Green synthesis of carbon adorned silver nanoparticles (AgNPs) and antibacterial studies

A.G. Al-Sehemi, S. Alrumman, A. Kalam, G. Du, M. Pannipara
King Khalid University,
Saudi Arabia

Keywords: silver nanoparticles, green synthesis, electron microscopy, antibacterial studies


Here, we report the synthesis and characterization of bio-functionalized silver nanoparticles (AgNPs) through modified solvothermal method using Lemon juice (bioextract) extract. In the current report, the indigenously synthesized AgNPs were adorned with carbon material and further characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM) and Fourier-transform infrared (FT-IR) spectroscopy techniques. The XRD results reveal the formation of bio functionalized AgNPs in one step. Furthermore, FT-IR spectroscopy results showed the interaction of AgNPs with bioextract. Transmission electron microscopic results show the formation of functionalized spherical silver nanoparticles (AgNPs) of average size of 37 nm, 29.5 nm and 24 nm, respectively. The bacterial activity of the synthesized silver nanoparticles (Ag-1, Ag-2 and Ag-3) was tested against both gram-negative (Proteus bacilli & Klebsiella pneumoniae) and positive (Staphylococcus aureus) bacteria. The results show that, all the synthesized AgNPs were active at 50 μg/disc against all the tested pathogen bacteria and the diameter of the zone of inhibition were 1.27 to 2.1 mm. Amongst three pathogen, only sample Ag-3 showed a maximum inhibition zone (2.10b ± 0.05 and 2.03b ± 0.027) against gram-negative bacteria K. pneumonia and P. bacilli respectively, while sample Ag-2 showed lowest inhibition zone (1.27a ± 0.22) against S. aureus as a gram-positive bacteria. This could be attributed to the smaller size, high surface area and more carbon material. The results offer that the sample Ag-3 nanoparticles could be efficient material for growth inhibitors in contrast to the tested negative and positive bacteria.