5 research outputs found
Синтез рH-чувствительных гидрогелей модифицированного декстрана с фосфорнокислыми и карбаматными группами
The synthesis of gelling dextran esters with phosphate and carbamate groups in the dextran - phosphoric acid - urea system has been described. The effect of reaction time on hydrogels' gel fraction yield, their functional composition and the degree of equilibrium swelling has been studied. Swelling of hydrogels in the wide range of pH has been studied. The obtained hydrogels may be used as drugs delivery systems.В системе декстран-ортофосфорная кислота-мочевина синтезированы гелеобразующие смешанные эфиры дек-страна с фосфорнокислыми и карбаматными группами. Изучено влияние продолжительности реакции на выход гель-фракции гидрогелей, их функциональный состав и степень равновесного набухания. Набухание гидрогелей изучено в широком диапазоне pH. Полученные гидрогели могут быть использованы в качестве систем для доставки лекарственных веществ
Реологические свойства и гидролитическая устойчивость in vitro композиции карбоксиметилцеллюлоза–диоксидин
The composition of carboxymethylcellulose–dioxydine was obtained and its structural, morphological and rheological characteristics in the processes of heat treatment and chemical hydrolysis were studied. Using IR spectroscopy, scanning electron microscopy, and viscometry, it has been established that the introduction of dioxidine into a solution of carboxymethylcellulose sodium salt with different molecular weights leads to partial disordering of hydrogen bonds between macromolecules, promotes thermal destruction of the polysaccharide and a decrease in the dynamic viscosity of solutions. Experimental kinetic curves of carboxymethylcellulose hydrolysis in the presence and absence of dioxidine were obtained, and it was shown that they could be described using a first-order equation. The hydrolysis rate coefficients were calculated, and it was shown that, as a result of heat treatment, as well as in the presence of an active substance, the rate of carboxymethylcellulose hydrolysis increased. The change in the rheological properties of carboxymethylcellulose sodium salt solutions with different degrees of polymerization in the presence of an antimicrobial substance should be taken into account when choosing the composition of viscous prolonged forms of biologically active substances. Получена композиция карбоксиметилцеллюлоза–диоксидин и изучены ее структурно-морфологические и реологические характеристики в условиях термообработки и химического гидролиза в фосфатном буферном растворе с рН 7,4. Методами ИК-спектроскопии, сканирующей электронной микроскопии, вискозиметрии установлено, что введение диоксидина в раствор натриевой соли карбоксиметилцеллюлозы с разной молекулярной массой приводит к частичному разупорядочиванию водородных связей между макромолекулами, способствует термодеструкции полиcахарида, понижению динамической вязкости растворов. Получены экспериментальные кинетические кривые гидролиза карбоксиметилцеллюлозы в присутствии и в отсутствие диоксидина и установлено, что они могут быть описаны с помощью уравнения первого порядка. Рассчитаны константы скорости гидролиза и показано, что в результате термообработки, а также в присутствии активного вещества скорость процесса гидролиза карбоксиметилцеллюлозы в условиях in vitro увеличивается. Изменение реологических свойств растворов натриевой соли карбоксиметилцеллюлозы с разной степенью полимеризации в присутствии антимикробного вещества следует учитывать в выборе состава вязких пролонгированных форм биологически активных веществ
Effect of the Composition of an Esterification Mixture on the Acid Properties of Gel-Forming Phosphorylated Polysaccharides
Bacterial Cellulose-Based Nanocomposites Containing Ceria and Their Use in the Process of Stem Cell Proliferation
A technique for the fabrication of bacterial cellulose-based films with CeO2 nanofiller has been developed. The structural and morphological characteristics of the materials have been studied, their thermal and mechanical properties in dry and swollen states having been determined. The preparation methodology makes it possible to obtain composites with a uniform distribution of nanoparticles. The catalytic effect of ceria, regarding the thermal oxidative destruction of cellulose, has been confirmed by TGA and DTA methods. An increase in CeO2 content led to an increase in the elastic modulus (a 1.27-fold increase caused by the introduction of 5 wt.% of the nanofiller into the polymer) and strength of the films. This effect is explained by the formation of additional links between polymer macro-chains via the nanoparticles’ surface. The materials fabricated were characterized by a limited ability to swell in water. Swelling caused a 20- to 30-fold reduction in the stiffness of the material, the mechanical properties of the films in a swollen state remaining germane to their practical use. The application of the composite films in cell engineering as substrates for the stem cells’ proliferation has been studied. The increase in CeO2 content in the films enhanced the proliferative activity of embryonic mouse stem cells. The cells cultured on the scaffold containing 5 wt.% of ceria demonstrated increased cell survival and migration activity. An analysis of gene expression confirmed improved cultivation conditions on CeO2-containing scaffolds