Pure protein Biocathodes

Mimicking natural systems for engineering bioelectronic setups is a fantastic challenge. We developed with the LCBM at CEA Grenoble a design of a protein-only redox film inspired by the architecture of bacterial conductive biofilms. The molecular brick is a chimeric protein resulting from the association of a prion domain to a rubredoxin, an electron-carrier metalloprotein. . The prion domain self-assembles into mechanically stable fibres and provides a suitable arrangement of redox metal centres to allow electron transport through the network of bionanowires. . This results into highly organised films, able to transport electrons over several microns, which can be exploited to wire enzymes to electrodes.  Hence, our bionanowires were used as electron mediators to build a cathode for electrocatalytic oxygen reduction by laccase. This new technology opens new opportunities for the engineering of protein-only electron mediators, with tuneable redox potentials and optimised interactions with enzymes, and applications in the field of protein-only bioelectrodes (more).