Photonic wiring of enzymatic reactions to photoactive entities for the construction of biohybrid electrodes In this work different strategies for the construction of biohybrid photoelectrodes are investigated and have been evaluated according to their intrinsic catalytic activity for the oxidation of the cofactor NADH or for the connection with the enzymes PQQ glucose dehydrogenase (PQQ GDH) FAD dependent glucose dehydrogenase (FAD GDH) and fructose dehydrogenase (FDH). The light controlled oxidation of NADH has been analyzed with InGaN GaN nanowire modified electrodes. Upon illumination with visible light the InGaN GaN nanowires generate an anodic photocurrent which increases in a concentration dependent manner in the presence of NADH thus allowing determination of the cofactor. Furthermore different approaches for the connection of enzymes to quantum dot (QD) modified electrodes via small redox molecules or redox polymers have been analyzed and discussed. First interaction studies with diffusible redox mediators such as hexacyanoferrate(II) and ferrocenecarboxylic acid have been performed with CdSe ZnS QD modified gold electrodes to build up photoelectrochemical signal chains between QDs and the enzymes FDH and PQQ GDH. In the presence of substrate and under illumination of the electrode electrons are transferred from the enzyme via the redox mediators to the QDs. The resulting photocurrent is dependent on the substrate concentration and allows a quantification of the fructose and glucose content in solution. [...]