What is the principle of alcohol disinfection?

Alcohol is very common in real life, and alcohol mainly contains ethanol. Medical alcohol is rich in various starches and is made by saccharification, fermentation and distillation. The concentration of alcohol is relatively high. It is an alcohol specifically for medical use. Alcohol has a disinfecting effect. This is because alcohol contains an ingredient that can destroy protein and achieve the effect of disinfection.

What is the principle of alcohol disinfection?

To denature protein, the long chains of curled and helical protein molecules must be stretched and relaxed. The key is to destroy the various forces that form the curling and helical. The alcohol molecule has two ends, one end is hydrophobic (-C2H5), which can destroy the attraction between the hydrophobic groups inside the protein; the other end is hydrophilic (-OH), but it is difficult to destroy the attraction between the hydrophilic groups outside the protein.

on the other hand. Although water molecules can relax the attraction between the hydrophilic groups of proteins, even if they penetrate into the bacteria, they cannot destroy the attraction between the hydrophobic groups in their proteins. Therefore, neither pure alcohol nor water is sufficient to denature the proteins in bacteria. Only when alcohol and water coexist and relax the various attractive forces that maintain the geometric shape of the proteins will the proteins lose their physiological activity. Therefore, only alcohol solutions with a certain concentration can achieve good disinfection and sterilization purposes.

Different concentrations

(The following concentrations refer to volume fractions)

95% alcohol is often used to wipe UV lamps. This type of alcohol is commonly used in hospitals, but at home it is only used to clean camera lenses.

75% alcohol is used for disinfection. This is because too high a concentration of alcohol will form a protective film on the surface of the bacteria, preventing it from entering the bacteria, making it difficult to kill the bacteria completely. If the alcohol concentration is too low, it can enter the bacteria but cannot coagulate the protein in their bodies, nor can it completely kill the bacteria.

40% to 50% alcohol can prevent bedsores. The back, waist and buttocks of bedridden patients may develop bedsores due to long-term pressure. If you pour a little 40% to 50% alcohol into your hands and evenly massage the pressure areas of the patient, you can promote local blood circulation and prevent the formation of bedsores.

25% to 50% alcohol can be used to physically reduce fever. Patients with high fever can use it to rub their bodies to reduce temperature. Because wiping the skin with alcohol can dilate the patient's skin blood vessels and increase the skin's heat dissipation capacity. Its volatility can also absorb and take away a large amount of heat, thereby relieving symptoms. However, the alcohol concentration should not be too high, otherwise it may irritate the skin and cause the epidermis to lose a large amount of water.

use

In daily life, it is common for some people to use medical alcohol to scrub wounds in order to achieve the purpose of sterilization and disinfection. It is worth noting that the alcohol purchased in pharmacies comes in two concentrations: 75% and 95%, and the uses of these two concentrations of alcohol are different.