Hypothesis: Amphiphilic molecules spontaneously adsorb to fluid polar-nonpolar interfaces. The timescale of such adsorption depends on the molecular size and structure of the solute. This process should be accompanied by a power heat exchange that could be detected by commercial isothermal calorimeters.
Experiments: Air is injected in the bulk of different aqueous solutions contained in the sample cell of an isothermal titration calorimeter. The formation of the resulting bubbles leads to a liquid/air interface to which the solute molecules spontaneously adsorb. Continuous injection experiments to produce multiple bubbles as well as experiments with static bubbles stand from the capillary tip, aiming to observe slow adsorption processes, were performed.
Findings: The power associated with the formation, growth and release of air bubbles in different liquids was measured. Different independent contributions that can be associated to the pressure change in the gas phase, the evaporation-condensation of the solvent, the increase of interfacial area, the change in the heat capacity of the sample cell content, and the release of the bubble were observed. The periodic pattern produced by the continuous injection of air at a constant rate is used to determine the surface tension of different liquids, including solutions of different molecules and (bio)macromolecules.
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http://dx.doi.org/10.1016/j.jcis.2021.03.098 | DOI Listing |
J Colloid Interface Sci
January 2025
College of Chemistry and Environment, Southwest Minzu University, Chengdu 610041 China. Electronic address:
We developed antibiotic-based micelles with bone-targeting and charge-switchable properties (P-CASMs) for treating infectious osteomyelitis. The amphiphilic molecules are formed by combining ciprofloxacin (CIP) with ligand 1 through a mild salifying reaction, and spontaneously self-assemble into antibiotic-based micelles (ASMs) in aqueous solution. Acrylate groups on ligand 1 enable cross-linking of ASMs with pentaerythritol tetra(mercaptopropionate) via a click reaction, forming pH-sensitive cross-linked micelles (CASMs).
View Article and Find Full Text PDFJ Cereb Blood Flow Metab
January 2025
KG Jebsen Centre for Brain Fluid Research, University of Oslo, Oslo, Norway.
A potential two-way passage of cells and substances between the brain and skull bone marrow may open for new insights into neurological disease. The arachnoid membrane was traditionally considered to restrict cells and larger molecules in CSF from entering the dura and bone marrow directly. However, new data on exchange between brain and skull bone marrow have recently emerged.
View Article and Find Full Text PDFJ Mol Model
January 2025
Processes, Materials and Environment Laboratory (LPME), Faculty of Sciences and Technology of Fez, Sidi Mohamed Ben Abdellah University, B.P. 2202, Fez, Morocco.
Context: Natural fluorapatite (FAP) has been investigated as an adsorbent for the removal of dyes such as methylene blue (MB) and crystal violet (CV) from aqueous solutions. Effective dye removal is crucial for water treatment, particularly for industrial wastewater containing toxic dyes. FAP, a naturally abundant material, was characterized using XRD, FTIR, and SEM analysis.
View Article and Find Full Text PDFMolecules
January 2025
Dipartimento di Chimica, Università di Pavia, Via Taramelli 12, 27100 Pavia, Italy.
Spontaneous cleavage reactions normally occur in vivo on amino acid peptide backbones, leading to fragmentation products that can have different physiological roles and toxicity, particularly when the substrate of the hydrolytic processes are neuronal peptides and proteins highly related to neurodegeneration. We report a hydrolytic study performed with the HPLC-MS technique at different temperatures (4 °C and 37 °C) on peptide fragments of different neuronal proteins (amyloid-β, tau, and α-synuclein) in physiological conditions in the presence of Cu and Zn ions, two metal ions found at millimolar concentrations in amyloid plaques. The coordination of these metal ions with these peptides significantly protects their backbones toward hydrolytic degradation, preserving the entire sequences over two weeks in solution, while the free peptides in the same buffer are fully fragmented after the same or even shorter incubation period.
View Article and Find Full Text PDFMolecules
January 2025
LSMTM, Laboratoire de Synthèse Macromoléculaire et Thio-organique Macromoléculaire, Faculty of Chemistry, University of Sciences and Technology Houari Boumediene USTHB, Algiers 16111, Algeria.
Effluents containing synthetic anionic dyes can pose a risk to ecosystems, and they must be treated before their release to the environment. Biosorption, a simple and effective process, may be a promising solution for treating these effluents. In this work, chitosan beads were crosslinked with epichlorohydrin to produce a highly stable and performant biosorbent to remove Brilliant Blue FCF dye.
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