Fabrication of Reduced Graphene Oxide-Ag Nanocomposites and Analysis on the Interaction with BSA

Graphene is an excellent platform to support and stabilize silver nanoparticles (AgNPs). The reduced graphene oxide-silver nanoparticles (rGO-AgNPs) were synthesized by the chemical reduction method and characterized by using ultraviolet-visible (UV-vis) absorption, transmission electron microscopy (TEM), X-ray diffractometer (XRD), and scanning probe microscopy (SPM). The binding reaction of rGO-AgNPs with bovine serum albumin (BSA) was investigated by using fluorescence spectrometry and SPM. As the concentration of AgNPs increased, the fluorescence spectrum was quenched, and the quenching process of rGO-AgNPs and BSA was static quenching. Thermodynamic parameters of the absorption process were evaluated at different temperatures, and the negative values of Gibbs free energy (Delta G) showed that this process was spontaneous. The main type of interaction was hydrophobic interaction according to the values of changes in standard enthalpy (Delta H) and entropy (Delta S). In addition, the morphology changes of proteins interacting with nanomaterials were detected by SPM.