Hantke, M.F. et al. Nat. Photonics 8, 943–949 (2014).

Single-particle diffractive imaging can be used to obtain structural information for large biological entities such as viruses or organelles, without crystallization. High-resolution, three-dimensional structure determination of such objects has remained challenging, however. Hantke et al. describe methods that allowed them to overcome two experimental difficulties in single-particle diffractive imaging. First, they developed an efficient aerosol injector to stream single particles into an X-ray free-electron laser beam. Second, they developed a computational purification approach to sort the heterogeneous population of particles. These advances allowed them to reconstruct a three-dimensional structure for the carboxysome, a micro-organelle responsible for carbon fixation in cyanobacteria, at 18.1-nanometer resolution—the highest resolution reported to date for a biological particle imaged with an X-ray laser.