Upconversion nanoparticles as the basis for versatile intracellular luminescence bioassays

上转换纳米颗粒作为多功能细胞内发光生物测定的基础

• 批准号: RGPIN-2019-05382
• 负责人: Krull, Ulrich
• 金额: $ 5.76万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=692077
• 关键词: Upconversion; nanoparticles; basis; versatile; intracellular

The intention of the proposed work is to learn to build multi-functional nanoparticle (NP) platforms for intracellular analysis of dynamic processes, and for interventions in cellular processes. The unique optical resonance energy transfer properties of luminescent NPs allow for local interrogation of selective biomolecular interactions at a distance scale confined to the surface of the NP, and the luminescence can also be used for induction of photo-reactions that can release a cargo or activate a bioprobe associated with the NP. ******NPs are made to luminescence by irradiation with a low-power laser. Excitation wavelengths towards the infrared would be well suited for penetrating into complex biological samples and would reduce background scatter and autofluorescence, but typically offer insufficient energy to stimulate electronic excitation to achieve the desired optical interrogation processes. A desire to optically switch on the functionality of bioprobes or to release a cargo conjugated to NPs also is limited by insufficient energy at long wavelengths for activation of photo-reactions. An elegant approach to convert near-infrared (NIR) excitation radiation into ultraviolet (UV) and visible light can be achieved by an upconversion process in which two or more photons are absorbed and then combined. This happens within upconversion nanoparticles (UCNPs) containing lanthanides. UCNPs can serve as donors to transfer energy to proximal acceptors via luminescence resonance energy transfer (LRET), providing a transduction method that is sensitive only to interactions at molecular distances, and affording opportunity to drive photo-cleavage reactions on the surface of UCNPs. The research work will address issues that must be overcome before such technology will be effective for intracellular studies, including:******Project 1 Core-shell-shell UCNP designs that can stabilize high luminescence intensity at desired wavelengths while concurrently managing the spatial proximity of conjugates for LRET. ******Project 2 Improvement of luminescence intensity from UCNPs by increasing the electric field strength associated with excitation using resonance-coupled gold nanorods assembled with UCNPs.******Project 3 Improving colloidal stability of UCNPs in biologically-relevant solutions with coatings of multi-dentate phosphonate-based ligands in combination with polyethylene glycol.******Project 4 Photo-reactions within polymeric coatings caused by UV emission from UCNPs to release cargo or activate bioprobes on-demand.******The long-term goal is to produce a versatile tool for intracellular applications. The short-term objectives of the projects are to learn how to build UCNPs of higher emissivity and to coat these UCNPs with assemblies that can concurrently perform multiple tasks.*****

提出的工作的目的是学习建立多功能纳米颗粒（NP）平台，用于细胞内动态过程的分析，以及细胞过程的干预。发光NP独特的光学共振能量转移特性允许在局限于NP表面的距离尺度上对选择性生物分子相互作用进行局部询问，并且发光也可用于诱导光反应，从而释放货物或激活与NP相关的生物探针。******NPs通过低功率激光照射而发光。红外激发波长将非常适合穿透复杂的生物样品，并将减少背景散射和自身荧光，但通常提供的能量不足以刺激电子激发，以实现所需的光学探测过程。想要在光学上开启生物探针的功能，或者释放共轭到NPs上的货物，也受到光反应激活所需的长波能量不足的限制。一种将近红外（NIR）激发辐射转换为紫外线（UV）和可见光的优雅方法可以通过上转换过程实现，其中两个或多个光子被吸收然后组合。这发生在含有镧系元素的上转换纳米颗粒（UCNPs）中。UCNPs可以作为供体，通过发光共振能量转移（LRET）将能量转移到近端受体，提供了一种仅对分子距离上的相互作用敏感的转导方法，并提供了在UCNPs表面上驱动光裂解反应的机会。研究工作将解决在这种技术有效用于细胞内研究之前必须克服的问题，包括：******项目1核-壳-壳UCNP设计，可以在所需波长下稳定高发光强度，同时管理LRET共轭物的空间接近性。******项目2利用装配有UCNPs的共振耦合金纳米棒，通过增加与激发相关的电场强度来提高UCNPs的发光强度。******项目三：用多齿状膦酸盐配体与聚乙二醇结合涂层改善UCNPs在生物相关溶液中的胶体稳定性。******项目4由UCNPs的紫外线发射引起的聚合物涂层内的光反应，以按需释放货物或激活生物探针。******长期目标是为细胞内应用提供一个通用的工具。该项目的短期目标是学习如何建造更高发射率的UCNPs，并为这些UCNPs涂上可以同时执行多个任务的组件。*****