Introduction

    Due to their ultra-fine size, magnetic properties and biocompatibility, superparamagnetic iron oxide nanoparticles (SPION) are emerging as promising candidates for various biomedical applications, such as enhanced resolution magnetic resonance imaging (MRI), targeted drug delivery and imaging, hyperthermia, magneto-transfections, gene therapy, stem cell tracking, molecular/cellular tracking, magnetic separation technologies (e.g. rapid DNA sequencing), detection of liver and lymph node metastases. In addition, their most recent applications for early detection of inflammatory, cancer, diabetes and atherosclerosis increased their popularity in academia.  Their superparamagnetism is particularly useful in applications such as externally guided drug delivery since removal of the external magnetic field prevents agglomeration and subsequent embolism.

   There are also numerous in vitro applications for SPION in medical diagnostics, such as immune magnetic separation of cells, proteins, DNA/RNA, bacteria, virus and other biomolecules. Inadequate characterization techniques, inhomogeneous properties, severe agglomeration in biological environment and fast recognition by the immune systems caused the usage limitation of SPIONs during last decades. Nevertheless, the employment of SPIONs in both diagnostics and therapeutics purposes has been extensively recognized nowadays due to the innovative technologies in both synthesis and analyzing in conjunction with new sophisticated and engineered organic and inorganic coatings which enhanced their properties.