Carbon-based quantum dots enhance platelets aggregation through migrasomes biogenesis

Structural features regulated photoluminescence intensity and cell internalization of carbon and graphene quantum dots for bioimaging

Carbon-based quantum dots and their nanocomposites have sparked immense interest for researchers as sensors due to their attractive physico-chemical properties caused by edge effects and quantum confinement. In this review article, we have discussed the synthesis and application of nanocomposites of graphene quantum dots (GQDs) and carbon quantum dots (CQDs). Different synthetic strategies for CQDs, GQDs, and their nanocomposites, are categorized as top-down and bottom-up approaches which include laser ablation, arc-discharge, chemical oxidation, ultrasonication, oxidative cleavage, microwave synthesis, thermal decomposition, solvothermal or hydrothermal method, stepwise organic synthesis, carbonization from small molecules or polymers, and impregnation. A comparison of methodologies is presented. The environmental application of nanocomposites of CQDs/GQDs and pristine quantum dots as sensors are presented in detail. Their applications envisage important domains dealing with the sensing of pollutant molecules. Recent advances and future perspective in the use of CQDs, GQDs, and their nanocomposites as sensors are also explored.

Carbon-based quantum dots (CbQDs), encompassing carbon quantum dots (CQDs) and graphene quantum dots (GQDs), are an emerging class of nanomaterials with strong potential to serve as multifunctional fuel additives for compression ignition (CI) engines. This is the first focused critical review to consolidate and evaluate the combustion, performance, and emissions impacts of CbQDs in diesel-based fuels. Compared to broader carbonaceous nanomaterials, CbQDs offer unique advantages, including tunable surface functionality, nanoscale dispersion stability, and catalytic radical-generation potential. The review systematically analyzes experimental findings on the influence of CQDs and GQDs on ignition delay, fuel reactivity, brake-specific fuel consumption (BSFC), brake thermal efficiency (BTE), and key exhaust emissions including carbon monoxide (CO), unburned hydrocarbons (UHC), particulate matter (PM), and nitrogen oxides (NOx). Results indicate that CbQDs can reduce BSFC and emissions of CO, UHC, and PM by up to 6.8%, 31%, 45% and 90% respectively, while enhancing BTE by up to 6.6% depending on formulation and dosing. However, NOx behavior remains formulation-dependent and often presents trade-offs. Despite encouraging outcomes, the review identifies major gaps in mechanistic understanding, standardization, and real-world validation. Key directions for future work are proposed, including deeper diagnostics, techno-economic analysis, and environmental risk assessments to support scalable deployment. This synthesis offers essential guidance for researchers and developers advancing next-generation, nanotechnology-enhanced diesel engine technologies.

ZnCl2 Enabled Synthesis of Highly Crystalline and Emissive Carbon Dots with Exceptional Capability to Generate O2⋅–

Chapter 28 - Physical properties of quantum dots

Luminescent quantum dots: Synthesis, optical properties, bioimaging and toxicity

Carbon dots (or carbon quantum dots in some literature reports), generally small carbon nanoparticles with various surface passivation effects, have attracted widespread attention in recent years, with a rapidly increasing number of research publications. The reported studies covered many aspects of carbon dots, from the development of many new synthetic methodologies to an improved mechanistic elucidation and to the exploration of application opportunities, especially for those in the fluorescence imaging of cells and tissues. There have also been significant advances in the establishment of a shared mechanistic framework for carbon dots and other carbon-based quantum dots, graphene quantum dots in particular. In this article, representative recent studies for more efficient syntheses of better-performing carbon dots are highlighted along with results from explorations of their various bioimaging applications in vitro and in vivo. Similar fluorescence properties and potential imaging uses of some graphene quantum dots are also discussed, toward a more consistent and uniform understanding of phenomenologically different carbon-based quantum dots.

Recent advances in agricultural and marine waste-derived carbon dots for clean energy technologies

Currently, graphene has attracted much attention in the fields of bioimaging, biolabeling and drug delivery. Theoretical and experimental studies have shown that the graphene quantum dots (GQDs) are expected to show good optical properties due to their quantum confinement and edge effect. In this report, using the electrochemical assay the fluorescent GQDs with a diameter between 5 and 10 nm could be obtained via electrolysing graphite in alkaline condition and with hydrazine hydrate as a reducing agent at room temperature. The structure of the GQDs was confimed by means of transmission electron microscope (TEM) and atomic force microscope (AFM). The finding showed that the GQDs have an uniform size, and most of them are separate graphene. The GQDs mainly consist of single layer with less than 1 nm. Their features and properties were characterized by fourier transform infrared spectroscopy (FTIR), photoluminescence spectra (PL), UV-visible spectroscopy (UV-vis) and X-ray diffraction (XRD). The results indicated that the GQDs have bright yellow luminescence with a 14 % quantum yield, which is higher than that of traditional carbon quantum dots reported previously. When they were excited by different excitation wavelengths, the intensity of photoluminescence increased to the maximum, and then decreased gradually. The fluorescent emission peak of the GQDs remained unshifted, suggesting a novel kind of quantum dots different from those of graphene oxide quantum dots depending excitation wavelengths. The luminescence of GQDs arises from the graphene modified with the phthalhydrazide-like groups and hydrazide groups at the edge. The highly fluorescent GQDs have high water solubility, good photostability and biocompatibility, indicating that the GQDs can easily enter the cells. By incorporating the GQDs with A549 (lung cancer) and MCF-7 (breast cancer) cells through MTT assay, the newly obtained GQDs exhibited low cytotoxicity with an advantage of strong photoluminescence in the cells, and thus the GQDs might be used as a bioimaging marker in tumor cell imaging.

Glioblastoma (GBM), classified as a grade IV glioma, poses a significant challenge in the medical field due to the lack of efficient early detection techniques and targeted treatment options. This review addresses this critical unmet need by evaluating the transformative potential of carbon quantum dots (CQDs) and graphene quantum dots (GQDs), along with their biofunctionalized derivatives. These advanced nanomaterials offer remarkable opportunities to revolutionize the diagnosis and treatment of GBM at the cellular level. The excellent biocompatibility, stability, and adjustable surface properties of biofunctionalized GQDs (bGQDs) and biofunctionalized CQDs (bCQDs) create a strong foundation for the targeted management of GBM. Careful surface modifications enable selective toxicity toward GBM cells while preserving the health of normal cells. This approach enhances penetration through the blood–brain barrier and targets tumor cell nuclei precisely. Furthermore, the photophysical properties of bCQDs and bGQDs make them suitable for innovative anticancer treatments, including photodynamic and photothermal therapies. By incorporating anticancer agents and receptor-mediated targeting systems within bCQDs and bGQDs, therapeutic effectiveness is significantly improved through enhanced drug delivery and increased tumor specificity. Developing sensitive and selective biosensors for GBM using bCQDs and bGQDs as fluorescent and electrochemical sensing platforms enables real-time monitoring of disease progression. This review emphasizes the promising future of fluorescent CQDs and GQDs as powerful alternatives to traditional GBM management strategies, paving the way for more effective and personalized approaches in nanomedicine.Clinical trial number Since this study is a review, it is not eligible for submission to the clinical trial registry.

Pollutants and contaminants are commonly found in the environment, affecting the air, soil, food, and drinking water. Consequently, the development of novel purification technologies and efficient detection devices for these pollutants is crucial. Many conventional procedures are labor-intensive, costly, require advanced skills, and are generally inconvenient because of their susceptibility. However, detection methods utilizing quantum dots (QDs) can overcome these conventional limitations, such as lengthy detection times and cumbersome processes. This paper seeks to delineate several categories of quantum dots, including metal-based quantum dots, graphene quantum dots (GQDs), and carbon quantum dots (CQDs). This also encapsulates the developments in quantum dot-based detection of environmental contaminants, including antibiotics, heavy metals, pesticides, and viruses, along with the applications of quantum dots in chemical gas sensing. In addition, the environmental issues and toxicity of the QDs were examined. In this review, QDs are presented as a rapidly evolving platform with transformative potential for environmental sensing and pollutant detection, provided their lifecycle impacts are carefully managed and innovative, and less toxic designs are advanced.

Carbon based quantum dots (CQDs) have found their applications in various areas due to their unique properties such as photoluminescence (PL) properties, good water solubility and biocompatibility, high chemical stability, low toxicity, environmental friendliness and light bleaching resistance. Herein, a novel functional sensing platform based on bright green fluorescent nitrogen-doped carbon quantum dots (N-CQDs) was prepared for the detection of a variety of ions. Using black tea as a new carbon source, ethylenediamine as nitrogen source and surface modifier, nitrogen doped carbon quantum dots (N-CQDs) with low crystallinity, spherical and uniformly dispersed graphite structure were prepared. Its diameter distribution is between 1.0 and 3.0 nm. Unlike the other transition metal ions such as Al3+, Cu2+, Cd2+ , Hg2+, Ni2+, Fe2+, Zn2+ , and Ag +, as well as the main group metal ions such as Na +, K + , Mg2+, Ca2+ , and Ba2+ , the addition of Pb2+ to the aqueous solution of the as prepared CQDs leads to the significant quenching of the fluorescence centered at 450 nm. Such quantitative quenching effect was used to develop a CQDs sensor that is able to detect the trace amount of Pb2+ in the aqueous solution. The sensor exhibits a detection limit of 13.3 nmol/L for Pb2+ , and the quenching efficiency reaches 70.2%. The quenching mechanism was also discussed. The results in the present work indicate the Pb2+ sensor developed from the tea based CQDs may find broad application in the real time monitoring of water quality and other environmental samples.

Resonant transport and negative differential resistance in the graphene and graphyne quantum dots

In the 21st century, the development of sustainable energy and advanced technologies to cope with energy shortages and environmental pollution has become vital. Semiconductor photocatalysis is a promising technology that can directly convert solar energy to chemical energy and is extensively used for its environmentally-friendly properties. In the field of photocatalysis, graphitic carbon nitride (g-C3N4) has obtained increasing interest due to its unique physicochemical properties. Therefore, numerous researchers have attempted to integrate quantum dots (QDs) with g-C3N4 to optimize the photocatalytic activity. In this review, recent progress in combining g-C3N4 with QDs for synthesizing new photocatalysts was introduced. The methods of QDs/g-C3N4-based photocatalysts synthesis are summarized. Recent studies assessing the application of photocatalytic performance and mechanism of modification of g-C3N4 with carbon quantum dots (CQDs), graphene quantum dots (GQDs), and g-C3N4 QDs are herein discussed. Lastly, challenges and future perspectives of QDs modified g-C3N4-based photocatalysts in photocatalytic applications are discussed. We hope that this review will provide a valuable overview and insight for the promotion of applications of QDs modified g-C3N4 based-photocatalysts.

An adequate avenue towards well-designed PBDT-DTNT:PCBM active layers via quantum dot/conductive polymer configurations