Methylene blue dye powder is a living dye. It is an alkaline dye in the form of blue powder and can be dissolved in water (solubility 9.5%) and alcohol (solubility 6%). Chromosomes are easily stained with alkaline dyes.
After staining with methylene blue solution, the dark blue part is the nucleus. Methylene blue can bind nucleic acids to make the nucleus blue. Mechanism of trypan blue coloring dead cells: normal living cells with complete membrane structure can reject trypan blue and prevent it from entering the cell; However, for cells with loss of activity or incomplete cell membrane, the permeability of cell membrane increases and can be dyed blue by trypan blue. It is generally considered that the cell has died if the integrity of the cell membrane is lost. Therefore, trypan blue staining can be very simple and rapid to distinguish living cells from dead cells. Trypan blue is one of the most commonly used deceased cell identification and staining methods in tissue and cell culture.
Normal living cells with complete membrane structure can reject trypan blue and prevent it from entering the cell; However, for cells with loss of activity or incomplete cell membrane, the permeability of cell membrane increases and can be dyed blue by trypan blue. It is generally considered that the cell has died if the integrity of the cell membrane is lost. Therefore, trypan blue staining can be very simple and rapid to distinguish living cells from dead cells. Trypan blue is one of the most commonly used deceased cell identification and staining methods in tissue and cell culture.
Methylene blue was first synthesized with zinc chloride in 1876. At present, the synthetic routes of it reported in the literature mainly include the following two methods:
Method 1: using N, n-dimethyl-p-phenylenediamine as raw material, 2-amino-5-dimethylaminophenyl thiosulfonic acid was obtained by oxidation with manganese dioxide and substitution with sodium thiosulfate. The latter was condensed with N, N-dimethylaniline and then oxidized and cyclized with manganese dioxide and copper sulfate to obtain methylene blue zinc chloride. The latter is neutralized with sodium carbonate to get the target compound methylene blue.
Method 2: n, n-dimethyl-phenylenediamine was obtained from n, N-dimethylaniline by nitrosation and reduction with iron powder. The latter is oxidized by sodium dichromate and replaced by sodium thiosulfate to get 2-amino-5-dimethylaminophenyl thiosulfonic acid. After condensation with N, N-dimethylaniline is corrupted and cyclized by sodium dichromate and copper sulfate to obtain methylene blue zinc chloride. The latter is neutralized with sodium carbonate to get the target compound methylene blue.
The reaction routes of the above two methods are repeated, and the difference mainly lies in the different selection of oxidants in the reaction process. Methods 1 and 2 react at low temperatures before cyclization. The feeding process is cumbersome, which is not conducive to industrial production; The reaction process is to obtain the bisulfate of methylene blue first and then treat it to obtain methylene blue so that the reaction time is relatively long.
Methylene blue is widely used in chemical indicators, dyes, natural dyes and drugs. Especially in the dyeing industry, it is used to make ink. However, methylene blue has caused severe harm to the ecological environment and unrecoverable damage to the human body due to its toxicity and difficult removal.