Effects of Reaction Temperature on the Antibacterial Activity of Silver Nanoparticles Synthesized from Psidium guajava Leaf Extract

Silver nanoparticles have been well known to possess efficient antibacterial properties. Many studies conducted on silver nanoparticles synthesized in different routes, from physical methods to chemical techniques to biological synthesis. In this study, the biological route was utilized using Psidium guajava leaves extract mixed with silver nitrate to synthesize silver nanoparticles. In addition, syntheses were done at varying temperatures to investigate its effect over antibacterial properties of the silver nanoparticles obtained. Results showed blueshifting of UV-Vis peaks suggesting decrease in particle size as synthesis temperature increases. FTIR also showed that the synthesized nanoparticles may have been capped by phenolic compounds from the biomolecules in guava leaves. Finally, antibacterial tests via Disc Diffusion Test suggested that the silver nanoparticles biologically synthesized at higher temperatures are more effective bactericides than those synthesized at lower temperatures as indicated by the measured zones of inhibition.