|Kumar, A. -|
|Rejeeth, C. -|
|Madhiyazhagan, P. -|
Submitted to: Acta Biomaterialia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 7, 2011
Publication Date: N/A
Interpretive Summary: New and improved methods are needed for the control of mosquito vectors of disease agents that infect humans and animals. The methods must be safe, effective, and economical. Scientists at ARS Gainesville, FL and Bharathiar University, India used leaf extract of custard apple, a plant cultivated throughout India and used for its edible fruit, as a "green" reducing agent in combination with aqueous silver nitrate to synthesize silver nanopartiles. When tested against mosquito larvae and pupae the nanoparticles were toxic at moderate to low concentrations and they reduced adult lifespan and egg production in female mosquitoes each by one-third. The results of the study showed that silver nanoparticles are comparatively easy to produce and that they have significant potential for the control of disease-transmitting mosquitoes.
Technical Abstract: A biological method was used to synthesize stable silver nanoparticles. The nanoparticles were tested as larvicides against Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus. Annona squamosa leaf broth (5%) reduced aqueous AgNO3 to stable silver nanoparticles with average particle size of 450 nm. The structure and quantity of the synthesized nanoparticles was characterized using UVspectrophotometry, X Ray diffraction (XRD), Fourier transform infra-red spectroscopy (FTIR) and scanning electron microscopy (SEM). Silver nanoparticles were effective for killing larvae and pupae of each mosquito species with LD50 for instar 4 of 0.30%, 0.41%, and 2.12% for Ae. aegypti, Cx. quinquefasciatus, and An. stephensi, respectively. In males and females exposed as larvae to 0.1% silver nanoparticles, adult longevity (days) was reduced 30% and 29%, respectively, whereas the number of eggs laid by females exposed to silver nanoparticles decreased by 36%.