Facile synthesis of water-soluble Fe3O4 and Fe3O4@PVA nanoparticles for dual-contrast T1-and T2-weighted magnetic resonance imaging

Superparamagnetic iron oxide nanoparticles (SPIONs) are widely used as a robust negative contrast agent on conventional MRI. The development of new types of high-performance nanoparticulate MR contrast agents with either positive (T1) or dual-contrast (both positive and negative, T1 + T2) ability is of great importance. Here we report a facile synthesis of Fe3O4 and Fe3O4@PVA nanoparticles for dual-contrast T1-and T2-weighted MRI. The produced iron oxide nanoparticles were of high crystallinity and size uniformity with an average diameter of 7.25 & 8.64 nm and can be individually dispersed in the physiological buffer with high stability. The functional compositions and formation of PVA-magnetite composite were confirmed by FTIR analysis. VSM studies have shown that magnetite and PVA-magnetite composite nanoparticles exhibit superparamagnetic behavior at room temperature with saturation magnetization value of 54.82 emu/g, 39.62 emu/g respectively. It's due to the presence of nonmagnetic PVA molecule on magnetite and decrease in the size of the magnetite. The XPS and Mo center dot ssbauer spectra reveals presence of pure Fe3O4 nanoparticles. In-vitro relaxivity and contrast enhancement analysis show that, among both tested nanoparticles, Fe3O4@PVA nanoparticles possess optimal molar relax-ivities and contrast enhancement values, which can shorten the spin-lattice and spin-spin relaxation times, simultaneously.