表面等离激元介导上转换纳米晶@Au-靶向配体系统的光物理

项目名称： 表面等离激元介导上转换纳米晶@Au-靶向配体系统的光物理

项目编号： No.11474035

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 数理科学和化学

项目作者： 陈力

作者单位： 长春工业大学

项目金额： 95万元

中文摘要： 上转换纳米晶在肿瘤诊疗方面极具应用前景,但发光效率低强度弱的内在缺陷严重制约了该类材料的应用。人们通过单独改善晶核内部因素,或引入外部金壳的表面增强效应使得荧光效率有所提高,但对表面等离激元(SP)的增强/猝灭机制尚不系统明晰,对统筹调制内外两种因素进一步显著提高荧光效率这一有效途径更缺乏系统研究。本项目通过改变核-壳比实现SP共振带可调并与激发光匹配,改变核壳间隔的组成/厚度,掺杂离子种类/浓度,靶向配体种类等内/外部影响条件实现材料可控合成及发光性能优化,利用发光学原理/等离子光子学理论及光谱技术手段,重点研究近红外光激发下体系的发光性质,电荷/能量传递及动力学规律,针对实际应用揭示SP影响纳米晶@Au-靶向配体系统荧光增强/猝灭规律及物理机制,给出该类材料的组成/结构最优化方案原则和标准,为研制有高效上转换荧光的,集成像诊断光热/X-ray辐射治疗于一体的多功能材料提供物理和材料基础。

中文关键词： 上转换发光；激光光谱学；表面增强荧光；稀土发光；纳米核/壳结构

英文摘要： Up-converting nanoparticle@Au core-shell nanostructure is considered as a promising functional structure of nanocomposites used in medical imaging and therapeutics. However, due to the intrinsic disadvantages of upconverting core including small absorption cross section, forbiddened f-f transition etc.,the up-conversion luminescence efficiency and intensity are weak(for NaYF4:Er,Yb nanoparticle,<1%),which is a main setback of their widely applications. Two protocols are adopted to improve the up-conversion luminescence. One is to change the main factors which intrinsically play important role on the efficiency and intensity like changing concentrations and species of doped lanthanide ions, surface modification of nanoparticles etc. The other is to introduce the external factor like surface-enhanced electromagnetic field generated by noble metal configuration to manipulate the up-conversion luminescence. But so far, it is still a big challenge to successfully achieve a satisfied result via just one of those two protocols alone.In addition, the nature of the fluorescence enhancement effect originated from surface plasmon is still unclear. Therefore, it is of great meaningfulness for both fundamental research and application to verify the rules and nature of the enhancement/quenching effect caused by surface plasmon in the core-shell system of up-converting nanoparticle@Au-targeting ligands. Wet chemistry methods such as hydrothermal technique are employed to fabricate core-shell nanostructures of NaYF4:Re3+@Au followed by targeting modification with PEG, anti-EGFR, folate, transferring and nuclear-localization signal. Surface plasmon resonance bands can be tuned across the visible into the near infrared region of electromagnetic spectrum by varying core-shell diameter ratio. To avoid the possible quenching of fluorescence layer by layer assembly of SiO2, PEG or polyelectrolytes as spacers between the nanophosphor and gold is deliberately designed and performed.Optical properties under near infrared excitations,charge/energy transfer along with the dynamic processes are investigated by means of electronic spectroscopy techniques including the emission and absorption spectroscopy, surface-enhanced Raman spectroscopy (SERS), etc. Clear and potent mechanisms and scenarios should be put forward to elucidate the surface enhanced/quenched luminescence, SERS effects of this sort of multifunctional materials bio-functionalized with various targeting ligands in such complex in vitro circumstances. Much more importantly and valuably to be addressed, our proposal is aiming at establishing the physical and experimental basis of clinical applications of dual modality imaging for tumor cells, synergetic photothermal treatment and X-ray radiotherapeutics, consequently in the long term view, developing a reliable theranostics strategy with high efficacy for both shallow and deep cancers.

英文关键词： up-conversion luminescence;laser spectroscopy;surface-enhanced fluorescence;lanthanide fluorescence;core/shell nanostructures