Visualization of the spatial distribution of Ag ions in cyanobacteria Anabaena sp. PCC 7120 by time-of-flight secondary ion mass spectrometry and two-photon luminescence microscopy

Cyanobacteria Anabaena sp. PCC 7120 have been analyzed by time-of-flight secondary ion mass spectrometry and two-photon luminescence microscopy. The reduction of Ag+ ions to silver nanoparticles inside the cells is detected. The silver ion signal is shown to be much greater inside certain cells. Comparing the distribution of Ag ions with optical images allows us to identify these cells as heterocysts, which are specialized nitrogen-fixing cells.