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The hydrogels based on cross-linked dextran-graft-polyacrylamide (D-g-PAA) and polyacrylamide (PAA) with different densities of chemical cross-links were synthesized by radical polymerization. They were used as nanoreactors for the photochemical synthesis of silver nanoparticles (AgNPs). The polymer hydrogels and nanocomposites with loaded AgNPs were characterized by SEM, FTIR- and UV–Vis spectroscopy. Swelling studies demonstrated differences in the internal structure of the cross-linked D-g-PAA and PAA samples. The morphology of the hydrogels affects the properties of the obtained nanocomposites. The microbiological tests have shown that the D-g-PAA-based hydrogels loaded with AgNPs are more active against Staphylococcus aureus than their PAA-based counterparts and can be an efficient alternative to antibiotic-containing coverings and dressings.

The multi-component nanosystems based on the branched copolymer dextran-graft-polyacrylamide in an anionic form (D-g-PAAan) with gold nanoparticles (AuNPs), photosensitizer Chlorine e6 (Ce6), and chemotherapeutic agent Doxorubicin (Dox) were developed for use in complex breast cancer therapy. The synthesized nanosystems were characterized by Quasi Elastic Light Scattering and Transmission Electron Microscopy and tested against the malignant cells MCF-7/Dox resistant to Dox. It is found that the addition of Dox as the fourth component to the three-component nanosystem D-g-PAAan/AuNPs/Ce6 leads to aggregation and, as a result, to decrease in efficiency of tumor treatment. The way to reduce unwanted aggregation in the four-component nanosystem D-g-PAAan/AuNPs/Ce6/Dox is proposed. The new nanosystems are shown to be effective in overcoming Dox resistance and killing cancer cells.

Because of the low content of chelating groups onto carbon fibers (CFs), their adsorptive parameters are poor, and this has negative effects on their applications as lightweight sorbents. In this work, we established a modification method to incorporate amine groups into carbon fiber surfaces by bromination followed by ammonolysis to create an interfacial layer which can adsorb heavy metal ions from solutions. The changed chemical composition, surface morphology, and thermal stability were investigated. Thermoprogrammed desorption mass-spectrometry and thermal analysis showed thermal transformation and interplay between forms of the grafted bromine groups of 0.5 mmol/g and the resulting amino groups of 0.44–0.56 mmol/g. After grafting, the surface chemistry parameters were improved due to the covalent bonding and grafting of the amine groups as interface modifier. Scanning electron microscopy observation also confirmed that the surface morphology maintains the same, without impairment of fiber properties. This work is therefore a beneficial approach towards enhancing the adsorption parameters by controlling the interface layer of CFs.

The functionalization of the carbon fiber based on polyacrylonitrile with sulfur-containing groups of high acidity was carried out in order to obtain the acid-base processes catalysts. Fibers were treated with sulfur vapors in the temperature range of 400-800°C, followed by surface oxidation with 30% hydrogen peroxide solution. Modified samples were investigated by chemical analysis, thermo-programmed desorption with mass spectrometric registration of products, IR spectroscopy and thermogravimetry. It is shown that the obtained materials contain SO3H-functional groups and oxygen-containing groups (carboxyl, lactone, phenolic, etc.) formed in the surface layer during the oxidation of the fiber surface. The chemical analysis showed that the concentration of sulfur in the samples of the modified fiber is 1.6-6.5 mmol/g. The synthesized samples have a satisfactory thermal stability. The synthesized catalysts were investigated in the model reaction - gas phase dehydration of isopropyl alcohol. It was found that obtained SO3H-containing carbon fibers were catalytically active and had high propylene selectivity. For all the samples obtained there is a complete conversion of alcohol into propylene. The activity of modified carbon fiber samples in the reaction indicated is a fairly high, temperatures of the total conversion of alcohol into propylene are in the range of 160-190°C. During the study of synthesized catalysts in several cycles of catalysis it have been shown that within repeated use (3 cycles) of all modified fiber samples, the yield of propylene does not decrease, the activity remains stable - the temperature of the dehydration reaction remains unchanged or increases insignificantly (by 5-10ºС). The temperatures of complete conversion of isopropyl alcohol in propylene for synthesized catalysts are lower than the temperatures of destruction maxima of surface sulfogroups. Thus, modified carbon fibers can be used as low-temperature catalysts of acid-base processes, in particular dehydration of alcohols.

Nanoporous activated carbon fibers (BusofitTM, BACF) showed effective adsorption of carbon tetrachloride (CTC) vapors. About 2.50 mmol × g−1 of chlorine, in the form of trichloromethyl and ...

Multicomponent nanocomposites for anticancer therapy were prepared, characterized, and tested for their antitumor efficacy. The water-soluble star-like dextran-graft-polyacrylamide copolymer was used as a nanoplatform for the creation of polymer-based multicomponent drug delivery systems for photodynamic and combined (photodynamic+chemotherapy) antitumor therapy. The three-component nanocomposites with incorporated gold nanoparticles and photosensitizer and the four-component ones additionally loaded by Doxorubicin into polymer nanoplatform were studied at 25 and 37°C by transmission electron microscopy and dynamic light scattering. Nanocomposites were tested for their photodynamic cytotoxicity for the cell line of breast cancer MCF-7/S. Three-component nanocomposites demonstrated higher efficacy than the four-component ones. The decrease in the activity of the four-component systems is explained by the aggregation process caused by the introduction of an additional component, which leads to a decrease in the hydrophilic-hydrophobic balance of the polymer macromolecule.

Hydrogels loaded with silver nanoparticles are promising materials for biomedical antibacterial application. This work was focused on the synthesis of hydrogel–silver nanocomposites based on Dextran-graft-Polyacrylamide copolymers in non-ionic and anionic form. A photochemical synthesis of colloidal silver particles through Ag seed-mediated growth under the UV solar radiation was carried out. All nanocomposites have revealed an absorption peaks at 420 nm corresponding to silver nanoparticles (AgNPs) Plasmon absorbance. However, the character of the absorption bands was dependent on the condition of AgNPs synthesis and chemical nature of polymer hydrogel. The obtained nanocomposites demonstrated high antibacterial efficiency against Escherichia coli and Staphylococcus aureus.