Nanohyperthermia of malignant tumors. II. In vivo tumor heating with manganese perovskite nanoparticles.

OBJECTIVES: To evaluate the ability of manganese perovskite nanoparticles (lanthanum-strontium manganite) to heat the tumor tissue in vivo under action of external alternating magnetic field. MATERIALS AND METHODS: The magnetic fluid on the basis of nanoparticles of perovskite manganite was tested in the heating experiments using of alternating magnetic field of frequency 300 kHz and amplitude 7.7 kA/m. Guerin carcinoma was transplanted into the muscle of rat. Magnetic fluid was injected intramuscularly or intratumorally. Temperature was measured by copper-constantan thermocouple. RESULTS: Temperature of magnetic fluid was increased by 56 °C for 10 min of alternating magnetic field action. Administration of magnetic fluid into the muscle followed by alternating magnetic field resulted in the elevation of muscle temperature by 8 °C after 30 min post injection. Temperature of the tumor injected with magnetic fluid and treated by alternating magnetic field was increased by 13.6 °C on the 30 min of combined influence. CONCLUSION: In vivo study with rat tissue has demonstrated that magnetic fluid of manganite perovskite injected in the tumor increases the tumor temperature under an alternating magnetic field. Obtained results emphasize that magnetic fluid of manganite perovskite can be considered as effective inducer of tumor hyperthermia.

Nanohyperthermia of malignant tumors. I. Lanthanum-strontium manganite magnetic fluid as potential inducer of tumor hyperthermia.

OBJECTIVES: To synthesize magnetic particles of lanthanum-strontium manganite, prepare the magnetic fluid (MF), evaluate the generation of heat by particles and determine their common toxiсity. METHODS: Nanoparticles based on the solid solutions of lanthanum-strontium manganite (La(1-x)Sr(x)MnO(3)) have been synthesized by a sol-gel method. Conventional methods of experimental oncology were used. RESULTS: Nanoparticles of ferromagnetic materials on the basis of solid solutions of lanthanum strontium manganite by sol-gel method were synthesized. It was shown the possibility to regulate the aggregate form of particles that are formed during the synthesis. Magnetic fluid based on the synthesized nanoparticles and water solutions of agarose have been produced. It was shown the possibility to heat this magnetic fluid up to 42-45 °Ð¡ in externally applied alternating magnetic field (AMF) operated at 100-400 kHz. It was determined that under long-term influence of AMF nanofluid is heated up to temperature which is not over that of magnetic phase transition. It was detected that magnetic powder as well as fluid have not displayed acute toxicity or side effects (intraperitoneal or intratumoral administration) in animals either intact or with transplanted tumors. CONCLUSIONS: Possibility of synthesized magnetic fluid to generate heat in externally applied AMF as well as lack of side effects allow to consider its as a potential mean for tumor hyperthermia (HT).