Nanogold®, a gold cluster with a core of gold atoms 1.4 nm in diameter, has proven to be a superior probe label for electron microscopy (EM),14,17 giving both higher labeling density28,31 and improved access to previously hindered or restricted antigens.29,31 It may be visualized by autometallography (AMG) for use in light microscopy (LM): silver-and gold-amplified Nanogold detection12,18 has proven to be one of the most sensitive methods available for the detection of low copy number targets such as viral DNA in cells and tissue specimens.32 AMG enhancement has also made Nanogold an effective detection label in blots15 and gels.10 The following protocols will be described:

• Labeling of nuclear components in cells.