Ultrasound-assisted synthesis and antibacterial activity of gallic acid-chitosan modified silver nanoparticles

Silver nanoparticles (AgNps) properties are affected due to the high surface area to volume ratio. The high thermal stability has been proved to be more efficient as antibacterial than bulk silver. Due to antibiotic resistance, the AgNps become a powerful weapon against the re-emergence of multidrug-resistant bacteria. The aim of this research article is to synthesize colloidal AgNps by a combination of ultrasonication and chemical reduction method using gallic acid and chitosan, respectively. Different spectroscopic and microscopic techniques were used to characterize the biophysical properties GC-AgNps. The results revealed that as-synthesized gallic acid-chitosan modified silver nanoparticles (GC-AgNps) were monodispersed, spherical shape with an average size of 26.23 +/- 9.92 nm, and stable for four weeks without any noticeable change in size. The X-ray diffraction (XRD) analysis and Infrared spectroscopy (FTIR) confirmed that as-synthesized GC-AgNps were face-centered cubic (FCC) crystalline structures and the most prominent Ag-O vibrations at 599 cm(-1). Further, GC-AgNps were studied for the antibacterial activity against Escherichia soli (E.coli) using a minimum inhibitory concentration at various concentrations of GC-AgNps. The sensibility caused by GC-AgNps against E. coli was 1 mu g/mL after 120 min of exposure. The adopted method was rapid, facile and straightforward, affording stabilized GC-AgNPs that exhibited good antibacterial activity.