A Novel Biodegradable Composite Polymer Material Based on PLGA and Silver Oxide Nanoparticles with Unique Physicochemical Properties and Biocompatibility with Mammalian Cells

A method for obtaining a stable colloidal solution of silver oxide nanoparticles has been developed using laser ablation. The method allows one to obtain nanoparticles with a monomodal size distribution and a concentration of more than 108 nanoparticles per mL. On the basis of the obtained nanoparticles and the PLGA polymer, a nanocomposite material was manufactured. The manufacturing technology allows one to obtain a nanocomposite material without significant defects. Nanoparticles are not evenly distributed in the material and form domains in the composite. Reactive oxygen species (hydrogen peroxide and hydroxyl radical) are intensively generated on the surfaces of the nanocomposite. Additionally, on the surface of the composite material, an intensive formation of protein long-lived active forms is observed. The ELISA method was used to demonstrate the generation of 8-oxoguanine in DNA on the developed nanocomposite material. It was found that the multiplication of microorganisms on the developed nanocomposite material is significantly decreased. At the same time, the nanocomposite does not inhibit proliferation of mammalian cells. The developed nanocomposite material can be used as an affordable and non-toxic nanomaterial to create bacteriostatic coatings that are safe for humans.

Composite Polymer Coatings for Repair of Concrete Linings of Channels

The paper is dedicated to the results of research on composite polymer material used for concrete casings repair. Field approbation of new material was carried out on the irrigation channel test site during the repair of concrete coating deformation joints and cracks. The paper provides the obtained theoretical formulae and results of water permeability calculation in concrete casing cracks with smooth and rough walls. A design chart for determining water permeability of damages in the form of cracks of various coating width on channel concrete coatings was obtained. A universal nomogram was obtained for determining the water permeability of damage in the form of cracks of various opening widths on the concrete coverings of channels.

Effects of Poloxamer Content and Storage Time of Biodegradable Starch-Chitosan Films on Its Thermal, Structural, Mechanical, and Morphological Properties

Biodegradable packaging prepared from starch is an alternative to fossil-based plastic packaging. However, the properties of starch packaging do not comply with the necessary physicochemical properties to preserve food. Hence, in a previous study, we reported the preparation of a composite polymer material based on starch-chitosan-pluronic F127 that was found to be an adequate alternative packaging material. In this study, we modified the physicochemical properties of this material by storing it for 16 months under ambient conditions. The results indicate that the incorporation of pluronic F127 in the blend polymer can help avoid the retrogradation of starch. Moreover, at higher concentrations of pluronic F127, wettability is reduced. Finally, after storage, the materials exhibited surface modification, which is related to a color change and an increase in solubility, as well as a slight increase in stiffness.

Comparative Analysis Of The Results Of The Endoscopic Treatment Of Gastroduodenal Ulcerative Bleeding

The study includes 557 patients with ulcer of the stomach and duodenal intestine complicated by bleeding. The control group was 290 patients, of which 48 patients with active bleeding were performed by standard endoscopic hemostasis techniques, and in 242 cases, when verifying stopping bleeding, endoscopy was limited to the diagnostic step with subsequent conservative patient management. The main group includes 267 patients in addition to endoscopic hemostasis with active bleeding (46 patients), the manipulation was supplemented with the implementation of the proposed method of endoscopic treatment of gastroduodenal bleeding of ulcerative genesis. When revealed bleeding (221 patients), endoscopic intervention was also accompanied by the implementation of the proposed method. The application of the composite polymer material over the ulcerative defect contributed to a decrease in the frequency of the nearest recurrences of hemorrhagic syndrome from 9.0% to 1.9%, reduce the need to perform operational treatment from 6.6% to 1.1% and levity indicator from 1.7% up to 0.7%, which generally affected the increase in the share of patients discharged without complications from 90.7% to 97.8% and reducing the timing of the hospital phase of treatment.

Research and implementation of innovative technologies for the use of composite polymer materials to protect the root systems of seedlings from desiccation and increase their establishment

In the presented materials, the physicochemical properties of composite polymer materials for protecting the root systems of forest seedlings from desiccation are studied. The conducted studies on the production of composite polymer materials allowed to establish their optimal ratios: the sodium salt carboxymethyl cellulose from 4 active substance wt.%, as target additives contains potassium chloride from 6.0 to 9.0 wt.% and ammonium nitrate from 0.004 to 0.006 wt.%. This ratio of target additives corresponds to the optimal relative viscosity of the composite polymer material equal to 170-175 s. Treatment of the root systems of seedlings with a composite polymer material allows not only to prevent desiccation, increase their establishment on the planting area, but also to reduce mechanical damage during transportation and forest planting.