EPR study of self-organized magnetic nanoparticles in biomaterials

An innovative approach based on the effect of bio-mineralization as a response reaction of cells to decrease their damage under stress was applied to Juniperus communis (JC) and JC-based biomaterials (Nefrovil and Immunostan drugs with properties increasing the antioxidant activity and improving the immune system of human organism, respectively). Electron paramagnetic resonance spectroscopy (EPR), also called electron spin resonance (ESR), was used as the main experimental tool for detecting paramagnetic species resulted from the existence of antioxidant activity system, represented by superoxide dismutase with manganese, catalase etc., as well as formation of superparamagnetic iron oxide nanoparticles (SPIONs). The influence of temperature and microwave power on the intensity of EPR signals detected in JC, Nefrovil and Immunostan was examined. Obtained g-factor values of EPR signals from JC shell and seeds as well as from Nefrovil and Immunostan were attributed to the paramagnetic species of Mn (g = 2.0), Fe3O4 SPIONs (g = 2.17…2.60), Fe aggregates (g = 3.22…3.94) and Fe3+ ions (g = 4.3). The EPR signals from SPIONs and Fe3+ ions in Immunostan were found to be fully correlated, showing an additional experimental evidence of the bio-mineralization effect (i.e., transformation of Fe3+ ions to Fe3O4 SPIONs). The results of the EPR study of Fe3O4 SPIONs incorporated into polymer matrix were taken into account in comparative analysis. The results reported in the present work support well self-organization of magnetic nanoparticles in the investigated biomaterials.