Microanalysis in biology and medicine. A review of results obtained with three microanalytical methods.

Three microanalytical methods have been used : X-ray emission, secondary ion emission and electron energy loss analysis. Althouth X-ray microanalysis is the most used method, many biological problems cannot be solved because of its relatively low sensitivity and inability to analyze light elements. New possibilities are offered by Secondary Ion Mass Analysis and Electron Energy Loss Analysis. Analysis by secondary ion emission permits the study of elements at low and even trace element concentration, and even the lightest elements such as hydrogen and beryllium are detected. Electron Energy Loss Analysis makes possible the study of very small volumes, less than 500 A in diameter. These methods have been applied to the study of a variety of biological tissues (mostly lungs, kidneys and biomineralized tissues) and typical applications to pathology and cell biology will be presented.