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

Abstract

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. In vitro experiments have shown that hydrogels are non-toxic to normal human fibroblast cells. The obtained materials could potentially be applied to regenerative medicine.

Fluoride-Ion-Responsive Sol–Gel Transition in an L-Cysteine/AgNO3 System: Self-Assembly Peculiarities and Anticancer Activity

“…The use of different anions as initiators of the gel formation of LMWGs [31] is of particular interest because of their essential role in the environment and many biological processes [32][33][34]. Our scientific group found that a system based on aqueous solutions of L-cysteine and various silver salts is capable of forming a stable hydrosol [35][36][37][38][39][40] at quite a low dispersed phase concentration (0.01%). The self-assembly process is caused by the high affinity of silver ions to the thiol group of the amino acid.…”

“…However, the role of single-charge and those most important in the human body, such as halide anions, has not been discovered. Due to the fact that sols obtained on the basis of sulfur-containing amino acids and silver salts have shown various properties, such as anticancer [36,37], photocatalytic [38], antibacterial/antibiofilm [39] and film-forming [40] properties, the need to investigate the influence of various biologically active compounds on hydrosol colloidal stability and activity is relevant.…”