Amylopectin Section Adhesive

This adhesive is not in common use, but was highly recommended for a time, predominantly because it was effective with ester and polyester waxes which were in vogue. It has two disadvantages: that it is PAS positive and can't be used with some methods, and that it is a single slide flotation method, i.e. sections are floated and flattened on some of the adhesive on a slide, then the excess drained away. It is not used in a regular flotation bath, which is inconvenient. In spite of that, for tissues which are difficult to adhere to slides, it is recommended.

Water
Nipa ester
Amylopectin
1.0 L
1.5 g
2.0 g

  1. Bring the water to the boil.
  2. While boiling, add the Nipa ester.
  3. Take 200 mL of this solution and cool to room temperature.
  4. Add the amylopectin and stir until a suspension forms.
  5. Slowly add this suspension to the remaining 800 mL while still boiling.
  6. Cool but do not filter.

To use, a few drops are placed on a clean, grease free slide. The section is then floated onto this fluid and allowed to flatten, with heat if required. The excess amylopectin solution must be drained off the slide and not allowed to evaporate, or it will form small dots which can be seen microscopically. This adhesive is recommended for difficult materials, but must not be used for any method which depends on the oxidation of carbohydrates to aldehydes and their subsequent demonstration (PAS, Jones, Grocott methenamine silver) or background staining will be seen.

Amylopectin is a component of starch and is similar to glycogen. It is a 1,6 linked polymer of glucose whereas glycogen is a 1,4 linked polymer. Nipa esters are esters of p-hydroxybenzoic acid used as antimicrobial preservatives. They may be more familiar under the name of Paraben. According to the internet site Surechem, Nipa 82121 is a mixture of methyl, ethyl, propyl, butyl and benzyl p-hydroxybenzoates.

Wikipedia has articles on amylopectin and paraben.

 

Reference
Steedman, H.F., (1960)
Section cutting in microscopy
Blackwell Scientific Publications, Oxford, UK.


 
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