Antioxidant action of L-cysteine anchored on the surface of magnetite nanoparticles

This study addresses the synthesis, characterization, and evaluation of L-Cysteine (L-Cys) molecules anchored on superparamagnetic iron oxide nanoparticles (SPIONs), mainly magnetite (Fe3O4), for potential drug delivery applications. Fe3O4 nanoparticles are obtained via co-precipitation and functionalized with L-Cys to improve biocompatibility and antioxidant activity. To optimize the functionalization process, the dimerization of cysteine to cystine is investigated by varying the reaction time and mass proportions. The samples are characterized by powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) and Raman spectroscopies, transmission electron microscopy (TEM), and magnetic curves. These results confirm that L-Cys molecules are anchored on the nanoparticle surface through their carboxylate groups, with free SH groups present in the dispersed nanoparticles. However, in the solid state, L-Cys dimerization leads to a cystine crystal structure, resulting in no free SH groups. The nanoparticles have a magnetite structure with an average crystallite size of (8.7±0.8) nm and superparamagnetic behavior. In vitro biological assays show the antioxidant effect of L-Cysteine on the surface of the nanoparticles. [Display omitted] •L-cysteine-covered superparamagnetic iron oxide nanoparticles (SPIONs) are successfully used in targeted tumor therapy.•l- Cysteine molecule anchored on SPIONs surface plays an important role in the cellular response to oxidative stress.•Cysteine concentration directly affects cell mortality rate, both in cells without stress and under stress.•L-Cysteine-SPIONs provide valuable insights into the importance of cysteine and its therapeutic potential in oxidative stress conditions.•SPIONs have relevance as a promising cysteine delivery approach.