Our biocompatible hydrogel systems obtained by the sol-gel technqiue and based on chitosan and silicon polyolates are promising for medical and biological applications. The surface microrelief of these sol-gel materials (hydrogels and xerogels) based on chitosan and silicon tetraglycerolate was explored by AFM and SEM. A significant influence of the component ratio in the mixed system on the morphology and surface profile of the hydrogels and xerogels prepared therefrom was established. An increased content of the structure-forming component (chitosan) in the system was shown to increase the roughness scale of the hydrogel surface and to promote the porosity of the xerogel structure.
The optical properties of aqueous chitosan solutions in L- and D-ascorbic acids were studied by optical rotatory dispersion and spectrophotometry. The specific optical rotation [α] of all chitosan solutions tested was positive, in contrast to aqueous solutions of the ascorbic acid enantiomers, which exhibit an inverse relationship of [α] values. Significant differences in the absolute values of [α] of the chitosan solutions at polymer-acid ratios exceeding the equimolar one were found.
The surface morphology and optical activity of films based on chitosan in different chemical forms were investigated by methods of scanning electron and atomic force microscopy, spectropolarimetry. These film samples are used as substrates for optical waveguides, sorption material and as substrates for cell culturing tissue-engineering and scaffold constructions. The essential differences in the structural and morphological relief of thin films from chitosan of different chemical forms are established. It was found that the spectra of optical rotatory dispersion and circular dichroism of films of chitosan in the form of polysalts and polybases are significantly different in absolute values of the optical rotation of the plane and circularly polarized light.