Polymeric Nanocarriers for the Visualization and Quantification of Molecular Release

当前提案的总体目标是开发一种技术平台，通过结合能够同时可视化和量化有效载荷传递的可切换荧光部分来跟踪和量化分子释放机制(例如药物释放)。聚合物纳米粒作为药物输送载体的发展促进了各种治疗药物的有效靶向释放策略。当与成像剂结合时，这些纳米颗粒可以可视化分子有效载荷的生物分布。然而，这些系统中的大多数不报告药物从载体上的释放，这是设计优化的有效载荷输送系统的关键，并将使人们能够深入了解生物效应。所寻求的项目将开发新型的聚合物纳米载体，它可以显示在哪里，何时以及多少分子有效载荷被运送到特定的目标位置。具有强烈的聚合物化学焦点，这将通过在输送系统中加入氮氧化物-荧光团对来实现。当荧光团被保持在接近氮氧化物的位置时，荧光团进入前荧光状态，并观察到荧光完全猝灭。当负载从载体上释放时-通过刺激引起共价键的断裂-将发生氮氧化物和荧光团部分的分离，并将观察到荧光立即增加，从而允许传递的量化。分子的设计将使一个荧光团的开启与一个交付分子的释放有关，从而产生可量化的释放量度。为了实现这一理想，已经确定了一些化学挑战，这些挑战是当前提案的核心，将得到解决，从而使人们对实现聚合物纳米载体递送的机制有更深刻的理解。这一概念将在体外和体内研究中得到证实，以证明其实际适用性。

The overarching aim of the current proposal is to develop a technology platform that can follow and quantify molecular release mechanisms (e.g. drug release) by incorporating a switchable fluorescent moiety which is able to simultaneously visualise and quantify payload delivery. The development of polymeric nanoparticles as drug delivery vehicles has facilitated effective targeted release strategies for a variety of therapeutics. When combined with imaging agents, these nanoparticles allow for the visualization of the biodistribution of a molecular payload. However, the majority of these systems do not report on the release of the drug from the carrier, an important facet which is crucial to the design of optimized payload delivery systems and will enable an in-depth understanding of biological effects. The sought project will develop novel polymeric nano-carriers which can show where, when and how much molecular payload is delivered to a specific target site. Featuring a strong polymer chemical focus, this will be achieved through the incorporation of a nitroxide-fluorophore couple into the delivery system. When a fluorophore is held in close proximity to a nitroxide, the fluorophore enters a profluorescent state and a complete quenching of the fluorescence is observed. When the load is released from the carrier - through stimuli-induced scission of a covalent linkage - separation of the nitroxide and fluorophore moieties will occur and an immediate increase in fluorescence will be observed, thereby allowing the quantification of the delivery. The molecules will be designed such that the switch on of one fluorophore will be related to the release of one delivered molecule, leading to a quantifiable measure of release. In order to realize such an ideal, a number of chemical challenges have been identified that are at the core of the current proposal and will be addressed, leading to a more profound understanding of the mechanisms by which delivery from polymeric nanocarriers is achieved. The concept will be evidenced in in vitro as well as in vivo studies to demonstrate its practical applicability.