تولویدین بلو او

Toluidine Blue O is a dark blue or purple organic dye belonging to the thiazine family. It is widely used as a biological stain due to its affinity for acidic tissue components and its ability to bind nucleic acids and polysaccharides with high specificity.

🏭⚗️ Production
Toluidine Blue O is synthesized through a multi-step chemical process involving the condensation of aromatic amines and sulfur-containing intermediates, followed by oxidation and purification. The final product is typically obtained as a chloride salt and may be further processed into aqueous or alcoholic solutions for laboratory use. The compound is manufactured under strict conditions to ensure dye purity and staining performance.

🔬 Properties
The chemical formula of Toluidine Blue O (chloride salt) is C₁₅H₁₆ClN₃S, with a molar mass of approximately 305.82 g/mol. It appears as a dark blue to violet powder and is highly soluble in water and ethanol. The dye exhibits metachromasia, meaning it can change color depending on the chemical environment or concentration. It binds strongly to acidic components such as nucleic acids and mast cell granules, making it especially useful for histological staining. It absorbs light strongly around 626–630 nm.

🧪 Applications
Toluidine Blue O is primarily used in histology and cytology as a metachromatic stain for tissues, including cartilage, mucins, and mast cells. It is widely employed in medical diagnostics, especially for detecting dysplastic or cancerous tissues in oral, cervical, and bladder lesions. In microbiology, it is used to stain bacteria and fungi. The dye is also used in forensic science and microscopy for enhancing contrast in cell and tissue samples. Additionally, it serves as a redox indicator and nucleic acid stain in biochemical research.

⚠️ Safety
Toluidine Blue O should be handled with care, as it may cause skin and eye irritation upon contact. Inhalation of dust or prolonged exposure to staining solutions may also cause irritation to the respiratory tract. Though generally considered to have low toxicity, protective gloves, eyewear, and lab coats are recommended during handling. It should be stored in a sealed container in a cool, dry, and well-ventilated area away from light and incompatible materials such as strong oxidizers.