Multimodal biomedical imaging with asymmetric single-walled carbon nanotube/iron oxide nanoparticle complexes
Multimodal biomedical imaging with asymmetric single-walled carbon nanotube/iron oxide nanoparticle complexes
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DOI：
10.1021/nl062306v
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发表时间：
2007-04-01
期刊：
影响因子：
10.8
通讯作者：
Strano, Michael S.
中科院分区：
文献类型：
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作者：
Choi, Jong Hyun;Nguyen, Freddy T.;Strano, Michael S.
磁性氧化铁纳米粒子和近红外（NIR）荧光单壁碳纳米管（SWNT）形成异质结构复合物，可用作多模式生物成像剂。 Fe催化剂生长的SWNT通过序列d(GT)(15)的寡核苷酸封装单独分散在水溶液中，并使用0.5 T磁性阵列富集。所得的纳米管复合物表现出与各种纳米管物种相对应的独特的近红外荧光、拉曼散射和可见光/近红外吸收特征。 AFM 和冷冻 TEM 图像显示 DNA 封装复合物由一端附着碳纳米管的类似 3 nm 颗粒组成。 X 射线衍射 (XRD) 和超导量子干涉装置 (SQUID) 测量表明，纳米粒子主要是 Fe2O3 和超顺磁性。富含 Fe2O3 颗粒的纳米管溶液的磁性颗粒含量约为 35 wt%，磁化饱和度约为 56 emu/g，磁弛豫时间尺度比 (T-1/T-2) 约为 12。这些复合物由于其磁性成分尺寸较小，因此比典型的铁磁颗粒具有更长的自旋-自旋弛豫时间（T-2 约为 164 ms），同时仍保留 SWNT 光学特征。使用磁共振成像（MRI）和近红外图谱对吞噬 DNA 包裹复合物的巨噬细胞进行成像，证明这些多功能纳米结构可能在多模式生物医学成像中有用。
Magnetic iron oxide nanoparticles and near-infrared (NIR) fluorescent single-walled carbon nanotubes (SWNT) form heterostructured complexes that can be utilized as multimodal bioimaging agents. Fe catalyst-grown SWNT were individually dispersed in aqueous solution via encapsulation by oligonucleotides with the sequence d(GT)(15), and enriched using a 0.5 T magnetic array. The resulting nanotube complexes show distinct NIR fluorescence, Raman scattering, and visible/NIR absorbance features, corresponding to the various nanotube species. AFM and cryo-TEM images show DNA-encapsulated complexes composed of a similar to 3 nm particle attached to a carbon nanotube on one end. X-ray diffraction (XRD) and superconducting quantum interference device (SQUID) measurements reveal that the nanoparticles are primarily Fe2O3 and superparamagnetic. The Fe2O3 particle-enriched nanotube solution has a magnetic particle content of similar to 35 wt %, a magnetization saturation of similar to 56 emu/g, and a magnetic relaxation time scale ratio (T-1/T-2) of approximately 12. These complexes have a longer spin-spin relaxation time (T-2 similar to 164 ms) than typical ferromagnetic particles due to the smaller size of their magnetic component while still retaining SWNT optical signatures. Macrophage cells that engulf the DNA-wrapped complexes were imaged using magnetic resonance imaging (MRI) and NIR mapping, demonstrating that these multifunctional nanostructures could potentially be useful in multimodal biomedical imaging.