Recent Advancements in Graphene Quantum Dot-Based Bioimaging and Drug Delivery Systems

Due to their unique physicochemical, optical, and electronic properties, traditional quantum dots (QDs) have been used for various optoelectronic applications, including semiconductor lasers, photodetectors, transistors, and solar cells. However, unlike other traditional QDs, graphene quantum dots (GQDs), nanosized graphene sheets that possess edge effects and quantum confinement along with a collective structural feature of graphene, have shown less toxicity and desirable biocompatibility, making them an appropriate part of the carbon family for use in biomedical applications. This review article highlights the recent advances and roles of GQDs in healthcare, with a particular focus on their applications involving bioimaging and drug delivery. Furthermore, we provide an overview of the different synthesis methods for GQDs, including the top-down and bottom-up approaches, and discuss the modifications that enhance their functionality, such as the incorporation of heteroatoms (e.g., nitrogen, sulfur, and phosphorus) to improve their properties. This review further considers the biological, optical, and toxicological attributes of GQDs, followed by recent developments involving the use of GQDs for drug delivery and bioimaging applications. Last, we describe the challenges, future prospects, and potential directions for advancing the real-time bioimaging and drug delivery applications of GQDs, including platforms for therapeutic agent release and medical diagnosis.