Synthesis of Reduced Graphene Oxide-Silver Nanocomposites and Assessing Their Toxicity on the Green Microalga Chlorella vulgaris

The growing demands for nanotechnology in the recent years have resulted in environmental release of nanomaterials. In the current study, reduced graphene oxide-silver nanocomposites (Ag-rGO) were synthesized by an easy method and their characteristics were determined using X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-Vis), energy dispersive X-ray spectroscopy (EDX), and scanning electron microscopy (SEM) techniques. Subsequently, toxicity of Ag-rGO was examined on the marine microalga Chlorella vulgaris. After treatment of algal cells with different concentrations of Ag-rGO for 24 h, growth parameters have been significantly decreased. In addition, a considerable reduction in viability of the treated cells was designated. Further considerable effects of Ag-rGO treatments have been revealed by increments in the activities of a number of antioxidant enzymes and reductions in the photosynthetic pigment contents. Our results showed that the main toxic effects of Ag-rGO are associated with the presence of Ag nanoparticles in the structure of these nanocomposites.