Folic acid-conjugated superparamagnetic iron oxide nanoparticles for tumor-targeting MR imaging

Abstract

Superparamagnetic iron oxide nanoparticles (SPIONs) have been the subject of extensive research due to their potential biomedical applications. In the present investigation, superparamagnetic FA-PEI-Fe₃O₄ were successfully prepared and evaluated as a targeted MRI contrast agent. FTIR characteristics, TGA, VSM, and MR imaging confirmed the composition and magnetic properties of the synthesized nanoparticles. TEM showed that FA-PEI-Fe₃O₄ were spherical in shape and well dispersed. The nanoparticles were superparamagnetic at room temperature with a saturation magnetization value of 67.1 emu/g. The nanoparticles showed higher uptake efficiency due to receptor-mediated endocytosis. Moreover, specificity of FA-PEI-Fe₃O₄ to target tumor cells was demonstrated by the increased nanoparticle uptake and significant contrast enhancement of KB cells over MCF7 cells. The competitive inhibition of FA-PEI-Fe₃O₄ by free FA further confirmed the specific interaction of this conjugate with FA receptors. In vivo MR imaging studies showed a decreased signal intensity and enhanced tumor contrast post-injection of FA-PEI-Fe₃O₄. These results indicate that FA-PEI-Fe₃O₄ can be used as a promising tumor-targeting agent as well as a T₂ negative-contrast agent in MR imaging applications.

• Fe₃O₄
• magnetic nanoparticles
• MR imaging
• poly(ethyleneimine)
• tumor targeting

Declaration of interest

The authors report that they have no conflicts of interest to report. The authors gratefully acknowledge the financial support of this research by the National Key Basic Research Program of China (2013CB932703), the Natural Science Foundation of China (81472851, 81101743, 21425522, 31200751, and 31300827), and Beijing Natural Science Foundation (7152158).