Histological Stains | Histological Stains

Parole chiave: contrast, Histology, immunocytochemistry, immunohistochemistry

Definizione:Agents used to provide contrast in tissue sections for microscopy

TECHNOLOGY:

Introducing color into tissue thin sections helps to add contrast and aids in the identification of tissue structure. Stains can be introduced into tissues by a variety of methods including:

• Chemical bonding of a chemical group on the dye to a chemical group in tissue
• Precipitation of a dye in tissue
• Adsorption of a dye onto the tissue surface
• Absorption of a dye into tissue
• Reaction of an enzyme with its substrate to produce a colored product
• Stains or dyes that fluoresce when excited by light of the appropriate wavelengths
• Immunohistochemical / immunocytochemical techniques

Color varies according to the specific stain used, the environment (pH, temperature) and with conditions of preparation (such as fixing solution, solvents, concentration of stain). Stains maybe general (staining large areas of the specimen) or highly specific for certain cellular components, such as connective tissue, lipid or DNA. Many stains used in histology are either acidic (negatively charged in solution) or basic (positively charged in solution). Acidic dyes bind to basic groups in tissue and basic dyes bind to acidic groups in tissue. Hematoxylin-eosin is perhaps the most commonly used general stain in histology, where hematoxylin acts as a basic dye and eosin as an acidic dye to stain tissues blue /brown/black and pink/red respectively.

APPLICATIONS:

Histological stains are widely used to study the microscopic anatomy of tissues across the biological and biomedical sciences.

MICROSCOPE CONFIGURATION:

Histological slides are generally examined using upright microscopes using routine brightfield, darkfield, phase contrast and fluorescence techniques. A variety of microscope systems are available from student models (such as the educational microscope Eclipse E100) suitable for educational applications, through to biomedical and research grade systems (such as Nikon's i-series microscopes). Digital microscopes, such as the Coolscope, are also available that enable viewing of images directly on a PC screen (rather than through oculars), the creation of digital slides, and image sharing via a network.

RECOMMENDED SYSTEM:

Please consult your local Nikon representative for advice related to your specific imaging needs.

LINKS:

Specimen contrast in optical microscopy [microscopyu]