As one of the most extensively studied human diseases, various cancer treatments have been developed by scientists. One such treatment has been steadily gaining traction in recent years, and it involves the use of high temperatures to destroy cancer cells. Known as hyperthermia treatment, this therapy is used in conjunction with other modalities, such as chemotherapy and radiation therapy.
Magnetic nanoparticles (MNPs) have a wide range of biomedical applications. One of the most recently proposed uses for MNPs is as a magnetic guide in drug delivery and as heat mediators in hyperthermia treatments.
In a recent study, Bulgarian researchers investigated the potential of using mixed ferrite nanoparticles to facilitate heat application during hyperthermia treatment. Using mice and cell cultures, they explored two methods of generating heat in MNPs, specifically, via direct or indirect coupling between the magnetic field and the magnetic moment of the particles.
The researchers reported their findings in an article published in The European Physical Journal B.
Hyperthermia treatment using MNPs can help ‘burn’ cancer tumors
Two types of hyperthermia are currently being explored in cancer therapy: Thermo cutting, which involves exposing a tumor to temperatures greater than 46 C, and moderate hyperthermia, which involves the application of heat ranging between 41 C and 46 C. The former is said to result in direct necrosis, while the latter leads to the activation of many degradation mechanisms, such as protein denaturation, protein folding and DNA crosslinking – a type of genetic damage that triggers cell death.
Moderate hyperthermia can be classified as either local, regional or whole body. Local hyperthermia, which has received great scientific interest, refers to heat treatment applied to a small area, such as a localized tumor. Regional hyperthermia is used to treat a whole organ, while whole body hyperthermia is used to target metastatic cancer cells that have spread to different parts of the body. Moderate hyperthermia, when combined with MNPs, allows heat to be applied selectively to tumors so that healthy cells remain undamaged.
MNPs can be delivered close to tumor cells and activated using alternating magnetic fields. This new type of treatment, called magnetic hyperthermia therapy, can be an effective cancer therapy if the MNPs are absorbed well by tumor cells but not by healthy cells. This function is measured as a cell’s specific absorption rate (SAR).
In their previous studies, the researchers explored the characteristics of MNPs made of an iron oxide material known as a ferrite. Doping ferrites, which involves the addition of small quantities of copper, nickel, manganese or cobalt atoms, is believed to affect the SAR of MNPs. Using MNPs doped with these elements, the researchers investigated the effectiveness of magnetic hyperthermia in tumor-bearing mice and in cultured tumor cells. (Related: Review explores the potential of fatty oils from TCM in cancer therapy.)
The researchers found that the tumor cells’ SAR of destructive heat depended on the diameter of the MNPs and the composition of the magnetic material used to deliver the heat. As particle diameter increased, SAR also increased, so long as the level of doping and the diameter of the MNPs did not exceed a set maximum value (e.g., 14 nanometers for cobalt doping and 16 nanometers for copper). With optimal SAR, doped ferrite nanoparticles successfully destroyed tumors without harming healthy cells.
Based on these findings, the researchers concluded that magnetic hyperthermia therapy is a viable and tunable new therapy that can kill cancer tumors.
Sources include:
Link.Springer.com [PDF]
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