Self-referenced photon upconversion nanosensors for imaging applications

用于成像应用的自参考光子上转换纳米传感器

• 批准号: 321104343
• 负责人: Dr. Ute Resch-Genger, since 3/2019
• 金额: --
• 依托单位: Fachbereich 1.2 - Biophotonik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/321104343?language=en
• 关键词: Self; referenced; photon; upconversion; nanosensors

Self-referenced photon upconversion nanosensors for imaging applications Upconverting nanomaterials are photoluminescent inorganic nanocrystals doped with rare earth ions that can convert infrared radiation into visible light. They can be surface-functionalized with polymeric shells and different (bio)molecular ligands, dyes, and indicators, which allows their use in various bioanalytical and sensing applications. They possess several advantages over currently used luminescent probes such as elimination of autofluorescence, multicolor emission, and exceptional photostability, thus enabling the development of new and the improvement of numerous existing applications. However, their use in chemical sensors or nanoprobes for chemical imaging is a comparatively unexplored field. In this application the utilization of upconversion nanoprarticles (UCNPs) in combination with analyte-sensitive dyes (indicators) as a new class of self-referenced nanoprobes with improved photostability for ratiometric intracellular sensing and imaging is proposed. Thereby, the UCNPs act as light emitting donors and the indicators coupled to the particle surface as acceptors. Different sensing mechanisms will be assessed such as sensitized emission of the indicator due to a resonance energy transfer or an emission-reabsorption mechanism, where the UCNP emission is modulated by analyte-induced changes in the indicator absorption via an inner filter effect. The aim is the preparation and evaluation of nanoprobes for the determination of oxygen, pH and Ca2+, which are key parameters of cellular metabolism and dysfunctions. A crucial factor for the rational development of UCNP-based nanoprobes is the study of interferences on the involved electronic transitions by environmental factors (e.g. quenching by water or heavy metal molecules) and how these interferences can be minimized by appropriate surface coatings. Therefore, this project will also include spectroscopic characterizations including lifetime measurements of the emissive states and their responses to external stimuli and FRET processes.

用于成像应用的自参考光子上转换纳米传感器上转换纳米材料是掺杂稀土离子的光致发光无机纳米晶体，可以将红外辐射转换为可见光。它们可以用聚合物壳和不同的(生物)分子配体、染料和指示剂进行表面功能化，这使得它们可以用于各种生物分析和传感应用。与目前使用的发光探针相比，它们具有几个优点，如消除自发荧光、多色发射和优异的光稳定性，从而使新的开发和现有的许多应用得到改进。然而，它们在化学传感器或用于化学成像的纳米探针中的应用是一个相对未被探索的领域。在这一应用中，提出将上转换纳米颗粒(UCNP)与分析物敏感染料(指示剂)相结合，作为一类新的具有更高光稳定性的自参考纳米探针，用于比率测量细胞内传感和成像。因此，UCNP充当发光给体，而连接到粒子表面的指示剂充当接受者。将评估不同的传感机制，例如由于共振能量转移引起的指示剂的敏化发射或发射-再吸收机制，其中UCNP发射由分析物通过内部过滤器效应引起的指示剂吸收的变化来调制。目的是制备和评价用于测定氧、pH和钙离子的纳米探针，这些都是细胞代谢和功能障碍的关键参数。合理开发基于UCNP的纳米探针的一个关键因素是研究环境因素(如水或重金属分子猝灭)对复杂的电子跃迁的干扰，以及如何通过适当的表面涂层将这些干扰降至最低。因此，该项目还将包括光谱表征，包括发射态的寿命测量及其对外部刺激和FRET过程的响应。