Photo-induced electron transfer between photosystem 2 via cross-linked redox hydrogels

Photosystem 2 (PS2) that catalyses light driven water splitting in photosynthesis was 'wired' to electrode surfaces via osmium-containing redox polymers based on poly(vinyl)imidazol. The redox polymer hydrogel worked as both immobilization matrix and electron acceptor for the enzyme. Upon illumination, the enzymatic reaction could be switched on and a catalytic current was observed at the electrode. The catalytic current is directly dependent on the intensity of light used for the excitation of PS2. A typical current density of 45 mu A cm(-2) at a light intensity of 2.65 mW cm(-2) could be demonstrated with a significantly improved operational stability.