Membrane Hydration

doi:10.1007/978-3-319-19060-0

Cited by 27 publications

(1 citation statement)

References 246 publications

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“…(iii) How does the addition of an inert salt affect the redox properties of the quinoid membrane constituents? Inert salts change not only the ionic strength, but also the water activity, which is known to have an effect on the intramolecular properties at catalytic sites (Disalvo 2015;George et al 1970). Here, we report attempts to partially answer these questions by experiments in which menaquinones have been incorporated in lipid monolayers on a stationary mercury drop electrode.…”

Section: Introductionmentioning

confidence: 97%

The effects of the chemical environment of menaquinones in lipid monolayers on mercury electrodes on the thermodynamics and kinetics of their electrochemistry

et al. 2021

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The effects of the chemical environment of menaquinones (all-trans MK-4 and all-trans MK-7) incorporated in lipid monolayers on mercury electrodes have been studied with respect to the thermodynamics and kinetics of their electrochemistry. The chemical environment relates to the composition of lipid films as well as the adjacent aqueous phase. It could be shown that the addition of all-trans MK-4 to TMCL does not change the phase transition temperatures of TMCL. In case of DMPC monolayers, the presence of cholesterol has no effect on the thermodynamics (formal redox potentials) of all-trans MK-7, but the kinetics are affected. Addition of an inert electrolyte (sodium perchlorate; change of ionic strength) to the aqueous phase shifts the redox potentials of all-trans MK-7 only slightly. The formal redox potentials of all-trans MK-4 were determined in TMCL and nCL monolayers and found to be higher in nCL monolayers than in TMCL monolayers. The apparent electron transfer rate constants, transfer coefficients and activation energies of all-trans MK-4 in cardiolipins have been also determined. Most surprisingly, the apparent electron transfer rate constants of all-trans MK-4 exhibit an opposite pH dependence for TMCL and nCL films: the rate constants increase in TMCL films with increasing pH, but in nCL films they increase with decreasing pH. This study is a contribution to understand environmental effects on the redox properties of membrane bond redox systems. Graphical abstract

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Section: Introductionmentioning

confidence: 97%

The effects of the chemical environment of menaquinones in lipid monolayers on mercury electrodes on the thermodynamics and kinetics of their electrochemistry

et al. 2021

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Microcirculatory Response to Photobiomodulation—Why Some Respond and Others Do Not: A Randomized Controlled Study

et al. 2020

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Conclusions: We demonstrated that PBM induces arteriolar vasodilatation that results in both immediate and long-lasting increased capillary flow and tissue perfusion in healthy individuals. This response was wavelengthdependent and modified by skin temperature. These findings regarding physiological parameters associated with sensitivity or resistance to PBM provide information of direct relevance for patient-specific therapy. Lasers Surg. Med.

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Understanding the Dehydration Stress in Lipid Vesicles by a Combined Quartz Crystal Microbalance and Dielectric Spectroscopy Study

Gennaro

Deschaume

Pfeiffer

et al. 2020

Physica Status Solidi (a)

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Herein, 1‐palmitoyl‐2‐oleoyl‐glycero‐3‐phosphocholine (POPC) vesicles are studied using a newly designed setup that combines dielectric and gravimetric (quartz crystal microbalance, QCM) measurements. This setup allows to monitor the molecular dynamics and phase transitions of lipid structures under controlled humidity and temperature conditions. The main relaxation process (R2), related to the intrinsic headgroups' dynamics, is found in all phases and reveals a systematic acceleration with increasing hydration level. In contrast, a faster relaxation mode (R1) is found exclusively in the “liquid‐crystalline,” high‐temperature state, favoring water clusters located in the disordered aliphatic phase as origin. A third process (R3), being slower than the R2 mode, is attributed to a decoupled dynamics of hydration water in the hydrophilic part of the lipid bilayers occurring at higher hydration levels. In addition to molecular dynamics, both QCM and dielectric relaxation spectroscopy (DRS) measurements are demonstrated to yield consistent information on the phase behavior of the POPC samples which show a marked sensitivity to the hydration level. Moreover, contact angle measurements and atomic force microscopy confirm irreversible changes from the initial vesicles to a stacked bilayer structure upon repeated hydration‐dehydration, which manifests in the hydrophobization of the surface and water reduced absorption kinetics.

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Membrane Hydration

Cited by 27 publications

References 246 publications

The effects of the chemical environment of menaquinones in lipid monolayers on mercury electrodes on the thermodynamics and kinetics of their electrochemistry

The effects of the chemical environment of menaquinones in lipid monolayers on mercury electrodes on the thermodynamics and kinetics of their electrochemistry

Microcirculatory Response to Photobiomodulation—Why Some Respond and Others Do Not: A Randomized Controlled Study

Understanding the Dehydration Stress in Lipid Vesicles by a Combined Quartz Crystal Microbalance and Dielectric Spectroscopy Study

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