Lanthanide Containing ZnS Nanoparticles

描述(由申请人提供)：本提案描述了一项计划，通过将硫化锌半导体纳米颗粒和发光稀土阳离子相结合来开发具有先进发光性能的纳米颗粒，从而充分利用各自的光物理优势。其目的是利用具有较大吸收截面的硫化锌纳米颗粒，通过“天线效应”敏化稀土阳离子的发射，并提供一种保护稀土离子不受非辐射失活的基质。硫化锌是一种理想的基质材料，因为它比广泛使用的硫化镉纳米晶体毒性小，但由于硫化锌的带隙位于紫外/蓝光区域，这使得它们与生物成像应用不兼容，因为紫外/蓝光与生物体系之间存在强烈的干扰。然而，稀土离子的加入使激发能在可见光和近红外光谱中以锐利发射带的形式通过稀土离子释放，这取决于稀土离子作用的性质。稀土阳离子具有清晰明确的发射带，对其环境(如温度、pH、压力或生物环境)不敏感，并允许从生物背景(自发荧光)中进行光谱区分。与许多其他荧光发射体相比，稀土离子还具有更长的发光寿命(微秒到毫秒)，允许分析物信号和背景荧光之间的时间区分。纳米颗粒表面的化学衍生化将被用来为纳米晶体探针提供生物化学选择性，并使材料安全和可溶于靶向生物应用。这些材料将在组织和细胞制剂中进行测试，并与用于荧光显微镜应用的商用探针进行比较。在原代细胞培养模型中，将使用高灵敏度的光学成像方法来检测细胞损伤和死亡，以评估纳米晶体的毒性。 与公众健康相关：我们将开发一种新型的发光纳米颗粒家族，它可以发出可见光或近红外光，并专门设计为在包括生物成像在内的广泛的“体内”和“体外”生物分析应用中作为荧光记者。最终，这些纳米颗粒将构成一个多功能的发光平台，其光学特性将补充现有的荧光团，它们的信号很容易与生物系统的天然荧光区分开来。

DESCRIPTION (provided by applicant): This proposal describes a program to develop nanoparticles with advanced luminescence properties by combining zinc sulfide (ZnS) semiconductor nanoparticles and luminescent lanthanide cations so that the photophysical advantages of each are exploited. The aim is to use ZnS nanoparticles, with their large absorption cross section, to sensitize the lanthanide cations emission by an "antenna effect" and to provide a matrix that protects the lanthanides from nonradiative deactivation. ZnS is a desirable matrix because it is less toxic than the widely used CdSe nanocrystals, however the ZnS bandgap lies in the ultraviolet/blue spectral region, which has made them incompatible with biological imaging applications because of the strong interference between UV/blue photons and biological systems. However, the addition of lanthanide cations to the ZnS matrix causes the excitation energy to be released through the lanthanide cations as sharp emission bands in the visible and near infrared, determined by the nature of the lanthanide action. The lanthanide cations have sharp well defined emission bands that are insensitive to their environment (such as temperature, pH, pressure or biological environment) and allows for spectral discrimination from biological background (autofluorescence). Lanthanide cations also have longer luminescent lifetimes (micro- to milliseconds) than many other fluorescence emitters, allowing for temporal discrimination between the analyte signal and the background fluorescence. Chemical derivatization of the nanoparticle surface will be used to provide the biochemical selectivity for the nanocrystal probe and to make the material safe and soluble for the targeted biological applications. These materials will be tested in tissue and cell-based preparations and compared to commercially available probes for use in fluorescence microscopy applications. The toxicity of the nanocrystals will be evaluated using highly sensitive optical imaging methodologies for detecting cellular damage and death in primary cell culture models. PUBLIC HEALTH RELEVANCE: We will develop a novel family of luminescent nanoparticles that emit visible or near infrared light and are specifically designed to operate as fluorescent reporters in a broad range of "in vivo" and "in vitro" bioanalytical applications, including biological imaging. Ultimately, these nanoparticles will constitute a versatile luminescence platform whose optical properties will complement existing fluorophores, their signal being easily discriminated from the native fluorescence of biological systems.