Preparation of Graphene Quantum Dots and Their Biological Applications

As the derivatives of graphene, graphene quantum dots (GQDs) have the excellent properties of graphene, and photoluminescence (PL) properties that ordinary graphene does not possess, which is attributed to quantum confinement effect and boundary effect. Moreover, GQDs perform well in terms of cytotoxicity and biocompatibil- ity. Recently, the synthetic method of GQDs is increasingly diverse, which is usually divided into two main groups: top-down and bottom-up. With increasing application of GQDs in biomedical field, higher requirements on their morphology and size control are put forward. In this paper, we focus on the synthetic methods that are promising to control morphology and size of GQDs. Advantages and disadvantages of these methods are listed and analyzed comparatively. The biological applications of GQDs, including biological imaging, biological sensors, drug delivery and antibacterial agents, etc. are introduced. Suggestions on the choice of synthetic method for preparation of GQDs are given based on the requirements of diverse applications. The remained problems and the development directions in the research of GQDs are put forward.