Search results for "DYNAMIC LIGHT SCATTERING"
showing 10 items of 211 documents
Self-assembly of programmed building blocks into structurally uniform dendrimers.
2005
Selective and independent dimerization of tri- and tetraurea derivatives was used to build up dendritic assemblies which are uniform in size and structure. Dendrimers with the total molecular masses of about 25 000 g/mol were obtained. The existence of uniform assemblies was proved by 1H and 1H DOSY NMR experiments and also by dynamic light scattering.
Self-assembling of poly(aspartic acid) with bovine serum albumin in aqueous solutions
2016
Abstract Macromolecular co-assemblies built up in aqueous solutions, by using a linear polypeptide, poly(aspartic acid) (PAS), and a globular protein, bovine serum albumin (BSA), have been studied. The main interest was to identify the optimum conditions for an interpenetrated complex formation in order to design materials suitable for biomedical applications, such as drug delivery systems. BSA surface possesses several amino- and carboxylic groups available for covalent modification, and/or bioactive substances attachment. In the present study, mixtures between PAS and BSA were investigated at 37 °C in dilute aqueous solution by viscometry, dynamic light scattering and zeta potential deter…
Organic salts and aromatic substrates in two-component gel phase formation: the study of properties and release processes
2015
To identify gel phases able to act as confined reaction media or materials for the removal of organic pollutants, we studied two-component gel phases formed by naphthalenedisulfonate diimidazolium salts in the presence of some organic guests, in 1-propanol solution. Guests differing in π-surface area, bulkiness and electronic properties were taken into account. Soft materials obtained were investigated for their thermal stability, self-repairing ability and morphology. Furthermore, two-component gel phase formation was studied using resonance light scattering (RLS) measurements. Guest release processes from the gel phase were also studied. These processes were monitored as a function of tim…
Multifunctional superparamagnetic MnO@SiO2 core/shell nanoparticles and their application for optical and magnetic resonance imaging
2012
Highly biocompatible multifunctional nanocomposites consisting of monodisperse manganese oxide nanoparticles with luminescent silica shells were synthesized by a combination of w/o-microemulsion techniques and common sol–gel procedures. The nanoparticles were characterized by TEM analysis, powder XRD, SQUID magnetometry, FT-IR, UV/vis and fluorescence spectroscopy and dynamic light scattering. Due to the presence of hydrophilic poly(ethylene glycol) (PEG) chains on the SiO2 surface, the nanocomposites are highly soluble and stable in various aqueous solutions, including physiological saline, buffer solutions and human blood serum. The average number of surface amino groups available for lig…
Structure and biological evaluation of amino-functionalized PVP nanogels for fast cellular internalization
2013
Abstract Aminopropyl methacrylamide chloride-graft-poly(N-vinyl pyrrolidone) nanogels (NGs) were designed to exploit the favorable properties of poly(N-vinyl pyrrolidone) (PVP), such as its high affinity to water and complexation ability of ions, molecules and macromolecules, with the availability of primary amino groups for bioconjugation reactions. A thorough structural characterization of the nanoscalar networks was performed via 1 H NMR and solid state 13 C NMR spectroscopies, while solid state NMR relaxation time measurements completed the NGs description in terms of polymer network density. Information on the hydrodynamic size and surface charge densities were sought via dynamic light…
Biogenic iron-silver nanoparticles inhibit bacterial biofilm formation due to Ag+ release as determined by a novel phycoerythrin-based assay
2020
Silver nanoparticles (Ag-NPs) can be considered as a cost-effective alternative to antibiotics. In the presence of Fe(III)-citrate and Ag+, Klebsiella oxytoca DSM 29614 produces biogenic Ag-NPs embedded in its peculiar exopolysaccharide (EPS). K. oxytoca DSM 29614 was cultivated in a defined growth medium–containing citrate (as sole carbon source) and supplemented with Ag+ and either low or high Fe(III) concentration. As inferred from elemental analysis, transmission and scanning electron microscopy, Fourier transform infrared spectrometry and dynamic light scattering, Ag-EPS NPs were produced in both conditions and contained also Fe. The production yield of high-Fe/Ag-EPS NPs was 12 times …
Orthogonal functionalisation of upconverting NaYF4 nanocrystals.
2013
A simple and straightforward method for the orthogonal functionalisation of upconverting NaYF4 nanocrystals (UCNCs)-doped withYb(3+) and Er(3+)-based on N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide/N-hydroxysuccinimide (EDC/NHS) selective reactions between two dyes and two different reactive groups present at the periphery of the upconverting nanocrystals is reported. Organic-soluble UCNCs of 10 and 50 nm in size are encapsulated efficiently in a 1:1 mixture of two commercial 3000 Da poly(ethylene glycol) derivatives with two different reactive groups (amino and carboxylic groups). The water-dispersible UCNCs are non-cytotoxic, stable in the physiological environment, and present free ami…
Solid lipid nanoparticles from amphiphilic calixpyrroles
2016
Abstract Hypothesis Macrocyclic amphiphiles form interesting self-assembling structures, including solid lipid nanoparticles, which have potential applications in drug encapsulation. Aryl-extended calixpyrroles, which act as anion binding hosts, are expected to form solid lipid nanoparticles, even though the alkyl chains have unusual perpendicular geometry with respect to the hydrophilic head group. The preparation conditions and the alkyl chain length should affect the size and stability of the particles. Experiments Solid lipid nanoparticles of two aryl-extended calixpyrroles with resorcinol walls and either meso-dodecyl or meso-methyl alkyl chains were compared. Ethanolic solutions of th…
Stability of parenteral nutrition admixtures containing organic phosphates
1995
The use of organic phosphates to avoid calcium phosphate precipitation in parenteral nutrition mixtures has been proposed. The purpose of this study was to evaluate the stability of total parenteral nutrition admixtures containing glucose-1-phosphate or glycerol phosphate as the phosphate source over 3 days. Three parenteral nutrition admixtures, each containing glucose-1-phosphate (30.0 mmol), glycerol phosphate (31.4 mmol) or inorganic phosphate (30.0 mmol), and their corresponding aqueous phases were prepared in 3-L ethylene vinyl acetate plastic bags and infusion bottles, and stored at 5 +/- 1 degrees C or 22 +/- 3 degrees C without light protection. Physical stability analysis and samp…
Protein crystallization: universal thermodynamic vs. specific effects of PEG
2008
The interest of nucleation of protein crystals and aggregates (including oligomerization) spans from basic physics theory all the way to biophysics, nanophysics, clinical sciences, biotechnologies, food technologies and polymer–solvent interactions. Understanding nucleation within a theoretical framework capable of providing quantitative predictions and control of nucleation rates, or even the very occurrence of crystallization, is a long-sought goal of remarkable relevance to each of the above fields. A large amount of work has been aimed at such goal, but success has been so far rather limited. Work at our laboratory has more recently highlighted a direct link between nucleation rates and…