Spectral triangulation: a 3D method for locating single-walled carbon nanotubes in vivo.
Spectral triangulation: a 3D method for locating single-walled carbon nanotubes in vivo.
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DOI：
10.1039/c6nr01376g
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发表时间：
2016-05-21
期刊：
影响因子：
6.7
通讯作者：
Bruce Weisman R
中科院分区：
文献类型：
--
作者：
Lin CW;Bachilo SM;Vu M;Beckingham KM;Bruce Weisman R
在短波红外（SWIR）区域发光的纳米材料由于该区域良好的组织透明度和低自发荧光背景而受到生物研究和医学诊断的特别关注。单壁碳纳米管 (SWCNT) 显示出众所周知的尖锐 SWIR 光谱特征，因此当与抗体等选择性靶向剂连接时，具有对癌症肿瘤进行无创检测和成像的潜力。然而，此类应用面临着灵敏检测和定位组织内部短波红外发射源的挑战。提出了一种称为光谱三角测量的新方法，使用在样本表面进行的稀疏光学测量来进行三维 (3D) 定位。结构未分类的单壁碳纳米管样品在一定波长范围内发射，并通过 LED 矩阵在组织模型内激发。通过连接 InGaAs 光谱仪或光谱过滤 InGaAs 雪崩光电二极管探测器的扫描光纤探头在表面上的点对由此产生的 SWIR 发射进行采样。由于吸水性，组织中单壁碳纳米管荧光的衰减与波长密切相关。因此，我们通过分析测得的单壁碳纳米管发射光谱的差异变化来测量单壁碳纳米管-探针距离。可以通过至少 20 毫米的组织模型清晰地检测到单壁碳纳米管荧光，并且可以在深度达 10 毫米的情况下以亚毫米精度找到嵌入的单壁碳纳米管测试样本的 3D 位置。我们的方法还可以区分和定位两个嵌入的单壁碳纳米管源在不同的位置。
Nanomaterials with luminescence in the short-wave infrared (SWIR) region are of special interest for biological research and medical diagnostics because of favorable tissue transparency and low autofluorescence backgrounds in that region. Single-walled carbon nanotubes (SWCNTs) show well-known sharp SWIR spectral signatures and therefore have the potential for noninvasive detection and imaging of cancer tumours, when linked to selective targeting agents such as antibodies. However, such applications face the challenge of sensitively detecting and localizing the source of SWIR emission from inside tissues. A new method, called spectral triangulation, is presented for three dimensional (3D) localization using sparse optical measurements made at the specimen surface. Structurally unsorted SWCNT samples emitting over a range of wavelengths are excited inside tissue phantoms by an LED matrix. The resulting SWIR emission is sampled at points on the surface by a scanning fibre optic probe leading to an InGaAs spectrometer or a spectrally filtered InGaAs avalanche photodiode detector. Because of water absorption, attenuation of the SWCNT fluorescence in tissues is strongly wavelength-dependent. We therefore gauge the SWCNT-probe distance by analysing differential changes in the measured SWCNT emission spectra. SWCNT fluorescence can be clearly detected through at least 20 mm of tissue phantom, and the 3D locations of embedded SWCNT test samples are found with sub-millimeter accuracy at depths up to 10 mm. Our method can also distinguish and locate two embedded SWCNT sources at distinct positions.