Carbon dots have gained tremendous interest attributable to their unique features. Two approaches are involved in the fabrication of quantum dots (Top-down and Bottom-up). Most of the synthesis methods are usually multistep, required harsh conditions, and costly carbon sources that may have a toxic effect, therefore green synthesis is more preferable. Herein, the current review presents the green synthesis of carbon quantum dots (CQDs) and graphene quantum dots (GQDs) that having a wide range of potential applications in bio-sensing, cellular imaging, and drug delivery. However, some drawbacks and limitations are still unclear. Other biomedical and biotechnological applications are also highlighted.

Graphene quantum dots (GQD) is an efficient nanomaterial composed of one or more layers of graphene with unique properties that combine both graphene and carbon dots (CDs). It can be synthesized using carbon-rich materials as precursors, such as graphite, macromolecules polysaccharides, and fullerene. This contribution emphasizes the utilization of GQD-based materials in the fields of sensing, bioimaging, energy storage, and corrosion inhibitors. Inspired by these numerous applications, various synthetic approaches have been developed to design and fabricate GQD, particularly bottom-up and top-down processes. In this context, the prime goal of this review is to emphasize possible eco-friendly and sustainable methodologies that have been successfully employed in the fabrication of GQDs. Furthermore, the fundamental and experimental aspects associated with GQDs such as possible mechanisms, the impact of size, surface alteration, and doping with other elements, together with their technological and industrial applications have been envisaged. Till now, understanding simple photo luminance (PL) operations in GQDs is very critical as well as there are various methods derived from the optical properties of manufactured GQDs can differ. Lack of determining exact size and morphology is highly required without loss of their optical features. Finally, GQDs are promising candidates in the after-mentioned application fields.

Amongst sulfur- and nitrogen-containing heterocyclic compounds, the 2-aminothiazole scaffold is one of the characteristic structures in drug development as this essential revelation has several biological activities abiding it to act as an anticancer, antioxidant, antimicrobial and anti-inflammatory agent, among other things. Additionally, various 2-aminothiazole-based derivatives as medical drugs have been broadly used to remedy different kinds of diseases with high therapeutic influence, which has led to their wide innovations. Owing to their wide scale of biological activities, their structural variations have produced attention amongst medicinal chemists. The present review highlights the recently synthesized 2-aminothiazole-containing compounds in the last thirteen years (2008–2020). The originality of this proposal is based on the synthetic strategies developed to access the novel 2-aminothiazole derivatives (N-substituted, 3-substituted, 4-substituted, multi-substituted, aryl/alkyl substituents or acyl/other substituents). The literature reports many synthetic pathways of these 2-aminothiazoles associated with four different biological activities (anticancer, antioxidant, antimicrobial and anti-inflammatory activities). It is wished that this review will be accommodating for new views in the expedition for rationalistic designs of 2-aminothiazole-based medical synthetic pathways.