Decoding ubiquinone-mediated transmembrane electron transfer in organic semiconductor-biohybrid systems

Efficient transmembrane electron transfer plays a critical role in regulating extracellular electron uptake and intracellular redox distribution in microbial cell factories and biohybrid biomanufacturing systems. However, the molecular mechanisms of how exogenous electrons enter cellular redox networks remain poorly understood, particularly in quinone-mediated pathways. Herein, organic semiconductor-ubiquinone model interfaces are constructed to simplify biological complexity and investigate interfacial electron transfer. Steady-state absorption spectroscopy, femtosecond transient absorption spectroscopy, and electron paramagnetic resonance spectroscopy are combined to establish a kinetic framework for electron transfer from organic semiconductors to ubiquinone. Ultrafast spectroscopy reveals charge transfer on femtosecond-to-picosecond timescales, confirming rapid interfacial electron transfer from organic semiconductors to ubiquinone. Furthermore, a structure-dynamics relationship is identified in which molecular planarity, π-conjugation, and interfacial electronic coupling govern electron transfer rates and charge delocalization. These results provide mechanistic insight into ubiquinone-mediated electron transfer and highlight its role as a universal and structurally adaptable electron acceptor. This work provides a molecular-level design framework for optimizing electron delivery and redox regulation in organic semiconductor-biohybrid systems for biomanufacturing. Graphic abstract The alternative text for this image may have been generated using AI.