Synthesis and Mössbauer study of 57Fe-based nanoparticles biodegradation in living cells

Biodegradation of nanoparticles includes the destruction of a stabilizing coating and the accompanying change in interparticle interaction, as well as the direct destruction of the inorganic nuclei of particles. These processes lead to characteristic changes in the shape of the Mossbauer spectra of iron oxide nanoparticles. In this work, we investigated the in vitro biodegradation of 57Fe-based magnetic nanoparticles with the aid of Mossbauer spectroscopy. For this purpose, two types of magnetic nanoparticles enriched with the 57Fe isotope were synthesized. Copolymer Pluronic F-127 and citric acid were used to stabilize nanoparticles in aqueous medium. Moreover, synthesized nanoparticles were analyzed by physicochemical methods and investigated for cytotoxicity. The study of magnetic nanoparticles biodegradation was performed on 4 T1 cell culture (breast cancer). We measured Mossbauer spectra of nanoparticles incubated with 4 T1 cells and spectra of control nanoparticle samples at different conditions. The analysis of spectra was carried out in the many-state relaxation model formalism. The study revealed that after 120-hours incubation of nanoparticles in cells, they did not undergo measurable changes typical of biodegradation processes. Nevertheless, we noted intense intracellular oxidation of ferrous iron of synthesized nanoparticles to the ferric phase. The results obtained indicate the possibility of using the obtained nanoparticles in Mossbauer in vitro studies.