Appreciate the magical chemical world of fluorescein_Kain Industrial Additives

There are many substances that can emit fluorescence in nature, and people use fluorescein in many places in daily life and scientific research. Today, the editor will take you to know some knowledge about fluorescein.

1. Luminol

Many detective novels and TV series have mentioned this magical compound – used to test blood stains left at crime scenes. Luminol can detect trace amounts of blood residues that are invisible to the naked eye and is widely used in criminal investigation, bioengineering, chemical tracing and other fields.

The chemical name of luminol is 3-Aminophthalhydrazide. It is a yellow crystal or beige powder at room temperature, and is a relatively stable synthetic organic compound.

The principle of luminol color reaction is because hemoglobin contains iron, so a mixed aqueous solution of hydrogen peroxide and a hydroxide base is used as an activator. Iron can catalyze the decomposition of hydrogen peroxide and turn hydrogen peroxide into water. and monooxygen, which then oxidizes luminol to make it emit blue fluorescence.

2. Fluorescein isothiocyanate

This is the general name for a class of reagents, including fluorescent orange red isothiocyanate, fluorescent yellow isothiocyanate, fluorescent red isothiocyanate, fluorescein isothiocyanate isomer I, etc.

This product is a biochemical reagent and a medical diagnostic drug. It is mainly used as a fluorescent dye in fluorescent antibody technology. It can bind to various antibody proteins. The combined antibody does not lose the specificity of binding to a certain antigen. And has strong green fluorescence in alkaline solution

The maximum emission wavelength is 520~530nm, showing bright yellow-green color. FITC can be stored in a cool, dark and dry place for many years and is currently the most widely used fluorescein. Its main advantage is that the human eye is more sensitive to yellow-green, and usually the green fluorescence in sectioned specimens is less than red.

Used in medicine, agriculture and animal husbandry, it can quickly diagnose diseases caused by local bacteria, viruses and parasites.

3. Rhodamine

Rhodamine is a catechol fluorescent dye, mainly used for biological dyeing. It is a general name for a class of compounds, including rhodamine B, rhodamine 123, etc. Its main structure is as follows:

Rhodamine can selectively stain the mitochondria of living cells through the cell membrane, showing yellow-green or blue-violet fluorescence. It is widely used to detect mitochondrial membrane potential and is also commonly used to detect cell apoptosis. It can quickly pass through cell membranes and be captured by active mitochondria in just a few minutes without any toxicity to cells.

Rhodamine is also used to stain many types of cells, including plant cells and bacteria. Since there is a correlation between the amount of intracellular ATP and the fluorescence intensity of rhodamine, it is also used to detect intracellular ATP.

At the same time, rhodamine is also used as a probe for many metal ions, which is very useful in testing the concentration of some heavy metal ions in the body.

4.Phycoerythrin

This is a new fluorescent labeling reagent that is isolated and purified from red algae and is currently commonly used. Under specific wavelength excitation, phycoerythrin can emit strong fluorescence, and its fluorescence intensity is 30-100 times that of ordinary fluorescein.

Phycoerythrin has good light absorption properties and high quantum yield, and has a wide excitation and emission range in the visible spectrum. The following is the chromogenic group structure of phycoerythrin:

Phycoerythrin also has pharmacological effects. After being excited by light of appropriate wavelength, phycoerythrin can produce singlet oxygen and other oxygen free radicals to kill biological macromolecules. It is expected to be developed into a new photodynamic drug with practical value, which can kill tumor cells with laser light sensitivity.