The Influence of Metal Ions on the Dynamics of Supported Phospholipid Langmuir Films

Baumler, Stephen M.; Blanchard, G. J.

doi:10.1021/acs.langmuir.7b00042

Cited by 21 publications

(18 citation statements)

References 42 publications

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“…The Ca:Si ratio is slightly higher than that seen for the analogous interface prepared by Langmuir-Blodgett deposition, and slightly less than phosphorylated surfaces prepared on gold. [16, 19] This is not a surprising result owing to the different type and extent of ordering for the gold and silica surfaces. While XPS provides only a semi-quantitative assessment of the relative abundance of metal ions at a surface, the surface density of calcium is sufficient to influence the dynamics of the supported bilayer ( vide infra ).…”

Section: Resultsmentioning

confidence: 97%

“…Addition of H + to interface without calcium leads to the fully protonated PO(OH) 2 surface where D T is mediated predominantly by hydrogen bonding interactions. [16]…”

Section: Resultsmentioning

confidence: 99%

“…FRAP measurements were conducted on a Nikon C2+ confocal laser scanning microscopy system described in detail elsewhere. [16] Briefly, the NBD-LPC was excited with the 488 nm line of a diode laser, and emission was detected at 525 nm using a standard PMT detector. A 20x objective lens was used for the films.…”

Section: Methodsmentioning

confidence: 99%

“…XPS measurements were performed on a Perkin-Elmer Phi 5600 ESCA instrument described previously. [16] Survey scans of 0 1100 eV binding energy and detailed scans for Ca2p, C1s, O1s, P2p, and Si2p were measured for each sample. All peaks were corrected in reference to the C1s peak associated with adventitious C at 284.8 eV.…”

Section: Methodsmentioning

confidence: 99%

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Surface charge and overlayer pH influence the dynamics of supported phospholipid films

Baumler

McHale

Blanchard

2018

Journal of Electroanalytical Chemistry

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Understanding the thermodynamics and kinetics of interactions between model lipid bilayers and planar supports is of critical importance in the furtherance of biosensing and the creation of biomimetic devices. Evaluating these properties can be accomplished through understanding the diffusional properties of the bilayer constituents. In this report, the dynamics of a model DMPC bilayer supported on a phosphorylated silica surface are studied in the presence and absence of interfacial Ca as a function of pH of the aqueous overlayer. The data for this system reveal the importance of the balance of ionic interactions between the interfacial species, and the dependence of the diffusional, kinetic and thermodynamic properties of the system on pH. The thermodynamic data suggest that interactions between the bilayer and surface are mediated enthalpically rather than entropically.

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Section: Resultsmentioning

confidence: 97%

“…Addition of H + to interface without calcium leads to the fully protonated PO(OH) 2 surface where D T is mediated predominantly by hydrogen bonding interactions. [16]…”

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Surface charge and overlayer pH influence the dynamics of supported phospholipid films

Baumler

McHale

Blanchard

2018

Journal of Electroanalytical Chemistry

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“…36 The presence of ions in Langmuir trough subphases have been reported to influence the interfacial behavior of polar lipids that can be found in milk. 37,38…”

Section: Resultsmentioning

confidence: 99%

Preparation of Non-Surface-Active Langmuir Trough Subphases from Milk

Hernandez

Jiménez-Flores

2019

ACS Omega

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Milk polar lipid interfacial behavior continues to be analyzed using Langmuir trough experiments, but the reported Langmuir trough subphases commonly used are not fully representative of milk. A method to transform liquids of biological origin, such as milk, into appropriate Langmuir trough subphases does not currently exist, which hinders the applicability of Langmuir trough experiments to nature. Here, a procedure to manufacture milk-derived Langmuir trough subphases with insignificant amounts of surfactants from bovine milk is presented. Ultrafiltration is used to remove the bulk of protein surfactants from milk followed by the creation of solvent-induced emulsions that remove trace proteins and lipids from collected skim milk permeates. Change in surface tension upon compression of resulting washed permeates from the surfactant removal process was ≤0.1 mN/m, terming the permeates non-surface-active (NSA). NSA permeates (72.4 ± 0.2 mN/m) had a surface tension similar to that of ultrapure water (72.6 ± 0.1 mN/m), but their pH, conductivity, percent total solids, Brix percentage, alkalinity, and hardness were not the same, with NSA permeates being more compositionally similar to skim milk than water. The lift-off points of milk ganglioside GM3 monolayer surface pressure–area isotherms spread on NSA permeates and ultrapure water subphases were significantly different when compared for the same sample, indicating that surface tension measurements obtained on ultrapure water are not the same as with NSA milk permeate. Overall, surfactants were removed from bovine milk without the addition of exogenous compounds, allowing for the production of a NSA solution derived from milk that can be used in the Langmuir trough experiment to more realistically resemble the natural environment of milk polar lipids. The procedure described here was able to produce NSA solutions for other dairy beverages aside from milk, indicating that it can be applicable to other biological fluids.

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Membrane‐Mediated Self‐Organization of Rod‐Like DNA Origami on Supported Lipid Bilayers

Khmelinskaia

Franquelim

Yaadav

et al. 2021

Adv Materials Inter

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Organization of elongated particles into ordered phases on 2D surfaces and interfaces has been extensively studied during the last decades both theoretically and experimentally. For mutually repulsive particles on solid nondeformable substrates, the process is controlled only by the aspect ratio and the surface density of the adsorbed particles. The local elastic response of soft substrates to particle adhesion can drastically change the collective behavior of adsorbed rod‐like particles resulting in their self‐organization via substrate‐mediated interparticle attraction. Here, high‐speed atomic force microscopy is used to study the organization of DNA origami particles on locally responsive supported lipid bilayers (SLBs) in comparison with that on nondeformable solid mica surfaces. At high surface coverage, the aspect ratio‐dependent anisotropic phases expected for densely packed particles are observed. At intermediate and low surface densities, however, a drastically different phenomenology is observed: surprisingly strong surface‐mediated interparticle attraction of DNA origami particles is found on SLBs resulting in their self‐organization compared to their purely repulsive interaction on a mica surface. The formation of organized aggregates of elongated DNA origami particles on SLBs is explained by exceptionally strong nanoparticle adhesion to the membrane that responds with a local deformation in spite of the presence of the solid support.

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The Influence of Metal Ions on the Dynamics of Supported Phospholipid Langmuir Films

Cited by 21 publications

References 42 publications

Surface charge and overlayer pH influence the dynamics of supported phospholipid films

Surface charge and overlayer pH influence the dynamics of supported phospholipid films

Preparation of Non-Surface-Active Langmuir Trough Subphases from Milk

Membrane‐Mediated Self‐Organization of Rod‐Like DNA Origami on Supported Lipid Bilayers

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