Application of surfactants in the field of disinfection

We usually refer to the interface between the phase of matter and the phase as the interface, such as gas/liquid, gas/solid, liquid/liquid, solid/solid, solid/liquid five. The interface containing a gas phase is called a surface, including a liquid surface and a solid surface. Surfactants can change the chemical properties of the surface by adsorption, forming an adsorption film on the surface (boundary), reducing the surface tension. Therefore, generally speaking, the surfactant is a functional fine chemical product, through a small amount of addition can make the surface (boundary) surface state significantly changed, so that the surfactant has wetting, penetration, foaming, emulsification, sterilization and other functions.

So, how can these functions of surfactants be applied to the field of disinfection to improve the elimination effect? Let's first discuss the improvement of wetting and permeating function on killing effect.

1. Biofilm formation

Most pathogenic microorganisms grow along the biofilm. First of all, the plankton adhere weakly to the surface (boundary) by van der Waals force, hydrophobic force, electrostatic force, etc. At this point, pathogenic microorganisms do not form a stable, firm biofilm, which can be easily removed. As the adhesive pathogens continue to secrete gelatinous extracellular polysaccharide matrix while growing and propagating, the adhesion to the surface (boundary) also becomes more solid, forming microbial colonies, and the formed biofilm becomes thin and thick, at this time, the formed biofilm is difficult to be removed.

2. Mechanism of biofilm resistance to disinfectants

The formation of biofilms can be resistant to disinfectants. The polymeric matrix structures such as exopolysaccharides and proteins of biofilms can form resistance and delay the matrix penetration of disinfectants and other substances. The presence of a biofilm reduces the accessibility of the disinfectant to microorganisms adhering to the surface (boundary) compared to direct action on free microorganisms.

A comparative study on the resistance of bacterial biofilm and free bacteria to disinfectants found that the average killing rates of Acinetobacter baumannii, Staphylococcus aureus and Pseudomonas aeruginosa with 800mg/L peracetic acid disinfectant were 90.53%, 87.64% and 83.16%, respectively. However, the average killing rate of the biofilm was only 82.56%, 84.81% and 82.85%. The average killing rates of Acinetobacter baumannii, Staphylococcus aureus and Pseudomonas aeruginosa were 96.95%, 96.18% and 96.05%, respectively, while the average killing rates of their biofilms were only 86.37%, 89.54% and 91.20%. It can be seen that biofilm-forming bacteria are more resistant to disinfectants than free bacteria.

In addition, some biofilm structural components can also react with some disinfectants, so that the disinfectant is partially consumed, thereby reducing the disinfectant's elimination effect. In addition, the wetting coverage of the surface (boundary) of the disinfectant will also affect the disinfection effect of the disinfectant, only when the droplet is completely covered on the surface (boundary), the possibility of leakage can be really avoided.

3, wetting, penetration function to improve the effect of killing

Based on the influence of the wetting degree of biofilm and surface (boundary) surface on the disinfectant effect, the wetting and permeation function of the surfactant can be combined with disinfection ingredients to improve the disinfectant disinfectant effect:

(1) Wettability can improve the killing effect: the wetting function of surfactants can enhance the wettability of disinfectants on the surface (boundary), especially the cracks and corners of walls, which are easy to accumulate pathogenic microbial colonies, and are not easy to be cleaned, so that the disinfectant can truly achieve full coverage of the killing interface and no dead corners; On the other hand, the wetting function also enables the disinfectant to contact the surface (boundary) more quickly. The combination of the two enhances the killing effect. The wetting degree of the droplet on the surface (interface) can be assessed by the contact Angle size of the Dataphysics OCA15EC video optical contact Angle measuring instrument (laboratory equipment of Chengdu Kehongda Surfactant Research Center).

(2) The improvement of the anti-killing effect of the permeability performance: the permeability function of the surfactant can make the disinfectant destroy the pathogen biofilm more quickly, and penetrate into the biofilm, and improve the degree of contact between the disinfectant and pathogenic microorganisms; At the same time, it can also help the disinfectant to destroy and penetrate into the membrane structure of the pathogen more easily and quickly, thus improving the disinfectant effect.

In summary, surfactants, with their unique wetting and penetrating functions, can effectively improve the contact between disinfectants and pathogenic microorganisms and improve the elimination effect.