Green-synthesized silver nanoparticles as a novel control tool against dengue virus (DEN-2) and its primary vector Aedes aegypti

Dengue is an arthropod-borne viral infection mainly vectored through the bite of Aedes mosquitoes. Recently, its transmission has strongly increased in urban and semi-urban areas of tropical and sub-tropical regions worldwide, becoming a major international public health concern. There is no specific treatment for dengue. Its prevention and control solely depends on effective vector control measures. In this study, we proposed the green-synthesis of silver nanoparticles (AgNP) as a novel and effective tool against the dengue serotype DEN-2 and its major vector Aedes aegypti. AgNP were synthesized using the Moringa oleifera seed extract as reducing and stabilizing agent. AgNP were characterized using a variety of biophysical methods including UV–vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and sorted for size categories. AgNP showed in vitro antiviral activity against DEN-2 infecting vero cells. Viral titer was 7 log₁₀ TCID₅₀/ml in control (AgNP-free), while it dropped to 3.2 log₁₀ TCID₅₀/ml after a single treatment with 20 μl/ml of AgNP. After 6 h, DEN-2 yield was 5.8 log₁₀ PFU/ml in the control, while it was 1.4 log₁₀ PFU/ml post-treatment with AgNP (20 μl/ml). AgNP were highly effective against the dengue vector A. aegypti, with LC₅₀ values ranging from 10.24 ppm (I instar larvae) to 21.17 ppm (pupae). Overall, this research highlighted the concrete potential of green-synthesized AgNP in the fight against dengue and its primary vector A. aegypti. Further research on structure–activity relationships of AgNP against other dengue serotypes is urgently required.