immobilized metal-affinity chromatography (IMAC)

IMAC is based on the interactions between a transition metal ion (Co2+, Ni2+, Cu2+, Zn2+) immobilized on a matrix and specific amino acid side chains. Histidine is the amino acid that exhibits the strongest interaction with immobilized metal ion matrices, as electron donor groups on the histidine imidazole ring readily form coordination bonds with the immobilized transition metal.

e.g. Polyhistidine-tag column

Jenner's Stain

Jenner's Stain (methylene blue eosinate) is used in microscopy for staining blood smears.

Wright's stain

Wright's stain is a histologic stain that facilitates the differentiation of blood cell types. It is used primarily to stain peripheral blood smears and bone marrow aspirates which are examined under a light microscope. In cytogenetics it is used to stain chromosomes to facilitate diagnosis of syndromes and diseases.

Warthin–Starry stain

The Warthin–Starry stain (WS) is a silver nitrate-based staining method (a silver stain) used in histology. It was first introduced in 1920 by American pathologists Aldred Scott Warthin (1866-1931) and Allen Chronister Starry (1890-1973), for the detection of spirochetes.[1][2] It has been considered the best stain for detection of spirochetes,[3] and is also used to stain Helicobacter pylori, Lawsonia intracellularis,[4] Microsporidia,[5][6] and particulates.[7]
WS stains organisms dark brown to black, and the background light golden brown/golden yellow.

Carbol fuchsin

Carbol fuchsin, carbol-fuchsin, or carbolfuchsin, is a mixture of phenol and basic fuchsin, used in bacterial staining procedures. It is commonly used in the staining of mycobacteria as it has an affinity for the mycolic acids found in their cell walls.
It is a component of Ziehl-Neelsen stain.  Carbol fuchsin is used as a dye to detect [acid fast bacteria] because it is more soluble in the cells wall lipids than in the acid alcohol. If the bacteria is acid fast the bacteria will retain the initial red color of the dye because they are able to resist the destaining by acid alcohol.
Carbol-fuchsin is also used as a topical antiseptic.

Dieterle stain

The Dieterle stain is a way of marking tissue for microscopic examination.
It is used to find the organisms that cause cat-scratch disease and syphilis and sensitive for mycobacterium tuberculosis.

Treponema pallidum particle agglutination assay

The treponema pallidum particle agglutination assay (also called TPPA test) is an indirect agglutination assay used for detection and titration of antibodies against the causative agent of syphilis, Treponema pallidum subspecies pallidum.
In the test, gelatin particles are sensitized with T. pallidum antigen. Patient serum is mixed with the reagent containing the sensitized gelatin particles. The particles aggregate to form clumps when the patient serum is positive for syphilis. In other words, the patient's serum contains antibodies to T. pallidum. A negative test shows no clumping of gelatin particles. This is a type of specific treponemal test for syphilis.