Mosquito-borne diseases are one of the major threats to human health. The long-term use of synthetic repellents has made mosquitoes resistant to them leading to search for novel methods of mosquito control. In the present study, we have developed a low cost, safe and effective formulation to impart mosquito larvicidal and antibacterial effect using essential oils. Oil in water nanoemulsion of three different oils: Lemongrass (cymbopogon flexuosus steud.) wats (CF) oil, Eucalyptus oil (EO) and Chrysnathemum Indicum were prepared using high shear homogenization of the organic with the aqueous phase in presence of surfactant. The oil biocomponents were studied using GCMS. An experimental study of oil in water nanoemulsion preparation, process optimization and stability based on the required size distribution and accelerated stability was performed with surfactant oil ratio (SOR), stirring time and speed as the variables for nanoemulsion preparation. The storage stability of the nanoemulsion was also studied in terms of particle size, pH, viscosity and zeta potential at room temperature and refrigeration temperature for a period of 6 months. The optimized emulsion was also tested for its mosquito larvicidal effect against both the susceptible and resistant species of mosquitoes. The antimicrobial efficacy of the emulsion was also assessed.In the present study, nylon net fabric was treated with Cymbopogon flexuosus (CF) oil nanoemulsion by depositing polyelectrolyte multilayers through the layer by layer (LBL) technique. The nanoemulsion was characterized for particle size, zeta potential, viscosity, pH and Poly Dispersity Index. Mosquito antennal response to pure CF oil and its nanoemulsion was noted. The application technique was optimized for the concentration of nanoemulsion used and the number of polymeric layers applied. The treated samples were tested against mosquito bioassays, microbial growth and fragrance retention. Wash durability of the treated samples was also analysed. GCMS and SEM analysis of the treated and washed samples was done to ensure the presence of active ingredient and finish on the fabric. The fabrics showed good mosquito repellency, fragrance retention and antimicrobial efficacy even after 25 washes, though the percentage mortality dropped. The repellent and anti-microbial fabrics developed may provide a safe, environment-friendly and effective alternative to the chemical-based repellents for achieving protection against mosquito bites.

No abstract