Oil Red O (Solvent Red 27, Sudan Red 5B, C.I. 26125, C₂₆H₂₄N₄O) is a

lysochrome A lysochrome is a soluble dye used for histochemical staining of lipids, which include triglycerides, fatty acids, and lipoproteins. Lysochromes such as Sudan IV dissolve in the lipid and show up as colored regions. The dye does not stick to any ...

(fat-soluble dye) diazo dye used for

staining Staining is a technique used to enhance contrast in samples, generally at the Microscope, microscopic level. Stains and dyes are frequently used in histology (microscopic study of biological tissue (biology), tissues), in cytology (microscopic ...

of neutral

triglycerides A triglyceride (from ''wikt:tri-#Prefix, tri-'' and ''glyceride''; also TG, triacylglycerol, TAG, or triacylglyceride) is an ester derived from glycerol and three fatty acids. Triglycerides are the main constituents of body fat in humans and oth ...

and

lipid Lipids are a broad group of organic compounds which include fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include storing ...

s on frozen sections and some

lipoproteins A lipoprotein is a biochemical assembly whose primary function is to transport hydrophobic lipid (also known as fat) molecules in water, as in blood plasma or other extracellular fluids. They consist of a triglyceride and cholesterol center, sur ...

on paraffin sections. It has the appearance of a red powder with an

absorbance Absorbance is defined as "the logarithm of the ratio of incident to transmitted radiant power through a sample (excluding the effects on cell walls)". Alternatively, for samples which scatter light, absorbance may be defined as "the negative log ...

maximum at 518 nanometers.

Uses

Oil Red O is one of the dyes used for Sudan staining. Similar dyes include Sudan III, Sudan IV, and

Sudan Black B Solvent Black 3 is an azo dye. It is a non-fluorescent, relatively thermostable lysochrome (fat-soluble dye) diazo dye used for Staining (biology), staining of neutral triglycerides and lipids on frozen sections and some lipoproteins on paraffin se ...

. The staining has to be performed on fresh samples, as alcohol fixation removes most lipids. Oil Red O largely replaced Sudan III and Sudan IV, as it provides much deeper red color and the stains are therefore much easier to see. Oil Red O can be used to mark lipid-containing vacuoles, particularly in cases of

acute lymphoblastic leukemia Acute lymphoblastic leukemia (ALL) is a cancer of the Lymphocyte, lymphoid line of blood cells characterized by the development of large numbers of lymphoblast, immature lymphocytes. Symptoms may include feeling tired, pale skin color, fever, ...

Burkitt's lymphoma Burkitt's lymphoma is a cancer of the lymphatic system, particularly B lymphocytes found in the germinal center. It is named after Denis Parsons Burkitt, the Irish surgeon who first described the disease in 1958 while working in equatorial Africa ...

. It can also be used to stain liver sections for histological analysis, quantify cell lipid content, and to stain the aorta to examine lesions from atherosclerosis. In

pyrotechnics Pyrotechnics is the science and craft of creating fireworks, but also includes safety matches, oxygen candles, Pyrotechnic fastener, explosive bolts (and other fasteners), parts of automotive airbags, as well as gas-pressure blasting in mining, q ...

, Oil Red O is used in some compositions of red

colored smoke Colored smoke is a kind of smoke created by an particulate, aerosol of small particles of a suitable pigment or dye. Colored smoke can be used for smoke signals, often in a military context. It can be produced by smoke grenades, or by various ...

Forensic

When staining, Oil Red O can make fat more visible in various cuts in pathology. It is also used in a technique (the method is called as the dye: Oil Red O), discovered in 2004 by Alexandre Beaudoin, for staining latent

fingerprint A fingerprint is an impression left by the friction ridges of a human finger. The recovery of partial fingerprints from a crime scene is an important method of forensic science. Moisture and grease on a finger result in fingerprints on surfa ...

s. This technique allows the development of latent fingerprints on porous exhibits (such as paper, cardboard, etc.) that are dry or wet. It mainly targets fat deposits on the surface of porous exhibits. It is a non-destructive technique (which does not destroy the exhibit nor prevents the use of other techniques). It is a safe alternative to the Physical Developer method, and is also used in sequence with other methods of fingerprints development.Guigui, K.; Beaudoin, A. The use of Oil Red O in sequence with other methods of fingerprint development. Journal of Forensic Identification, 2007, 57 (4), 550-581.

References

External links

Stains File
entry

{{Stains Azo dyes Forensic chemicals Staining dyes Sudan dyes 2-Naphthols