Ferumoxytol of ultrahigh magnetization produced by hydrocooling and magnetically internal heating co-precipitation.

Ferumoxytol, which is originally intended for MRI and anemia treatment, is currently the only inorganic nanodrug approved by FDA for clinical application in vivo. Common ferumoxytol seems incapable of meeting the requirements for diverse applications. Thus, the development of a novel strategy based on co-precipitation to produce ferumoxytol with high quality is an imminent task. Herein, we proposed a physically assisted strategy, namely hydrocooling and magnetically internal heating co-precipitation, to optimize the properties of ferumoxytol and thus significantly enhance its magnetic performance. Magnetization of the newly developed ferumoxytol can reach 104-105 emu g-1 Fe, which is the highest value among the reported results. It has been found that the crystalline structures of the newly developed ferumoxytol have been greatly improved on the basis of pharmaceutical quality criteria.

Assembly-Induced Thermogenesis of Gold Nanoparticles in the Presence of Alternating Magnetic Field for Controllable Drug Release of Hydrogel.

Films of gold nanoparticles are easily fabricated by layer-by-layer assembly. With increasing number of layers a transition of the electric property from insulating to conducting can be achieved. This conductivity leads to controllable thermogenesis of the film, which can be employed for drug release of loaded hydrogels.

Orientation-Dependent Thermogenesis of Assembled Magnetic Nanoparticles in the Presence of an Alternating Magnetic Field.

Thanks to thermogenesis in the presence of an alternating magnetic field, magnetic nanoparticles could play a promising role in local heating in vivo. However, the flexible control of thermogenesis for the given nanomaterials remains challenging. Here, we propose that the thermogenesis of assembled magnetic nanoparticles can be controlled by orientation of the film relative to an external field. This idea arises from the principle of energy conservation that is formulated by Poynting's theorem in electromagnetics. We firstly prove that the thermogenesis of magnetic nanoparticles under an alternating magnetic field is directly related to the energy flux of the field rather than to the field's intensity. Then, alteration of the orientation can lead to different incident electromagnetic energies for the nanoparticle film, where the cross-section of the energy absorption plays a crucial role. We developed a method to directly measure the complex susceptibility of an assembled film to confirm this point. This work could be of great importance for applications based on the electromagnetic energy conversion of nanomaterials.