In a paper published in NANO, researchers from Hubei, China discuss the top-down and bottom-up strategies for the synthesis of Graphene quantum dots (GQDs). The respective advantages and disadvantages of these methods are summarized. With regard to some important or novel ones, the mechanisms are proposed for reference. In addition, the application of GQDs in biosensors is highlighted in detail.
At present, various top-down methods, such as oxidative cutting, hydrothermal or solvothermal reactions, electrochemical oxidation, ultrasonic-assisted or microwave-assisted process, chemical vapor deposition (CVD) have been reported to produce GQDs. Meanwhile, the bottom-up methods have been developed rapidly, which mainly include carbonization methods and stepwise organic synthesis. Owing to excellent photoelectric properties, good biocompatibility and low cytotoxicity, GQDs are of great value in various domains. In particular, as a novel luminescent nanomaterial, GQDs have played a leading role in the development of biosensors.
The authors review the latest progresses on the synthesis of GQDs. Different methods are presented in order to study their characteristics and the influence on the final properties of the GQDs. The mechanisms of some novel methods are proposed for offering enlightenment in the synthesis. Furthermore, the potential application of GQDs in biosensors and their design solution are introduced. Finally, a brief outlook and further development for GQDs are discussed. This review not only provides a useful guide on the synthesis of GQDs, but also facilitates designing novel biosensor devices for researchers.