Department of Chemistry, National Taiwan University , Taipei, Taiwan.
J Am Chem Soc. 2013 Dec 11;135(49):18621-8. doi: 10.1021/ja409490q. Epub 2013 Nov 27.
A novel T1 agent, antiferromagnetic α-iron oxide-hydroxide (α-FeOOH) nanocolloids with a diameter of 2-3 nm, has been successfully prepared. These nanocolloids, together with a post synthetic strategy performed in mesoporous silica, are a great improvement over the low T1-weighted contrast common in traditional magnetic silica nanocomposites. The intrinsic antiferromagnetic goethite (α-FeOOH) shows very low magnetization (M(z)) of 0.05 emu g(-1) at H = 2 T at 300 K (0.0006 emu g(-1) for FeOOH/WMSN-PEG), which is 2 orders of magnitude smaller than any current ultrasmall iron oxide NPs (>5 emu g(-1)) reported to date, hence ensuring the low r2 (∝ Mz) (7.64 mM(-1) s(-1)) and r2/r1 ratio (2.03) at 4.7 T. These biodegradable α-FeOOH nanocolloids also demonstrate excellent in vitro cellular imaging and in vivo MR vascular and urinary trace imaging capability with outstanding biocompatibility, which is exceptionally well secreted by the kidney and not the liver as with most nanoparticles, opening up a new avenue for designing powerful antiferromagnetic iron T1 contrast agents.
一种新型的 T1 造影剂，即具有 2-3nm 直径的反铁磁α-氧化铁-水合物（α-FeOOH）纳米胶体，已被成功制备。这些纳米胶体与介孔硅中的后合成策略一起，与传统磁性硅纳米复合材料中常见的低 T1 加权对比相比有了很大的改进。本征反铁磁针铁矿（α-FeOOH）在 300K 时在 H=2T 下显示出非常低的磁化强度（M(z)）为 0.05 emu g(-1)（FeOOH/WMSN-PEG 为 0.0006 emu g(-1)），比迄今为止报道的任何当前超小氧化铁 NPs（>5 emu g(-1))都低 2 个数量级，因此保证了低 r2（∝Mz）（在 4.7T 时为 7.64mM(-1)s(-1))和 r2/r1 比值（2.03）。这些可生物降解的α-FeOOH 纳米胶体还表现出优异的体外细胞成像和体内 MR 血管和尿痕成像能力，具有出色的生物相容性，它们异常好地被肾脏分泌，而不是像大多数纳米颗粒那样被肝脏分泌，为设计强大的反铁磁铁 T1 造影剂开辟了新途径。
