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

- 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.

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.

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