Investigating the Effectiveness of Plant-Mediated Cerium Oxide Nanoparticles as Larvicidal Agents against the Dengue Vector <i>Aedes aegypti</i>

Abstract

Aedes aegypti mosquito is responsible for the transmission of some of the most serious vector-borne diseases affecting humans, including dengue fever, chikungunya, and Zika. The only effective method for minimizing their transmission is vector control. In this work, an environmentally friendly method for synthesizing cerium oxide nanoparticles (CeO2 NPs) is highlighted, and the larvicidal activity against Ae. aegypti was studied. This method uses the aqueous extract of Bruguiera cylindrica leaves (BL) as an oxidizer and stabilizing agent. UV–Vis spectroscopy presented a distinctive absorbance band at 303 nm for CeO2 NPs with a band gap of 3.17 eV. The functional groups from the plant extract connected to CeO2 NPs were identified by FT-IR analysis, while X-ray diffraction revealed the cubic fluorite orientation of CeO2 NPs. Zeta potential revealed a surface charge of −20.7 mV on NPs. The formation of CeO2 NPs was confirmed by an energy dispersive spectral analysis, and TEM and DLS revealed an average diameter of 40–60 nm. The LC50 of synthesized CeO2 against Ae. aegypti fourth instar larvae was reported to be 46.28 μg/mL in 24 h. Acetylcholinesterase (47%) and glutathione S-transferase (13.51%) activity were significantly decreased in Ae. aegypti larvae exposed to synthesized CeO2 NPs versus the control larvae. All these findings propose the potential for using B. cylindrica leaves-synthesized CeO2 NPs as an efficient substitute for insecticides in the management of mosquitoes.

Keywords

• green synthesis
• cerium oxide nanoparticles
• <i>Bruguiera cylindrica</i> extract
• larvicidal activity
• acetylcholinesterase activity
• glutathione S-transferase activity