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

• Applicant: Professor Dr. Johannes Brendel
• Subject Area: Polymer Materials ; Preparatory and Physical Chemistry of Polymers
• Term: since 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 358263073

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.

• DFG Programme: Independent Junior Research Groups