Supramoleculare Polymer Brushes as Drug Carrier Systems – Design of defined and reactive systems

在自然界中，超分子间的相互作用是可逆生成有序纤维结构的关键驱动力。目前埃米·诺特的项目采用了这个概念，目的是控制聚合物自组装成超分子纤维，也被称为聚合物刷。由于其刚性的圆柱形，不同功能聚合物的集成以及模块化设计，相应的结构对生物医学应用具有很高的吸引力。迄今为止获得的结果表明，超分子构建块的化学结构与其聚集之间存在明确的结构-性质关系。在这个项目的延续中，扩展的目标是对聚合过程的控制和由此产生的结构形成以及反应性组装和分解过程的集成进行重大改进。首先，在先前实验的基础上进行的全面调查将确定基于动力控制装配的定义生长的合适条件。理想情况下，可以确定一个亚稳态区域，在添加合适的细胞核后启动活的生长过程。或者，在微流体装置中产生的定义相变诱导更均匀的聚集过程并改善结构控制。同时，这个延续项目的目标是开发合适的构建块，分别促进反应驱动的组装或相应的组装结构的分解。聚集可以通过原位形成必要的疏水屏蔽来诱导。另一方面，疏水元素中的活性基团打开了反应性裂解或转化的潜力，这随后导致结构的分解。按照这些过程，可以制造出对不同刺激有非常特殊反应的瞬态聚合物刷。类似于自然界中已知的纤维状结构的能量驱动材料的开发代表了该项目的后续步骤。因此，需要由化学燃料可逆激活的构建块，从而触发依赖能量的聚集。与聚合物链上的互补反应性相结合，增加了控制这种方法的机会，例如通过可逆固定结构。从长远来看，这个项目可能会成为智能，尤其是适应性合成材料发展的基石，这些材料可以对环境的变化做出特异性和选择性的反应，并且在生物医学应用方面，开辟了新的方法，例如药物运输或组织结构。

Supramolecular interactions are a key driving force in nature for reversible creation of hierarchically ordered fibrous structures. The current Emmy Noether project takes up this concept with the aim of controlling the self-assembly of polymers into supramolecular fibers, also called polymer brushes. Due to their rigid, cylindrical shape, the integration of different functional polymers, and their modular design, the corresponding structures are highly attractive for biomedical applications. The results obtained so far show clear structure-property relationships between the chemical structure of the supramolecular building blocks and their aggregation. In continuation of this project, the expanded goal is a significant improvement of the control over the aggregation process and the resulting structure formation and an integration of reactive assembly and disintegration processes. First, comprehensive investigations in continuation of previous experiments will determine suitable conditions for a defined growth based on a kinetically controlled assembly. Ideally, a metastable region can be identified that initiates a living growth process upon addition of suitable nuclei. Alternatively, defined phase transitions generated in microfluidic devices induce a more uniform aggregation process and improve structural control. In parallel, this continuation project aims to develop suitable building blocks that facilitate a reaction-driven assembly or a corresponding disintegration of the assembled structures, respectively. The aggregation can exemplarily be induced by the in-situ formation of the necessary hydrophobic shielding. On the other hand, reactive groups in the hydrophobic elements open up the potential for reactive cleavage or transformation, which subsequently leads to disintegration of the structures. Following these processes, transient polymer brushes can be created that react very specifically to different stimuli. The development of energy-driven materials analogous to known fiber-like structures in nature represents a subsequent step in this project. Therefore, building blocks are required that are reversibly activated by a chemical fuel and consequently trigger an energy-dependent aggregation. The combination with complementary reactivities at the polymer chains extends the opportunities to control this approach, e.g. by reversible fixation of the structures. In the long term, this project might represent a cornerstone for the development of intelligent and, above all, adaptive synthetic materials that can react specifically and selectively to changes in their environment and, with regard to biomedical applications, open up new approaches, e.g. in drug transport or the structuring of tissue.