Application of functional magnetic particles to diagnosis and therapy of cancer

摘要

We have developed functional magnetic particles which can specifically be adsorbed by cancer cells. These particles were at first applied to magnetic resonance imaging (MRI) of tumor-bearing mouse and we found that these particles can be used as contrast agents of MRI. Under alternating magnetic field, magnetic particles generate heat by hysteresis loss. We have developed magnetoliposomes (ML) with the ability to target and heat cancer intracellularly, and reported their suitability for hyperthermia. Moreover, we have developed new magnetoliposomes, 'magnetite cationic liposomes (MCL)'. The MCL had ten times higher affinity for cancer cells than that of the ML, because of the positive charge on the surface. Due to this high affinity for the cancer cells, the MCL were able to heat a glioma cell pellet of about 5 mm in diameter to above 43 deg C and kill the tumor tissue by hyperthermic effect. Besides these application, we have studied combined therapies with anti-cancer agents or gene therapy.