<i>Tradescantia pallida</i>-derived silver nanoparticles for the management of <i>Aedes aegypti</i>

Aedes aegypti is a cosmopolitan vector of arboviral diseases like dengue, Zika, chikungunya, and yellow fever. The management of these diseases requires effective mosquito control strategies due to the lack of suitable medications and vaccines. In addition, the inefficacy of insecticides due to multiple resistances and environmental safety concerns has raised interest in the use of botanicals for this purpose. Hence, the present study synthesized silver nanoparticles (AgNPs) at 3 mM AgNO3 using varying volumes (0.5, 1.0, 1.5, and 2.0 mL) of aqueous leaf extract of Tradescantia pallida (Tp-AgNPs) and estimated their efficacy against Ae. aegypti larvae. The results showed the highest larvicidal potential of Tp-AgNPs at 3 mM of silver nitrate, the efficacy increasing with exposure time. The larval mortality increased by 9.31–34.58% after 48 h of treatment as compared to 24 h, while a noticeable increase of 45.15–53.53% was observed after 72 h of treatment. The efficient Tp-AgNPs were characterized using various biophysical techniques, including UV-Vis spectroscopy, Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray (EDX) Spectroscopy, X-ray diffraction (XRD), and Fourier Transform Infrared (FT-IR). The results showed that they were synthesized at 312 nm. The nanoparticles were mostly spherical, with a solid face-centred cubic structure and were widespread, ranging in size from 15 to 40 nm. The FT-IR bands indicated that plant phytochemicals were involved in both breaking down and stabilizing AgNPs. Overall, the results show that T. pallida-mediated silver nanoparticles are cost-effective and efficient larvicidal agents against Ae. aegypti. The study recommends using Tp-AgNPs as an alternate to traditional chemical insecticides for controlling mosquito vectors.