can help preventing sections from falling off slides
Gelatin coated slides can hold sections on slides more securely therefore preventing sections from falling off slides. Here we introduce a method on how to make gelatin coated slides. This technique has been proven successful.
Gelatin, type A, 220
or 275 Bloom -------- 1.5 g
Chromium potassium sulfate
-------------- 0.25 g
Distilled water ------------------------------- 500 ml
Heat the water to 60 ºC and completely dissolve the gelatin with the aid of a magnetic stirrer. Stir in the chromium potassium sulfate (The solution should turn a pale blue). Add a few crystals of thymol as a preservative.
Dip racks of clean slides in the warm gelatin solution (40-50 ºC), drain the slides onto paper tissue, and then stand the slides (covered with foil to keep off dust) on end to air dry or 37 ºC incubator overnight. Store in dust-free container at room temperature. Throw out the gelatin mixture after use.
1. Paraffin Sections (up to 50um):
Cut 20-50 um paraffin
sections with the aid of a warm water drop on the block face by
using hair brush gently. Briefly, trim paraffin block to cutting
surface, dip hair brush in warm water in water bath, brush paraffin
block surface gently to make sure the block surface is fully
moisturized. Then cut and transfer the section to water bath
(set water bath temperature to 50 ºC or higher. If temperature is
too low, the folds will not be flatten). Allow the sections remain in water bath
for 5-10 minutes or until
they are flatten (no wrinkles, some sections, especially middle part of
brain, will not be completely flatten, and some wrinkles will go away
during air dry). Mount the sections onto gelatin-coated slides. Air
dry slides overnight to several days or bake slides in
45ºC oven overnight (NEVER
allow oven temperature go higher than 50 ºC or sections will crack).
Take slides out of oven and proceed with deparaffinization.
Before or after staining of frozen/vibratome sections, mount the sections on gelatin-coated slides and air dry overnight or 2-3 days.
This protocol has been tested successfully on formalin-fixed, paraffin embedded brain tissue sections at 50 um thick. The sections went through antigen retrieval (steam) procedure and still intact without detaching from slides.
Regular slides (uncoated slides) can be used to replace gelatin-coated slides for 20-50 um paraffin embedded brain sections, but additional gelatin powder in water bath is needed at 0.03% concentration (3 g gelatin needed in 10L of water bath).
For more section adhesives recipes, click here.