Magneto-optical binding in the near field

In this paper we show analytically and numerically the formation of a near-field stable optical binding between two identical plasmonic particles, induced by an incident plane wave. The equilibrium binding distance is controlled by the angle between the polarization plane of the incoming field and the dimer axis, for which we have calculated an explicit formula. We have found that the condition to achieve stable binding depends on the particle’s dielectric function and happens near the frequency of the dipole plasmonic resonance. The binding stiffness of this stable attaching interaction is four orders of magnitude larger than the usual far-field optical binding and is formed orthogonal to the propagation direction of the incident beam (transverse binding). The binding distance can be further manipulated considering the magneto-optical effect and an equation relating the desired equilibrium distance with the required external magnetic field is obtained. Finally, the effect induced by the proposed binding method is tested using molecular dynamics simulations. Our study paves the way to achieve complete control of near-field binding forces between plasmonic nanoparticles.

Aggregation behavior and thermodynamic properties of the mixture of sodium carboxymethyl cellulose and cetyltrimethylammonium bromide in numerous temperatures and mixed solvents

Interaction of sodium carboxymethylcellulose (SCMC) with cetyltrimethylammonium bromide (CTAB; cationic in nature) in H2O and additives (alcohols and diols) media has been investigated using conductivity technique. The micellar parameters such as critical micelle concentration (cmc), fraction of counter ion binding (β), thermodynamic parameters, transfer properties, and enthalpy-entropy compensation parameters of CTAB + SCMC mixture have been assessed in water and aq. alcohols/diols media. One cmc value was achieved for CTAB + SCMC mixtures in the entire circumstances and the attendance of SCMC disfavors the CTAB micellization. The cmc values were obtained to be greater in alcohols and diols media compared to H2O medium. The cmc values also exhibit a dependency on the solvent composition and temperature variation. In all the cases, the ΔG 0 m values were achieved to be negative which signifying the spontaneous formation of micelles while the extent of spontaneity is decreased in alcohols and diols media. Both the ΔH 0 m and ΔS 0 m reveal that hydrophobic, ion-dipole as well as electrostatic interactions are the proposed binding forces between CTAB and SCMC. The compensation parameters (ΔH 0* m and T c ) are in decent agreement with the biological fluid.

Quantitative and bioinformatics integrated strategy to investigate the pharmacological mechanism of Ermiao Wan against eczema

BackgroundErmiao Wan (EMW) is used to treat eczema in China. However, its underlying pharmacological mechanisms against eczema remain unclear. MethodsIn this study, the components of EMW were quantitatively analyzed using HPLC. The role of the components, targets, and signaling pathways were predicted by network pharmacology. Moreover, molecular docking was used to verify the binding forces of the components with the target proteins. ResultsThe results showed that the established HPLC method is simple and reliable, and can be used for the simultaneous determination of seven components in EMW. Moreover, 57 primary causal targets of EMW against eczema were identified. Among them, 10 hub targets were identified, including EGFR, AKT1, STAT3, MMP9, ICAM1, MAPK8, JUN, MAPK1, and VCAM1. The potential signaling pathways involved in the effect of EMW against eczema were identified, including ErbB, estrogen, and Epstein-Barr virus infection. Furthermore, palmatine, chlorogenic acid, and jatrorrhizine from EMW were shown to bind to the identified targets. Accordingly, EGFR, AKT1, and PTGS2 had good binding forces with EMW components. ConclusionOur study revealed a possible pharmacological mechanism of EMW in treating eczema. This simple and effective method can help increase our understanding of the mechanisms of Chinese herbal formulations and further promote their research and development.

Differential Regulation of Bilastine Affinity for Human Histamine H1 Receptors by Lys 179 and Lys 191 via Its Binding Enthalpy and Entropy

Bilastine, a zwitterionic second-generation antihistamine containing a carboxyl group, has higher selectivity for H1 receptors than first-generation antihistamines. Ligand-receptor docking simulations have suggested that the electrostatic interaction between the carboxyl group of second-generation antihistamines and the amino group of Lys179ECL2 and Lys1915.39 of human H1 receptors might contribute to increased affinity of these antihistamines to H1 receptors. In this study, we evaluated the roles of Lys179ECL2 and Lys1915.39 in regulating the electrostatic and hydrophobic binding of bilastine to H1 receptors by thermodynamic analyses. The binding enthalpy and entropy of bilastine were estimated from the van ’t Hoff equation using the dissociation constants. These constants were obtained from the displacement curves against the binding of [3H] mepyramine to membrane preparations of Chinese hamster ovary cells expressing wild-type human H1 receptors and their Lys179ECL2 or Lys1915.39 mutants to alanine at various temperatures. We found that the binding of bilastine to wild-type H1 receptors occurred by enthalpy-dependent binding forces and, more dominantly, entropy-dependent binding forces. The mutation of Lys179ECL2 and Lys1915.39 to alanine reduced the affinity of bilastine to H1 receptors by reducing enthalpy- and entropy-dependent binding forces, respectively. These results suggest that Lys179ECL2 and Lys1915.39 differentially contribute to the increased binding affinity to bilastine via electrostatic and hydrophobic binding forces.

Interpenetrating Gels as Conducting/Adhering Matrices Enabling High-Performance Silicon Anodes

Three-dimensional (3D) conductive polymers are promising conductive matrices for electrode materials toward electrochemical energy storage. However, their fragile nature and weak binding forces with active materials could not guarantee long-term...

Cross-Kingdom Cell-to-Cell Interactions in Cariogenic Biofilm Initiation

Candida albicans is known to form polymicrobial biofilms with various Streptococcus spp., including mitis and mutans group streptococci. Streptococcus gordonii (mitis group) has been shown to bind avidly to C. albicans hyphae via direct cell-to-cell interaction, while the cariogenic pathogen Streptococcus mutans (mutans group) interacts with the fungal cells via extracellular glucans. However, the biophysical properties of these cross-kingdom interactions at the single-cell level during the early stage of biofilm formation remain understudied. Here, we examined the binding forces between S. mutans (or S. gordonii) and C. albicans in the presence and absence of in situ glucans on the fungal surface using single-cell atomic force microscopy and their influence on biofilm initiation and subsequent development under cariogenic conditions. The data show that S. gordonii binding force to the C. albicans surface is significantly higher than that of S. mutans to the fungal surface (~2-fold). However, S. mutans binding forces are dramatically enhanced when the C. albicans cell surface is locally coated with extracellular glucans (~6-fold vs. uncoated C. albicans), which vastly exceeds the forces between S. gordonii and C. albicans. The enhanced binding affinity of S. mutans to glucan-coated C. albicans resulted in a larger structure during early biofilm initiation compared to S. gordonii–C. albicans biofilms. Ultimately, this resulted in S. mutans dominance composition in the 3-species biofilm model under cariogenic conditions. This study provides a novel biophysical aspect of Candida-streptococcal interaction whereby extracellular glucans may selectively favor S. mutans binding interactions with C. albicans during cariogenic biofilm development.