Study of Dextran Coated Magnetic Nanoparticles Incorporation into Glioblastoma Cells

For therapeutic applications it is important to know quantitative uptake of nanoparticles by the cells. In this work incorporation of superparamagnetic iron oxide nanoparticles (SPIONs) coated by the dextran shell into malignant glioma cells, as well as into human fibroblast cells in vitro was studied. Nanoparticles were synthesized by co-precipitation and the presence of chemical impurities in them was assessed by X-ray fluorescence measurements. Geometrical parameters of nanoparticles were characterized by X-ray diffraction and dynamic light scattering. Magnetic and dynamic parameters of SPIONs in the medium before co-incubation with cells as well as in cells after incubation were found using highly sensitive method of nonlinear response to a weak ac magnetic field parallel to the steady field with registration of the second harmonic of magnetization M₂ followed by processing the obtained data with the formalism based on the Gilbert-Landau-Lifshitz equation for stochastic dynamics of superparamagnetic particles. The formation of SPION aggregates in the incubation medium was established, accompanied by a decrease in magnetostatic and, accordingly, free energy of the SPIONs system. The uptake of SPIONs by the cells at co-incubation was studied depending on the concentration of nanoparticles, duration of the co-incubation and the seeding density. The data obtained indicate: (i) close values of the magnetic and dynamic parameters of nanoparticle aggregates absorbed by the cells and in the medium before incubation; (ii) the decrease in the amount of SPIONs absorbed by cells at a higher seeding density; (iii) dependence of the SPIONs uptake on their concentration (characterized by the iron content) in the medium and on the time of co-incubation as well as on the cell type, with minimal uptake by cells of normal morphology.