To overcome the negative contrast limitations, and to improve the sensitivity of the magnetic resonance signals, the mesoporous silica coated Fe/Mn multilayered nanowires (NWs) were used as a T₁–T₂ dual‐mode contrast agents (CAs). The single component Fe and Mn NWs, and Fe/Mn multilayer NWs were synthesized by electrodeposition in the homemade anodic aluminum oxide (AAO) templates with the aperture of about 30 nm. The structural characterization and morphology of single component and multisegmented NWs was done by X‐ray diffraction and transmission electron microscopy. The elemental composition of Fe/Mn multilayerd NWs was confirmed by energy‐dispersive X‐ray and energy‐dispersive spectrometer. Vibrating sample magnetometer was used to test the magnetic properties, and 1.5 T magnetic resonance imaging (MRI) scanner was used to measure the relaxation efficiency. Importantly, the MRI study indicated that the Fe/Mn multilayer NWs showed a significant T₁–T₂ imaging effect, and have longitudinal relaxivity (r₁) value, that is, 1.25 ± 0.0329 × 10⁻⁴ μM⁻¹ s⁻¹ and transverse relaxivity (r₂), that is, 5.13 ± 0.123 × 10⁻⁴ μM⁻¹ s⁻¹, which was two times of r₁ value (0.654 ± 0.00899 × 10⁻⁴ μM⁻¹ s⁻¹) of Mn NWs, and r₂ value (2.96 ± 0.0415 × 10⁻⁴ μM⁻¹ s⁻¹) of Fe NWs. Hence, Fe/Mn multilayer NWs have potential to be used as T₁–T₂ dual‐mode CAs.

中文翻译：

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Fe/Mn 多层纳米线作为双模 T1-T2 磁共振成像造影剂

为了克服负对比度的限制，并提高磁共振信号的灵敏度，介孔二氧化硅涂层的 Fe/Mn 多层纳米线 (NW) 被用作 T ₁ -T ₂双模式造影剂（CA）。通过电沉积在孔径约为 30 nm 的自制阳极氧化铝 (AAO) 模板中合成了单组分 Fe 和 Mn 纳米线以及 Fe/Mn 多层纳米线。通过 X 射线衍射和透射电子显微镜对单组分和多段 NW 的结构表征和形态进行了表征。通过能量色散 X 射线和能量色散光谱仪确认了 Fe/Mn 多层纳米线的元素组成。使用振动样品磁力计测试磁性能，并使用1.5 T磁共振成像（MRI）扫描仪测量弛豫效率。重要的是，MRI 研究表明，Fe/Mn 多层 NW 显示出显着的 T ₁ -T ₂成像效果，并具有纵向弛豫（r ₁）值，即1.25 ± 0.0329 × 10 ^-4 μM ^-1 s ^-1和横向弛豫（r ₂），即5.13 ± 0.123 × 10 ^-4 μM ^-1 s ^-1是Mn NWs的r ₁值(0.654 ± 0.00899 × 10 ^-4 μM ^-1 s ^-1 )和r ₂值(2.96 ± 0.0415 × 10 ^-4 μM ^-1 s ^-1 )的两倍Fe NWs。因此，Fe/Mn 多层纳米线有潜力用作 T ₁ –T ₂双模 CA。