稀土复合纳米晶在近红外二区荧光增强机制及光磁双功能生物成像研究

Fluorescence imaging has been applied in the field of bio-marking, disease diagnosis and drug development. In comparison with fluorescence imaging in the region of visible window and near-infrared (NIR) first window (750-900 nm), the fluorescence at NIR second window (1000-1400 nm) has deeper penetration depth and higher ratio of signal/noise, which recently attracts more and more worldwide attention in the field of bio-imaging. This project devotes to design a rare-earth composite nanocrystals with enhanced fluorescence and magnetic property through a controllable synthesis for bifunctional fluorescence imaging at NIR second window and magnetic resonance imaging (MRI).It is planned to change the type and ratio of alkali metals to establish the relation between morphology, size, crystal structure and fluorescence as well as magnetic property, and to screen the suitable rare-earth nanocrystals. The rare-earth complex with the NIR dye molecule on the surface will be created for the enhancement of fluorescence efficiency, followed by the mechanism investigation of fluorescence resonance energy transfer; next, water soluble rare-earth composite nanocrystals will be used for the bifunctional in vivo fluorescence imaging at NIR second window and MRI of small animals, the synergistic effect of which will be subsequently studied.

荧光成像技术已广泛应用在生物标记、疾病诊断、药物开发等领域。相对于普通可见光和近红外一区（750-900 nm）荧光成像技术，近红外二区（1000-1400 nm）荧光对生物组织穿透能力强，成像信噪比高，近年来已成为国际研究活体荧光成像的最新热点方向。本课题通过设计一种形貌尺寸可控、荧光效率提升、兼具磁学性能的稀土复合纳米材料，用于近红外二区荧光和磁共振双功能生物成像。拟通过调控碱金属的种类和比例，建立起稀土纳米晶尺寸、形貌、晶型同荧光和磁性之间的关系，筛选出适配的稀土纳米晶；构建近红外染料分子包覆的稀土复合纳米晶结构，增强荧光发射效率，并揭示其荧光共振能量转移机理；进一步制备水溶性的稀土复合纳米晶用于小动物活体荧光和磁共振双功能成像，评价其协同效应。

在医学诊断方面，荧光成像技术已广泛应用在生物标记、疾病诊断、药物开发等领域。相对于普通可见光和近红外一区（750-900 nm）荧光成像技术，近红外二区（1000-1400 nm）荧光对生物组织穿透能力强，成像信噪比高，近年来已成为国际研究活体荧光成像的最新热点方向。本课题通过设计一种形貌尺寸可控、荧光效率提升的稀土复合纳米材料，用于近红外二区荧光生物成像。通过调控碱金属的种类和比例，建立起稀土纳米晶尺寸、形貌、晶型同荧光之间的关系，筛选出荧光强度最优的的复合碱金属稀土纳米晶；随后包覆近红外染料分子（IR-780）在稀土复合纳米晶表面，增强荧光发射效率，并揭示其荧光共振能量转移机理；进一步制备水溶性的稀土复合纳米晶用于生物体猪皮荧光成像，评价其效果。