Biophysical characterization of Acacia caesia-fabricated silver nanoparticles: effectiveness on mosquito vectors of public health relevance and impact on non-target aquatic biocontrol agents.
Mosquito-borne diseases lead to serious public health concerns in tropical and sub-tropical countries worldwide, due to development of mosquito resistance to synthetic pesticides, non-target effects of pesticides, and socioeconomic reasons. Currently, green nanotechnology is a promising research field, showing a wide range of potential applications in vector control programs. The employ of natural products as reducing agents to fabricate insecticidal nanocomposites is gaining research attention worldwide, due to low costs and high effectiveness. Interestingly, biophysical features of green-synthesized nanoparticles strongly differ when different botanicals are employed for nanosynthesis. In this study, a cheap Acacia caesia leaf extract was employed to fabricate silver nanoparticles (Ag NPs) with ovicidal, larvicidal, and adulticidal toxicity against three mosquito vectors, Anopheles subpictus, Aedes albopictus, and Culex tritaeniorhynchus. Ag NPs were analyzed by various biophysical methods, including spectroscopy (UV-visible spectrophotometry, XRD, FTIR, EDX) and microscopy (SEM, TEM, AFM) techniques. High acute larvicidal potential was observed against larvae of An. subpictus (LC50= 10.33 μg/ml), Ae. albopictus (LC50= 11.32 μg/ml), and Cx. tritaeniorhynchus (LC50= 12.35 μg/ml). Ag NPs completely inhibited egg hatchability on three vectors at 60, 75, and 90 μg/ml, respectively. In adulticidal assays, LD50values were 18.66, 20.94, and 22.63 μg/ml. If compared to mosquito larvae, Ag NPs were safer to three non-target aquatic biocontrol agents, with LC50ranging from 684 to 2245 μg/ml. Overall, our study highlights the potential of A. caesia as an abundant and cheap bioresource to fabricate biogenic Ag NPs effective against mosquito young instars and adults, with moderate impact on non-target aquatic biocontrol agents.
Department of Agriculture, Food and Environment, University of Pisa, via del Borghetto 80, 56124, Pisa, Italy. benelli.giovanni@gmail.com.
Giovanni
G
Benelli
Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia.
Shine
S
Kadaikunnan
Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia.
Naiyf S
NS
Alharbi
Unit of Vector Control, Phytochemistry and Nanotechnology, Department of Zoology, Annamalai University, Annamalai Nagar, Tamil Nadu, 608 002, India. drgovind1979@gmail.com.
Marimuthu
M
Govindarajan
D000045:Acacia / Q000737:chemistry*; D000330:Aedes / Q000187:drug effects; D000818:Animals; D000852:Anopheles / Q000187:drug effects; D003465:Culex / Q000187:drug effects; D007887:Fabaceae / Q000737:chemistry*; D007306:Insecticides / Q000737:chemistry*; D007814:Larva / Q000737:chemistry / Q000187:drug effects*; D053768:Metal Nanoparticles / Q000737:chemistry*; D000072138:Mosquito Vectors; D010936:Plant Extracts / Q000737:chemistry*; D011634:Public Health; D012834:Silver / Q000737:chemistry*
D007306:Insecticides; D010936:Plant Extracts; D012834:Silver
Biological control; Chikungunya; Dengue; Japanese encephalitis; Mosquito control; Non-target predators