UCNPs核壳结构的合成与多模生物成像

发布时间：2018-01-12 08:06

本文关键词：UCNPs核壳结构的合成与多模生物成像　出处：《湘潭大学》2015年硕士论文　论文类型：学位论文

【摘要】：稀土上转换纳米材料(UCNPs)由于其独特的发光性质在生物荧光成像领域有着很好的应用前景,而且还可以作为药物载体通过靶向作用到达病理位置并进行可视化监控。除了在荧光(UCL)成像方面,UCNPs还可以用作其它成像技术(如计算机断层扫描(CT)、磁共振(MRI)等)的探针,但是其组织穿透深度低、发光效率不够高等缺陷限制了其发展脚步。如何制备出穿透深度高、发光效率高、分散性好、形貌尺寸可控的多模式生物成像探针成为关键问题。因此,针对这些关键问题,本文的主要研究内容分为以下主要两个方面:(1)在油酸(OA)/十八烯(ODE)/油铵(OM)的反应体系中通过热分解法合成了一系列形貌均一、尺寸均匀、分散性非常好的超细Tm3+和Er3+分别掺杂的NaYbF4纳米晶,同时又在OA/ODE的体系中通过热分解法在其表面包覆一层NaGdF4纳米晶,得到了Tm3+和Er3+分别掺杂的NaYF4@NaGdF4核壳结构的纳米晶。首先通过透射电镜(TEM)和高分辨透射电镜(HRTEM)对其形貌、尺寸和结构进行表征,通过X射线粉末衍射(XRD)确认了其立方相的结构,从场发射透射电镜得到的先扫描图中可以看出纳米材料的这种核壳结构。在980 nm激光激发下,NaYbF4:Tm及NaYbF4:Tm@NaGdF4在800 nm处发射较强的近红外光及较弱的蓝光和红光,由于人眼对蓝光比较敏感,所以,当分散在溶液中时,肉眼观察到的是蓝光。在980 nm激光激发下,Na YbF4:Er与Na YbF4:Er@NaGdF4纳米颗粒的上转换光谱呈现出较高的红绿比,激光照射下肉眼看到的颜色为橙色。(2)对以上合成的纳米材料进行水相改性,并接上生物相容性比较好的柠檬酸配体,通过傅里叶红外光谱分析(FTIR)、热重分析(TGA)、动态光散射(DLS)和Zeta电位等分析方法对改性后的亲水性纳米材料进行表征。酶联免疫检测仪(MTT实验)测试了材料对细胞没有明显的毒性,另外,经苏木精和伊红染色后,光学显微镜下观察到纳米材料对生物组织没有毒性。将这种接有配体的材料通过尾静脉注射入小鼠体内,可以观察到来自肝和脾的信号,而其他器官则没有信号,可以说明,Cit-NaYbF4:Tm@NaGdF4主要分布在小鼠的肝脾部位。没有接柠檬酸配体的NaYbF4:Er@NaGdF4裸粒子15分钟后则主要富集在肝脏之处以及皮下肌肉组织中,没有进入脾脏。这种多功能性的纳米探针不仅可以作为细胞和小动物活体UCL成像,还可以作为CT和MRI成像造影剂,成功的实现了UCL/CT/MRI多模生物成像。
[Abstract]:Due to its unique luminescence properties, UCNPshas a good application prospect in the field of bioluminescence imaging. It can also be used as a drug carrier to reach the pathological location through targeted action and to carry out visual monitoring, except for the imaging of fluorescent UCLs. UCNPs can also be used as a probe for other imaging techniques, such as computed tomography (CT), magnetic resonance imaging (MRI), etc., but its tissue penetration depth is low. The defects such as low luminescence efficiency restrict its development. Therefore, it is a key problem to prepare multi-mode biometric imaging probes with high penetration depth, high luminescence efficiency, good dispersion and controllable morphology and size. To address these key issues. The main contents of this paper are as follows: 1) A series of morphologies have been synthesized by thermal decomposition in the system of oleic acid / 18 oleic acid / oleic acid. Ultrafine Tm3 and Er3 doped NaYbF4 nanocrystals with uniform size and good dispersion. At the same time, a layer of NaGdF4 nanocrystalline was coated on the surface of OA/ODE by thermal decomposition method. Nanocrystalline of NaYF4@NaGdF4 core-shell structure doped with Tm3 and Er3 were obtained. First, the nanocrystalline of NaYF4@NaGdF4 core-shell structure was obtained by transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM). On the morphology. The structure of cubic phase was confirmed by X-ray powder diffraction (XRD). The core-shell structure of the nanomaterials can be seen from the first scanning diagram obtained by the field emission transmission electron microscope (TEM) under the excitation of 980nm laser. NaYbF4:Tm and NaYbF4:Tm@NaGdF4 emit strong near infrared light and weak blue and red light at 800nm, because the human eyes are sensitive to blue light. When dispersed in the solution, blue light was observed in the naked eye under the excitation of a 980nm laser. The upconversion spectra of Na YbF4:Er and Na YbF4:Er@NaGdF4 nanoparticles showed a high red-green ratio. The color seen by the naked eye under laser irradiation is orange. 2) the synthesized nanomaterials were modified in aqueous phase and the citric acid ligands with good biocompatibility were added. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). Dynamic light scattering (DLS) and Zeta potential were used to characterize the modified hydrophilic nanomaterials. In addition, after hematoxylin and eosin staining, it was observed under optical microscope that the nanomaterials were not toxic to biological tissue. The ligand was injected into mice via tail vein. Signals from the liver and spleen can be observed, while other organs have no signals, which can be explained. Cit-NaYbF4:Tm@NaGdF4 was mainly distributed in the liver and spleen of mice, and NaYbF4 without citric acid ligand. The Er@NaGdF4 naked particles were mainly concentrated in the liver and subcutaneous muscle tissue 15 minutes later. Not into the spleen. This versatile nano-probe can be used not only as a cell and small animal in vivo UCL imaging, but also as a CT and MRI imaging contrast agent. UCL/CT/MRI multimode biometric imaging is successfully realized.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB34

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