Wiring photosynthetic enzymes to electrodes

The efficient electron transfer between redox enzymes and electrode surfaces can be obtained by wiring redox enzymes using, for instance, polymer-bound redox relays as has been demonstrated as a basis for the design of amperometric biosensors, logic gates or sensor arrays and more general as a central aspect of bioelectrochemistry. Related devices allow exploiting the unique catalytic properties of enzymes, among which photosynthetic enzymes are especially attractive due to the possibility to trigger the redox reactions upon irradiation with light. Photocatalytic properties such as the light-driven water splitting by photosystem 2 make them unique candidates for the development of semiartificial devices which convert light energy into stable chemical products, like hydrogen. This review summarizes recent concepts for the integration of photosystem 1 and photosystem 2 into bioelectrochemical devices with special focus on strategies for the design of electron transfer pathways between redox enzymes and conductive supports.