Synthesis of Photo Crosslinked and pH Sensitive Polymersomes and Applications in Synthetic Biology

As an inspiration from nature, polymeric vesicles can be formed from amphiphilic block-copolymers. These vesicles are called polymersomes and have applications in drug delivery and as nanoreactors. Within this thesis, photo cross-linked and pH sensitive polymersomes were synthesized, characterized and applied on cells as well as bionanoreactors. The stability due to the crosslinking yielded polymersomes which show a distinct and reproducible swelling upon repeated pH changes. If the non cross-linked vesicles were exposed to a plasma-cleaned surface, they formed a tethered singly and multiple bilayers. Upon studying these membranes, they turned out to harden upon crosslinking and showed a completely non-fluid behaviour. Additionaly, the polymersome-cell interactions were studied and yielded a high influence of the crosslinking conditions on cellular toxicity. If crosslinked for a long time in a phosphate-free enviroment, the polymersomes proved to be least toxic. Finally, an enzyme was incorporated into the polymersomes to create bionanoreactors. Due to the pH sensitivity and swelling, the vesicles created yielded a pH controlled nanoreactor with enzymatic activity and a swollen, e.g. acidic, state only