Fluorescent dyes refer to substances that absorb light waves of a certain wavelength and emit light waves with a wavelength greater than that of the absorbed light. Most of them are compounds containing a benzene ring or a heterocyclic ring with a conjugated double bond. Fluorescent dyes can be used alone or combined into composite fluorescent dyes.
1. Industrial application of fluorescent dyes
Fluorescent dyes are often used in the preparation of fluorescent dye products, as whitening agents in whitening washing powder, various fluorescent road marking paints for indicating signals, fluorescent marking clothing, etc.
Other uses of fluorescent dyes include: leaking sewage systems including water and industrial contaminants, connecting systems, measuring liquids discharged from power plants, leaks in toilets, monitoring of illegally connected sewage pipes, studying flow and mapping, analyzing corrupt systems , In addition, it is also used for fabric printing and dyeing and some special signs (such as dark symbols) and military tracking.
2. the scientific research application of fluorescent dyes
Fluorescent dyes, due to their high sensitivity and convenient operation, have gradually replaced radioisotopes as detection markers, which are widely used in fluorescent immunology, fluorescent probes, and cell staining. Including specific DNA staining, for chromosome analysis, cell cycle, apoptosis and other related research. Numerous nucleic acid dyes are also useful counterstains in multicolor staining systems as background controls, labeling nuclei so that the spatial relationships of intracellular structures can be seen at a glance.
Fluorescence-labeled monoclonal antibody technology expands infinite application space for flow cytometry in the study of cell membranes and various functional antigens in cells, tumor gene proteins and other fields. Fluorescent probes can be covalently bound to monoclonal antibodies via protein cross-linkers. The most commonly used dyes for immunofluorescence labeling are fluorescein isothiocyanate (FITC), phycoerythrin (PE) and AlexaFluor series dyes.
2) Nucleic acid detection
Nucleic acid fluorescent dyes stain the nucleus and quantitatively measure the fluorescence intensity of the cell, so that the content of DNA and RNA in the nucleus can be determined, and the cell cycle and cell proliferation can be analyzed. There are a variety of fluorescent dyes that can stain DNA or RNA in cells. Commonly used DNA dyes include propidium iodide (PI), DAPI, Hoechst 33342, etc., and RNA dyes include thiazole orange, acridine orange, etc.
3. How to judge the brightness of fluorescent dyes?
Fluorescent dyes are an indispensable tool in scientific research such as cell biology, and fluorescence color filters are a crucial component in fluorescence microscopy. So how to compare the brightness of general fluorescent dyes?
The brightness of fluorescent dyes can be used to compare the fluorescent labeling effect of different fluorescent dyes, which is expressed by the relationship between the fluorescent signals of negative and positive cell populations. However, the fluorescence signal of the negative cell population is related to many factors such as signal intensity, autofluorescence, non-specific staining, and electronic noise of the instrument.
The fluorochrome staining index is half the ratio between the difference between the mean fluorescence intensity of the positive cell population and the mean fluorescence intensity of the negative cell population and the standard deviation of the fluorescence intensity of the negative cell population. The staining coefficient of fluorescent dyes is only related to factors such as antibody clone and quality, fluorophore purity and quality, fluorescence modification ratio, laser line and its power, long-pass and band-pass filters, and target cells.
The dyeing index of fluorescent dyes is positively correlated with the brightness of fluorescent dyes, that is, the higher the brightness of fluorescent dyes, the higher the dyeing coefficient.