Reproducibility and applicability of gallium replication as evaluated by biological specimen use

Structures of biological surfaces pressed on to a pure liquid gallium surface were successfully traced on to the gallium surface by quick-freezing below the melting point (28.78 degrees C) in air or water for replication in scanning electron microscopy. Gallium's high surface tension (approximately 700 mN m(-1) at 30 degrees C) deteriorates the spatial resolution of replicas and destroys some types of specimens. Five different biological surfaces were replicated on to gallium surfaces to evaluate spatial resolution and specimen resistance, i.e. reproducibility and applicability. Gallium replication of jewel beetle wing and human hair demonstrated submicron spatial resolution in the horizontal direction at least. Trials of protozoa, bacteria, and culture cell replication showed that protozoa are suited to replication because the cell membrane has characteristic structures with sufficient resistance to the gallium surface.