Tyrosine-Mediated Facile Synthesis of a Graphene Oxide-Silver Nanocomposite for Antibacterial Applications

Silver-based nanomaterials have emerged as a promising class of antibacterial agents for various applications. However, complexity entangled with the synthesis procedure (such as the use of toxic reagents, difficult and tedious synthesis process, etc.) limits their widespread usage. In this direction, herein, we report the synthesis of a nanocomposite material consisting of silver (Ag) nanoparticles and graphene oxide (GO) nanosheets. Silver nanoparticles are decorated on the surface of GO sheets through the tyrosine moiety, which functions as both a reducing agent and a stabilizing agent in the process of silver nanoparticle formation. The growth of silver nanoparticles on the tyrosine-functionalized graphene oxide (GO-Ty) surface was monitored through the characterization of the surface plasmon resonance peak by using UV–visible spectroscopy. The formation of nanocomposite material was optimized by varying different parameters, such as the pH of the reaction condition and the concentration of AgNO3, which suggested that the formation of silver nanoparticles occurs only under basic conditions, and the maximum amount of nanoparticles was observed for a 1:2 ratio of GO-Ty to AgNO3. Furthermore, the kinetic study suggested that the highest nanoparticle formation occurs within 240 min. The morphological analysis indicated the formation of a silver-decorated GO nanocomposite (Ag/GO-Ty), which was further confirmed by a powder X-ray diffraction study. The thermal analysis suggested high stability of Ag/GO-Ty, compared to GO and GO-Ty, which clearly revealed the presence of a metallic component in the nanocomposite. Furthermore, the antibacterial study suggested that the nanocomposite material is highly effective against both Gram-positive and Gram-negative bacteria, where the complete killing of bacteria was observed within 6 h. More importantly, this class of nanocomposite material was stable for long-lasting applications. Altogether, the results therefore suggested that the silver-containing GO nanocomposite bears significant potential for development as an antibacterial agent for various applications.