Perturbation of Hydrogen Bonding Networks over Supported Lipid Bilayers by Poly (Allylamine Hydrochloride)

<div><div><div><p>Water is vital to many biochemical processes and is necessary for driving many fundamental interactions of cell membranes with their external environments, yet it is difficult to probe the membrane/water interface directly and without the use of external labels. Here, we employ vibrational sum frequency generation (SFG) spectroscopy to understand the role of interfacial water molecules above bilayers formed from zwitterionic (phosphatidylcholine, PC) and anionic (phosphatidylglycerol, PG, and phosphatidylserine, PS) lipids as they are exposed to the common polycation poly (allylamine hydrochloride) (PAH) in 100 mM NaCl. We show that as the concentration of PAH is increased, the interfacial water molecules are irreversibly displaced and find that it requires 10 times more PAH to displace interfacial water molecules from membranes formed from purely zwitterionic lipids when compared to membranes that contain the anionic PG and PS lipids. This outcome is likely due to difference in (1) the energy with which water molecules are bound to the lipid headgroups, (2) the number of water molecules bound to the headgroups, which is related to the headgroup area, and (3) the electrostatic interactions between the PAH molecules and the negatively charged lipids that are favored when compared to the zwitterionic lipid headgroups. The findings presented here contribute to establishing causal relationships in nanotoxicology and to understanding, controlling, and predicting the initial steps that lead to the lysis of cells exposed to membrane disrupting polycations, or to transfection.</p></div></div></div>

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Hydrogen Bond Networks Near Supported Lipid Bilayers from Vibrational Sum Frequency Generation Experiments and Atomistic Simulations

10.26434/chemrxiv.5946556 ◽

2018 ◽

Author(s):

Merve Dogangun ◽

Paul E. Ohno ◽

Dongyue Liang ◽

Alicia C. McGeachy ◽

Ariana Gray Be ◽

...

Keyword(s):

Hydrogen Bond ◽

Lipid Bilayers ◽

Sum Frequency Generation ◽

Atomistic Simulations ◽

Supported Lipid Bilayers ◽

Water Molecules ◽

Specific Interactions ◽

Sum Frequency ◽

Hydrogen Bond Networks ◽

Frequency Generation

<div> <div> <p>We report vibrational sum frequency generation (SFG) spectra in which the C–H stretches of lipid alkyl tails in fully hydrogenated single- and dual-component supported lipid bilayers are detected along with the O–H stretching continuum above the bilayer. As the salt concentration is increased from ~10 μM to 0.1 M, the SFG intensities in the O–H stretching region decrease by a factor of 2, consistent with significant absorptive-dispersive mixing between χ(2) and χ(3) contributions to the SFG signal generation process from charged interfaces. A method for estimating the surface potential from the second-order spectral lineshapes (in the OH stretching region) is presented and discussed in the context of choosing truly zero-potential reference states. Aided by atomistic simulations, we find that the strength and orientation distribution of the hydrogen bonds over the purely zwitterionic bilayers are largely invariant between sub-micromolar and hundreds of millimolar concentrations. However, specific interactions between water molecules and lipid headgroups are observed upon replacing phosphocholine (PC) lipids with negatively charged phosphoglycerol (PG) lipids, which coincides with SFG signal intensity reductions in the 3100 cm-1 to 3200 cm-1 frequency region. The atomistic simulations show that this outcome is consistent with a small, albeit statistically significant, decrease in the number of water molecules adjacent to both the lipid phosphate and choline moieties per unit area, supporting the SFG observations. Ultimately, the ability to probe hydrogen-bond networks over lipid bilayers holds the promise of opening paths for understanding, controlling, and predicting specific and non-specific interactions between membranes and ions, small molecules, peptides, polycations, proteins, and coated and uncoated nanomaterials.<br></p></div></div>

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Hydrogen Bond Networks Near Supported Lipid Bilayers from Vibrational Sum Frequency Generation Experiments and Atomistic Simulations

10.26434/chemrxiv.5946556.v2 ◽

2018 ◽

Cited By ~ 1

Author(s):

Merve Dogangun ◽

Paul E. Ohno ◽

Dongyue Liang ◽

Alicia C. McGeachy ◽

Ariana Gray Be ◽

...

Keyword(s):

Hydrogen Bond ◽

Lipid Bilayers ◽

Sum Frequency Generation ◽

Atomistic Simulations ◽

Supported Lipid Bilayers ◽

Water Molecules ◽

Specific Interactions ◽

Sum Frequency ◽

Hydrogen Bond Networks ◽

Frequency Generation

<div> <div> <p>We report vibrational sum frequency generation (SFG) spectra in which the C–H stretches of lipid alkyl tails in fully hydrogenated single- and dual-component supported lipid bilayers are detected along with the O–H stretching continuum above the bilayer. As the salt concentration is increased from ~10 μM to 0.1 M, the SFG intensities in the O–H stretching region decrease by a factor of 2, consistent with significant absorptive-dispersive mixing between χ(2) and χ(3) contributions to the SFG signal generation process from charged interfaces. A method for estimating the surface potential from the second-order spectral lineshapes (in the OH stretching region) is presented and discussed in the context of choosing truly zero-potential reference states. Aided by atomistic simulations, we find that the strength and orientation distribution of the hydrogen bonds over the purely zwitterionic bilayers are largely invariant between sub-micromolar and hundreds of millimolar concentrations. However, specific interactions between water molecules and lipid headgroups are observed upon replacing phosphocholine (PC) lipids with negatively charged phosphoglycerol (PG) lipids, which coincides with SFG signal intensity reductions in the 3100 cm-1 to 3200 cm-1 frequency region. The atomistic simulations show that this outcome is consistent with a small, albeit statistically significant, decrease in the number of water molecules adjacent to both the lipid phosphate and choline moieties per unit area, supporting the SFG observations. Ultimately, the ability to probe hydrogen-bond networks over lipid bilayers holds the promise of opening paths for understanding, controlling, and predicting specific and non-specific interactions between membranes and ions, small molecules, peptides, polycations, proteins, and coated and uncoated nanomaterials.<br></p></div></div>

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Hydrogen Bond Networks Near Supported Lipid Bilayers from Vibrational Sum Frequency Generation Experiments and Atomistic Simulations

10.26434/chemrxiv.5946556.v1 ◽

2018 ◽

Cited By ~ 1

Author(s):

Merve Dogangun ◽

Paul E. Ohno ◽

Dongyue Liang ◽

Alicia C. McGeachy ◽

Ariana Gray Be ◽

...

Keyword(s):

Hydrogen Bond ◽

Lipid Bilayers ◽

Sum Frequency Generation ◽

Atomistic Simulations ◽

Supported Lipid Bilayers ◽

Water Molecules ◽

Specific Interactions ◽

Sum Frequency ◽

Hydrogen Bond Networks ◽

Frequency Generation

<div> <div> <div> <p>We report vibrational sum frequency generation (SFG) spectra in which the C–H stretches of lipid alkyl tails in fully hydrogenated single- and dual-component supported lipid bilayers are detected along with the O–H stretching continuum above the bilayer. As the salt concentration is increased from ~10 μM to 0.1 M, the SFG intensities in the O–H stretching region decrease by a factor of 2, consistent with significant absorptive-dispersive mixing between χ(2) and χ(3) contributions to the SFG signal generation process from charged interfaces. A method for estimating the surface potential from the second-order spectral lineshapes (in the OH stretching region) is presented and discussed in the context of choosing truly zero-potential reference states. Aided by atomistic simulations, we find that the strength and orientation distribution of the hydrogen bonds over the purely zwitterionic bilayers are largely invariant between sub-micromolar and hundreds of millimolar concentrations. However, specific interactions between water molecules and lipid headgroups are observed upon replacing phosphocholine (PC) lipids with negatively charged phosphoglycerol (PG) lipids, which coincides with SFG signal intensity reductions in the 3100 cm-1 to 3200 cm-1 frequency region. The atomistic simulations show that this outcome is consistent with a small, albeit statistically significant, decrease in the number of water molecules adjacent to both the lipid phosphate and choline moieties per unit area, supporting the SFG observations. Ultimately, the ability to probe hydrogen-bond networks over lipid bilayers holds the promise of opening paths for understanding, controlling, and predicting specific and non-specific interactions between membranes and ions, small molecules, peptides, polycations, proteins, and coated and uncoated nanomaterials. Pre-edited version, 14 pages main text, 5 Figures, 1 Table, 29 pages Supporting Information available upon request.</p></div></div></div>

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Adsorption of α-Synuclein to Supported Lipid Bilayers: Positioning and Role of Electrostatics

ACS Chemical Neuroscience ◽

10.1021/cn400066t ◽

2013 ◽

Vol 4 (10) ◽

pp. 1339-1351 ◽

Cited By ~ 54

Author(s):

Erik Hellstrand ◽

Marie Grey ◽

Marie-Louise Ainalem ◽

John Ankner ◽

V. Trevor Forsyth ◽

...

Keyword(s):

Lipid Bilayers ◽

Supported Lipid Bilayers

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The role of surface charge in the interaction of nanoparticles with model pulmonary surfactants

Soft Matter ◽

10.1039/c8sm00925b ◽

2018 ◽

Vol 14 (28) ◽

pp. 5764-5774 ◽

Cited By ~ 11

Author(s):

F. Mousseau ◽

J.-F. Berret

Keyword(s):

Surface Charge ◽

Lipid Bilayers ◽

Pulmonary Surfactant ◽

Lipid Vesicles ◽

Electrostatic Charge ◽

Supported Lipid Bilayers ◽

Pulmonary Surfactants ◽

Inhaled Nanoparticles

Inhaled nanoparticles reaching the respiratory zone in the lungs enter first in contact with the pulmonary surfactant. It is shown here that nanoparticles and lipid vesicles formulated from different surfactant mimetics interact predominantlyviaelectrostatic charge mediated attraction and do not form supported lipid bilayers spontaneously.

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The molecular structure and surface accumulation dynamics of hyaluronan at the water/air interface

10.1101/2021.04.29.441779 ◽

2021 ◽

Author(s):

Carolyn J. Moll ◽

Giulia Giubertoni ◽

Jan Versluis ◽

Gijsje H. Koenderink ◽

Huib J. Bakker

Keyword(s):

Molecular Weight ◽

Electrostatic Interactions ◽

Inflammatory Responses ◽

Strong Dependence ◽

Aqueous Media ◽

Interfacial Water ◽

Sum Frequency ◽

Sum Frequency Generation Spectroscopy ◽

Air Interface ◽

Kinetics Of

AbstractHyaluronan is a biopolymer that is essential for many biological processes in the human body, like the regulation of tissue lubrication and inflammatory responses. Here we study the behavior of hyaluronan at aqueous surfaces using heterodyne-detected vibrational sum-frequency generation spectroscopy (HD-VSFG). We find that high-molecular weight hyaluronan (>1 MDa) does not come to the surface, even hours after addition of the polymer to the aqueous solution. In contrast, low-molecular weight hyaluronan (~150 kDa) gradually covers the water-air interface within hours, leading to a negatively charged surface and a reorientation of the interfacial water molecules. This strong dependence on the polymer molecular weight can be explainend from entanglements of the hyaluronan polymers. We also find that the migration kinetics of hyaluronan in aqueous media shows an anomalous dependence on the pH of the solution, which can be explained from the interplay of hydrogen-bonding and electrostatic interactions of the hyaluronan polymers.

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Microenvironment alterations enhance photocurrents from photosystem I confined in supported lipid bilayers

Journal of Materials Chemistry A ◽

10.1039/c8ta00898a ◽

2018 ◽

Vol 6 (26) ◽

pp. 12281-12290 ◽

Cited By ~ 9

Author(s):

Hanieh Niroomand ◽

Ravi Pamu ◽

Dibyendu Mukherjee ◽

Bamin Khomami

Keyword(s):

Lipid Bilayers ◽

Photosystem I ◽

Charge Separation ◽

Critical Role ◽

Supported Lipid Bilayers ◽

Induced Charge

This work elucidates the role of natural membrane confinements of photosystem I complexes (PSI) in light-induced charge separation by comparing the photocurrents of isolated PSI with PSI encapsulated within solid-supported lipid bilayers on electrodes. Our results indicate the critical role of the microenvironment alterations in achieving enhanced photocurrent and stability.

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