One-pot synthesis of silver nanocomposites from Achyranthes aspera:An eco-friendly larvicide against Aedes aegypti L.

Objective:To formulate silver nanocomposites from Achyranthes aspera leaf extracts and evaluate its larvicidal activity against Aedes aegypti.Methods:The silver nanocomposites were synthesized from Achyranthes aspera leaf extracts.The process was optimized and traced through UV-visible and photon correlation spectroscopy.The larvicidal potential of silver nanocomposites of Achyranthes aspera leaf extracts was assessed against the early fourth instars of Aedes aegypti and three non-target organisms.Furthermore,the most effective and eco-safe nanocomposite was characterized by different biophysical techniques including scanning electron microscopy(SEM),energy dispersive X-ray(EDX) spectroscopy,transmission electron microscopy(TEM),X-ray diffraction(XRD) and Fourier transform-infrared spectroscopy(FT-IR).Results:The formulated silver nanocomposites exhibited efficient larvicidal efficacy against Aedes aegypti.Bioassay with silver nanocomposites formulated using different Ag NO3 concentrations(3,4,and 5 m M) revealed respective LC50 values of 37.570,6.262 and 1.041 μg/m L;5.819,1.412 and 0.489 μg/m L;and 5.519,1.302 and 0.267 μg/m L after 24,48 and 72 h.The silver nanocomposites with 4 m M Ag NO3 were selected for characterization.SEM and TEM analysis revealed spherical,poly-dispersed structure with varied diameters of 1-25 nm.The XRD analysis established the crystalline and face-centred-cubic structure of silver nanocomposites with the maximum peak at a 2θ value of 37.42°.The EDX pattern showed the presence of Ag,O and C in the nanocomposites in their order of weight%.The FT-IR displayed visibly distinct peaks in different ranges demonstrating the intricacy of silver nanocomposites.In addition,the lethal concentrations of silver nanocomposites of Achyranthes aspera leaf extracts against Aedes aegypti larvae were non-toxic to non-target organisms including Gambusia affinis,Daphnia magna and Moina macrocopa.Conclusions:Silver nanocomposites synthesized with leaf extract of Achyranthes aspera provide a cost-effective and eco-safe alternative to conventional insecticides,and can be utilized as a potent mosquito nano-larvicide.