Widely used in electron microscopy to enhance contrast of biological specimens such as viruses, proteins, and cellular structures. It binds to the surface of macromolecules, providing a dense, electron-scattering layer that outlines fine structural details. Commonly applied in virology and structural biology for quick, reliable imaging without requiring complex sample preparation. Also used in histology as a component of staining protocols for light microscopy, particularly for demonstrating fibrin and basement membranes. Its high electron density and fine grain make it ideal for negative staining techniques where background contrast is critical.