In situ imaging of oxygen-protective reaction fronts in biohybrid redox-active hydrogel thin films

Speaker: Dr. Rafał Białek, Technical University of Munich (TUM), Germany

Abstract: Confinement of enzymatic reactions within redox-active polymer hydrogel films extends beyond simple electrode wiring and offers substantial additional benefits. A prominent example is the embedding of [FeFe] hydrogenase within viologen-based redox-active polymer films, which provides effective protection against molecular oxygen, significantly reducing enzyme deactivation under otherwise detrimental aerobic conditions [1]. This protective mechanism is crucial for advancing the industrial applicability of this highly efficient yet oxygen-sensitive enzyme in hydrogen processing technologies. Although the mechanism underlying this protection – namely, the formation and possible progressive growth of an oxidized layer at the film surface, influenced by buffer pH – has previously been proposed and modelled, direct experimental evidence supporting this model has remained elusive. Here, we introduce an innovative experimental and data-analysis protocol employing confocal fluorescence microscopy that enables in situ visualization and quantification of oxidized-layer front propagation. This methodology provides definitive experimental validation of previous electrochemical interpretations and theoretical models. Furthermore, this versatile imaging approach can be broadly adapted to monitor reactive-layer dynamics across diverse thin-film systems beyond the specific viologen-polymer-protein construct described herein. [1] Plumeré, N., Rüdiger, O., Oughli, A.A., Williams, R., Vivekananthan, J., Pöller, S., Schuhmann, W., Lubitz, W., 2014. A redox hydrogel protects hydrogenase from high-potential deactivation and oxygen damage. Nature Chemistry 6, 822–827. https://doi.org/10.1038/nchem.2022

Those who cannot participate in person can follow the talk using Microsoft Teams:

Google Calendar

iCal Export