Examination of mucosal surfaces by scanning electron microscopy before and after removal of debris

A rapid method is described whereby gastrointestinal biopsy specimen surfaces can be examined by scanning electron microscopy with overlying tract contents (debris) intact, and also re-examined after cleaning to determine the structure of the underlying mucosal surface. The conductive coating of gold is removed using mercury, a non-wetting agent. The specimen surface is suitably cleaned of debris after a brief ultrasonication in absolute ethanol which mixes with the transitional fluid (CO2) used for critical point drying.