Insecticidal activity of polycaprolactone nanoparticles decorated with chitosan containing two essential oils againstTribolium confusum

Essential oils are composed of volatile components, and rapidly evaporate. It is desirable to formulate them in a cover protecting the essential oils against environmental conditions. Applying nanotechnology to preparing desirable formulations of essential oils can be provided in a cover along with controlled release, increased oil life and greater mobility. In this study, nanoparticles were prepared using polycaprolactone and chitosan aimed at encapsulation ofRosmarinus officinalisandZataria multifloraessential oils. The nanoparticles were characterized in terms of size, polydispersity, encapsulation efficiency, and scanning electron microscope photomicrographs. The nanoparticles showed a positive surface charge ranging between +11.60 and +29.20 mV and a mean particle radius ranging between 181-407 nm. Encapsulation efficiency was obtained between 75.8-84.4% under different preparation conditions. The LC(50)values of fumigant toxicity ofR. officinalisessential oil and nanoparticles were equal to 103.53 and 112.64 mu L/L air, and forZ. multifloraessential oil and nanoparticles, they were equal to 195.13 and 206.66 mu L/L air, respectively for 24 h exposure time againstTribolium confusum. The effectiveness of non- formulated essential oils was significantly (P < 0.05) lower than nanoencapsulated oils in the confused flour beetle adults for a long period under the same condition, due to the sustained release of the essentials provided by the formulation.

Automated summary

Nanoparticles made from polycaprolactone and chitosan were successfully prepared and used to encapsulate essential oils. The nanoparticles showed positive surface charge and controlled release, resulting in improved effectiveness against the confused flour beetle adults.