Synthesis of silver nanoparticles from Azadirachta indica—a most effective method for mosquito control

Abstract

Mosquitoes transmit major communicable diseases such as dengue, malaria, filariasis, Japanese encephalitis, chikungunya, and so on. Vector control is important in epidemic disease situations as there is an urgent need to develop new and improved mosquito control methods that are economical and effective yet safe for non-targeted organisms. In the present study, silver nanoparticles (AgNPs) were synthesized from the aqueous leaf extract of neem plant (Azadirachta indica), and their effects on mosquito vectors (Aedes aegypti and Culex quinquefasciatus) were assessed. The synthesised AgNPs were characterized by UV-vis spectroscopy, scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction analysis (XRD). The nanoparticles have maximum absorption at 442 ± 1.5 nm with an average size of 41-60 nm. The XRD data showed six well-defined diffraction peaks, corresponding to a relative intensity of the crystal structure of metallic silver 36.42, 100.00, 53.70, 14.20, 16.05, and 6.79, respectively. The FT-IR data showed strong prominent peaks in different ranges, reflecting its complex nature. The mosquito larvae were exposed to varying concentrations of AgNPs synthesized from the neem leaves under investigation (0.07-25 mg/l) for 24 h; this revealed larvicidal activity of AgNPs with LC50 and LC90 values of 0.006 and 0.04 mg/l for A. aegypti, respectively. Further, the LC50 and LC90 values were also identified as 0.047 and 0.23 mg/l for Cx. quinquefasciatus, respectively. The result obtained from this study presents biosynthesized silver nanoparticle from A. indica as the biolarvicidal agent with the most potential for mosquito control.

Biosynthesized silver nanoparticles performing as biogenic SERS-nanotags for investigation of C26 colon carcinoma cells

“…3b identifies the presence of the A. indica characteristic bands. In particular, the bands at 1574 and 1045 cm -1 are assigned to amide II band and C-O stretching mode, according to literature [42]. The ability of these classes of nanoparticles to generate intrinsic SERS signal from the stabilizing molecules is a key precondition in view of their applicability as contrast agents for intracellular detection and SERS imaging.…”

ControllingAedes albopictusandCulex pipiens pallensusing silver nanoparticles synthesized from aqueous extract ofCassia fistulafruit pulp and its mode of action

“…To synthesize AgNPs, 50 mL of fruit pulp extract was mixed with 200 mL of aqueous solution of AgNO 3 (3mmol/L) and it was stirred for 1 h at 60 C. The reduction occurred rapidly as indicated by a reddish brown colour of the sample after 24 h indicating the formation of AgNPs. The mixture of AgNPs with proteins, carbohydrates and flavonoids materials obtained was purified two times from impurities by centrifugation (10,000 rpm/30 min) and the pellet was collected and dried according to the method described by Poopathi et al [25].…”

Tackling the growing threat of dengue: Phyllanthus niruri-mediated synthesis of silver nanoparticles and their mosquitocidal properties against the dengue vector Aedes aegypti (Diptera: Culicidae)

“…Several plants have been successfully used for efficient and rapid extracellular synthesis of silver, copper, and gold nanoparticles (Veerakumar et al 2014a;Dinesh et al 2015). Good examples include neem, Azadirachta indica (Shankar et al 2004;Poopathi et al 2014), Feronia elephantum (Veerakumar et al 2014b), Catharanthus roseus and Pongamia pinnata (Rajesh et al 2010). Nanoparticles possess peculiar toxicity mechanisms due to surface modification (Oberdorster et al 2005).…”