Influence of Chitosan Ascorbate Chirality on the Gelation Kinetics and Properties of Silicon-Chitosan-Containing Glycerohydrogels

Abstract

The influence of the chirality of chitosan ascorbate on the gelation kinetics and the properties of hybrid silicon-chitosan-containing glycerohydrogels were studied with a deep estimation of the stereospecificity of chitosan polysalts with l- and d-ascorbic acid diastereomers and their biological effects. It has been established that l- and d-diastereomerically enriched chitosan ascorbates are characterized by a positive Cotton effect and differ in the wavelength of the maximum of the dichroic band (250 and 240 nm), as well as in the values of its specific ellipticity (21.8 × 105 and 39.2 × 105 deg·mL·dm−1·g−1), the sign of specific optical rotation (+ and −), the type of dispersion curves (anomalous and smooth), as well as the condensed phase morphology (anisodiametric particles with optical anisotropy and confocal domains of spherical shape, respectively). In the biomimetic sol-gel synthesis of silicon-chitosan-containing glycerohydrogels using silicon tetraglycerolate as a precursor, it was found that chitosan d-ascorbate retarded gelation. Thin congruent plates obtained from the corresponding glycerohydrogels based on chitosan d-ascorbate have higher mechanical strength and elasticity under uniaxial stretching and lower values of Young’s modulus. It has been shown that the systems based on chitosan d-ascorbate show the greatest antibacterial activity against Staphylococcus aureus 209P and Escherichia coli 113-13 and significantly promote the viability of normal human dermal fibroblasts. The results of our assessment of the biological properties of chitosan polysalts are unexpected, since ascorbic acid exhibits biological activity as its l-isomer only.

Naturally based ionic liquids with indole-3-acetate anions and cations derived from cinchona alkaloids

“…Similar changes in the kinetics of various chemical processes due to the differences in chirality have been described previously. [41][42][43] 1-Ethylquinidinium bromide was obtained with a yield of 82%. On the basis of the nuclear magnetic resonance spectra obtained, it was possible to conrm that the chemical structure of the product was correct.…”

Physico-mechanical Properties of Silicon-chitosan-containing Glycerohydrogels Plates Based on Chitosan L- and D-ascorbates

“…Показано, что в практическом плане для синтеза фармакологически актив-ных гидрогелей наиболее перспективны соли хитозана с фармакопейными органическими кислотами, в частности, аскорбиновой [20]. При исследовании стереоспецифичности полисолей хитозана с диастереомерами аскорбиновой кислоты установлено, что морфология конденсированной фазы L-аскорбата хитозана представлена анизодиаметрическими частицами с ярко выраженной оптической анизотропией, D-аскорбата хитозана -плотно упакованными конфокальными доменами сферической формы [28]. Обнаружено также, что гидрогелевые системы на основе D-аскорбата хитозана проявляют наибольшую антибактериальную активность и значимо ускоряют процессы адгезии и пролиферации клеточной культуры дермальных фибробластов.…”

Features of L-Menthol Crystallization in Optically Active Medium Based on L- and D-Asparaginate Chitosan

“…We have previously found that the interaction of an aqueous solution of chitosan ascorbate and an L-menthol solution in ethyl alcohol or its mixture with acetone is accompanied by crystalline phase separation of the mixture system to form anisodiametric fibrillar entities in the case of CS in L-AscA, which exhibit pronounced optical anisotropy in polarized light, or densely packed confocal domains of a shape close to spherical in the case of CS in D-AscA [5,6]. In this work, we will consider features of the crystallization of the L-menthol + ethanol system in an aqueous solution of CS in L-and D-AspA.…”