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Ullmann K, Fachet L, Nirschl H, Leneweit G. Monolayer/Bilayer Equilibrium of Phospholipids in Gel or Liquid States: Interfacial Adsorption via Monomer or Liposome Diffusion? Gels 2023; 9:803. [PMID: 37888376 PMCID: PMC10606027 DOI: 10.3390/gels9100803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 09/25/2023] [Accepted: 09/30/2023] [Indexed: 10/28/2023] Open
Abstract
Phospholipids (PLs) are widely used in the pharma industry and a better understanding of their behavior under different conditions is helpful for applications such as their use as medical transporters. The transition temperature Tm affects the lipid conformation and the interfacial tension between perfluoroperhydrophenanthrene (PFP) and an aqueous suspension of 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC), 1,2-distearoyl-sn-glycero-3-phosphatidylcholine (DSPC), as well as a mixture of these PLs with cholesterol. Interfacial tensions were measured with the Du Noüy ring at quasi-equilibrium; the area per molecule was calculated according to the Gibbsian approach and a time-dependent tension gradient. Results show that the time tε to reach quasi-equilibrium was shorter when the temperature was above Tm, indicating a faster adsorption process (tε,DPPC,36 °C = 48 h, tε,DPPC,48 °C = 24 h) for PL in the liquid crystalline state than in the gel state (T < Tm). In addition, concentration-dependent results of the interfacial tension revealed that above the respective Tm and at all concentrations c > 0.1 mM, the average minimum interfacial tension for DPPC and DSPC (14.1 mN/m and 15.3 mN/m) does not differ significantly between those two lipids. Equilibrium between monolayers and bilayers shows that for T < Tm, surface pressures ∏ ≈ 31 mN/m are reached while for T > Tm, ∏ ≈ 41 mN/m. Mixtures with cholesterol only reach ∏ ≤ 31 mN/m Tm, with no significant difference between the two PLs. The higher interfacial tension of the mixture indicates stabilization of the liposomal conformation in the aqueous phase by the addition of cholesterol. The high diffusion coefficients show that adsorption is mainly based on liposomes.
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Affiliation(s)
- Kirsten Ullmann
- Karlsruhe Institute of Technology (KIT), Department of Mechanical Process Engineering and Mechanics, Straße am Forum 8, 76131 Karlsruhe, Germany;
| | - Lea Fachet
- Independent Researcher, 76131 Karlsruhe, Germany
| | - Hermann Nirschl
- Karlsruhe Institute of Technology (KIT), Department of Mechanical Process Engineering and Mechanics, Straße am Forum 8, 76131 Karlsruhe, Germany;
| | - Gero Leneweit
- Carl Gustav Carus-Institute, Association for the Promotion of Cancer Therapy, Allmendstr. 55, 75223 Niefern-Oeschelbronn, Germany
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Li G, Zuo YY. Molecular and colloidal self-assembly at the oil–water interface. Curr Opin Colloid Interface Sci 2022. [DOI: 10.1016/j.cocis.2022.101639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Gellert F, Ahrens H, Wulff H, Helm CA. Seaweed and Dendritic Growth in Unsaturated Fatty Acid Monolayers. MEMBRANES 2022; 12:membranes12070698. [PMID: 35877901 PMCID: PMC9318918 DOI: 10.3390/membranes12070698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Revised: 07/04/2022] [Accepted: 07/05/2022] [Indexed: 02/05/2023]
Abstract
The lateral movement in lipid membranes depends on their diffusion constant within the membrane. However, when the flux of the subphase is high, the convective flow beneath the membrane also influences lipid movement. Lipid monolayers of an unsaturated fatty acid at the water-air interface serve as model membranes. The formation of domains in the liquid/condensed coexistence region is investigated. The dimension of the domains is fractal, and they grow with a constant growth velocity. Increasing the compression speed of the monolayer induces a transition from seaweed growth to dendritic growth. Seaweed domains have broad tips and wide and variable side branch spacing. In contrast, dendritic domains have a higher fractal dimension, narrower tips, and small, well-defined side branch spacing. Additionally, the growth velocity is markedly larger for dendritic than seaweed growth. The domains' growth velocity increases and the tip radius decreases with increasing supersaturation in the liquid/condensed coexistence region. Implications for membranes are discussed.
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Perazzo A, Gallier S, Liuzzi R, Guido S, Caserta S. Quantitative methods to detect phospholipids at the oil-water interface. Adv Colloid Interface Sci 2021; 290:102392. [PMID: 33740709 DOI: 10.1016/j.cis.2021.102392] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 02/23/2021] [Accepted: 02/23/2021] [Indexed: 01/29/2023]
Abstract
Phospholipids are the main constituents of cell membranes and act as natural stabilizers of milk fat globules. Phospholipids are used in a wide range of applications, e.g. as emulsifiers in cosmetic, pharmaceutical and food products. While processed emulsion droplets are usually stabilized by a monolayer of phospholipids, cell membranes have a phospholipid bilayer structure and milk fat globules are stabilized by a complex phospholipid trilayer membrane. Despite the broad relevance of phospholipids, there are still many scientific challenges in understanding how their behavior at the fluid-fluid interface affects microstructure, stability, and physico-chemical properties of natural and industrial products. Most of these challenges arise from the experimental difficulties related to the investigation of the molecular arrangement of phospholipids in situ at the fluid-fluid interface and the quantification of their partitioning between the bulk phase and the interface, both under static and flow conditions. This task is further complicated by the presence of other surface-active components, such as proteins, that can interact with phospholipids and compete for space at the interface. Here, we review the methodologies available from the literature to detect and quantify phospholipids, focusing on oil-water interfaces, and highlight current limitations and future perspectives.
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Affiliation(s)
- Antonio Perazzo
- Novaflux Inc., 1 Wall Street, Princeton, NJ, 08540, United States; Advanced BioDevices LLC., 1 Wall Street, Princeton, NJ, 08540, United States
| | - Sophie Gallier
- Dairy Goat Co-operative (N.Z.) Limited, 18 Gallagher Drive, PO Box 1398, Hamilton 3240, New Zealand
| | - Roberta Liuzzi
- Department of Chemical, Materials and Production Engineering, University of Naples "Federico II", P.le Ascarelli 80, 80125 Napoli, Italy
| | - Stefano Guido
- Department of Chemical, Materials and Production Engineering, University of Naples "Federico II", P.le Ascarelli 80, 80125 Napoli, Italy; Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali (INSTM), UdR INSTM Napoli Federico II, P.le Ascarelli 80, 80125 Napoli, Italy; CEINGE - Biotecnologie Avanzate, Via G. Salvatore 486, 80145 Napoli, Italy.
| | - Sergio Caserta
- Department of Chemical, Materials and Production Engineering, University of Naples "Federico II", P.le Ascarelli 80, 80125 Napoli, Italy; Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali (INSTM), UdR INSTM Napoli Federico II, P.le Ascarelli 80, 80125 Napoli, Italy; CEINGE - Biotecnologie Avanzate, Via G. Salvatore 486, 80145 Napoli, Italy
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Kale SK, Cope AJ, Goggin DM, Samaniuk JR. A miniaturized radial Langmuir trough for simultaneous dilatational deformation and interfacial microscopy. J Colloid Interface Sci 2021; 582:1085-1098. [PMID: 32932179 DOI: 10.1016/j.jcis.2020.08.053] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 08/12/2020] [Accepted: 08/13/2020] [Indexed: 12/29/2022]
Abstract
INNOVATION Interfacial rheological properties of complex fluid-fluid interfaces are strongly influenced by the film microstructure. Experimental investigations for correlating interfacial morphology and rheology are notoriously challenging. A miniaturized radial Langmuir trough was developed to study complex fluid-fluid interfaces under purely dilatational deformations that operates in tandem with a conventional inverted microscope for simultaneous interfacial visualization. EXPERIMENTS Two materials were investigated at an air-water interface: poly(tert-butyl methacrylate) (PtBMA) and dipalmitoylphosphatidylcholine (DPPC). Surface pressure measurements made in the radial Langmuir trough were compared with a commercial rectangular Langmuir trough. Interfacial in situ visualization for each material was performed during the compression cycle in the radial trough. Challenges associated with the small size of the radial Langmuir trough, such as the influence of capillary deformation on the measured surface pressure, are also quantified. FINDINGS Measured surface pressures between the newly developed radial trough and the rectangular Langmuir trough compare well. Micrographs obtained in the radial Langmuir trough were used to obtain film properties such as Young's modulus. The new advance in colloid and interface science is the ability to capture structure-property relationships of planar interfaces using microscopy and purely dilatational deformation. This will advance the development of constitutive modeling of complex fluid-fluid interfaces.
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Affiliation(s)
- Shalaka K Kale
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, CO 80401, USA
| | - Andrew J Cope
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, CO 80401, USA
| | - David M Goggin
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, CO 80401, USA
| | - Joseph R Samaniuk
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, CO 80401, USA
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Ullmann K, Poggemann L, Nirschl H, Leneweit G. Adsorption process for phospholipids of different chain lengths at a fluorocarbon/water interface studied by Du Noüy ring and spinning drop. Colloid Polym Sci 2020. [DOI: 10.1007/s00396-020-04618-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
AbstractFluorocarbons are novel systems in the fast-growing fields of diverse biomedical applications and fluorocarbon-water emulsions. However, characterization of these systems with modern measuring techniques such as drop profile analysis tensiometry is almost impossible because of practically identical refractive indexes and high-density differences. Due to the material properties of the fluorocarbon-water system, the invasive Du Noüy ring is the most appropriate method to measure interfacial tensions over long times. However, the influence of the ring on a fluorocarbon/water interface packed with phospholipids needs careful analysis. For the proof of methodology, the spinning drop tensiometry was used for comparison as a non-invasive technique to measure interfacial tension between water and perfluoroperhydrophenanthrene (PFPH) covered by 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) proving almost identical results. This demonstrates the validity of the invasive measurement technique for the studied system. The Du Noüy ring method was applied for further measurements of phospholipids with different chain lengths (1,2-dmyristoyl-sn-glycero-3-phostphatidylcholine, DMPC; 1,2-distearoyl-sn-glycero-3-phosphatidylcholine, DSPC) which revealed a difference in interfacial adsorption kinetics and equilibrium tensions. The Du Noüy ring tensiometry is appropriate to examine the slow adsorption kinetics of phospholipids emulsifying fluorocarbons. The results enable functional optimization of fluorocarbon emulsions regarding physical emulsification parameters and the selection of lipids.
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Mottola M, Caruso B, Perillo MA. Langmuir films at the oil/water interface revisited. Sci Rep 2019; 9:2259. [PMID: 30783164 PMCID: PMC6381208 DOI: 10.1038/s41598-019-38674-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 01/07/2019] [Indexed: 11/09/2022] Open
Abstract
We studied monomolecular layers at the oil/water interface (O/Wint) in a Langmuir interfacial trough using egg-yolk phosphatidylcholine (EPC) (the model phospholipid) and Vaseline (VAS) as oil phase. The temporal dynamics in the surface pressure (π) evolution depended on the method (spreading/adsorption) used for monolayers preparation and reflected the different distribution of EPC between all the system compartments (bulk phases and interfaces). We distinguished between EPC located either stable at the interface or hopping between the interface and bulk phases. The size order of the apparent mean molecular area, at constant π, of EPC at different interfaces (EPCO/W > EPC/VAS0.02;A/W > EPCA/W), suggested that VAS molecules intercalated between the hydrocarbon chains of EPCO/W, at a molar fraction xVAS > 0.02. However, EPC/VAS0.02;A/W showed the highest compressional free energy. This leaded us to study the EPC/VAS0.02 mixture at A/W by Brewster Angle Microscopy (BAM), finding that upon compression VAS segregated over the monolayer, forming non-coalescent lenses (as predicted by the spreading coefficient S = −13 mN/m) that remained after decompression and whose height changed (increase/decrease) accompanied the compression/decompression cycle. At the O/Wint, while some VAS molecules remained at the interface up to the collapse, others squeezed out towards the VAS bulk phase with an energy requirement lower than towards the air.
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Affiliation(s)
- Milagro Mottola
- Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Depto. de Química, Cátedra de Química Biológica. Córdoba, Argentina. Av. Vélez Sarsfield 1611, X5016GCA, Córdoba, Argentina.,CONICET, Instituto de Investigaciones Biológicas y Tecnológicas (IIBYT). Córdoba, Argentina. Av. Vélez Sarsfield 1611, 5016, Córdoba, Argentina
| | - Benjamín Caruso
- Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Depto. de Química, Cátedra de Química Biológica. Córdoba, Argentina. Av. Vélez Sarsfield 1611, X5016GCA, Córdoba, Argentina.,CONICET, Instituto de Investigaciones Biológicas y Tecnológicas (IIBYT). Córdoba, Argentina. Av. Vélez Sarsfield 1611, 5016, Córdoba, Argentina
| | - Maria A Perillo
- Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Depto. de Química, Cátedra de Química Biológica. Córdoba, Argentina. Av. Vélez Sarsfield 1611, X5016GCA, Córdoba, Argentina. .,CONICET, Instituto de Investigaciones Biológicas y Tecnológicas (IIBYT). Córdoba, Argentina. Av. Vélez Sarsfield 1611, 5016, Córdoba, Argentina.
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Hysteresis of Contact Angle of Sessile Droplets on Deformable Substrates: Influence of Disjoining Pressure. Colloids Surf A Physicochem Eng Asp 2018. [DOI: 10.1016/j.colsurfa.2018.03.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Javadi K, Moezzi-Rafie H, Goodarzi-Ardakani V, Javadi A, Miller R. Flow physics exploration of surface tension driven flows. Colloids Surf A Physicochem Eng Asp 2017. [DOI: 10.1016/j.colsurfa.2016.12.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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10
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Hildebrandt E, Sommerling JH, Guthausen G, Zick K, Stürmer J, Nirschl H, Leneweit G. Phospholipid adsorption at oil in water versus water in oil interfaces: Implications for interfacial densities and bulk solubilities. Colloids Surf A Physicochem Eng Asp 2016. [DOI: 10.1016/j.colsurfa.2015.12.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Xu W, Gu H, Zhu X, Zhong Y, Jiang L, Xu M, Song A, Hao J. CO2-Controllable Foaming and Emulsification Properties of the Stearic Acid Soap Systems. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:5758-5766. [PMID: 25961406 DOI: 10.1021/acs.langmuir.5b01295] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Fatty acids, as a typical example of stearic acid, are a kind of cheap surfactant and have important applications. The challenging problem of industrial applications is their solubility. Herein, three organic amines-ethanolamine (EA), diethanolamine (DEA), and triethanolamine (TEA)-were used as counterions to increase the solubility of stearic acid, and the phase behaviors were investigated systematically. The phase diagrams were delineated at 25 and 50 °C, respectively. The phase-transition temperature was measured by differential scanning calorimetry (DSC) measurements, and the microstructures were vesicles and planar sheets observed by cryogenic transmission electron microscopy (cryo-TEM) observations. The apparent viscosity of the samples was determined by rheological characterizations. The values, rcmc, for the three systems were less than 30 mN·m(-1). Typical samples of bilayers used as foaming agents and emulsifiers were investigated for the foaming and emulsification assays. CO2 was introduced to change the solubility of stearic acid, inducing the transition of their surface activity and further achieving the goal of defoaming and demulsification.
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12
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Interfacial pressure and phospholipid density at emulsion droplet interface using fluorescence microscopy. Colloids Surf B Biointerfaces 2013; 117:545-8. [PMID: 24373642 DOI: 10.1016/j.colsurfb.2013.11.033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 11/14/2013] [Accepted: 11/15/2013] [Indexed: 11/22/2022]
Abstract
Phospholipids are widely used to stabilize oil in water micron size emulsion droplets; the interfacial phospholipid density and tension of such droplets are difficult to estimate. In the present paper, we describe a simple approach by which the measurement of a micron size oil droplet interface fluorescence intensity provides directly both the interfacial phospholipid density and the interfacial tension. This method relies on two prior calibration steps: (i) the quantitative variation of the interfacial tension with fluorescence intensity at droplets interface through micro-manipulation techniques; (ii) the variation of interfacial tension with phospholipid density through monolayer isotherm. Here, we show the validity of this approach with the example of micron size oil droplets stabilized with a phosphatidylcholine phospholipid, in aqueous buffer.
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Arnold G, Schade E, Schneider Y, Friedrichs J, Babick F, Werner C, Rohm H. Influence of Individual Phospholipids on the Physical Properties of Oil-Based Suspensions. J AM OIL CHEM SOC 2013. [DOI: 10.1007/s11746-013-2361-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Phospholipids at the interface: current trends and challenges. Int J Mol Sci 2013; 14:11767-94. [PMID: 23736688 PMCID: PMC3709755 DOI: 10.3390/ijms140611767] [Citation(s) in RCA: 128] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 05/03/2013] [Accepted: 05/28/2013] [Indexed: 11/30/2022] Open
Abstract
Phospholipids are one of the major structural elements of biological membranes. Due to their amphiphilic character, they can adopt various molecular assemblies when dispersed in water, such as bilayer vesicles or micelles, which give them unique interfacial properties and render them very attractive in terms of foam or emulsion stabilization. This article aims at reviewing the properties of phospholipids at the air/water and oil/water interfaces, as well as the recent advances in using these natural components as stabilizers, alone or in combination with other compounds such as proteins. A discussion regarding the challenges and opportunities offered by phospholipids-stabilized structure concludes the review.
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Mitsche MA, Wang L, Small DM. Adsorption of egg phosphatidylcholine to an air/water and triolein/water bubble interface: use of the 2-dimensional phase rule to estimate the surface composition of a phospholipid/triolein/water surface as a function of surface pressure. J Phys Chem B 2010; 114:3276-84. [PMID: 20151713 DOI: 10.1021/jp908730t] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Phospholipid monolayers play a critical role in the structure and stabilization of biological interfaces, including all membranes, the alveoli of the lungs, fat droplets in adipose tissue, and lipoproteins. The behavior of phospholipids in bilayers and at an air-water interface is well understood. However, the study of phospholipids at oil-water interfaces is limited due to technical challenges. In this study, egg phosphatidylcholine (EPC) was deposited from small unilamellar vesicles onto a bubble of either air or triolein (TO) formed in a low-salt buffer. The surface tension (gamma) was measured using a drop tensiometer. We observed that EPC binds irreversibly to both interfaces and at equilibrium exerts approximately 12 and 15 mN/m of pressure (Pi) at an air and TO interface, respectively. After EPC was bound to the interface, the unbound EPC was washed out of the cuvette, and the surface was compressed to study the Pi/area relationship. To determine the surface concentration (Gamma), which cannot be measured directly, compression isotherms from a Langmuir trough and drop tensiometer were compared. The air-water interfaces had identical characteristics using both techniques; thus, Gamma on the bubble can be determined by overlaying the two isotherms. Both TO and EPC are surface-active, so in a mixed TO/EPC monolayer, both molecules will be exposed to water. Since TO is less surface-active than EPC, as Pi increases, the TO is progressively ejected. To understand the Pi/area isotherm of EPC on a TO bubble, a variety of TO-EPC mixtures were spread at the air-water interface. The isotherms show an abrupt break in the curve caused by the ejection of TO from the monolayer into a new bulk phase. By overlaying the compression isotherm above the ejection point with a TO bubble compression isotherm, Gamma can be estimated. This allows determination of Gamma of EPC on a TO bubble as a function of Pi.
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Affiliation(s)
- Matthew A Mitsche
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, Massachusetts 02118, USA
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16
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Ca2+ adsorption to lipid membranes and the effect of cholesterol in their composition. Colloids Surf B Biointerfaces 2010; 76:215-20. [DOI: 10.1016/j.colsurfb.2009.10.037] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2009] [Revised: 10/20/2009] [Accepted: 10/22/2009] [Indexed: 11/21/2022]
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17
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Prudent M, Méndez MA, Jana DF, Corminboeuf C, Girault HH. Formation and study of single metal ion–phospholipid complexes in biphasic electrospray ionization mass spectrometry. Metallomics 2010; 2:400-6. [DOI: 10.1039/c003647a] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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He Q, Zhang Y, Lu G, Miller R, Möhwald H, Li J. Dynamic adsorption and characterization of phospholipid and mixed phospholipid/protein layers at liquid/liquid interfaces. Adv Colloid Interface Sci 2008; 140:67-76. [PMID: 18279818 DOI: 10.1016/j.cis.2007.12.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2007] [Revised: 08/16/2007] [Accepted: 12/17/2007] [Indexed: 10/22/2022]
Abstract
Drop profile analysis tensiometry is applied to study the adsorption dynamics of phospholipids, proteins and phospholipid/protein mixtures at liquid/liquid interfaces. Measurements of the dynamic interfacial tension of phospholipid layers give information on the adsorption mechanism and the structure of the adsorption layer. The equilibrium and dynamic adsorption of pure protein solutions, i.e. human serum album (HSA), beta-lactoglobulin (beta-LG), beta-casein (beta-CA), can be explained well by the thermodynamic model of Frumkin and the diffusion-controlled adsorption theory. The adsorption behavior from mixed phospholipid/protein solutions was also investigated in terms of dynamic interfacial tensions. Interestingly, a "skin-like" folded film of pure protein or phospholipid/protein complex layers can be observed at curved surfaces at the water/oil interfaces. The addition of phospholipids accelerates the formation of the folded structure at the drop surface through co-adsorption of proteins.
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Duncan SL, Larson RG. Comparing experimental and simulated pressure-area isotherms for DPPC. Biophys J 2008; 94:2965-86. [PMID: 18199666 PMCID: PMC2275714 DOI: 10.1529/biophysj.107.114215] [Citation(s) in RCA: 163] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2007] [Accepted: 12/03/2007] [Indexed: 11/18/2022] Open
Abstract
Although pressure-area isotherms are commonly measured for lipid monolayers, it is not always appreciated how much they can vary depending on experimental factors. Here, we compare experimental and simulated pressure-area isotherms for dipalmitoylphosphatidylcholine (DPPC) at temperatures ranging between 293.15 K and 323.15 K, and explore possible factors influencing the shape and position of the isotherms. Molecular dynamics simulations of DPPC monolayers using both coarse-grained (CG) and atomistic models yield results that are in rough agreement with some of the experimental isotherms, but with a steeper slope in the liquid-condensed region than seen experimentally and shifted to larger areas. The CG lipid model gives predictions that are very close to those of atomistic simulations, while greatly improving computational efficiency. There is much more variation among experimental isotherms than between isotherms obtained from CG simulations and from the most refined simulation available. Both atomistic and CG simulations yield liquid-condensed and liquid-expanded phase area compressibility moduli that are significantly larger than those typically measured experimentally, but compare well with some experimental values obtained under rapid compression.
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Affiliation(s)
- Susan L Duncan
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan, USA
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Surface rheology and phase transitions of monolayers of phospholipid/cholesterol mixtures. Biophys J 2008; 94:3924-34. [PMID: 18234814 DOI: 10.1529/biophysj.107.104851] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The dynamic surface elasticity and the surface dilational viscosity of three binary phospholipid/cholesterol mixtures were determined with axisymmetric drop shape analysis on a harmonically oscillating pendent drop. Dipalmitoylphosphatidylcholine, dimyristoylphosphatidylcholine, and dioleoylphosphatidylcholine were used to explore the rheological properties and phase transitions of mixtures of saturated and unsaturated phospholipids with cholesterol. The growth rates for surface dilational viscosity and dynamic elasticity are parallel for all film pressures studied. Characteristic breaks and plateaus could be found for these growth rates, indicating phase transitions. For dipalmitoylphosphatidylcholine/cholesterol and dimyristoylphosphatidylcholine/cholesterol mixtures, phase diagrams with six regions separated by phase boundaries were found, which are in good agreement with phase transitions reported in the literature for static measurements of isotherms and isobars on a Langmuir film balance and from fluorescence microscopy. Some phase boundaries were only found by dynamic, but not by static, elasticity measurements. Imaging methods revealed phase separations produced by the formation of condensed stoichiometric complexes leading to micron-sized and mostly circular domains. The effects of these complexes on monolayer rheology in liquid/liquid phases is described. Furthermore, liquid/solid and solid phase transitions are discussed.
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Vrânceanu M, Winkler K, Nirschl H, Leneweit G. Surface rheology of monolayers of phospholipids and cholesterol measured with axisymmetric drop shape analysis. Colloids Surf A Physicochem Eng Asp 2007. [DOI: 10.1016/j.colsurfa.2007.06.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Anton N, Saulnier P, Boury F, Foussard F, Benoit JP, Proust JE. The influence of headgroup structure and fatty acyl chain saturation of phospholipids on monolayer behavior: a comparative rheological study. Chem Phys Lipids 2007; 150:167-75. [PMID: 17868664 DOI: 10.1016/j.chemphyslip.2007.06.226] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2006] [Revised: 06/04/2007] [Accepted: 06/04/2007] [Indexed: 11/18/2022]
Abstract
This paper compares six phospholipidic monolayers at the water/chloroform interface by performing dilational rheological measurements with a drop tensiometer apparatus. The chosen lipids differ both in their headgroup structure and fatty acyl chain saturation or symmetry. The study concentrated on monolayers formed with DPPC, DPPE, DOPC, DOPE, POPC and POPE. Using a generalized Maxwell rheological model, transposed at the interface, the intimate intermolecular interactions between amphiphilic molecules are studied on and off the monolayer plane. The equilibrium and nonequilibrium phenomena are analyzed and, respectively, correlated with monolayer cohesion and with monolayer/sub-surface interactions. The purpose of this work is to gain further insights into the influences (as slight as they are) of the weak changes in phospholipid structure and on the behavior of the monolayers. The results, widely described, provide further details on nuances existing between very similar molecules, and likewise, on the synergies created between the different effects.
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Affiliation(s)
- Nicolas Anton
- Inserm U646, Ingénierie de la Vectorisation Particulaire, 10 rue A. Boquel, F-49100 Angers, France
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Chourpa I, Ducel V, Richard J, Dubois P, Boury F. Conformational Modifications of α Gliadin and Globulin Proteins upon Complex Coacervates Formation with Gum Arabic as Studied by Raman Microspectroscopy. Biomacromolecules 2006; 7:2616-23. [PMID: 16961325 DOI: 10.1021/bm060131d] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
As a molecular model of gelatin-free coacervates, complexes of pea globulin and alpha gliadin proteins with gum arabic prepared at different acidic pH values are studied using Raman microspectrometry. Raman spectra confirm higher content of beta-sheets and random coils in pea globulin and dominating alpha-helical structures in alpha gliadin. For protein-gum arabic complexes, Raman data support the existence of specific pH conditions for optimal complex coacervation (pH 2.75 for globulin and pH 3.0 for gliadin(1)), when (i) pH-induced conformational perturbations of free protein structure are the strongest and (ii) compensation of these perturbations by gum arabic is the most pronounced. Conformations implied in the protein-gum complexes are mainly beta-sheets in pea globulin and alpha-helix in alpha gliadin. The role of electrostatic and non-Coulombic interactions (intermolecular hydrogen bonds) in stabilizing of protein-polysaccharide complexes is discussed in relation with the overall structure and the charge density profile of these two proteins.
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Affiliation(s)
- Igor Chourpa
- Laboratoire de Chimie Analytique, UFR de Pharmacie, IFR 135 Imagerie Fonctionnelle, Université François Rabelais de Tours, 31, avenue Monge, 37200 Tours, France.
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24
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Mu L, Seow PH. Application of TPGS in polymeric nanoparticulate drug delivery system. Colloids Surf B Biointerfaces 2006; 47:90-7. [PMID: 16412619 DOI: 10.1016/j.colsurfb.2005.08.016] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2004] [Revised: 08/18/2005] [Accepted: 08/18/2005] [Indexed: 11/17/2022]
Abstract
d-alpha-Tocopheryl polyethylene glycol 1000 succinate (TPGS) has great potential in pharmacology and nanotechnology. The present work investigated the molecular behaviour of TPGS at the air-water interface, its effect on a model bio-membrane composed of dipalmitoylphosphatidylcholine (DPPC) lipid monolayer, and the interaction between the TPGS coated nanoparticles with the lipid model membrane. Paclitaxel loaded polymeric nanoparticles with TPGS as surfactant stabiliser were fabricated and characterised in terms of their drug incorporation capability and release kinetics. The result showed that TPGS exhibited notable effect on the surface properties of air-water interface as well as the lipid monolayer. The inter-particle force and the interaction between nanoparticles and lipid monolayer varied with the surface substance. The penetration of various nanoparticles into the model membrane indicated that an optimal balance between hydrophilicity and hydrophobicity on nanoparticle surface is needed to achieve an effective cellular uptake of nanoparticles. The results also demonstrate that the drug incorporation capability and the release characteristics of drug-loaded nanoparticles can be influenced by surfactant stabiliser.
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Affiliation(s)
- L Mu
- Division of Bioengineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576, Singapore.
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Bothun GD, Kho YW, Berberich JA, Shofner JP, Robertson T, Tatum KJ, Knutson BL. Surface Activity of Lysozyme and Dipalmitoyl Phosphatidylcholine Vesicles at Compressed and Supercritical Fluid Interfaces. J Phys Chem B 2005; 109:24495-501. [PMID: 16375453 DOI: 10.1021/jp0548772] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The surface activities of lysozyme and dipalmitoyl phosphatidylcholine (DPPC) vesicles at aqueous/compressed fluid interfaces are examined via high-pressure interfacial tension measurements using the pendant drop technique. The density and interfacial tension in compressible fluid systems vary significantly with pressure, providing a versatile medium for elucidating interactions between biomolecules and fluid interfaces and a method to elicit pressure-dependent interfacial morphological responses. The effects of lysozyme concentration (0.0008, 0.01, and 1 mg/mL) and pressure (> or = 7 MPa) on the dynamic surface response in the presence of ethane, propane, N2, and CO2 at 298 K were examined. Interfacial lysozyme adsorption reduced the induction phase and quickly led to interfacial tensions consistent with protein conformational changes and monolayer saturation at the compressed fluid interfaces. Protein adsorption, as indicated by surface pressure, correlated with calculated Hamaker constants for the compressed gases, denoting the importance of dispersion interactions. For DPPC at aqueous/compressed or aqueous/supercritical CO2 interfaces (1.8-20.7 MPa, 308 K), 2-3-fold reductions in interfacial tension were observed relative to the pure binary fluid system. The resulting surface pressures infer pressure-dependent morphological changes within the DPPC monolayer.
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Affiliation(s)
- Geoffrey D Bothun
- NSF-STC Environmentally Responsible Solvents and Processes, Department of Mechanical and Chemical Engineering, North Carolina A&T State University, Greensboro, North Carolina 27411, USA
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He Q, Zhang H, Tian Y, Li J. Comparative investigation of structure characteristics of mixed β-lactoglobulin and different chain-length phophatidylcholine monolayer at the air/water interface. Colloids Surf A Physicochem Eng Asp 2005. [DOI: 10.1016/j.colsurfa.2004.10.068] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Chen P, Kwok D, Prokop R, del Rio O, Susnar S, Neumann A. Axisymmetric Drop Shape Analysis (ADSA) and its Applications. STUDIES IN INTERFACE SCIENCE 1998. [DOI: 10.1016/s1383-7303(98)80019-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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