Antibacterial mechanism and antibacterial properties of quaternary ammonium salt antibacterial materials
The antibacterial effect of quaternary ammonium salts is good, and people have studied the antibacterial effects of small molecule quaternary ammonium salts. As early as the last century, it was found that long-chain alkyl quaternary ammonium salts such as cetylpyltrimethylammonium bromide have strong antibacterial abilities.
Moreover, people have more research on the antibacterial mechanism, and it is currently believed that the antibacterial action process of small molecule quaternary ammonium salts can be divided into six steps:
1. Adsorption to the surface of the fungus;
2. Penetrate the cell wall;
3. Binding to cell membranes;
4. Disturb the composition of cell membranes; 5. Leakage of intracellular substances such as K+, DNA, RNA, etc.;
6. Bacterial death.
The antibacterial effect of quaternary ammonium salt antibacterial materials is closely related to the structure. Studies have shown that the relationship between the antibacterial effect of quaternary ammonium salts with alkyl groups and their structural changes is:
For monoalkyl types, the length of the alkyl chain has a greater impact on antibacterial properties. With optimal chain length there is maximum activity. For the dialkyl type, the length of the R carbon chain has a greater effect on the bactericidal force, and the bactericidal force is the greatest when the number of carbon atoms in the R carbon chain is optimal. R is that benzyl groups and their derivatives have much higher bactericidal power than methyl groups.
The relationship between its toxicity and structure is: the toxicity of the alkyl chain of the same quaternary ammonium salt antibacterial material is shorter than the long one. At the same length of the alkyl chain, the toxicity of the band methyl group is greater than that of the band benzyl group, and the toxicity of the monoalkyl group is greater than that of the bialkyl group.
In addition, the anions contained in the quaternary ammonium salt antibacterial material will also have an effect on its antibacterial effect, for example: benzalkonium bromide (dodecyldimethylbenzyl ammonium bromide) and benzalkonium chloride (dodecyldimethylbenzyl ammonium chloride), the two have similar activity, in the same test case, benzalkonium bromide has better bactericidal activity than benzalkonium chloride.
At the dosage of 10mgL of active substance, the killing rate of benzalkonium bromide to heterotrophic bacteria was 98.9%, while benzalkonium chloride was 983%, and benzalkonium bromide had lower toxicity than benzalkonium chloride. Chen Chris Zhisheng et al. studied the antibacterial properties of quaternary ammonium salts with dendritic molecular structures, and also found that quaternary ammonium salt antibacterial materials with anion Br were stronger than quaternary ammonium salt antibacterial materials with anionized CT.