Novel electro-responsive protein separation method with magnetic nanoparticles
Pharmaceuticals for cancer therapies and other diseases are very since the production of therapeutic molecules such as antibodies is costly and every production process needs to be developed individually. Especially purification processes, which make up to 80-90% of the whole production, need to be improved or new ideas need to be developed. Short peptide sequences, so called “tags”, can be used to create new purification strategies based on the biomolecule recognition of these sequences. Magnetic iron oxide nanoparticles are an interesting counterpart for peptide tags as their properties facilitate an easy handling and manipulation. The key to the design of high-affinity peptide tags lies in an in-depth understanding of surface-peptide recognition patterns. I developed such a magnetite-binding peptide tag which allows the purification of tagged model proteins from fermentation broths by changing the surrounding media. However, such pH and buffer switches might also alter the properties of pharmaceutically relevant proteins such as antibodies. The challenge of this project is to establish a novel elution process based on an electrical potential switch instead of a pH switch. The process contains the magnetic separation of proteins containing the peptide tags and the elution of proteins based on the change of tag-particle interactions with electric fields. The use of this system will help to understand the binding of proteins to iron oxide nanoparticles and the formation of an electrochemical double layer in external fields. The electrical double layer formation is not only interesting in biotechnological processes but for the understanding of electrochemical catalysis and energy storage. This idea might pave the way to completely new approaches in biomolecule recognition, protein detection and purification.