Reporting their results in the journal Nanotechnology, researchers in France have used sophisticated electron microscopy techniques to investigate the biochemical effects of silver stress on the model yeast S. cerevisiae (eukaryotic cell) induced by exposure to a solution of silver nitrate or a nanosilver-containing organosilicon thin film.

The team used a large set of diagnostic methods based on transmission electron microscopy to investigate the impact of silver on intra- and extra-cellular structure and on biochemical components.

A chemical and structural analysis performed at the nanoscale (HRTEM, STEM, EDS) showed a clear differentiation between the observed electron-dense nodules. The silver nitrate solution induced the formation of silver nanocrystals and silver sulphur clusters whereas nanosilver-containing coating favoured the formation of clusters containing silver, phosphorus and sulphur. Moreover, an elemental mapmaking of each kind of treated cell indicated no identical behaviour of subcellular structure but underlined the key role of proteinaceous coumpounds in silver mass transfer.

The origin of such interactions should be explored in more detail in future work by coupling biochemical and physiological approaches.

Key points

The team's results provide new insight into the variety of silver effects (Ag+ and nanosilver) on microorganisms from a physicochemical point of view. Besides, this work emphasizes the ability of sophisticated electron microscopy techniques to perform structural and chemical analysis of cells at micro- and nanoscales.

Further details can be found in the journal Nanotechnology.