We calculated the pressure-area isotherm of a dipalmitoyl-phosphatidylcholine (DPPC) lipid monolayer from molecular dynamics simulations using a coarse-grained molecular model. We characterized the monolayer structure, geometry, and phases directly from the simulations and compared the calculated isotherm to experiments. The calculated isotherm shows liquid-expanded and liquid-condensed phases and their coexistence plateau. At high pressure, the monolayer surface is rippled; upon further compression, the monolayer undergoes a collapse. We studied the effect of temperature and system size on the isotherm slope and phase coexistence region. Thermodynamic and dynamic properties of the monolayer phases were also investigated.
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http://dx.doi.org/10.1021/la702286h | DOI Listing |
Phys Chem Chem Phys
January 2025
Department of Physics, School of Natural Sciences, Shiv Nadar Institution of Eminence, NH91, Tehsil Dadri, G. B. Nagar, Uttar Pradesh 201314, India.
Graphene and its derivatives, such as graphene oxide (GO) and reduced graphene oxide (rGO), have propelled advancements in biosensor research owing to their unique physicochemical and electronic characteristics. To ensure their safe and effective utilization in biological environments, it is crucial to understand how these graphene-based nanomaterials (GNMs) interact with a biological milieu. The present study depicts GNM-induced structural changes in a self-assembled phospholipid monolayer formed at an air-water interface that can be considered to represent one of the leaflets of a cellular membrane.
View Article and Find Full Text PDFJ Mater Chem B
November 2024
Department of Physics, School of Natural Sciences, Shiv Nadar Institution of Eminence, NH 91, Tehsil Dadri, G. B. Nagar, Uttar Pradesh 201314, India.
Antimicrobial-resistant bacteria pose a significant threat to humans, prompting extensive research into developing new antimicrobial peptides (AMPs). The biomembrane is the first barrier of a biological cell, hence, comprehending the interaction and self-assembly of AMPs in and around such membranes is of great importance. In the present study, several biophysical techniques have been applied to explore the self-assembly of ubiquicidin (29-41), an archetypical AMP, in and around the phospholipid monolayers formed at air-water interface.
View Article and Find Full Text PDFPhys Rev E
July 2024
Department of Physics, Kent State University, Kent, Ohio 44242, USA.
Molecularly thin films of the smectic liquid crystal 4'-octyl-4-biphenylcarbonitrile (8CB) at the air-water interface phase separate into regions with different numbers of layers, in analogy with freestanding smectic liquid crystalline films. This paper reports the line tension associated with the boundary of coexisting trilayer and monolayer phases of in Langmuir films of 8CB at the air-water interface as a function of temperature and humidity and infers information on the boundary profile between the coexisting phases. Two complementary techniques are used to characterize the 8CB thin films: surface pressure-area isotherm and Brewster angle microscopy (BAM).
View Article and Find Full Text PDFNanoscale Adv
July 2024
Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki P.O. Box 64 Helsinki FI-00014 Finland
Mixed phospholipid and glycolipid monolayers likely coat the surfaces of pressurised gas nanobubbles within the hydraulic systems of plants. The lipid coatings bond to water under negative pressure and are thus stretched out of equilibrium. In this work, we have used molecular dynamics simulations to produce trajectories of a biologically relevant mixed monolayer, pulled at mild negative pressures (-1.
View Article and Find Full Text PDFChem Phys Lipids
September 2024
Department of Physics, School of Natural Sciences, Shiv Nadar Institution of Eminence, NH 91, Tehsil Dadri, Uttar Pradesh 201214, India. Electronic address:
Tricyclic medicine such as amitriptyline (AMT) hydrochloride, initially developed to treat depression, is also used to treat neuropathic pain, anxiety disorder, and migraines. The mechanism of functioning of this type of drugs is ambiguous. Understanding the mechanism is important for designing new drug molecules with higher pharmacological efficiency.
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