Prolonged and highly efficient intracellular extraction of photosynthetic electrons from single algal cells by optimized nanoelectrode insertion

Harvesting photosynthetic electrons (PEs) from plant or algal cells can be a highly efficient and environmentally friendly way of generating renewable energy. Recent work on nanoelectrode insertion into algal cells has demonstrated the possibility to directly extract PEs from living algal cells with high efficiencies. However, the instability of the inserted cells limits the practicality of this technology. Here, the impact of nanoelectrode insertion on intracellular extraction of PEs is characterized with the goal of stabilizing algal cells after nanoelectrode insertion. Using nanoelectrodes < 500 nm in diameter, algal cells remained stable for over one week after insertion and continued to provide PEs through direct extraction by the inserted nanoelectrodes. After nanoelectrode insertion, a photosynthetic current density of 6 mA·cm^-2, which is several fold higher than the current densities attained using approaches based on isolated thylakoid membranes or photosystem Ⅰ complexes, was observed in the dark and during illumination at various light intensities.