Zinc-formalin will give what kind of ultrastructure preservation?

• A. Poor ultrastructure preservation
• B. Excellent ultrastructure preservation
• C. No effect on ultrastructure
• D. Superior to formalin for all samples

Answer: (A)

Ultrastructure preservation refers to keeping the fine cellular details intact for electron microscopy. The fixative used greatly influences how well membranes, organelles, and other subcellular features are preserved. For electron microscopy, fixatives like glutaraldehyde and osmium tetroxide are preferred because they crosslink proteins strongly and stabilize lipids, maintaining membrane integrity and delicate structures.

Zinc-formalin, while useful for routine light microscopy and some antigen preservation, is not optimized for ultrastructural detail. Its crosslinking and interaction with tissues can lead to less reliable membrane preservation and more artifacts, resulting in poorer visualization of fine subcellular structures. That’s why zinc-formalin is associated with poor ultrastructure preservation rather than excellent or superior preservation for all samples.