Recently, there has been increasing interest in the use of magnetic particles of different compositon, shape and size in the broad area of biomedicine because of their unique multifunctional properties. When the size of the magnetic particles decreases to below a critical size, generally less than 15 nm, each nanoparticle becomes a single magnetic domain and exhibits remarkable superparamagnetic behavior when the temperature is above the so-called blocking temperature. Each individual nanoparticle has a large constant magnetic moment and behaves like a giant paramagnetic atom with a fast response to applied magnetic fields with negligible remanence and coercivity. These features make superparamagnetic nanoparticles very attractive for a broad range of biomedical applications because the risk of forming agglomerates due to magnetic interactions is negligible at room temperature. Specifically, superparamagnetic MnFe2O4 nanoparticles have been found to be biocompatible and highly useful for magnetic resonance imaging, and in the design of biosensors. Herein, we focus on magnetic hyperthermia cancer treatment using multifunctional chitosan coated MnFe2O4 nanoparticles. This hyperthermia strategy has been developed for the combined therapy with chemotherapy or radiotherapy. Although hyperthermia treatment has been shown to slow the growth of cancerous tumors, combination therapy has proven much more successful, though each technique brings with it severe side effects. In our work, we describe a polymer- inorganic hybrid material that can be localized to cancerous cells (even metasized cancers) and activated to heat single cells or small areas of tissue to cause hyperthermia in combination with heat-activated delivery of chemotherapy agents.
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