Comparative study of chitosan/Ag nanocomposites synthesis and test their antibacterial activity on Staphylococcus aureus and Escherichia coli

A green and simple method has been successfully developed to synthesize chitosan/Ag nanocomposites using Kumquat extract and River-leaf creeper extract as biological reducing agents. It indicates to be an eco-friendly and green method for the synthesis providing a cost effective and an efficient route for the chitosan/Ag nanocomposites’ synthesis. The prepared chitosan/Ag nanocomposites have been characterized by UV-vis, TEM, FTIR, and XRD. Result showed those chitosan/Ag nanocomposites have been obtained with average particle size of ~15-25 nm (using kumquat extract) and ~15-41 nm (using river-leaf creeper extract). Moreover, the synthesized chitosan/Ag nanocomposites also showed their efficient antimicrobial activity against on S. aureus and E. coli. The chitosan/Ag nanocomposite was found to have significantly higher antimicrobial activity than its components at their respective concentrations. The presence of a small percentage (2.75%, w/w) of metal nanoparticles in the nanocomposite was enough to significantly enhance inactivation of S. aureus and E. coli as compared with unaltered chitosan. Thus, this eco-friendly method could be a competitive alternative to the conventional physical/chemical methods used for the synthesis of chitosan/Ag nanocompoites. Since, it has a potential to use in biomedical applications, opto-electronics and medical devices in future.