**2. Nanomedicine and magnetic nanomaterials**

Nanomedicine stands at the boundaries between the physical, the chemical, biological and medical sciences. It originated from the imaginative idea that robots and other related machines at the nanometer scale could be designed, fabricated and introduced into the human body for repairing malignant cells at the molecular level. According to its original vision, nanomedicine is a process including the diagnosis, treatment and prevention of diseases and traumatic injuries, and the preservation and improvement of human health, using molecular tools and molecular knowledge of the human body (*Freitas 2005*). The progress in both nanoscience and nanotechnology makes nanomedicine practical. From a technical viewpoint, nanomedicine consists of the applications of particles and systems at the nanometer scale for the detection and treatment of diseases at the molecular level, and it plays an essential role in eliminating suffering and death from many fatal diseases, such as cancer (*Yih and Wei 2005*). Based on nanofabrication and molecular self-assembly, various biologically functional materials and devices, such as tissue and cellular engineering scaffolds, molecular motors and biomolecules, can be fabricated for sensor, drug delivery and mechanical applications (Royal Society and Royal Academy of Engineering 2004). Nanomedicine has obvious advantages. First, nanoparticles are potentially invaluable tools for investigating cells because of their small size. Second, as their size can be controlled, from that of large molecules to that of small cells, the ability of nanoparticles to escape the vasculature *in vivo* can also be controlled. Third, because of their small size, nanoparticles can circulate systemically in the bloodstream and thus serve in roles such as magnetic resonance enhancement, iron delivery for the production of red blood cells and drug delivery to improve the availability of serum-insoluble drugs (*Whitesides 2005*).
