Regrettably, cancer is more than a single disease, and even now, certain types of this medical disorder, like liver, brain, or pancreas tumors, cannot be easily treated with surgery, radiation therapy, or chemotherapy, resulting in low survival rates for patients.
Fortunately, novel treatments like hyperthermia therapy are evolving, in which tumors are heated by firing nanoparticles into tumor cells. In a recent study reported in EPJ B, Angl Apostolova from the University of Architecture, Civil Engineering and Geodesy in Sofia, Bulgaria, and coworkers have demonstrated that in tumor cells, their particular absorption rate of destructive heat largely relies on the nanoparticles’ diameter and the magnetic material’s composition used for delivering the heat to the tumor.
Alternating magnetic fields are used to activate magnetic nanoparticles delivered close to the tumor cells. Hyperthermia therapy will be effective only if the tumor cells, not the cells in healthy tissue, are able to absorb the nanoparticles well. Hence, the effectiveness of this therapy is dependent on the particular absorption rate. In this regard, Bulgarian researchers have examined a number of nanoparticles composed of an iron oxide material known as ferrite, to which small amounts of cobalt, copper, manganese, or nickel atoms are added. This method is referred to as doping.
The team studied magnetic hyperthermia on the basis of these particles, in cell cultures and also in mice, for two separate heating techniques. These techniques vary in terms of how the heat is produced in the particles: through indirect or direct coupling between the magnetic moment and magnetic field of the particles.
It was demonstrated by the authors that the diameter of the nanoparticles considerably controls the rate of tumor absorption. Unexpectedly, as particle diameter increases, the rate of absorption also increases, provided the level of material doping is adequately high and that the diameter of the nanoparticles does not surpass a set maximum value (maximum 16 nm for copper doping and 14 nm for cobalt doping).