Development of low-temperature and high vacuum atomic force microscope with freeze-fracture function

A high vacuum low temperature atomic force microscope (AFM) for the direct observation of biological freeze-fracture samples has been developed. This AFM has an integrated vacuum system and a freeze-fracture mechanism inside the vacuum chamber. It is possible to observe the fractured sample surface without exposing the freshly fractured surface to the ambient atmosphere. T he design is described in detail. A sample temperature up to -175 degreesC is achieved, with the temperature fluctuation less than 0.1 degreesC. Tempe rature control is possible from -175 to 0 degreesC for deep etching. An ult imate vacuum pressure of 8.7x10(-6) Pa has been achieved. Freeze-fractured human red blood cell has been examined, and fine structure within the cell has been observed. It is demonstrated that this is convenient and useful fo r the direct observation of a biological freeze-fractured surface. (C) 2001 American Institute of Physics.