ABSTRACT: BACKGROUND: Alpha 1- antitrypsin (alpha1AT) belongs to the superfamily of serpins and inhibits different proteases. alpha1AT protects the lung from cellular inflammatory enzymes. In the absence of alpha1AT, the degradation of lung tissue results to pulmonary complications. The pulmonary route is a potent noninvasive route for systemic and local ...

Attention has begun to focus on the pulmonary delivery of antifungal agents for invasive fungal infections as inhalation of the fungal spores is often the initial step in the pathogenesis of many of these infections, including invasive pulmonary aspergillosis (IPA). IPA in immunocompromised patients has high mortality rates despite current ...

Adsorption of phenanthrene on carbon nanotubes (CNTs) was examined in the presence of pulmonary surfactant (Curosurf) and its main components, dipalmitoyl phosphatidylcholine (DPPC) and bovine serum albumin (BSA). A passive-dosing method based on the equilibrium partitioning from a preloaded polymer was successfully employed to measure phenanthrene binding and speciation at ...

The pulmonary route represents one of the most important portals of entry for nanoparticles into the body. However, the in vivo interactions of nanoparticles with biomolecules of the lung have not been sufficiently studied. Here, using an established mouse model of pharyngeal aspiration of single-walled carbon nanotubes (SWCNT), we recovered ...

PURPOSE: To investigate DSPE-PEG(2000)-based micellar formulations of salmon calcitonin (sCT) for their ability to improve pulmonary delivery. METHODS: Micelles were characterised by DLS and (31)P-NMR spectroscopy. Stability against sCT degrading peptidases, trypsin, α-chymotrypsin and neutrophil elastase as well as their influence on transepithelial absorption was investigated in vitro. In vivo ...

The pulmonary surfactant film spanning the inner alveolar surface prevents alveolar collapse during the end-exhalation and reduces the work of breathing. Nanoparticles (NPs) present in the atmosphere or nano-carriers targeted through the pulmonary route for the medical purposes challenge this biological barrier. During interaction with or passage of NPs through ...

The behavior in the stochastic collapse of lipid monolayers of a 7:3 mixture of DPPC (dipalmitoylphosphatidylcholine) and POPG (palmitoyloleoylphosphatidylglycerol), a model system of pulmonary surfactant assembly, was studied using Langmuir isotherms, fluorescence microscopy, and atomic force microscopy. The monolayers at the air-water interface appeared to be phase separated under compression ...

The larvicidal activity of 11 Myrtaceae essential oils and their constituents was evaluated against Aedes aegypti L. Of the 11, Melaleuca linariifolia Sm., Melaleuca dissitiflora F. Muell., Melaleuca quinquenervia (Cav.) S. T. Blake, and Eucalyptus globulus Labill oils at 0.1 mg/ml exhibited > or = 80% larval mortality. At this ...

The viscosity profiles of four different IgG(1) molecules were studied as a function of concentration at pH 6.0. At high concentrations, MAb-H and -A showed significantly higher viscosities as compared to MAb-G and -E. Zeta Potential (ξ) measurements showed that all the IgG(1) molecules carried a net positive charge at ...

We present strong evidence for the oxidation of conjugated polymers in the formation of conjugated polymer dots (CPdots) using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Although recent studies show that folding of the polymer chain into a compact 3D structure is involved in the formation of these nanoparticles, ...

The complex formation between β-lactoglobulin and pectins of varying overall charge and local charge density were investigated. Isothermal titration calorimetry experiments were carried out to determine the enthalpic contribution to the complex formation at pH 4.25 and various ionic strengths. Complex formation was found to be an exothermic process for ...

Using micro-Raman spectroscopy and scanning tunneling microscopy, we study the relationship between structural distortion and electrical hole doping of graphene on a silicon dioxide substrate. The observed upshift of the Raman G band represents charge doping and not compressive strain. Two independent factors control the doping: (1) the degree of ...

The reentrant condensation of 21-bp oligonucleotide in the presence of spermidine was investigated by laser light scattering and capillary electrophoresis. 21-bp oligonucleotide showed a bimodal distribution in 1 × TE buffer, with the slow mode being the characteristic diffusion of polyelectrolyte in solution without enough salt. At the fixed spermidine ...

The effect of traces of water on the relative strengths of acids (ΔpK(a) values) in acetonitrile was quantitatively evaluated experimentally and computationally (COSMO-RS). Water affects first of all the anions by selective solvation. Expectedly, the more localized is the charge in acid anions the higher is the effect of water. ...

Hydrophobic homopolymers collapse into globular structures in water driven by hydrophobic interactions. Here we employ extensive molecular dynamics simulations to study the collapse of heteropolymers containing one or two pairs of oppositely charged monomers. We show that charging a pair of monomers can dramatically alter the most stable conformations from ...

This article reports patterned transfer of charge between conformal material interfaces through a concept referred to as nanocontact electrification. Nanocontacts of different size and shape are formed between surface-functionalized polydimethylsiloxane (PDMS) stamps and other dielectric materials (PMMA, SiO(2)). Forced delamination and cleavage of the interface yields a well-defined charge pattern ...

Crosslinked polymers with hydrolytically cleavable linkages are highly interesting materials for the design of biodegradable drug carriers. The aim of this study was to investigate if nanoparticles made of such polymers have the potential to be used also for intracellular drug delivery. PEGylated nanoparticles were prepared by copolymerization of methacrylic ...

We developed a new model for the water molecule which contains only three Gaussian charges. Using the gas-phase geometry the dipole moment of the molecule matches, the quadrupole moment closely approximates the experimental values. The negative charge is connected by a harmonic spring to its gas-phase position. The polarized state ...

Various particle manipulations including enrichment, movement, trapping, separation, and focusing by floating electrodes attached to the bottom wall of a straight microchannel under an imposed DC electric field have been experimentally demonstrated. In contrast to a dielectric microchannel possessing a nearly uniform surface charge (or ζ potential), the metal strip ...

The electrostatic stabilization of colloidal dispersions is usually considered the domain of polar media only because of the high energetic cost associated with introducing electric charge in nonpolar environments. Nevertheless, some surfactants referred to as "charge control agents" are known to raise the conductivity of liquids with low electric permittivity ...

Two different gibbsites, one commercial and one synthesized according to a frequently applied recipe, were studied in an interlaboratory attempt to gain insight into the origin of widely differing reports on gibbsite acid-base surface properties. In addition to a thorough characterization of the two solids, several methods relevant to the ...

Dependence of surface potential (electrostatic potential at the inner Helmholtz plane, Ψ(0)) at the silver bromide aqueous electrolyte interface was measured as a function of the activities of Br(-) and Ag(+) by using a single crystal silver bromide electrode (SCr-AgBr). Absolute values of surface potentials were obtained from electrode potentials ...

Repulsive electrostatic double-layer forces are responsible for the stabilization of charged colloidal particles in the presence of adsorbed polyelectrolytes of opposite and high line charge densities. This mechanism is revealed by studies of electrophoretic mobility and colloidal stability performed with dynamic light scattering as a function of the polyelectrolyte dose ...

Purely ionic interactions in natural and synthetic macromolecules involve the mutual interaction of fixed charges and their interaction with mobile ions. Such charge-dependent interactions lead to well-documented effects, including chain expansion of polyelectrolytes, globularization of polyampholytes, distributions of mobile ions according to charge screening, or ion condensation models. A variety ...

Gray-Weale and Beattie's rationalization of the negative charge observed on the surface of water in terms of accumulation of OH(-) is based on the supposedly uniquely large dielectric decrement of hydroxide solutions [A. Gray-Weale and J. K. Beattie, Phys. Chem. Chem. Phys., 2009, 11, 10994]. We challenge this rationalization and ...

The interaction between dengue virus particles (DENV), sedimentation hemagglutinin particles (SHA), dengue virus envelope protein (Eprot), and solid surfaces was investigated by means of ellipsometry and atomic force microscopy (AFM). The surfaces chosen are bare Si/SiO2 wafers and Si/SiO2 wafers covered with concanavalin A (ConA), jacalin (Jac), polystyrene (PS), or ...

The solution properties of a novel pH sensitive and intrinsically hydrophobic polyelectrolyte poly(sodium(sulfamate-carboxylate)isoprene) (SCPI) were investigated by means of dynamic, static, and electrophoretic light-scattering and fluorescence spectroscopy techniques. Because of the pH dependent charge density of the polyelectrolyte chain, the dynamics and structure of the solution were studied at both ...

DFT-GGA calculations, enhanced to include effects of dispersion, are used to investigate the adsorption process of corannulene on a Cu(111) surface. In accord with experiments, we consider the dynamics of corannulene approaching the surface in a tilted fashion, concave side-up, enabling interactions between one of the six-membered rings and the ...

The points of zero charge (PZC) and isoelectric points (IEP) from the recent literature are discussed. This study is an update of the previous compilation [M. Kosmulski, Surface Charging and Points of Zero Charge, CRC, Boca Raton, FL, 2009] and of its previous update [J. Colloid Interface Sci. 337 (2009) ...

Experimental excess enthalpies of ionic liquid and water mixtures in combination with calculated CHELPG atomic charges were used to investigate the interactions between the species in solution. The excess enthalpies of ionic liquids in water were obtained by calorimetry, using a Setaram C80 calorimeter, including temperatures from (313.15 to 348.15) ...

Coulomb repulsion due to the surface charge on semi-conductor nanorods works against the dipole-dipole attraction that tends to direct the nanorods to self-assemble; the nature of this self-assembly for CdSe nanorods can be thus altered by pyridine washing, which charges the rods surface--thereby allowing the Coulomb repulsion to tailor the ...

Aqueous nanodroplets that contain excess charge carriers play a central role during the electrospray ionization (ESI) process. An interesting question concerns the charge carrier location in these systems. In analogy to the behavior of metallic conductors, it is often assumed that excess ions are confined to a thin layer on ...

This work aimed to obtain information on the water dispersibility of a 1:1 stoichiometric polyelectrolyte nanogel complex (SPENC). We synthesized a cationic polyelectrolyte nanogel (CPENG) composed of a cross-linked copolymer of 1-vinylimidazole and N-isopropylacrylamide. SPENC was then prepared at 25 degrees C from the mixing of equimolar amounts (based on ...

Electrical manipulation of charged droplet has attracted much attention owing to its potential applications in various industrial and laboratorial units. In this paper, deformation and electrical charging of large conductive water drops on the electrode surface studied experimentally. Moreover, the quality of drop motion and deformation near the electrode surface ...

Negative electrophoretic mobilities of oil in water are widely interpreted in terms of adsorption of hydroxide leading to negative surface charge. Challenging this traditional view, an increasing body of evidence suggests surface depletion of hydroxide and surface accumulation of hydronium leading to a positive surface charge. We present results from ...

Chemical and biological sensors based on graphene field-effect transistors (G-FETs) were investigated. A single-layer of graphene was prepared by mechanical cleavage of natural graphite. The G-FETs were driven by a reference-gate operating in buffer solution, and exhibited very good transport characteristics. The G-FETs detected the pH value of the solution ...

Polymeric hollow spheres can be tailored as efficient carriers of various therapeutic molecules due to their tunable properties. However, the entry of these synthetic vehicles into cells, their cell viability and blood compatibility depend on their physical and chemical properties e.g. size, surface charge. Herein, we report the effect of ...

The present work examines the effect of alkyl-silane treatment on the charging of colloids in apolar solvent using two otherwise identical 250 nm diameter, spherical silica particles, one with untreated surface and the other treated with hexadecyltrimethoxysilane (C16), dispersed in an apolar isoparaffin solvent (Isopar-L) containing one of three oil-soluble ...

Electrostatic interactions may promote or abate polyelectrolyte adsorption onto a charged surface depending on a number of interrelated factors including the surface and polymer charge densities, the salt concentration, and nonelectrostatic interactions such as van der Waals and hydrophobic forces. Even without the nonelectrostatic interactions, the electrostatic behavior of polyelectrolyte ...

Self-assembling icosahedral protein cages have potentially useful physical and chemical characteristics for a variety of nanotechnology applications, ranging from therapeutic or diagnostic vectors to building blocks for hierarchical materials. For application-specific functional control of protein cage assemblies, a deeper understanding of the interaction between the protein cage and its payload ...

High cationic charge densities in polymeric vectors result in tight DNA condensation, leading to small highly positively charged polyplexes which show generally high cellular uptake in vitro. However, high cationic charge densities also introduce membrane-disruptive properties to the polymers, thereby frequently causing high cytotoxities. We previously developed poly(amido amine)s with ...

The electrostatic interaction of charged spherical colloids trapped at an interface between a nonpolar medium and water is analyzed. Complementary experiments provide consistent values for the dipole-dipole interaction potential over a wide range of interparticle distances. After accounting for the contribution from the compact inner double layer arising from the ...

The interaction of a photodegradable surfactant (PS, 4-hexylphenylazosulfonate, C(6)PAS) with microgels (MGs) of poly(2-vinyl pyridine) (MGA) in the protonated state (pH 3) has been investigated. Electrophoretic mobility measurements confirm that negatively charged PS interacts with positively charged MGA to form mixed PS-MG complexes. This was sensed by a decrease in ...

Reaction-limited aggregation of soft elastomer particles has been studied with specific attention to the fate of surface charges during coalescence. The employed system is an aqueous dispersion of fluoroelastomer particles, which are known to coalesce completely at 70 degrees C. In contrast to diffusion-limited conditions, under reaction-limited conditions the stability ...

We study the effective interaction between differently charged polyelectrolyte-colloid complexes in electrolyte solutions via Monte Carlo simulations. These complexes are formed when short and flexible polyelectrolyte chains adsorb onto oppositely charged colloidal spheres, dispersed in an electrolyte solution. In our simulations the bending energy between adjacent monomers is small compared ...

An understanding of the electrostatic interactions that exist between charged particles of dielectric materials has applications that span much of chemistry, physics, biology, and engineering. Areas of interest include cloud formation, ink-jet printing, and the stability of emulsions. A general solution to the problem of calculating electrostatic interactions between charged ...

Metal surfaces in contact with water, surfactants and biopolymers experience attractive polarization owing to induced charges. This fundamental physical interaction complements stronger epitaxial and covalent surface interactions and remains difficult to measure experimentally. We present a first step to quantify polarization on even gold (Au) surfaces in contact with water ...

In this study, using the iterative finite difference method, the effect of an irregular condition at boundary, the surface undulation, in a charged surface system on the two dimensional electrokinetic flow near the surface is analyzed. The results reveal that, for the electrokinetic flow, the undulation of charged surface may ...

Measurements of ion distributions at a charged solid-liquid interface using X-ray standing waves (XSW) are presented. High energy synchrotron radiation (17.48 keV) is used to produce an XSW pattern inside a thin water film on a silicon wafer. The liquid phase is an aqueous solution containing Br and Rb ions. ...

Metal-containing polymer networks are widespread in biology, particularly for load-bearing exoskeletal biomaterials. Mytilus byssal cuticle is an especially interesting case containing moderate levels of Fe(3+) and cuticle protein-mussel foot protein-1 (mfp-1), which has a peculiar combination of high hardness and high extensibility. Mfp-1, containing 13 mol % of dopa (3, ...