What happens when you touch the liquid in the virus transport medium?

What is the red liquid in the virus transport medium?

The red liquid in the virus transport medium is called virus preservation fluid. There are usually two types, inactivated and non-inactivated.

Components of inactivated virus transport media

Guanidine salt, bis-imidazolidine, phenol red, buffer, etc.

What role do these ingredients play? Are they toxic?

Guanidine salts are one of the important components of virus preservation solution. Guanidine is a very strong monobasic base, similar in alkalinity to sodium hydroxide, and can absorb carbon dioxide from the air to form carbonates. Guanidine is unstable under alkaline conditions, easily hydrolyzed to ammonia and urea, and more stable under acidic conditions, so it is generally made into guanidine salt for preservation. Commonly used guanidine salts are guanidine isothiocyanate or guanidine hydrochloride, etc.

Guanidine salt is a commonly used protein denaturant, which can destroy the surface protein shell of the virus so that the virus loses its activity and infection ability. Since guanidine salts are eventually hydrolyzed into ammonia and urea in aqueous solution, and ammonia is converted into urea by liver metabolism, the toxicity of guanidine salts can be equated to urea as well. And the excess urea in our body will be excreted through the kidneys with urine.

Preservation fluid also contains a certain amount of bis-imidazolidine because it has a certain bactericidal and antibacterial effect and is usually used as a preservative. We commonly used masks. Lotions have also been added, low doses of exposure to the basic risk-free, in case of staining on the skin with water to wash off.

Phenol red is a kind of acid-base indicator. It is red in a neutral environment, alkaline will become purple, and acidic is yellow. Suppose the preservation fluid is contaminated with bacteria (commonly when the preservation fluid fails or the sample carries bacteria). In that case, the pH value of the fluid drops, and it will change from red to yellow.

In addition, the buffer in the virus preservation fluid maintains a relatively stable pH value; the other components will ensure that the viral nucleic acids will not lyse for a short period. above. For example, if the patient is allergic to alcohol or iodophor, then other disinfection methods will be chosen.