Methods for removing uranyl acetate precipitate from ultrathin sections

Area of Science:

• Electron microscopy techniques
• Biological sample preparation

Background:

• Uranyl acetate is a common stain in electron microscopy.
• Staining with uranyl acetate can lead to precipitate formation.
• Precipitate can obscure cellular ultrastructure.

Purpose of the Study:

• To develop effective methods for removing uranyl acetate precipitate.
• To assess the impact of precipitate removal on sample integrity.

Main Methods:

• En bloc staining precipitate removal: 15% oxalic acid in 50% methanol at 40°C for 30 minutes.
• Poststaining precipitate removal: Rinsing in 0.25-0.50% aqueous oxalic acid at room temperature for 10-15 seconds.

Main Results:

• Both en bloc and poststaining precipitate removal methods were successful.
• Optimized rinsing times prevented destaining.
• Procedures did not compromise embedding medium or cellular detail.

Conclusions:

• Oxalic acid treatments provide an effective solution for uranyl acetate precipitate.
• These methods preserve ultrastructural integrity for electron microscopy analysis.