Pharmaceuticals for cancer therapies and other diseases are very expensive since the production of therapeutic molecules, such as antibodies, is costly and each production process needs to be developed individually. In particular, purification processes, which generally make up to 80-90% of the production train, need to be improved or new concepts need to be developed. Short peptide sequences, so called “tags”, can be used to create new purification strategies based on biomolecular recognition of these sequences. Magnetic iron oxide nanoparticles are an interesting counterpart for peptide tags as their properties facilitate 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. We have developed such a magnetite-binding peptide tag which allows the purification of tagged model proteins from fermentation broths by changing the environment afforded by the surrounding media. However, such pH and buffer switches might also alter the properties of pharmaceutically relevant proteins such as antibodies. We show that the interactions between the particles and the proteins can be modulated by an applied electrical potential which causes changes in the electrochemical double layer; such a process may make it unnecessary to use chemical switching for control of the protein capture.<br/>The iron oxide nanoparticles have been well-characterized by spectroscopy, microscopy and diffraction. The binding affinity between the proteins and the particles was investigated by cyclic voltammetry and impedance spectroscopy of immobilized iron oxide nanoparticles on carbon-based electrodes. The change in the particle properties was monitored by electron microscopy and infrared spectroscopy. The binding and release of biomolecules was studied with UV-Vis spectroscopy.<br/>The process entails the magnetically facilitated separation of biomolecules and their elution based on changes in molecule-particle interactions with electric fields. The study of this system will help to understand the binding of proteins to iron oxide nanoparticles and the formation of an electrochemical double layer under external fields. The electrical double layer formation is not only interesting in biotechnological processes but also in electrochemical catalysis and energy storage. The principles developed here could pave the way to new approaches in biomolecule recognition, protein detection and purification.

Intermolecular binding within the electrochemical double layer on iron oxide nanoparticles: Effect of potential

ACS Fall 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.