Green synthesis of Silver nanoparticles through Calotropis gigantea leaf extracts and evaluation of antibacterial activity against Vibrio alginolyticus

Abstract

Green synthesized silver nanoparticles by <em>Calotropis gigantea</em> leaf extract were used to study the inhibitory activity against pathogenic <em>Vibrio alginolyticus</em>, isolated from wild <em>Artemia franciscana</em> cysts. Silver nanoparticle synthesis was observed using UV-visible spectroscopy and the morphological characteristics were analyzed by atomic force microscope (AFM). In the present study, increasing concentrations of silver nanoparticles synthesized on LB agar plates effectively reduced the number of colonies of <em>V. alginolyticus</em>. A decrease in colonies (CFUs) was observed at 5 mg/mL of silver nanoparticle concentration and the complete inhibition of V. alginolyticus was observed at 20 mg/mL of silver nanoparticle concentration on LB agar plates. In vivo controlling efficiency of silver nanoparticles was tested in an <em>A. franciscana</em> hatching system. Effective control of <em>V. alginolyticus</em> in brine shrimp <em>A. franciscana</em> hatching units was achieved by experimental infection and treatment with silver nanoparticles. Experimental infection studies showed that <em>V. alginolyticus</em> infected <em>Artemia</em> nauplii treated with silver nanoparticles (10 mg/mL) had greater survival (>40%) than silver nanoparticles not treated with nauplii. Based on the findings of this study, it is recommended that low concentrations of green synthesized silver nanoparticles should be further investigated for other potential experimental models to control potential medical pathogens.