Nanosilica for head lice control

ISABEL ORTEGA-INSAURRALDE; VASSENA C. V; TOLOZA A; PICOLLO M. I.

Salt Lake City, Utah

Congreso; ICP5. Fifth International Conference on Phthiraptera; 2014

International Society of Phthirapterists

Nanostructured inorganic compounds are considered as environmentally friendly alternatives for insect pests. Nanomaterial are defined as materials that have at least one dimension <100 nm and because of their surface-volume ratios, they exhibit chemical, physical and biological properties distinctly different from the same materials in the bulk form. Nanosilica (SiO2) was proposed as bio-pesticide for agricultural and domestic use. In this study, we used Aerosil®, a nanostructured silicon dioxide that has been extensively used in the pharmaceutical industry, to assess the insecticidal activity against permethrin-resistant head lice. Insects were collected from infested children from 6 to 12 years old in schools of Buenos Aires, Argentina. Each louse was transferred into a glass dish and 0,2 µl of different solutions of Aerosil® were applied directly on the dorsal part of the louse. After the contact, the louse was transferred into filter paper and observed for knockdown (10 m) and mortality (18 h). The results showed high louse mortality of the product in concentrations equal or higher than 0,1%. Nanoparticles attached to the cuticle of treated insects were visible by scanning electron microscope. It is proposed that these nanosilicas were absorbed into the cuticular lipids and caused death of insects purely by physical means. As a result of this research we developed a highly effective pediculicide lotion based on silica nanoparticles (NOPUCID CRYSTAL®) which is actually marketed by ELEA Laboratory in Argentine