Eco-friendly synthesis of size-controllable amine-functionalized graphene quantum dots with antimycoplasma properties.

Size-controllable amine-functionalized graphene quantum dots (GQDs) are prepared by an eco-friendly method with graphene oxide sheets, ammonia and hydrogen peroxide as starting materials. Using a Sephadex G-25 gel column for fine separation, for the first time we obtain GQDs with either single or double layers. By atomic force microscopy characterization, we confirm that hydrogen peroxide and ammonia play a synergistic role on graphene oxide (GO), in which the former cuts the GO into small pieces and the latter passivates the active surface to give amine-modified GQDs. Due to the low cytotoxicity and excellent biocompatibility of the obtained amine-functionalized GQDs, besides the multiwavelength imaging properties of GQDs, for the first time we find that this kind of GQD exhibits good antimycoplasma properties. Given the superior antimycoplasma effect of the GQDs and their eco-friendly mass production with low cost, these new GQDs may offer opportunities for the development of new antimycoplasma agents, thus extending their widespread application in biomedicine.