Ultrasonically Assisted Polysaccharide Microcontainers for Delivery of Lipophilic Antitumor Drugs: Preparation and in Vitro Evaluation.

High toxicity, poor selectivity, and severe side effects are major drawbacks of anticancer drugs. Various drug delivery systems could be proposed to overcome these limitations. The aim of this study was to fabricate polysaccharide microcontainers (MCs) loaded with thymoquinone (TQ) by a one-step ultrasonication technique and to study their cellular uptake and cytotoxicity in vitro.

Theory of Brushes Formed by Ψ-Shaped Macromolecules at Solid-Liquid Interfaces.

We present a theoretical analysis targeted to describe the structural properties of brushes formed by Ψ-shaped macromolecules tethered by terminal segment of stem to planar surface while exposing multiple free branches to the surrounding solution. We use an analytical self-consistent field approach based on the strong stretching approximation, and the assumption of Gaussian elasticity for linear chain fragments of the tethered macromolecules. The effect of weak and strong polydispersity of branches is analyzed.

Chitosan-isoniazid conjugates: Synthesis, evaluation of tuberculostatic activity, biodegradability and toxicity.

Novel water-soluble chitosan-isoniazid conjugates were synthesized by two methods: (1) the carbodiimide method using isoniazid (INH) and N-(2-carboxyethyl)chitosan (CEC), and (2) the reaction between INH and N-(3-chloro-2-hydroxypropyl)chitosan (CHPC). The solubility of the conjugates under physiological conditions was enhanced by phosphorylation. Method (1) is preferable in terms of obtaining conjugates with a high content of active substance; depending on reaction conditions, the degree of substitution in the INH-CEC conjugates varies from 0.

The interaction of amino acids, peptides, and proteins with DNA.

Amino acids that carry charges on their side groups can bind to double stranded DNA (dsDNA) and change the strength of the double helix. Measurement of the DNA melting temperature (Tm) confirmed that acidic amino acids (Glu, Asp) weaken the H-bonds between DNA strands, whereas basic amino acids (Arg, Lys) strengthen the interaction between the strands. A rank correlation exists between the amino acid isoelectric points and the observed changes in Tm.

Recombinant interleukin-1 receptor antagonist conjugated to superparamagnetic iron oxide nanoparticles for theranostic targeting of experimental glioblastoma.

Cerebral edema commonly accompanies brain tumors and contributes to neurologic symptoms. The role of the interleukin-1 receptor antagonist conjugated to superparamagnetic iron oxide nanoparticles (SPION-IL-1Ra) was assessed to analyze its anti-edemal effect and its possible application as a negative contrast enhancing agent for magnetic resonance imaging (MRI). Rats with intracranial C6 glioma were intravenously administered at various concentrations of IL-1Ra or SPION-IL-1Ra.

Neurotherapeutic activity of the recombinant heat shock protein Hsp70 in a model of focal cerebral ischemia in rats.

Recombinant 70 kDa heat shock protein (Hsp70) is an antiapoptotic protein that has a cell protective activity in stress stimuli and thus could be a useful therapeutic agent in the management of patients with acute ischemic stroke. The neuroprotective and neurotherapeutic activity of recombinant Hsp70 was explored in a model of experimental stroke in rats. Ischemia was produced by the occlusion of the middle cerebral artery for 45 minutes.

Structural optimization of calcium carbonate cores as templates for protein encapsulation.

The calcium carbonate (CaCO3) cores being templates for model proteins encapsulation were obtained for developing oral drug delivery systems. The influence of the characteristics of the core formation (the time, the temperature, the stirring intensity, the ultrasound treatment and drying conditions) on the size and morphology of the carbonate cores was studied. The core size was shown to decrease with increasing the stirring time and stirring intensity.

Superparamagnetic iron oxide nanoparticles conjugated with epidermal growth factor (SPION-EGF) for targeting brain tumors.

Superparamagnetic iron oxide nanoparticles (SPIONs) conjugated with recombinant human epidermal growth factor (SPION-EGF) were studied as a potential agent for magnetic resonance imaging contrast enhancement of malignant brain tumors. Synthesized conjugates were characterized by transmission electron microscopy, dynamic light scattering, and nuclear magnetic resonance relaxometry. The interaction of SPION-EGF conjugates with cells was analyzed in a C6 glioma cell culture.

Effect of Block Copolymer Architecture on Morphology of Self-Assembled Aggregates in Solution.

We predict how equilibrium morphology of self-assembled aggregates in dilute solution could be tuned by replacing a linear AB diblock copolymer by a heteroarm star-like or cyclic block copolymer. We demonstrate that in selective solvent AB miktoarm stars or diblock copolymers with cyclic associating block may give rise to cylindrical assemblies or vesicles, while linear diblock copolymers with same composition form only spherical micelles. The theoretical predictions are in line with experimental observations.

The polymer brush model of neurofilament projections: effect of protein composition.

Applying self-consistent field theory, we consider a coarse-grained model for the polymerlike projections of neurofilament (NF) proteins that form a brush structure around neurofilaments. We focus on effects of molecular composition, which is the relative occurrence of NF-H, NF-M, and NF-L proteins, on the organization of NF projection domains. We consider NF brushes with selectively truncated projections, and with a varied ratio L:H:M of constituent tails.

Modeling of charged amphiphilic copolymer stars near hydrophobic surfaces.

Numerical self-consistent field theory has been applied to amphiphilic copolyelectrolyte stars in the solution and at interfaces both in one- and two-gradient coordinate systems. Our focus is on polymer stars for which the solvent is poor for the short blocks in the center and good for the longer charged chain parts at the periphery of the star. Both in solution as well as near an interface, the structure of the core is influenced by the hydrophobic interactions that tend to form a compact globule with size Rc and the forces exerted by the charged peripheral chain parts that like to expand the core.

Effect of the ionic strength and pH on the equilibrium structure of a neurofilament brush.

Using the numerical model of Scheutjens and Fleer, we investigated, on a self-consistent field level, the equilibrium structure of the neurofilament brush formed by projection domains of the constituent NF-H, NF-M, and NF-L proteins. The phosphorylation of such a brush is a major regulatory process that triggers the relocation of the H tails from the NF core to the brush periphery. We explore how the pH and the ionic strength affect the rearrangements in the NF brush structure upon phosphorylation.

Curved polymer and polyelectrolyte brushes beyond the Daoud-Cotton model.

We revise the classical Daoud-Cotton (DC) model to describe conformations of polymer and polyelectrolyte chains end-grafted to convex spherical and cylindrical surfaces. In the framework of the DC model, local stretching of chains in the brush does not depend on the degree of polymerization of grafted chains, and the polymer density profile follows a single-exponent power law. This model, however, does not correspond to a minimum in free energy of the curved brush.

Annealing polyelectrolytes at charged interfaces.

The conformation of a weakly dissociating (annealing) polyelectrolyte chain end-tethered to a similarly or oppositely charged planar surface is analyzed in the framework of scaling arguments. For a similarly charged interface an analytical model is also utilized. We demonstrate that at low salt concentration in bulk solution there is a strong coupling between the polyelectrolyte conformation and its degree of ionization.