Larvicidal activity of titanium dioxide nanoparticles synthesized using Morinda citrifolia root extract against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus and its other effect on non-target fish

Objective To assess the larvicidal activity of titanium dioxide nanoparticles (TiO 2 NP S ) synthesized from the root aqueous extract of Morinda citrifolia ( M. citrifolia ) against the larvae of Anopheles stephensi (An. stephensi) , Aedes aegypti (Ae. aegypti) and Culex quinquefasciatus (Cx. quinquefasciatus) . Methods The M. citrifolia broth solution was prepared by taking 8 g of the powdered root of M. citrifolia in 250 mL Erlenmeyer flask along with 100 mL of distilled water and boiled for 5 min. About 20 mL of M. citrifolia root extract was added into the 80 mL of an aqueous solution of 5 mmol/L TiO(OH) 2 for the reduction under continuous stirring for 4 h at 50 °C. Synthesized TiO 2 NP S were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy and energy dispersive X-ray spectroscopy. X-ray diffraction confirmed the crystalline nature of the nanoparticles. Toxicity studies were carried out against non-target fish species Poecilia reticulata , the most common organism in the habitats of An. stephensi , Ae. aegypti and Cx. quinquefasciatus. Results The Fourier transform infrared spectroscopy for TiO 2 NP S synthesized by M. citrifolia root extract showed band at 3 426 cm −1 , 1 637 cm −1 and 714 cm −1 . The 3 426 cm −1 showed O-H stretching due to alcoholic group; 1 637 cm −1 showed N-H bend due to alcoholic group. In particular, the 1 637 cm −1 indicated the presence of H bend bond for 1° for proteins. A peak was observed around 714 cm −1 due to Ti-O-O bond. Field emission scanning electron microscopy and transmission electron microscopy showed the spherical nature of the nanoparticles with a size of 20.46–39.20 nm. The biosynthesized TiO 2 NP S showed maximum activity against the larvae of An. stephensi , Ae. aegypti and Cx. quinquefasciatus when compared to the aqueous extract of M. citrifolia . Toxicity studies revealed no toxicity towards Poecilia reticulata at LC 50 and LC 90 doses of TiO 2 NP S . Conclusions TiO 2 NP S could be used along with Poecilia reticulata in integrated vector control.