title: Eco-friendly microbial route to synthesize cobalt nanoparticles using Bacillus thuringiensis against malaria and dengue vectors.
abstract: The developments of resistance and persistence to chemical insecticides and concerns about the non-target effects have prompted the development of eco-friendly mosquito control agents. The aim of this study was to investigate the larvicidal activities of synthesized cobalt nanoparticles (Co NPs) using bio control agent, Bacillus thuringiensis against malaria vector, Anopheles subpictus and dengue vector, Aedes aegypti (Diptera: Culicidae). The synthesized Co NPs were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), Field-emission scanning electron microscopy (FESEM) with energy dispersive X-ray spectroscopy, and Transmission electron microscopy (TEM). XRD analysis showed three distinct diffraction peaks at 27.03°, 31.00°, and 45.58° indexed to the planes 102, 122, and 024, respectively on the face-centered cubic cobalt acetate with an average size of 85.3 nm. FTIR spectra implicated role of the peak at 3,436 cm(-1) for O-H hydroxyl group, 2924 cm(-1) for methylene C-H stretch in the formation of Co NPs. FESEM analysis showed the topological and morphological appearance of NPs which were found to be spherical and oval in shape. TEM analysis showed polydispersed and clustered NPs with an average size of 84.81 nm. The maximum larvicidal mortality was observed in the cobalt acetate solution, B. thuringiensis formulation, and synthesized Co NPs against fourth instar larvae of A. subpictus and A. aegypti with LC50 values of 29.16, 8.12, 3.59 mg/L; 34.61, 6.94, and 2.87 mg/L; r (2) values of 0.986, 0.933, 0.942; 0.962, 0.957, and 0.922, respectively.
authors.affiliation: Unit of Nanotechnology and Bioactive Natural Products, Post Graduate and Research Department of Zoology, C. Abdul Hakeem College, Melvisharam, 632 509, Vellore District, Tamil Nadu, India.
authors.forename: Sampath
authors.initials: S
authors.lastname: Marimuthu
authors.forename: Abdul Abdul
authors.initials: AA
authors.lastname: Rahuman
authors.forename: Arivarasan Vishnu
authors.initials: AV
authors.lastname: Kirthi
authors.forename: Thirunavukkarasu
authors.initials: T
authors.lastname: Santhoshkumar
authors.forename: Chidambaram
authors.initials: C
authors.lastname: Jayaseelan
authors.forename: Govindasamy
authors.initials: G
authors.lastname: Rajakumar
mesh_terms: D000330:Aedes; D000818:Animals; D000852:Anopheles; D001413:Bacillus thuringiensis / Q000378:metabolism*; D003035:Cobalt / Q000737:chemistry* / Q000494:pharmacology; D009033:Culicidae / Q000187:drug effects; D007303:Insect Vectors / Q000187:drug effects; D007306:Insecticides / Q000737:chemistry* / Q000494:pharmacology; D007814:Larva / Q000187:drug effects; D053768:Metal Nanoparticles / Q000737:chemistry*; D009032:Mosquito Control
chemical_list: D007306:Insecticides; D003035:Cobalt