# Magnetic Nanoparticles as Mediators for Magnetic Hyperthermia Therapy Applications: A Status Review
## 4 Conclusions  
The potential of superparamagnetic nanoparticles in magnetic hyperthermia holds great promise. In this concise review, we explored different synthesis methods employed for the preparation of Fe\({}_{2}\)O\({}_{3}\), Mg\({}_{1+x}\)Fe\({}_{2-2x}\)Ti\({}_{x}\)O\({}_{4}\), Ni\({}_{1-x}\)Cu\({}_{x}\), Cr\({}_{x}\)Ni\({}_{1-x}\) MNPs, their resulting size, shape, functionalization, \(T_{\rm C}\), magnetic, and calorimetric properties. The results indicate that the described synthesis method of superparamagnetic nanoparticles with adjustable Curie temperature offers a convenient approach for producing controlled \(T_{\rm C}\) nanoparticles. These synthesized particles demonstrate excellent suitability, particularly when optimized for MH applications. Through the coprecipitation method, maghemite nanoparticles were successfully synthesized, and a supplementary CM-dextran coating was applied. The resulting nanoparticles displayed a distinct crystalline structure, as confirmed by both XRD and TEM analysis. The magnetization ranged from 55 to 65 emu/g, with the results of calorimetric measurements showing that the size of the nanoparticles and the thickness of the CM-dextran coating affect the SAR. The (Mg, Ti)-ferrite nanoparticles were also synthesized by coprecipitation, obtaining nanoparticles of two crystallites, 20 and 200 nm. The TEM analysis revealed the presence of larger nanoparticles, displaying low magnetization. Nevertheless, these nanoparticles exhibited a favorable thermal response under the influence of alternating magnetic fields (AMF), with the measured \(T_{\rm C}\) falling within the therapeutic range for magnetic hyperthermia (MH) applications. The NiCu and NiCr nanoparticles were successfully synthesized using the microemulsion technique. However, in both cases, additional homogenization was required, resulting in partial agglomeration and the formation of larger nanoparticle clusters. Despite achieving a \(T_{\rm C}\) of approximately 45 \({}^{\circ}\)C for NiCu nanoparticles, their dissipation and/or heating efficiency (SAR) proved inadequate. We also synthesized NiCu and NiCr nanoparticles of different compositions by mechanical milling. We obtained nanoparticles of different sizes and shapes, which in turn affected their magnetization and thermal response under the influence of AMF, but again the \(T_{\rm C}\) were within the therapeutic temperature range for MH. The sol-gel method proved to be the most promising. We obtained nanoparticles with a size of about 18 nm, which could otherwise be further homogenized. Although the particles partially grew during homogenization, they did not agglomerate because the silica matrix prevented this. The only weakness of silica is that it affects magnetization, but when silica is successfully removed, nanoparticles with higher magnetization and good thermal response under the influence of AMF are obtained. Also, the \(T_{\rm C}\) of the mentioned nanoparticles is in the therapeutic range for use in MH. Through XRD measurements, we substantiated the successful completion of each synthesis process. This assessment not only validated the creation of magnetic nanoparticles (MNPs) with the intended composition but also allowed for the simultaneous estimation of the MNPs' size, employing Sherrer's equation. The size of the nanoparticles ranged from 5 to 25 nm, and in the case of homogenization, the particles were larger, or the growth of the nanoparticles proved to be a result of the aforementioned homogenization. The TM curves and corresponding \(T_{\text{C}}\) were determined by thermal demagnetization. The \(T_{\text{C}}\) is very important in the field of MH. It is the temperature at which the material passes from the magnetic to the non-magnetic state, which means that it no longer gives off heat or heats up under the influence of an external magnetic field. The therapeutic temperature in MH is between 41 and 46 \({}^{\circ}\)C. Most of the synthesized nanoparticles have a \(T_{\text{C}}\) in the therapeutic range.