Atomic force microscopy imaging of dried or living bacteria

Atomic force microscopy (AFM) was used to obtain micrographs of dried bacte ria in air, and of living ones in their culture medium. Images of dried bac teria were very similar to images obtained elsewhere by the much more compl icated cryoetching preparation technique for transmission electron microsco py. Living bacteria were immobilized on a poly-L-lysine film, and directly observed in their culture medium at a resolution unattainable by any other technique applicable to living material. The images were similar to those o btained in scanning electron microscopy where the specimen must be fixed, d ried and coated with conductive material, and as a result, no longer viable . (C) Academie des Sciences/Elsevier, Paris.