Assembly of graphene oxide reduced graphene oxide in a phospholipid monolayer at air-water interfaces.

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.

Selective assembly and insertion of ubiquicidin antimicrobial peptide in lipid monolayers.

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.

Modulating a model membrane of sphingomyelin by a tricyclic antidepressant drug.

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.

Role of Cholesterol in Interaction of Ionic Liquids with Model Lipid Membranes and Associated Permeability.

In this work, we explored how the amount of cholesterol in the lipid membrane composed of phosphatidylcholine (POPC) or phosphatidylglycerol (POPG) affects the interaction with 1-dodecyl-3-methylimidazolium bromide ([CMIM]Br) ionic liquids using various biophysical techniques. On interacting with the membrane, [CMIM]Br leads to enhanced membrane permeability and induces membrane fusion, leading to an increase in vesicle size. The H-based solid-state NMR investigations of cholesterol-containing lipid membranes reveal that [CMIM]Br decreases the lipid chain order parameters and counteracts the lipid condensation effect of cholesterol to some extent.

Graphene-Based Nanomaterials and Their Interactions with Lipid Membranes.

Graphene-based nanomaterials (GNMs) have captured increasing attention in the recent advancement of materials science and nanotechnology owing to their excellent physicochemical properties. Despite having unquestionable advances, the application of GNMs in biological and medical sciences is still limited due to the lack of knowledge and precise control over their interaction with the biological milieu. The cellular membrane is the first barrier with which GNMs interact before entering a cell.

Ionic Liquid-Induced Assembly of DNA at Air-Water Interface.

DNA nanotechnology is the future of many products in the pharmaceutical and cosmetic industries. Self-assembly of this negatively charged biopolymer at surfaces and interfaces is an essential step to elaborate its field of applications. In this study, the ionic liquid (IL) monolayer-assisted self-assembly of DNA macromolecules at the air-water interface has been closely monitored by employing various quantitative techniques, namely, surface pressure-area (π-) isotherms, surface potential, interfacial rheology, and X-ray reflectivity (XRR).

Effects of ionic liquids on biomembranes: A review on recent biophysical studies.

Ionic liquids (ILs) have been emerged as a versatile class of compounds that can be easily tuned to achieve desirable properties for various applications. The ability of ILs to interact with biomembranes has attracted significant interest, as they have been shown to modulate membrane properties in ways that may have implications for various biological processes. This review provides an overview of recent studies that have investigated the interaction between ILs and biomembranes.

Cholesterol-Controlled Interaction of Ionic Liquids with Model Cellular Membranes.

While ionic liquids (ILs) are considered as prospective ingredients of new antimicrobial agents, it is important to understand the adverse effects of these molecules on human cells. Since cholesterol is the essential component of a human cell membrane, in the present study, the effect of an imidazolium-based IL has been investigated on the model membrane in the presence of cholesterol. The area per sphingomyelin lipid is found to reduce in the presence of the IL, which is quantified by the area-surface pressure isotherm of the lipid monolayer formed at the air-water interface.

Temperature-dependent anomalous viscosity of aqueous solutions of imidazolium-based ionic liquids.

Ionic liquids (ILs) are organic salts with a low melting point compared to inorganic salts. Room temperature ILs are of great importance for their widespread potential industrial applications. The viscosity of aqueous solutions of two imidazolium-based ILs, investigated in the present study, exhibits an anomalous temperature variation.

Shear-induced phase transition in the aqueous solution of an imidazolium-based ionic liquid.

An ionic liquid (IL) is a salt in the liquid state that consists of a cation and an anion, one of which possesses an organic component. Because of their non-volatile property, these solvents have a high recovery rate, and, hence, they are considered as environment-friendly green solvents. It is necessary to study the detailed physicochemical properties of these liquids for designing and processing techniques and find suitable operating conditions for IL-based systems.

Discerning perturbed assembly of lipids in a model membrane in presence of violacein: Effects of membrane hydrophobicity.

For the lack of effective antibiotics towards antibiotic resisting bacteria, it is required to discover new antibiotics and to understand their antimicrobial mechanism. Violacein is a violet pigment found in several gram-negative bacteria possessing antimicrobial properties to gram-positive bacteria. This present article investigates the insertion ability of this molecule into a model membrane composed of zwitterionic phospholipids.

How 1,-Bis(3-alkylimidazolium-1-yl) Alkane Interacts with the Phospholipid Membrane and Impacts the Toxicity of Dicationic Ionic Liquids.

Ionic liquids based on doubly charged cations, often termed dicationic ionic liquids (DILs), offer robust physicochemical properties and low toxicity than conventional monocationic ionic liquids. In this design-based study, we used solid-state NMR spectroscopy to provide the interaction mechanism of two DILs, 1,-bis(3-alkylimidazolium-1-yl) alkane dibromide ([C(CIM)]·2Br, = 1, 6), with 1-palmitoyl-2-oleoyl--glycero-3-phosphocholine (POPC) and 1-palmitoyl-2-oleoyl--glycero-3-phospho-(1'--glycerol) (POPG) phospholipid membranes, to explain the low toxicity of DILs toward HeLa, , , and cell lines. Dications with a short linker and long terminal chains cause substantial perturbation to the bilayer structure, making them more membrane permeabilizing, as shown by fluorescence-based dye leakage assays.

Thermodynamics and In-Plane Viscoelasticity of Anionic Phospholipid Membranes Modulated by an Ionic Liquid.

This article presents the effects of an imidazolium-based ionic liquid (IL) on the thermodynamics and in-plane viscoelastic properties of model membranes of anionic phospholipids. The negative Zeta potential of multilamellar vesicles of 14 carbon lipid 1,2-dimyristoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (DMPG) is observed to reduce due to the presence of few mole % of an IL 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF]). The effect was found to be stronger on enhancing the chain length of the lipid.

1,3 Dialkylated Imidazolium Ionic Liquid Causes Interdigitated Domains in a Phospholipid Membrane.

Amphiphilic imidazolium-based ionic liquids (ILs) have proven their efficacy in altering the membrane integrity and dynamics. The present article investigates the phase-separated domains in a 1,2-dipalmitoyl--glycero-3-phosphocholine (DPPC) membrane induced by 1,3 dialkylated imidazolium IL. Isotherm measurements on DPPC monolayers formed at the air-water interface have shown a decrease in the mean molecular area with the addition of this IL.

Bioinspired micro/nano structured aluminum with multifaceted applications.

Inspired by many biological systems such as lotus leaves, insect wings and rose petals, great attention has been devoted to the study and fabrication of artificial superhydrophobic surfaces with multiple functionalities. In the present study, a simple and ecological synthesis route has been employed for large scale fabrication of self-assembled, sustainable nanostructures on unprocessed and micro imprinted aluminum surfaces named 'Nano' and 'Hierarchy'. The processed samples show extreme wettability ranging from superhydrophilicity to superhydrophobicity depending on post-processing conditions.

Partitioning of a Hybrid Lipid in Domains of Saturated and Unsaturated Lipids in a Model Cellular Membrane.

The cellular membranes are composed of hundreds of components such as lipids, proteins, and sterols that are chemically and physically distinct from each other. The lipid-lipid and lipid-protein interactions form domains in this membrane, which play vital roles in membrane physiology. The hybrid lipids (HLs) with one saturated and one unsaturated chain can control the shape and size of these domains, ensuring the thermodynamic stability of a membrane.

Self-Assembly of Graphene Oxide Nanoflakes in a Lipid Monolayer at the Air-Water Interface.

The graphene family, especially graphene oxide (GO), has captured increasing prospects in the biomedical field due to its excellent physicochemical properties. Understanding the health and environmental impact of GO is of great importance for guiding future applications. Although their interactions with living organisms are omnipresent, the exact molecular mechanism is yet to be established.

Rare earth and financial markets: Dynamics of return and volatility connectedness around the COVID-19 outbreak.

This study examines the return and volatility connectedness between the rare earth stock market and clean energy markets, world equity, base metals, gold, and crude oil. Using daily data from September 21, 2010 to August 28, 2020, a time-varying parameter vector autoregression (TVP-VAR) approach to connectedness is applied to uncover the dynamics of connectedness during the entire period and the COVID-19 pandemic period. Volatility connectedness is generally stronger than return connectedness.

Interaction of cyclotide Kalata B1 protein with model cellular membranes of varied electrostatics.

A uni-molecular layer of lipids at air-water interface mimicking one of the leaflets of the cellular membrane provides a simple model to understand the interaction of any foreign molecules with the membrane. Here, the interactions of protein Kalata B1 (KB1) of cyclotide family with the phospholipids 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-dipalmitoyl-sn-glycero-3-phospho-rac-(1-glycerol) sodium salt (DPPG), and 1,2-distearoyl-sn-glycero-3-ethylphosphocholine chloride salt (DSEPC) have been investigated. The addition of KB1 induces a change in pressure of the lipid monolayers.

Discerning perturbed assembly of lipids in a model membrane in presence of violacein.

Violacein is a naturally found pigment that is used by some gram negative bacteria to defend themselves from various gram positive bacteria. As a result, this molecule has caught attention for its potential biomedical applications and has already shown promising outcomes as an antiviral, an antibacterial, and an anti-tumor agent. Understanding the interaction of this molecule with a cellular membrane is an essential step to extend its use in the pharmaceutical paradigm.

Thermodynamics and structure of model bio-membrane of liver lipids in presence of imidazolium-based ionic liquids.

Ionic liquids (ILs) are the attractions of researchers today due to their vast area of potential applications. For biomedical uses, it becomes essential to understand their interactions with cellular membrane. Here, the membrane is mimicked with lipid bilayer and monolayer composed of liver lipids extract.

Ionic Liquid-Induced Phase-Separated Domains in Lipid Multilayers Probed by X-ray Scattering Studies.

A cellular membrane, primarily a lipid bilayer, surrounds the internal components of a biological cell from the external components. This self-assembled bilayer is known to be perturbed by ionic liquids (ILs) causing malfunctioning of a cellular organism. In the present study, surface-sensitive X-ray scattering techniques have been employed to understand this structural perturbation in a lipid multilayer system formed by a zwitterionic phospholipid, 1,2-dipalmitoyl--glycero-3-phosphocholine.

Enhanced Microscopic Dynamics of a Liver Lipid Membrane in the Presence of an Ionic Liquid.

Ionic liquids (ILs) are an important class of emerging compounds, owing to their widespread industrial applications in high-performance lubricants for food and cellulose processing, despite their toxicity to living organisms. It is believed that this toxicity is related to their actions on the cellular membrane. Hence, it is vital to understand the interaction of ILs with cell membranes.

Relating the physical properties of aqueous solutions of ionic liquids with their chemical structures.

The physical properties of an aqueous solution of a macromolecule primarily depend on its chemical structure and the mesoscopic aggregates formed by many of such molecules. Ionic liquids (ILs) are the macromolecules that have caught significant research interests for their enormous industrial and biomedical applications. In the present paper, the physical properties, such as density, viscosity, ionic conductivity of aqueous solutions of various ILs, have been investigated.