In order for tissue sections to be retained on histological slides during staining and washing steps, slides need to be coated with adhesive compounds. Although there are a variety of such compounds, gelatin is the most frequently used for histological purposes.
Please read the protocol in its entirety before starting.
- Gelatin-coating solution: 1 L deionized H2O, 5 g gelatin, 0.5 g chromium potassium sulfate CrK(SO4)2
- Filter units
- Histological slides
- Hot plate with magnetic stirrer
- Slide racks
- Staining dish
- Prepare the gelatin-coating solution by dissolving 5 g of gelatin in 1 L of heated, deionized H2O (temperature should not exceed 45 °C).
- After the gelatin has dissolved, add 0.5 g of chromium potassium sulfate. Chromium potassium sulfate will positively charge the slides allowing them to attract negatively charged tissue sections.
- Filter this solution and store at 2-8 °C until use. It is recommended that this solution be filtered again immediately before use (adjust to room temperature before filtration).
- Place the histological slides into metal racks.
Note: The slides should be cleaned by washing them in soapy water and rinsing them thoroughly, first in tap water and finally in deionized water.
- Dip the racks containing the slides 3 to 5 times (~5 seconds each) into the gelatin-coating solution.
- Remove the racks containing the slides and let them drain. Blot excess solution from the racks onto filter paper (gently tap the racks against the filter paper for better drainage).
- Place the racks containing the slides on the lab bench and cover them with paper towels to protect them from dust.
- Dry at room temperature for 48 hours.
- Dried slides can be put back into the boxes that they arrived in and stored at room temperature until use. Slides intended for cryostat sections can be stored at -20 °C.