L-Cysteine/Silver Nitrate/Iodate Anions System: Peculiarities of Supramolecular Gel Formation with and Without Visible-Light Exposure.

In this study, novel anion photo-responsive supramolecular hydrogels based on cysteine-silver sol (CSS) and iodate anions (IO) were prepared. The peculiarities of the self-assembly process of gel formation in the dark and under visible-light exposure were studied using a complex of modern physico-chemical methods of analysis, including viscosimetry, UV spectroscopy, dynamic light scattering, electrophoretic light scattering, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. In the dark phase, the formation of weak snot-like gels takes place in a quite narrow IO ion concentration range.

Preparation of Composite Hydrogels Based on Cysteine-Silver Sol and Methylene Blue as Promising Systems for Anticancer Photodynamic Therapy.

In this study, a novel supramolecular composite, "photogels", was synthesized by mixing of cysteine-silver sol (CSS) and methylene blue (MB). A complex of modern physico-chemical methods of analysis such as viscosimetry, UV spectroscopy, dynamic and electrophoretic light scattering, scanning electron microscopy and energy-dispersive X-ray spectroscopy showed that MB molecules are uniformly localized mainly in the space between fibers of the gel-network formed by CSS particles. Molecules of the dye also bind with the surface of CSS particles by non-covalent interactions.

Fluoride-Ion-Responsive Sol-Gel Transition in an L-Cysteine/AgNO System: Self-Assembly Peculiarities and Anticancer Activity.

Supramolecular hydrogels based on low-molecular-weight compounds are a unique class of so-called "soft" materials, formed by weak non-covalent interactions between precursors at their millimolar concentrations. Due to the variety of structures that can be formed using different low-molecular-weight gelators, they are widely used in various fields of technology and medicine. In this study, we report for the first time an unusual self-assembly process of mixing a hydrosol obtained from L-cysteine and silver nitrate (cysteine-silver sol-CSS) with sodium halides.

Cysteine-Silver-Polymer Systems for the Preparation of Hydrogels and Films with Potential Applications in Regenerative Medicine.

Herein, the problem concerning the poorer mechanical properties of gels based on low molecular weight gelators (LMWGs)-L-cysteine and silver nitrate-was solved by the addition of various polymers-polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP) and polyethylene glycol (PEG)-to the initial cysteine-silver sol (CSS). The physicochemical methods of analysis-viscosimetry, UV spectroscopy, DLS, and SEM-identified that cysteine-silver hydrogels (CSG) based on PVA possess the best rheological properties and porous microstructure (the average pore size is 2-10 µm) compared to gels without the polymer or with PVP or PEG. Such gels are able to form cysteine-silver cryogels (CSC) and then porous cysteine-silver films (CSF) with an average pore size of 10-20 µm and good mechanical, swelling, and adhesion to skin characteristics as long as the structure of CSS particles remains stable.