稀土上转换纳米材料的优化设计及应用

发布时间：2018-03-18 08:24

本文选题：上转换纳米材料　切入点：近红外光　出处：《大连理工大学》2015年博士论文　论文类型：学位论文

【摘要】：稀土上转换纳米材料(UCNPs)是近年来在有机染料和量子点基础上发展起来的一种新型光学材料。由于其具有能将高能量的近红外光转换成低能量的紫外、可见甚至近红外光的独特光学性能,此类材料被广泛用于生物传感、生物体内成像、药物传递、光动力学治疗以及光活化等领域；并且在太阳能电池甚至临床诊断等领域展现出良好的应用前景。本论文通过调节稀土Yb3+的掺杂量并引入近红外有机染料作为敏化剂来优化设计UCNPs的发光性能,且应用于光动力学治疗及光学成像等相关领域。旨在解决UCNPs发光效率低,激发波长受限的问题。主要研究成果如下：(1)通过调节稀土yb3+在核中的掺杂量制备了一系列CaF2作为壳层的立方核/壳结构UCNPs,其中80%Yb掺杂的UCNP (a-NaYF4:Yb(80%),Er(2%)@CaF2)展示出最佳上转换红光发射,其绝对量子产率经测定(10 W/cm2,980 nm)达到3.2%。选择5-氨基酮戊酸(ALA)(一种临床上应用于光动力学疗法的前体药物)共轭连接在UCNP上制成ALA-UCNPs,在体内生物相容性的激光功率密度(0.5 W/cm2,980 nm)照射下,ALA-UCNPs在肿瘤治疗上显示出明显的光动力学治疗效果,并且能够深入到组织内1.2cm。体内治疗结果表明,980 nm近红外光激发在深层肿瘤治疗上优于临床使用的红色光照射。(2)通过引入具有不同吸收波谱的近红外有机染料分子敏化UCNPs的上转换发光来系统调节UCNPs的激发波长。实验证实近红外染料类似于一系列的“天线”,可以在不同激发带捕获近红外光子传递给UCNPs,相对于单个染料敏化的UCNPs, UCNPs的激发带可以通过“混合和匹配”一对有机染料来进行扩展。最后,利用这个概念实现了在一个选择性正交成像中的应用。(3)利用近红外有机染料IR-806敏化一系列不同壳层厚度的核/NaYF4壳结构β-NaYF4:20%Yb,2%Er@β-NaYF4 UCNPs上转换发光,发现一定厚度的NaYF4壳层会阻止染料向UCNPs的能量传递。通过在核/壳结构的壳层掺杂Yb3+作为从染料到内核层的能量传递桥梁,证实其能够在核/壳结构UCNPs基础上显著增强上转换发光,在2 W/cm2,800 nm连续光激发下,测得IR-806敏化p-NaYF4:20%Yb,2%Er@β-NaYF4:10%YB核/Yb壳结构UCNP的绝对量子产率达到6%,比截止目前报道的最强800 nm激发下UCNP强33倍。最后,通过两亲性三嵌段共聚物Pluronic F127包裹IR-806敏化核/Yb壳结构上转换纳米材料,将其成功转移至水相。
[Abstract]:UCNPsis a new optical material developed in recent years on the basis of organic dyes and quantum dots. Due to the unique optical properties of visible and even near-infrared light, such materials are widely used in biosensor, imaging in vivo, drug delivery, photodynamic therapy and photoactivation. In this paper, the luminescent properties of UCNPs are optimized by adjusting the doping amount of rare earth Yb3 and introducing near infrared organic dyes as sensitizer. And it is used in photodynamic therapy and optical imaging. The aim is to solve the problem of low luminescence efficiency of UCNPs. The main results of this study are as follows: 1) A series of UCNPs with cubic nucleus / shell structure of CaF2 as shell layer have been prepared by adjusting the doping amount of rare earth yb3 in the nucleus. The absolute yield of ALA-UCNPs was determined to reach 3.2nm.ALAA (a precursor drug used in clinical photodynamic therapy) was conjugated to make ALA-UCNPsin vivo biocompatible laser power density. ALA-UCNPs under 0.5 W / cm ~ (2) (980 nm) irradiation showed significant photodynamic effects in tumor therapy. The results of in vivo treatment showed that 980 nm NIR excitation was superior to the clinical use of red light irradiation in the treatment of deep tumor by introducing NIR organic dye molecules with different absorption spectra. The up-conversion luminescence of sensitized UCNPs is used to adjust the excitation wavelength of UCNPs. The experimental results show that the near infrared dye is similar to a series of "antennas" and can capture near infrared photons in different excitation bands to transfer to UCNPs. The excitation band of UCNPs, UCNPs, can be expanded by "mixing and matching" a pair of organic dyes. By using this concept, the application in a selective orthogonal imaging is realized. The near-infrared organic dye IR-806 is used to sensitize a series of core / NaYF4 shell structures with different shell thickness 尾 -NaYF4: 20 and Yb2Er@ 尾 -NaYF4 UCNPs up-conversion luminescence. It is found that a certain thickness of NaYF4 shell can prevent the energy transfer from dye to UCNPs. By doping Yb3 into the shell of core / shell structure as a bridge of energy transfer from dye to inner layer, It is proved that it can significantly enhance up-conversion luminescence on the basis of core-shell structure UCNPs, and it can be excited by 2 W / cm ~ (2) O _ (800) nm continuous light. The absolute yield of IR-806 sensitized p-NaYF4: 20 and Yb2Er@ 尾 -NaYF4: 10YB core / yb shell structure UCNP has reached 6%, 33 times higher than that of UCNP excited by the strongest 800nm excitation so far reported. Finally, the nanomaterials were transformed by the amphiphilic triblock copolymer Pluronic F127 to encapsulate the IR-806 sensitized core / yb shell structure. It was successfully transferred to the water phase.
【学位授予单位】：大连理工大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TB383.1

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