The measurement of the boundary shape dependence of the entropic force from long polymers was attempted. The pyramidal cone-plate geometry was chosen. The polymer molecules were covalently bound to a well-defined Au patch at the apex of a pyramidal cantilever tip of the atomic force microscope (AFM). A smooth hydrophobic plate was used as the second boundary to confine the polymer molecules. The use of the hydrophobic plate allows neglect of polymer adhesion forces. The measurements were made in salt water solution to decrease the effect of electrostatic forces from any uncompensated charges on the boundary. As the functionalized AFM tip approaches the flat hydrophobic surface, the induced entropic forces were measured as a function of the separation distance. The measured force-distance curves are compared with a model of polymer-mediated entropic force between scale-free objects and the Alexander-de Gennes (AdG) theory for a polymer brush.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1088/1361-648X/aaf51a | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Molecular Insights into the Adsorption of Deposit Control Additives from Hydrocarbon Fuels.
Langmuir
January 2025
Department of Mechanical Engineering, Imperial College London, South Kensington Campus, London SW7 2BX, United Kingdom.
Engine deposits can reduce performance and increase emissions, particularly for modern direct-injection fuel delivery systems. Surfactants known as deposit control additives (DCAs) adsorb and self-assemble on the surface of deposit precursors to keep them suspended in the fuel. Here, we show how molecular simulations can be used to virtually screen the ability of surfactants to bind to polyaromatic hydrocarbons, comprising a major class of carbonaceous deposits.
View Article and Find Full Text PDFπ-π stacking interactions in tryptophan-lumiflavin-tyrosine: a structural model for riboflavin insertion into riboflavin-binding protein.
J Mol Model
January 2025
Department of Natural Sciences, University of Michigan-Dearborn, Dearborn, MI, 48128, USA.
Context: Riboflavin (RF), also known as B2 vitamin, is the precursor to flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), two co-enzymes involved in many electron transport processes. Interactions of the isoalloxazine ring, common to all three compounds, are of great interest due to their biological function in flavoproteins and relevance in the transport by the carrier protein leading to development of drug delivery strategies and non-invasive diagnostics techniques. Based on protein crystallographic data, a computational investigation of the interactions in the complexes between lumiflavin, a model compound, and aromatic amino acids, tyrosine and tryptophan, was pursued with the goal of characterizing noncovalent interactions.
View Article and Find Full Text PDFEnd-Point Affinity Estimation of Galectin Ligands by Classical and Semiempirical Quantum Mechanical Potentials.
J Chem Inf Model
January 2025
Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Gilead Sciences & IOCB Research Centre, Flemingovo nám. 2, 166 10 Prague, Czech Republic.
The use of quantum mechanical potentials in protein-ligand affinity prediction is becoming increasingly feasible with growing computational power. To move forward, validation of such potentials on real-world challenges is necessary. To this end, we have collated an extensive set of over a thousand galectin inhibitors with known affinities and docked them into galectin-3.
View Article and Find Full Text PDFEntropy generation and water conservation in the mammalian nephron.
J Comp Physiol B
January 2025
Departamento de Fisiologia, Instituto de Biociências da Universidade de São Paulo, São Paulo, Brazil.
During the transition from fresh waters to terrestrial habitats, significant adaptive changes occurred in kidney function of vertebrates to cope with varying osmotic challenges. We investigated the mechanisms driving water conservation in the mammalian nephron, focusing on the relative contributions of active ion transport and Starling forces. We constructed a thermodynamic model to estimate the entropy generation associated with different processes within the nephron, and analyzed their relative importance in urine formation.
View Article and Find Full Text PDFInfluence of the glycocalyx on the size and mechanical properties of plasma membrane-derived vesicles.
Soft Matter
January 2025
Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY 14853, USA.
Recent studies have reported that the overexpression of MUC1 glycoproteins on cell surfaces changes the morphology of cell plasma membranes and increases the blebbing of vesicles from them, supporting the hypothesis that entropic forces exerted by MUC1 change the spontaneous curvature of cell membranes. However, how MUC1 is incorporated into and influences the size and biophysical properties of plasma-membrane-blebbed vesicles is not understood. Here we report single-vesicle-level characterization of giant plasma membrane vesicles (GPMVs) derived from cells overexpressing MUC1, revealing a 40× variation in MUC1 density between GPMVs from a single preparation and a strong correlation between GPMV size and MUC1 density.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!