Lipoic acid functionalized SiO₂@Ag nanoparticles. Synthesis, characterization and evaluation of biological activity

A novel nanocomposite was obtained through the covalent immobilization of lipoic acid on the surface of silver nanoparticles-decorated silica nanoparticles (SiO₂@Ag). The hybrid organic – inorganic material obtained was characterized by Fourier transform infrared spectroscopy, thermal analysis, scanning and transmision electron microscopy, X-ray photoelectron spectroscopy and UV-Visible spectroscopy. Its antioxidant, cytotoxic, antimicrobial activity and influence on mammalian cells cycle were evaluated. The results of this study have shown that the functionalization of SiO₂@Ag with lipoic acid resulted in a composite with increased specificity of interaction with different mammalian cell lines and antioxidant activity, but with decreased cytotoxicity and antimicrobial properties. Therefore, the SiO₂@Ag functionalized with lipoic acid could be successfully used in certain concentrations to modulate the cell cycle, in order to obtain the desired anti-proliferative or stimulatory therapeutic effect. - Highlights: • Silica particles were prepared by Stöber method and served for immobilization of silver nanoparticles. • This composite was further functionalized with lipoic acid. • The obtained materials were characterized by structural methods (UV–Vis, IR, TG, XPS) and their size and morphology evaluated by TEM, SEM. • Antimicrobial and antioxidant activity were evaluated. • Interaction of the obtained materials with the tumoral and spontaneously immortalized human cells, was investigated.