Modified Harris' Hematoxylin Stain Solution

Hematoxylin is a basic natural dye that stains cell nuclei. The primary component of nuclear chromatin is DNA; within the double helix structure of DNA, phosphate groups on the two nucleotide chains face outward, causing the exterior of the DNA double helix to carry a negative charge and exhibit acidic properties. Consequently, it readily binds to the positively charged hematoxylin basic dye via ionic or hydrogen bonds, resulting in staining.

This solution is an improvement upon the classic Harris hematoxylin staining method. It contains no mercury, is non-toxic, and does not form oxide films. It stains nuclear chromatin darkly and with fine detail. Clinically, it is often used as a substitute for the traditional Harris hematoxylin staining solution. The staining time is generally 5–8 minutes. Characterized by a high degree of hematoxylin oxidation and strong staining power, it tends to cause overstaining of the nucleus, cytoplasm, and fibers despite the short staining duration. Therefore, hydrochloric acid ethanol differentiation is required following staining, classifying it as a regressive stain.