l-Cysteine and N-acetyl-l-cysteine-mediated synthesis of nanosilver-based sols and hydrogels with antibacterial and antibiofilm properties

Abstract

The problem of the synthesis of a new generation of medicines aimed at combating bacteria and biofilms caused various infections is a great urgency. There is a gradual departure from...

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

“…The UV spectra of the gels are presented in Figure 4A. One can see that the addition of the fluoride anions to the CSS does not change the position of the absorption bands at 310 and 390 nm, corresponding to argentophilic interactions in the L-cysteine/Ag + complexes and the surface plasmon resonance of the crystalline phase of the silver nanoparticles [39]. This suggests that fluoride ions do not influence the electronic structure of the CSS nanoparticles but interact only with their surface.…”

“…Furthermore, these CSGs possessed thixotropic properties (Figure 1F). According to our early investigations, the interaction of L-cysteine with silver ions leads to the medium's acidification (pH = 2.6) and the formation of nanoparticles constructed from a silver nanoparticle (AgNP) "core" and L-cysteine/Ag + complex inner "shell" [35,39]. The outer side of the "shell" is formed by amino and carboxyl groups.…”

“…An increase in the content of the fluoride ions in the system leads to growth in the particle size and a drop in the polydispersity coefficient, while the distribution becomes bimodal. The hydrodynamic diameter of the CSS particles is 50 nm [39]. Measurements of the zeta potentials of the systems are given in Figure 4C.…”

“…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.…”