Bio-Synthesis of Silver Nanoparticles Decorated on Hydrotalcite using Psidium Guajava']java Leaf Extract and Its Anti-Bacterial Effect

Phenolic compounds are widely known for its well-reduced behavior and surprisingly appeared in many leaf extracts, including Psidium guajava (P. guajava) leaf. This leaf extract has been confirmed as an efficiency reducing agent to reduce Ag(I) ions to silver nanoparticles (AgNPs). This work focused on the development of a "green" synthesis of nanosilver-hydrotalcite nanoparticles (HT-AgNPs) based on the bio-reduction of the P. guajava leaf extract and the application of HT-AgNPs as an antibacterial material. To assess factors affecting on synthesis process of the HT-AgNPs, experiments have been carried out with a fixation of HT/AgNO3 precursors while varying concentration of P. guajava leaf extract as well as solvent for the extraction. The methods, including ultraviolet-visible (UV-Vis) spectroscopy, infrared (IR) spectroscopy, field emission scanning electron microscopy (FESEM), dynamic light scattering (DLS), X-ray diffraction (XRD) and energy dispersive X-Ray (EDX), transmission electron microscopy (TEM) have been used to characterize the HT-AgNPs. The yield of reduction process of Ag(I) ions to AgNPs on HT reached 55.12 to 90.55 % depending on the content of AgNO3 precursor. In particular, the antibacterial activity of HT-AgNPs against to E. coli and S. aureus was also assessed and discussed.