Kao's New Surfactant Can Safely Kill Mosquitoes Without the Use of Insecticides

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Kao’s New Surfactant Can Safely Kill Mosquitoes Without the Use of Insecticides

Kao’s New Surfactant Can Safely Kill Mosquitoes Without the Use of Insecticides

Researchers have developed a surfactant spray that combats the natural water-repelling properties of mosquitoes, providing a safe and effective way to eradicate mosquitoes without the use of insecticides.

The spray can be used to protect people from the spread of mosquito-borne diseases. Mosquitoes are known to transmit potentially deadly diseases such as dengue, malaria, Japanese encephalitis and Zika, and climate change and urbanization have expanded mosquito habitats, allowing them to spread disease to more people.

Kao's New Surfactant Can Safely Kill Mosquitoes Without the Use of Insecticides

Mosquitoes have traditionally been controlled using insecticides, usually pyrethroids, but overuse can and has led to resistance. Not to mention that pesticides can cause human health problems. Now, researchers have used the mosquito’s own morphology to develop a way to knock it down without the use of insecticides.

Because of the many micro- and nano-scale structures on its surface, the mosquito’s body and wings are highly water-repellent (hydrophobic), meaning water rolls off. Also, their bodies are coated with a waxy substance, which also keeps them from getting wet.

In 2020, Kao Corporation’s Personal Health Products Research Laboratory and Materials Science Research Laboratory developed technology that uses silicone oil to moisten the legs of mosquitoes, preventing them from landing on and biting humans. Now, Kao has expanded this technology to focus on using surfactants to wet insects’ bodies and wings and alter their flight behavior.

Kao's New Surfactant Can Safely Kill Mosquitoes Without the Use of Insecticides

Surfactants are molecules with water-resistant (hydrophobic) and water-absorbing (hydrophilic) parts that lower surface tension. They are widely used in detergents and cosmetics.

Knowing that previous studies had found that surfactants could wet houseflies, the researchers set out to test the surfactants on mosquitoes. They use many surfactants that are considered safe for humans.

Applying water to the mosquitoes’ wings had no effect because, as the researchers expected, they were able to shake off the water and continue flying.

However, using an aqueous surfactant solution wetted the mosquito’s wings, causing them to drop and immobilizing them.

The researchers next focused on the insect’s body, which is covered with small openings called stomata through which the insect draws in air.

They found that covering one’s body with a solution of extremely low surface tension not only caused the mosquito to fall, but also blocked the air pores, preventing the mosquito from taking in oxygen and causing the mosquito to suffocate to death.

Dead or dying mosquitoes could be preyed on by ants or spiders.

Kao's New Surfactant Can Safely Kill Mosquitoes Without the Use of Insecticides

The researchers say their method could be used as a replacement for traditional insecticides. Additionally, they say mosquitoes are unlikely to develop resistance to the surfactant.

“Effectively, we envision using sprayers and sprinklers to spray these solutions,” the researchers said. “Therefore, we suggest that the use of surfactant solutions is an effective measure for mosquito control.

This approach has the potential to overcome the problem of insecticide resistance and effectively and safely control mosquitoes.”

The study was published in the journal Scientific Reports, and the video below, produced by Kao, demonstrates how the surfactant spray kills mosquitoes.