“The key design principle of natural photosynthesis is the closing of the photosynthetic cycle on the shortest possible length scale under membrane separation of the incompatible water oxidation and proton reduction environments,” said Heinz Frei, a senior scientist in Biosciences’ Molecular Biophysics and Integrated Bioimaging (MBIB) Division. With collaborators Eran Edri, a former postdoctoral fellow in MBIB now at Ben-Gurion University, and Shaul Aloni in the Molecular Foundry Division, Frei developed a fabrication method to make a square-inch sized artificial photosystem, in the form of an inorganic core-shell nanotube array, that implements this design principle for the first time. The method was described in a paper published earlier this year in ACS Nano.