Anopheles gambiae Control Potential and Antibacterial Activity of Opuntia ficus-indica (Cactus Plant) Mediated Nanoparticles

Abstract

Infected mosquitoes transmit malaria globally, and their resistance to insecticides has sparked a global search for biological control strategies. This study investigated the insecticidal and antibacterial potential of previously greensynthesised and characterised silver nanoparticles (AgNPs), gold nanoparticles (AuNPs), and silver-gold alloy nanoparticles (Ag-AuNPs) derived from Opuntia ficus-indica (OF). Larvicidal and pupicidal effects were tested at 1-30 µg/ml concentrations over 12 to 24h. Simultaneously, the impact of nanoparticle- infused coil fumes on adult mosquitoes was assessed at 170 µg/ml. Antibacterial activitybwas evaluated using the agar well diffusion method against eight clinical isolatesbat concentrations ranging from 10–50 µg/ml. The results showed that mortalitybrates in larvae and pupae increased with concentration over time, with the highestbeffect observed at 170 µg/ml in adult mosquitoes exposed to fumes. Antibacterial evaluations showed that the nanoparticles exhibited zones of inhibition between 5band 12 mm against eight clinical bacterial isolates, with OF-AuNPs and OF-AgAuNPs being particularly effective against Pseudomonas aeruginosa. Overall, the findings highlight the potential of OF-derived nanoparticles for larvicidal, pupicidal, adulticidal, and antibacterial applications in insect and bacterial control, respectively.