Search results
Results from the WOW.Com Content Network
Micrograph of a GFAP immunostained section of a brain tumour.. In biochemistry, immunostaining is any use of an antibody-based method to detect a specific protein in a sample. . The term "immunostaining" was originally used to refer to the immunohistochemical staining of tissue sections, as first described by Albert Coons in 1941.
Some staining methods are based on this property. Those stains excluded by the living cells but taken up by the already dead cells are called vital stains (e.g. trypan blue or propidium iodide for eukaryotic cells). Those that enter and stain living cells are called supravital stains (e.g.
Toluidine blue is often used to identify mast cells, by virtue of the heparin in their cytoplasmic granules. [3] It is also used to stain proteoglycans and glycosaminoglycans in tissues such as cartilage. The strongly acidic macromolecular carbohydrates of mast cells and cartilage are coloured red by the blue dye, a phenomenon called metachromasia.
Live cells or tissues with intact cell membranes are not coloured. Since cells are very selective in the compounds that pass through the membrane, in a viable cell trypan blue is not absorbed; however, it traverses the membrane in a dead cell. Hence, dead cells appear as a distinctive blue colour under a microscope.
Immunofluorescence (IF) is a light microscopy-based technique that allows detection and localization of a wide variety of target biomolecules within a cell or tissue at a quantitative level. The technique utilizes the binding specificity of antibodies and antigens .
Propidium iodide (or PI) is a fluorescent intercalating agent that can be used to stain cells and nucleic acids. PI binds to DNA by intercalating between the bases with little or no sequence preference. When in an aqueous solution, PI has a fluorescent excitation maximum of 493 nm (blue-green), and an emission maximum of 636 nm (red).
DAPI can be used for fixed cell staining. The concentration of DAPI needed for live cell staining is generally very high; it is rarely used for live cells. [7] It is labeled non-toxic in its MSDS [8] and though it was not shown to have mutagenicity to E. coli, [9] it is labelled as a known mutagen in manufacturer information. [2]
In pap smears, Light Green SF confers a blue staining for the cytoplasm of active cells such as columnar cells, parabasal squamous cells, and intermediate squamous cells. [3] It usually comes as a disodium salt. Its maximum absorption is at 630 (422) nm. The dye is not very durable — it has a tendency to fade.