Geranium wallichianum Leaf Extract Mediated Synthesis of Silver Nanoparticles: Characterization and its Antimicrobial Activity

Abstract

In present study, the Geranium wallichianum leaf extract (aqueous) and 1 mM silver nitrate solution (aqueous) were amalgamated to synthesize silver particles within the nanometer range. Initial colour changes and surface-plasmon-resonance (SPR) absorbance band observed in UV-visible spectroscopic study gave support to configuration of silver nano-particles. Silver nanoparticles were characterized by XRD, TEM and FTIR spectroscopy. Then antimicrobial (antibacterial and antifungal) activities of silver nanoparticles against selected microbial strains were studied by well diffusion method. During this work, silver SPR absorption bands between 405-425 nm range were shown by Geranium wallichianum leaf extract mediated synthesized silver nanoparticles sample solutions at different intervals. X-ray diffraction pattern displayed the formation of face centred cubic phase silver nano-structures. TEM measurements confirmed that silver nanoparticles are spherically shaped and maximum particles in 9-16 nm size range having average diameter 12.5 nm. Important FT-IR peaks at 3314.11, 1710.60, 1587.11 and 1347.77 cm-1 were predicted for hydroxyl, carbonyls, unsaturated C-C bonds and phenolic groups respectively. Further from antimicrobial results, it has been found that values of diameter of zone of inhibition (mm) of synthesized silver nanoparticles against B. subtilis, S. aureus, L. plantarum, P. aeruginosa, A. niger and C. albicans strains were 32, 28, 25, 25 35 and not active, respectively. MIC-MLC (μL) values were also determined. At last, it can be concluded that antimicrobial agents of 9-16 nm size range and stabilized by polyhydroxy-bioactive-components present in extract, in the form of silver nanoparticles has been productively synthesized.