LAPONITE®-stabilized iron oxide nanoparticles for in vivo MR imaging of tumors

Abstract

We report the synthesis, characterization and utilization of LAPONITE®-stabilized magnetic iron oxide nanoparticles (LAP-Fe₃O₄ NPs) as a high performance contrast agent for in vivo magnetic resonance (MR) detection of tumors. In this study, Fe₃O₄ NPs were synthesized by a facile controlled coprecipitation route in LAP solution, and the formed LAP-Fe₃O₄ NPs have great colloidal stability and about 2-fold increase of T₂ relaxivity than Fe₃O₄ NPs (from 247.6 mM⁻¹ s⁻¹ to 475.9 mM⁻¹ s⁻¹). Moreover, cytotoxicity assay and cell morphology observation demonstrate that LAP-Fe₃O₄ NPs display good biocompatibility in the given Fe concentration range, and in vivo biodistribution results prove that NPs can be metabolized and cleared out of the body. Most importantly, LAP-Fe₃O₄ NPs can not only be used as a contrast agent for MR imaging of cancer cells in vitro due to the effective uptake by tumor cells, but also significantly enhance the contrast of a xenografted tumor model. Therefore, the developed LAP-based Fe₃O₄ NPs with good colloidal stability and exceptionally high transverse relaxivity may have tremendous potential in MR imaging applications.