monolayer is fully detached from the electrode surface at (E − E pzc ) < −0.6 V. The conformation and orientation of the acyl chains and the orientation of the cytosine moiety were determined with the help of photon polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS). The IR measurements demonstrate that the acyl chains are predominantly in the gel phase in the adsorbed state and tilted at an angle of ∼30°with respect to the electrode surface normal. The tilt angle of the acyl chains increases when the film is detached from the gold surface, indicating that the monolayer becomes more disordered. At (E − E pzc ) > 0.0 V, the plane of the cytosine moiety assumes a small angle of ∼20°with respect to the surface. At negative potentials, the tilt angle of the cytosine fragment increases and rotates. With the help of DFT calculations, these changes were explained by the repulsion of the positive pole of the cytosine permanent dipole moment by the positively charged gold surface and its attraction to the metal surface at negative electrode potentials. This work provides unique information for the future development of sensors based on the molecular recognition of nucleoside targets.

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“…Representative compressibility modulus curves are plotted in blue in Figure 6 for the LCA and HDCA films. The maximum of K , in general, reflects some kind of configurational transition in the monolayer structure [ 39 ]: the films can either collapse or condense or undergo orientational ordering [ 38 , 39 ]. For the BA films represented by LCA and HDCA, the maximum of K is observed at the inflection point of the isotherms (orientational ordering) marked with black vertical lines.…”

Section: Resultsmentioning

confidence: 99%

The Effect of Hydroxyl Moieties and Their Oxosubstitution on Bile Acid Association Studied in Floating Monolayers

Szekeres

Viskolcz

Poša

et al. 2014

The Scientific World Journal

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Bile salt aggregates are promising candidates for drug delivery vehicles due to their unique fat-solubilizing ability. However, the toxicity of bile salts increases with improving fat-solubilizing capability and so an optimal combination of efficient solubilization and low toxicity is necessary. To improve hydrophilicity (and decrease toxicity), we substituted hydroxyl groups of several natural bile acid (BA) molecules for oxogroups and studied their intrinsic molecular association behavior. Here we present the comparative Langmuir trough study of the two-dimensional (2D) association behavior of eight natural BAs and four oxoderivatives (traditionally called keto-derivatives) floated on an aqueous subphase. The series of BAs and derivatives showed systematic changes in the shape of the compression isotherms. Two types of association could be distinguished: the first transition was assigned to the formation of dimers through H-bonding and the second to the hydrophobic aggregation of BA dimers. Hydrophobic association of BA molecules in the films is linked to the ability of forming H-bonded dimers. Both H-bond formation and hydrophobic association weakened with increasing number of hydroxyl groups, decreasing distance between hydroxyl groups, and increasing oxosubstitution. The results also show that the Langmuir trough method is extremely useful in selecting appropriate BA molecules to design drug delivery systems.

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Thermodynamic and elastic fluctuation analysis of langmuir mixed monolayers composed by dehydrocholic acid (HDHC) and didodecyldimethylammonium bromide (DDAB)

Cited by 11 publications

References 32 publications

Rational design of didodecyldimethylammonium bromide-based nanoassemblies for gene delivery

Rational design of didodecyldimethylammonium bromide-based nanoassemblies for gene delivery

Spectroelectrochemical Characterization of 1,2-Dipalmitoyl-sn-glycero-3-cytidine Diphosphate Nucleolipid Monolayer Supported on Gold (111) Electrode

The Effect of Hydroxyl Moieties and Their Oxosubstitution on Bile Acid Association Studied in Floating Monolayers

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