What type of staining was used to visualize lipids or unsaturated fats in the sample?

What type of staining was used to visualize lipids or unsaturated fats in the sample?

• A. Masson's trichrome
• B. H&E
• C. OsO4
• D. Gram stain

Answer: (C)

Staining lipids requires a reagent that specifically reacts with the unsaturated bonds in fatty acids. Osmium tetroxide does this by reacting with carbon–carbon double bonds in unsaturated fats, forming dark, electron-dense deposits that make lipid-rich structures stand out. This is why it’s used to visualize lipids and membranes, especially in contexts like electron microscopy where lipid preservation and contrast are crucial. The other stains target different tissue components: Masson's trichrome highlights connective tissue and muscle, H&E is a general stain for nuclei and cytoplasm, and Gram stain differentiates bacteria. So the stain that best visualizes lipids or unsaturated fats is osmium tetroxide.

Staining lipids requires a reagent that specifically reacts with the unsaturated bonds in fatty acids. Osmium tetroxide does this by reacting with carbon–carbon double bonds in unsaturated fats, forming dark, electron-dense deposits that make lipid-rich structures stand out. This is why it’s used to visualize lipids and membranes, especially in contexts like electron microscopy where lipid preservation and contrast are crucial. The other stains target different tissue components: Masson's trichrome highlights connective tissue and muscle, H&E is a general stain for nuclei and cytoplasm, and Gram stain differentiates bacteria. So the stain that best visualizes lipids or unsaturated fats is osmium tetroxide.