Synthesis, Characterization and Remedial Action of Biogenic Silver Nanoparticles and Chitosan-Silver Nanoparticles against Bacterial Pathogens

Custard apple is a dry land fruit. Its leaves exhibit different pharmacological activities. In the present study, both silver (Ag) nanoparticles and chitosan-coated Ag (Chi-Ag) nanoparticles were fabricated using the aqueous leaf extract of the custard apple plant. During preliminary phytochemical analysis, various types of phytocompounds were found in the aqueous leaf extract of the same plant. Next, both nanoparticles were physiochemically characterized. FTIR analysis exhibited the fingerprint vibrational peaks of active bioactive compounds in plant extract, Ag nanoparticles, and Chi-Ag nanoparticles. UV/Visible spectral analysis revealed the highest absorbance peak at 419 nm, indicating the presence of Ag nanoparticles. XRD analysis presented the face-centered cubic (FCC) structure of both prepared nanomaterials. Further, the average crystalline size of both Ag nanoparticles and Chi-Ag nanoparticles was calculated to be 23 and 74 nm, respectively. FESEM analysis showed the spherical and cubical shapes of Ag nanoparticles and Chi-Ag nanoparticles, respectively. EDS analysis indicated a peak around 3.29 keV, conforming to the binding energies of Ag ions. The biogenic nanomaterial also showed strong antibacterial activity against all tested bacterial pathogens.