In Operando Investigation of Electrical Coupling of Photosystem 1 and Photosystem 2 by Means of Bipolar Electrochemistry

Electrochemical communication between two photobioelectrochemical half-cells based on photosystem 1 and photosystem 2 is investigated in operando. The driving force for the electron-transfer reactions is applied in a wireless mode using bipolar electrochemistry with the actual electrode potentials being self-regulated by the redox processes. Four parameters are assessed to understand the overall performance and elucidate the limiting reactions of the photobioelectrochemical cell. In addition to the potential differences for oxidation and reduction reactions, the current flowing between the half-cells as well as in situ collection of locally evolved O₂ by photosystem 2 using a positioned scanning electrochemical microscopy tip are evaluated. In this way, changes in the enzymatic performances as a result of inactivation of either of the protein complexes or variations in the external conditions are monitored