Characterization of the samples were carried out using a Bruker AXS
D8 Advance X-ray diffractometer (XRD) operated at a voltage of 40 kV
and a current of 30 mA with Cu Kα radiation (1.540 Å) between 2θ°
angles of (30°–80°) for analyzing the crystal structure and peak data respectively.
UV–vis spectral analysiswas carried out using a JASCO V-700
spectrophotometer. UV–Visible spectrums of SNPs were recorded
between the range from 300 to 600 nm. Particle size distribution was
carried out by a Dynamic Light Scattering (DLS)-Horiba nanoparticle analyzer
SZ-100 equipped with a 532 nm laser. Fourier transforminfrared
spectroscopy (FT-IR) studies were carried out using a Shimadzu FTIR
spectrophotometer (FTIR 8400). The obtained samples were prepared
using the KBr pellet technique andwere analyzed to check the presence
of bio-functional moieties of coffee extract and the surface chemistryof the reduced silver ion. The FTIR spectrums were collected at a
spatial resolution of 4 cm−1 in the transmission mode, between
4000–400 cm−1 respectively. Morphology of the obtained silver nanoparticles
was analyzed using electron microscopes (SEM: Hitachi
S520: EDXA: Oxford Link ISIS-300 and TEM: Tecnai-12 FEI) along with
elemental fingerprinting after sonicating the SNPs for 1 h in ethanol. Antibacterial
activities of the bio-synthesized silver nanoparticles were
carried out on the E. coli and S. aureus using the standard well
diffusion method. The zone of inhibition (ZI) during the sensitivity
test was assessed using a standard antibiotic (ampicillin). The growth
of the bacterial culture was carried out in a sterilized nutrient agar
medium.