For this technique, the tissue should be sectioned at which thickness?

• A. 1-2 nm
• B. 5-10 µm
• C. 10-20 µm
• D. 0.1-0.2 µm

Answer: (A)

The technique requires extremely thin tissue sections to achieve the highest possible resolution and to minimize background scattering. Slicing tissue down to about 1–2 nanometers makes the sample effectively electron-transparent and preserves fine molecular details that would be obscured if thicker sections were used. While thicker sections in the micrometer range (such as 5–10 µm or 10–20 µm) are standard for light microscopy, they are far too thick for techniques that demand maximal resolution at the molecular or atomic level. A thickness of 0.1–0.2 µm (100–200 nm) is thinner than typical light-microscopy sections and sometimes used for certain electron-based methods, but it still doesn’t reach the ultrathin level required for this technique, making 1–2 nm the best choice in this context. Cutting sections that thin requires specialized ultramicrotomy and meticulous sample preparation to preserve structure.