Magnetic heating has been used to induce cell death in hyperthermia therapy, stimulate neurons, alter cellular function, and facilitate tissue warming. Due to their very attractive properties, the Bao lab has been synthesizing and characterizing magnetic nanoparticles, such as magnetic iron oxide nanoparticles (MIONs) and iron oxide nanocrystal clusters (IONCs), for magnetic heating. The Bao lab has developed a novel method for coating MIONs with a phospholipid-PEG layer that achieves a high level of heating per gram of iron (Fe), and quantified the size-dependence of heating by MIONs. With this method, better control of surface coating density and the amount of reactive groups on the nanoparticle surface can be achieved. This allows for the conjugation of different moieties with desirable surface concentrations, thus facilitating biomedical applications of nanoparticles. Using IONCs as a nanoplatform, the Bao lab has developed cancer magnetotherapy, a new cancer therapeutic modality that combines magnetic heating with free radicals. The IONC-based magnetotherapy can induce immunogenic cell death in cancer cells and stimulate dendritic cell maturation. When combined with immune checkpoint blockade, the resulted magneto-immunotherapy not only eradicates the primary tumors, but also suppresses the growth of distant tumors. This technique has the potential in treating cancers at advanced stages.