Graphene Quantum Dots (GQDs) for Bioimaging and Drug Delivery Applications: A Review

Abstract

Quantum dots (QDs) exhibit unique physicochemical and optical properties that are suitable for photovoltaic cells, light-emitting diodes, and optoelectronic devices; however, unlike selenium and tellurium/metalsulfide-based QDs, graphene quantum dots (GQDs) are comparatively less toxic and biocompatible, making them promising candidates for biological applications such as bioimaging, drug delivery agents, therapeutics, and theranostics. Various synthesis techniques such as top-down and bottom-up methods along with novel green synthesis methods for the preparation of pure and doped GQDs are thoroughly discussed in this study. Physicochemical, optical, and biological properties such as size-and chemical-compositiondependent fluorescence, therapeutics, disease diagnostics, biocompatibility, and cellular toxicity are extensively studied and summarized. Finally, the prospects and potential directions of GQDs in drug delivery and bioimaging systems are discussed in regards to challenges such as the synthesis, biocompatibility, and cellular toxicity.

Cost-effective synthesis of 2D molybdenum disulfide (MoS2) nanocrystals: An exploration of the influence on cellular uptake, cytotoxicity, and bio-imaging

“…The EDAX study proved that the as-synthesized MoS2 nanostructure comprises Mo and S elements, including oxygen atoms. Further, no other elements were found, which verified the purity of as-prepared samples [ 1 , 12 , 32 ].…”

“…MoS 2 nanocrystals can be used in many biomedical applications because of their tunable size and adequate luminescence properties. It has been widely applied in medicine, drug delivery, diagnostics, and outstanding biocompatibility in living organisms [ 1 , 2 ].…”

Recent Advances in Functional Carbon Quantum Dots for Antitumour

“…The excellent biocompatibility of CQDs is due to their small size and surface groups, 88 as well as biocompatibility of precursors, distribution of the surface charges and even the structural properties of carbon elements. [89][90][91] The particle size of CQDs is generally less than 10 nm, which makes it impossible to observe through ordinary optical microscopy.…”

Facile Synthesis of N-Doped Graphene Quantum Dots as Novel Transfection Agents for mRNA and pDNA

“…Additionally, we showed that GQDs exhibit low cytotoxicity and do not affect microbiome environment when fed to mice via oral administration [39]. GQDs also can be loaded with various drug molecules and genes through physicochemical conjugation between their functional groups [40][41][42][43][44]. Like GOs, GQDs need additional functionalization to interact electrostatically or covalently with therapeutic molecules or genes [45,46].…”