Abstract
Extremely small-sized iron oxide nanoparticles(IONPs)are of great interest in magnetic resonance imaging(MRI)due to their biosafety as an alternative to clinical gadolinium(Ⅲ)complexes-based contrast agents.Espe-cially when the particle size is less than 10 nm,it has strong diffusion ability and deep penetration distance in tumor tis-sue.Substitution doping can significantly enhance the T1 contrast effect of nanoparticles by regulating the surface exposed atoms.However,the nucleation and growth pro-cesses of multi-component synthesis systems are complex and difficult to be accurately controlled,leading to great challenges in the synthesis of ultra-small-sized nanoparticles with different components and sizes.Here,extremely small-sized superparamagnetic gadolinium-doped iron oxide nanoparticles(GdIONPs,GdxFe3-xO4 NPs)with adjustable doping amount and controllable size in the range of 3.5-7.5 nm were synthesized by thermal decomposition.Then,as-synthesized GdIONPs were surface modified with a highly water-soluble and biocompatible carboxyl-poly-ethylene glycol-phosphoric acid ligand with high binding affinity.Gd0.65Fe2.35O4 NPs exhibited very high r1 relaxivity of 10.6 mmol-1·L·s-1 in terms of all metal concentrations and 49.0 mmol-1·L·s-1 in terms of gadolinium alone,respectively,3 and 14 times higher than clinical T1 contrast agents(Gd-DTPA).GdIONPs can continuously obtain high resolution images of blood vessels,and can be used as an efficient and multifunctional contrast agent for MR T1 imaging.This stable and efficient doping strategy provides an easy and effective method to individually optimize the magnetic properties of complex oxides and their relaxation effects for a variety of biomedical applications.
基金项目
Project of Highlevel Teachers in Beijing Municipal Universities in the Period of 13th Five-Year Plan(CIT&TCD201804025)
Beijing Municipal Education Commission(KM201910011009)
Graduate Student Scientific Research Ability Promotion of BTBU()
NETL
NSTL
万方数据