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Glioblastoma multiforme (GBM) is the most common primary malignant brain tumor and known for its challenging prognosis. Sonodynamic therapy (SDT) is an innovative therapeutic approach that shows promise in tumor elimination by activating sonosensitizers with low-intensity ultrasound. In this study, a novel sonosensitizer is synthesized using Cu-doped carbon dots (Cu-CDs) for the sonodynamic treatment of GBM. Doping with copper transforms the carbon dots into a p-n type semiconductor having a bandgap of 1.58 eV, a prolonged lifespan of 10.7 µs, and an improved electron- and hole-separation efficiency. The sonodynamic effect is efficiency enhanced. Western blot analysis reveals that the Cu-CDs induces a biological response leading to cell death, termed as cuproptosis. Specifically, Cu-CDs upregulate dihydrosulfanyl transacetylase expression, thereby establishing a synergistic therapeutic effect against tumor cell death when combined with SDT. Furthermore, Cu-CDs exhibit excellent permeability through the blood-brain barrier and potent anti-tumor activity. Importantly, the Cu-CDs effectively impede the growth of glioblastoma tumors and prolong the survival of mice bearing these tumors. This study provides support for the application of carbon-based nanomaterials as sonosensitizers in tumor therapy., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

Aggregation-induced emission luminogens (AIEgens) have garnered significant attention because of their outstanding photophysical characteristics. AIEgens are used in fluorescence imaging, sensors, tumor treatment, and other related fields. However, the synthese of these AIEgens are relatively complicated and requires expensive raw materials. These drawbacks limit their applications and development to a certain extent. In this study, using cheap and convenient materials, we developed a new type of carbon dots (O-CDs) using a one-step solvothermal method, which has the potential to become a new AIEgen. O-CDs exhibit different fluorescence colors in different solvents, and they exist as monomers in ethylic acid and, ethanol alcohol, etc., exhibiting blue fluorescence. After adding water, the fluorescence of O-CDs gradually turns orange red, because the internal rotation of the disulfide bond molecules is restricted and the AIE effect occurs. Using the unique AIE performance of O-CDs, we fabricated an anti-counterfeiting luminous ink, that can be used for encryption in the reversible double switch mode., (Copyright © 2022 Elsevier B.V. All rights reserved.)

As the second messenger in cells, calcium ions are indispensable in various physiological activities of the body. In this work, a special red fluorescent carbon dot was designed and synthesized using the secondary hydrothermal method with yttrium, p-phenylenediamine, and ethylene glycol tetraacetic acid as precursors for the detection of calcium ions. The designed carbon dot exhibited bright red fluorescence, and the fluorescence emission wavelength showed good photostability. When the calcium ion concentration was controlled from 0 to 400 μM, the carbon dot tended to respond to fluorescence quenching. At the same time, a test paper experiment was carried out, which proved the potential application of the nano-sensor in detecting calcium ions., (© 2021 John Wiley & Sons Ltd.)

Photodynamic therapy, as an effective treatment for superficial tumors, has attracted more and more attention. The development of safe, biocompatible and in vivo photosensitive materials is helpful to promote photodynamic therapy. Here we report green fluorescent carbon quantum dots prepared from a natural vitamin, riboflavin (VB2), as a photosensitizer. The VB2-based carbon dots have excellent water solubility and biocompatibility, and their singlet oxygen generation ability is much stronger than that of riboflavin itself. Through endocytosis, the carbon dots can easily enter the cells and show bright green fluorescence. In vivo experiments show that after photodynamic therapy the carbon dots can significantly inhibit the growth of tumors, and will not have toxic and side effects on other organs.

Copper ions (Cu 2+ ) and l-cysteine (l-Cys) in the human body always play critical roles in various physiological processes, while abnormal Cu 2+ and l-Cys concentrations in the biological system lead to many diseases. In this manuscript, Si-doped carbon dots (Si-CDs) with near-infrared fluorescence were designed for the detection of Cu 2+ and l-Cys through the fluorescence "on-off-on" mode. The carbon dots exhibited not only excellent optical merits including good stability against photobleaching and high chemical stability, but also superior biological compatibility. Interestingly, due to the abundant amino groups distributed on the surface of Si-CDs, they could bind to copper ions to form cupric amine complexes and then quench the fluorescence of Si-CDs due to an electron transfer process. In addition, upon the addition of l-Cys, the FL intensity of Si-CDs could be effectively recovered accompanied with complexation between Cu 2+ and the functional groups in l-Cys, due to which Cu 2+ was removed from the surface of Si-CDs. Notably, as far as we know, these are the first red-emitting carbon dots for copper ion and l-Cys assays in water samples and human plasma samples. Furthermore, this strategy was successfully applied to the determination of Cu 2+ and l-Cys in living systems, demonstrating great practicability in biomedical applications.

Carbon dots (CDs) with red fluorescence emission are highly desirable for use in bioimaging and trace- substance detection, with potential applications in biotherapy, photothermal therapy, and tumor visualization. Most CDs emit green or blue fluorescence, thus limiting their applicability. We report a novel fluorescent detection platform based on high-brightness red fluorescence emission carbon dots (R-CDs) co-doped with nitrogen and bromine, which exhibit pH and oxidized L -glutathione (GSSG) dual-responsive characteristics. The absolute quantum yield of the R-CDs was as high as 11.93%. We discovered that the R-CDs were able to detect acidic pH in live cells and zebrafish owing to protonation and deprotonation. In addition, GSSG was detected in vitro over a broad linear range (8–200 μM) using the R-CDs with excitation-independent emission. Furthermore, cell imaging and bioimaging experiments demonstrated that the R-CDs were highly cytocompatible and could be used as fluorescent probes to target lysosomes and nucleolus. These studies highlight the promising prospects of R-CDs as biosensing tools for bioimaging and trace-substance detection applications. [ABSTRACT FROM AUTHOR]

The presence of excessive ROS can cause much harm to the human body and can even cause diseases. Therefore, it is important to detect and remove ROS, but there is no ideal method available for this at present. In this research, using procyanidins, a type of plant extract with strong reducibility, as raw materials, fluorescent carbon dots (CDs) were prepared by a hydrothermal method. The proanthocyanidin-based carbon dots (PCDs) emit a light-green colored light under UV irradiation. The PCDs retain the strong reducibility of procyanidins and are highly water-soluble compared with procyanidins. The PCDs, in addition to having good biocompatibility, also have the superior properties of radical scavenging activity and cell imaging. In in vitro experiments, 1,1-diphenyl-2-picrylhydrazyl (DPPH; 100 μM) was reduced by 30% when PCDs were added up to a concentration of 87.5 μg mL−1. At the same time, the fluorescence quenching correlates with the concentration of hypochlorite and hydrogen peroxide and has a good linearity in the range of 250–2250 nM and 60–180 μM with a detection limit of 3.676 nM and 0.602 μM, respectively. Based on the previously described advantages, PCDs have potential as a biomedicine. [ABSTRACT FROM AUTHOR]

Reactive oxygen species (ROS) in the body play an important role in various processes. It is well known that harmful high levels of ROS can cause many problems in living organisms in a variety of ways. One effective way to remove intracellular ROS is to use reducing materials that can enter the cell. Herein, we developed a strong reducing carbon nano-dot from a natural product, lutein, as an initial raw material. This is a hydrothermal synthesis method with the advantages of simplicity, high yield, mild reaction conditions, and environmental friendliness. The prepared carbon dots exhibit bright blue fluorescence, and have good water solubility and biocompatibility. In particular, the carbon dots can easily enter the cell and effectively remove ROS. Therefore, the carbon dots are thought to protect cells from oxidative damage by high levels of ROS. [ABSTRACT FROM AUTHOR]

Despite the numerous reports on carbon dots (CDs) synthesized from o-phenylenediamine (o-pd), the precise mechanism of fluorescence and formation processes of o-pd CDs have not been investigated. In this study, we purified o-pd CDs and obtained five compounds with yellow, green and blue emission. For the first time, two actual molecular fluorophores named 2,3-Diaminophenazine (DAP) and 2-Amino-3-hydroxyphenazine (AHP) were confirmed. More sophisticated investigations showed the DAP was dominant for the yellow emission, which confirmed molecule states in detail. More interestingly, DAP could form nanoparticles (NPs) with various sizes at different concentrations. In this regard, we propose that the formation processes of o-pd CDs were similar to those of carbonized polymer dots (CPDs), where DAP structures initially aggregated with themselves to form polymeric clusters, further carbonization of polymeric clusters endowed the polymer clusters with a preliminary core-shell structure. With the collapse of the shell and aromatization of the core, the CPDs like structure formed eventually. This study supplements those on the yellow-emissive fluorophores region and could be the potential reference for the preparation of CDs in a similar system. Two fluorophores corresponded to yellow emission named DAP and AHP were separated from o-pd CDs solution by HPLC for the first time, further investigation suggested these CDs formed from the aggregation of DAP. [Display omitted] • The chemical structure of DAP and AHP were confirmed for the first time. • The blank of yellow-emissive fluorophores was supplemented. • The existence of molecule state prepared by rigid precursor was first verified. • The formation of CDs was originated from DAP. • The multi-colors LEDs with high CRI were successfully prepared by fluorophores. [ABSTRACT FROM AUTHOR]

Schematic illustration for the formation procedure of N-CDs and MA nanocomposite and their applications. [Display omitted] • We put forward a facile route to realize RTP emission by constructing nanocomposite. • The nanocomposite can be utilized to Fe3+ ions detection based on dual emission feature. • The RTP materials promising in information encryption with a higher level of security. Carbon dots (CDs) have received much attention in constructing metal-free phosphorescence materials, but it is still a huge challenge to develop a material with long lifetime and phosphorescence emission in aqueous environments. In this work, we designed and synthesized a universal approach to produce N-doped carbon dots (N-CDs) with efficient room-temperature phosphorescence (RTP) through simple heating treatment. Then, we prepared a kind of highly efficient N-CDs/MA nanocomposite phosphorescence materials by synthesized through N-CDs mixed with melamine. Excitingly, the characterizations indicate that the nanocomposite materials not only have an ultralong phosphorescence lifetime in the solid state, but also exhibit blue-green RTP in aqueous medium. In addition, based on their unusual RTP features, the obtained RTP materials can be successfully applied in ion determination and shows great potentials in the fields of anti-counterfeiting and information encryption. [ABSTRACT FROM AUTHOR]