Periodic acid–Schiff (PAS) stain is a classical histochemical staining technique widely used in microbiology, mycology, pathology, and infectious disease research for the visualization of polysaccharides and other carbohydrate-containing biomolecules. The method is based on the oxidation of vicinal glycol groups by periodic acid, generating aldehydes that subsequently react with Schiff reagent to produce a characteristic magenta reaction product. Because fungal cell walls contain abundant oxidizable polysaccharides, including β-glucans and mannans, PAS provides excellent contrast for detecting fungal structures in cultured specimens and tissue sections. PAS also stains glycogen, neutral mucins, glycoproteins, glycolipids, basement membranes, and other glycoconjugates, making it valuable for investigating microbial morphology, host–pathogen interactions, and carbohydrate-rich extracellular matrices. Its high sensitivity for carbohydrate-rich structures, excellent reproducibility, and compatibility with formalin-fixed, paraffin-embedded (FFPE) and frozen specimens have established PAS as a widely used histochemical technique for research and diagnostic applications.

Key Features

• Sensitive Histochemical Detection : Visualizes polysaccharides, glycogen, neutral mucins, glycoproteins, glycolipids, basement membranes, and other glycoconjugates.

• Reliable PAS Chemistry : Based on periodic acid oxidation followed by Schiff reagent detection, producing a stable magenta reaction product with excellent contrast for bright-field microscopy.

• Broad Specimen Compatibility : Suitable for formalin-fixed, paraffin-embedded (FFPE) and frozen tissue sections.

• PAS-D Compatibility :Can be combined with diastase digestion (PAS-D) to distinguish glycogen from other PAS-positive carbohydrate-containing structures.

• Highly Reproducible: Suitable for routine histological, microbiological, and infectious disease research.

Typical Applications

• Detection and visualization of pathogenic fungi, including Candida, Aspergillus, Cryptococcus, and Histoplasma, in cultured specimens and tissue sections.

• Morphological characterization of fungal cell walls in microbiology and mycology research.

• Histopathological investigation of fungal infections and host–pathogen interactions.

• Histochemical visualization of extracellular polysaccharide-rich components of microbial biofilms.

• Detection of glycogen and other carbohydrate-containing structures in microbiology, glycobiology, and infectious disease research.