上转换研究方向的拓展：从发光调控到三维生物成像

A central goal in biology and medicine is to develop new imaging probes and technologies that enable monitoring of physiological processes in living cells, tissues, and organisms with high spatial resolution. Over the past decade, the development of nanoparticle research has resulted in a great deal of information about imaging probes available with considerable potential for biological researchers. Lanthanide-doped upconversion nanoparticles represent an important, growing class of imaging probes being developed. These nanoparticles are excited by near infared where biological samples show minmial absorptions, thereby allowing maximal light penetration through tissues. Upconversion nanoparticles also offer sharp emission peaks, large anti-Stokes shifts, long-lived excited electronic states, and high photostability that are essential for bioimaging studies. Despite these attractions, the adaptation of upconversion nanoparticles to confocal microscopy and 3D imaging has not been established yet, largely owing to the long life times (~ 1 ms) of the lanthanide ions commonly used for upconversion. The goal of this proposal is to develop upconversion nanoparticles that incorporate transition metal ions which feature shorter lifetimes but have not been adapted to generate upconversion. We also intend to build a luminescent imaging setup to apply these nanoparticles to 3D imaging. Once refined, we envisage that our research not only will generate new direction for materials research, but also will greatly promote further development in biology and medicine sciences.

生物学和医学研究的一个主要题目是开发新型探针技术用于灵敏细致地监测各种生理学过程，如细胞的活动规律和生物组织的变异机理。经过几十年的探索，人们已经发展了一系列生物探针技术，并总结出了一套建立生物荧光探针的指导思想。以此为基础，近年来发展了一类基于上转换发光纳米晶的荧光标记技术，其特点是以近红外光为激发源，有效的避开了生物组织对激发光的吸收，这不仅可以获得高的信号穿透深度，同时也避免了激发光对生物体的伤害。然而现有的上转换发光材料普遍依赖于激发态寿命长（~1 ms）的镧系离子，因而单位时间内发光亮度太低，不适合扫描荧光显微成像技术。针对这一问题，我们拟基于过渡金属离子，开发一种瞬时发光亮度高的新型上转换荧光探针，并以此为基础建立一种有效的基于上转换发光的三维扫描成像系统。我们相信，该目标的实现将拓宽发光材料学的研究范畴并对生物学研究产生非常积极的推动作用。

生物学和医学研究的一个主要题目是开发新型探针技术用于灵敏细致地监测各种生理学过程，如细胞的活动规律和生物组织的变异机理。经过几十年的探索，人们已经发展了一系列生物探针技术，并总结出了一套建立生物荧光探针的指导思想。以此为基础，近年来发展了一类基于上转换发光纳米晶的荧光标记技术，其特点是以近红外光为激发源，有效的避开了生物组织对激发光的吸收，这不仅可以获得高的信号穿透深度，同时也避免了激发光对生物体的伤害。本项目旨在完善基于上转换发光纳米晶的生物标记技术，克服已有材料发光亮度低，激发及发射谱带并未完全避开生物组织的吸收等问题。目前，我们已经开发了一系列新型核壳纳米结构，籍此获得了高的上转换发光亮度，并实现激发和发射光谱的灵活调控。同时，我们也建立了一套通用的纳米晶表面修饰及生物标记技术，为这类纳米晶在诊疗方面的应用铺平了道路。