Magnetic nanoparticles for imaging technology

In recent years, paramagnetic nanoparticles have shown great potential applications in many biological fields. Versatility in the use of super paramagnetic iron oxide nanocrystals in the field of biomedical applications, including targeted drug delivery, bioseparation, tissue repair, cancer treatment through hyperthermia, and magnetic resonance imaging (MRI) contrast enhancement make this particle an appropriate choice for research. Magnetic nanoparticles have been extensively investigated as a contrast agent for MRI, which are easily assimilated by the human body. MRI is an important non invasive diagnosis and research technique, employed in the study of tumours, tissue lesions or in the identification of specific types of cells in the body. It can also be employed for in vitro studies or even for drug delivery. MRI analysis presents a high spatial resolution and the advantage of visualising transplanted cells within their anatomical surroundings, which is crucial for the description of migration processes. A variety of nanoparticles can be constructed to obtain MRI contrast, and peptide-conjugation approaches can be realised to label cells with multiple-detecting nanoparticles (magnetic, fluorescent, isotope); those currently in use typically range from 5 nm to 350 nm in diameter. These include super paramagnetic iron oxides (50-500 nm) and ultrasmall super paramagnetic iron oxides (5-50 nm), which are generally coated with dextran or other polymers to maintain solubility and reduce particle agglomeration. Magnetic nanoparticles are the most widely used contrast agents for the detection of implanted cells in vivo because of their contrast effect. This paper provides a critical view of applications of magnetic nanoparticles in different fields of biomedical engineering applications.