| In recent years, magnetic nanoparticles have played an increasing role in biomedical applications and have been the subject of extensive research investigations. Physical properties, including nanoparticle size, composition and surface chemistry, vary widely and influence their biological and pharmacological properties and, ultimately, their clinical applications and utilities. Among different magnetic nanoparticles, superparamagnetic iron oxide nanoparticles (SPIOs) were found non-toxic and used in multiple applications including magnetic resonance imaging (MRI) contrast agents, molecular and cellular imaging, and potential therapeutic options. Herein, a mixed spinel strategy was devised to increase the magnetization of SPIO by incorporation of non-magnetic Zn 2+. Addition of a normal spinel (ZnFe2O4) to an inverse spinel (Fe3O4) results in a magnetic disorder which leads to increased magnetization. Hydrophobic ZnxFe 1-xO˙Fe2O3 (x = 0.34) nanoparticles encapsulated in polymeric micelles exhibited increased T2 relaxivity and sensitivity of detection over commercially used FeridexRTM sample. The superb MR relaxivity of these Zn-SPIO nanoparticles and stability of micellar carriers make them excellent candidates for in vivo MR imaging of cancer. |
