Abstract：
Iron oxide nanomaterials has good biocompatibility and safety, and has been used as contrast agents for magnetic resonance imaging (MRI). However, its clinical usefulness is hampered by its difficult preparation on large scale, its rapid clearance in vivo and low target tissue enrichment efficiency. Here, we report the synthesis of water-soluble, biocompatible, superparamagnetic non-stoichiometric zinc ferrite nanoclusters (nZFNCs) of approximately 50 g in a single batch using a one-pot synthesis technique. nZFNCs is a secondary cluster structure with a size of about 40 nm composed of zinc-doped iron oxide nanoparticles with a size of about 6 nm. The surface of nZFNCS is endowed with a large number of carboxyl groups as active sites. By simply controlling the synthesis process and adjusting the proportion of metal precursors, the amount of zinc doping can be controlled, while maintaining the same size to ensure similar pharmacokinetics. Compared with undoped, the magnetic responsiveness and relaxation efficiency of nZFNCs are significantly improved, and the transverse relaxation efficiency (r2) can reach 425.5 mM-1 s-1 (doping amount x = 0.25), which is 7 times higher than that of commercial Resovist and 10 times higher than that of Feridex. In vivo imaging results also further confirmed the excellent contrast enhancement performance of the nanoclusters, which can achieve high contrast for more than 2 h in the liver. The advantage of this platform over comparable systems is that the contrast enhancement features are derived from simple techniques that do not require complex physical and chemical methods.
摘要：
氧化铁纳米材料具有良好的生物相容性和安全性,并已被用作磁共振成像（MRI）的造影剂。然而,由于难以大规模制备，其临床实用性受到阻碍，体内清除速度快,靶组织富集效率低。这里,我们报道了水溶性的合成，生物相容性使用一锅法合成技术在单个批次中大约50g的超顺磁性非化学计量锌铁氧体纳米团簇（nZFNC）。nZFNC是尺寸约为40nm的二级簇结构，由尺寸约为6nm的锌掺杂氧化铁纳米颗粒组成。nZFNCS的表面具有大量的羧基作为活性位点。通过简单地控制合成过程和调整金属前驱体的比例，锌的掺杂量可以控制，同时保持相同的大小以确保相似的药代动力学。与未掺杂相比，nZFNC的磁响应性和弛豫效率显著提高，横向弛豫效率（r2）可以达到425.5mM-1s-1（掺杂量x=0.25），比商业Resovist高7倍，比Feridex高10倍。体内成像结果也进一步证实了纳米团簇优异的对比度增强性能，可以在肝脏中达到高对比度超过2小时。该平台相对于可比较系统的优点在于,对比度增强特征源自不需要复杂的物理和化学方法的简单技术。
