Light Triggered Electron Transfer between a Conjugated Polymer and Cytochrome C for Optical Modulation of Redox Signalling

Summary Protein reduction/oxidation processes trigger and finely regulate a myriad of physiological and pathological cellular functions. Many biochemical and biophysical stimuli have been recently explored to precisely and effectively modulate intracellular redox signalling, due to the considerable therapeutic potential. Here, we propose a first step towards an approach based on visible light excitation of a thiophene-based semiconducting polymer (P3HT), demonstrating the realization of a hybrid interface with the Cytochrome C protein (CytC), in an extracellular environment. By means of scanning electrochemical microscopy and spectro-electrochemistry measurements, we demonstrate that, upon optical stimulation, a functional interaction between P3HT and CytC is established. Polymer optical excitation locally triggers photo-electrochemical reactions, leading to modulation of CytC redox activity, either through an intermediate step, involving reactive oxygen species formation, or via a direct photo-reduction process. Both processes are triggered by light, thus allowing excellent spatio-temporal resolution, paving the way to precise modulation of protein redox signalling.