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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. [ABSTRACT FROM AUTHOR]

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. [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]

[Display omitted] • Rare earth-doped carbon dots with aggregation-induced emission (AIE) for enhanced fluorescence. • Y-CDs exhibit bright yellow fluorescence upon water addition and UV light exposure. • Y-CDs show sensitivity to temperature and pH changes, with stable fluorescence intensity reduction. • Y-CDs enable specific imaging of the nucleus in HeLa cells for targeted cellular imaging. • Y-CDs demonstrate safety and efficiency in imaging zebrafish embryos for extended durations, offering potential for long-term vertebrate or ocular imaging. Carbon dot (CDs) materials are typically hindered by aggregation-caused quenching (ACQ) effect. However, there are limitations in terms of their development and application. The introduction of aggregation-induced emission (AIE) characteristics into CDs has emerged as a viable solution to this challenge. In this work, we synthesized a novel yellow fluorescence (FL) rare earth-doped AIE CDs (named Y-CDs), which integrate the benefits of AIE materials, rare earth materials, and CDs. Y-CDs exhibit bright yellow FL, good temperature sensitivity and pH response properties. In cell imaging, Y-CDs showed excellent targeting capability towards the nuclear in HeLa cells. Y-CDs also showed excellent biocompatibility and safety in imaging of zebrafish embryos and zebrafish. Even on the 10th day following culture of zebrafish embryos, the digestive system and lens of zebrafish can be accurately located and imaged. The work presented here suggests the great potential of replacing commercial dyes with Y-CDs for highly specific nuclear labeling and bioimaging. [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]

Aggregation-induced emission–fluorescent carbon dots (AIE-CDs) have applications in both academia and industry. In this study, triphenylamine-based CDs (T-CDs) prepared in acetic acid showing both intramolecular charge transfer (ICT) and aggregation-induced emission (AIE) were designed and synthesized. Intriguingly, the T-CDs fluoresced with different colors in solvents of different polarities: for example, in acetic acid, they showed blue fluorescence. In contrast, in the presence of water, aggregation and precipitation occurred because of the hydrophobic nature of the compound. With time, the increasing aggregation resulted in a loss in intramolecular rotational degrees of freedom, resulting in bright red emissions as a result of ICT and AIE. Interestingly, the T-CDs could be used for intracellular imaging and the lysosome-specific targeting of live cells. [Display omitted] • Synthesis of T-CDs by solvothermal method. • T-CDs display bright red fluorescence in aggregated state. • T-CDs are available in different fluorescence colors in different solvents. • T-CDs are biocompatible and selectively accumulate in lysosomes. [ABSTRACT FROM AUTHOR]

Compared to ultraviolet light, visible light is much more accessible and less damaging. However, afterglow materials that are excited by visible light remain a challenging issue. In this study, visible-light-excited phosphorescence combined with thermally activated delayed fluorescence were achieved by embedding Rose bengal (R) CDs (R-CDs) with a high quantum yield in a boric acid (BA) matrix. The R-CDs were prepared by thermally cleaving Rose bengal in an aqueous solution. At room temperature, the R-CDs@BA composite exhibited a dual-emission afterglow spectrum with an afterglow lifetime of 583 ms at an emission wavelength of 450 nm. The afterglow time was visible to the naked eye for up to 5 s, and the photoluminescence quantum yield reached 18.09%. The quantum yield of phosphorescence is 0.6%. Consequently, the R-CDs@BA composite materials were successfully employed in anti-counterfeiting, graphic security and white led emitting diodes. In summary, R-CDs@BA hold great promises for the application in different fields. New afterglow materials and applications that are stimulated by visible light may be made possible as a result of these discoveries. [Display omitted] • A simple and economical method for the synthesis of visible light-activated afterglow carbon dots is demonstrated. • The afterglow phenomenon can be inspired under visible light. • The afterglow carbon dots have been employed for information security and double encryption of data. • New afterglow materials and applications may be made possible as a result of these discoveries. [ABSTRACT FROM AUTHOR]

Tea polyphenols (TP), which is accounting for 15–30% of the dry weight of green tea and are widely used in the food industry as antioxidants, preservatives, color preservatives, and flavoring agents. To determine the concentration of TP, a fluorescent method based on nitrogen and chlorine co-doped carbon dots (R-CDs) was investigated. The R-CDs we prepared showed red emission with an absolute quantum yield (QY) of approximately 16.67 ± 0.85%. The limit of detection (LOD) was calculated to be approximately 68 ± 0.94 ng/mL, with an R2 of 0.999 over the TP range of 1–20 μg/mL. Compared to the ferrous tartrate standard curve method, the concentration of TP in green tea, which was purchased from the market, detected using our method showed an error within 5%, indicating good potential applications in the food industry. Cell imaging experiments suggested that the R-CDs exhibit excellent lysosomal targeting as the Pearson's correlation coefficient (PCC) in colocalization analysis was found to be 0.91. Further experiments showed that owing to their excitation-independent emission and high QY, the R-CDs could be applied to not only for detecting TP content but also for targeting lysosomes as substitute for commercial dyes. • The prepared R-CDs possess red emission with high quantum yield. • The R-CDs could detect TP with high selectivity and sensitivity. • The R-CDs showed wonderful lysosomal targeting compared to commercial dyes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Sliver nanoparticles@carbon dots were made from one simple method. • Sliver nanoparticles@carbon dots have good water solubility and dispersibility. • Sliver nanoparticles@carbon dots can efficiently inhibit the growth of bacteria. A novel composite material named sliver nanoparticles@carbon dots (AgNPs/CDs) was fabricated with CDs as the capping agents through one simple method. The images of TEM showed that CDs were embedded in the gaps of AgNPs and the as-prepared AgNPs/CDs can be self assembled into nanochains through electrosatic interaction between silver nanoparticles and carbon dots. With higher redox properties than AgNPs, the as-prepared composites exhibited excellent synergistic antibacterial performance against Gram-positive bacterium and Gram-negative bacterium in the antibacterial assays, which indicates potential application as an effective antibacterial material. And the results of antibacterial assy showed that the minimum inhibitory concentrations (MIC) of AgNPs/CDs were 40 μg/mL for E. coli and 20 μg/mL for S. aureus in LB medium. In addition, the oxidative stress induced by AgNPs/CDs-mediated reactive oxygen species further confirmed good application prospects in antibacterial. [ABSTRACT FROM AUTHOR]

[Display omitted] • Carbon dots with aggregation induced fluorescence were synthesized using a one-step solvothermal method. • The prepared carbon dots exhibit different fluorescence colors in different solvents. • The carbon dots were used to make an anti-counterfeiting luminous ink, which can be used for encryption in reversible double switch mode. 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. [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]

Schematic illustration of the preparation of CDs and their application for progesterone detection. [Display omitted] • CDs were designed from single curcumin by a one-pot facile dry-heating procedure. • CDs showed yellow-green emission under UV light illumination and exhibited excellent photostability. • CDs can be further served as fluorescent nanoprobe to achieve a high selectivity, sensitive and rapid response to P4 and result in a distinctly signal readout. • CDs exhibited good potential for detection of P4 in practical samples. Progesterone (P4) is an important steroid hormone that act as an indicator in the female reproductive processes; thus, following its concentration levels in human serum is important for diagnosis of early pregnancy. In this work, carbon dots (CDs) were designed via a dry-heating method, and the novel CDs exhibited good dispersion stability and excellent photostability. Under optimal conditions, the as-prepared CDs displayed high selectivity and sensitivity for P4 and exhibited a fast-responsive (within 1 min) fluorescence intensity enhancement signal in aqueous solution. For further application, the fluorescence sensing system was further extended to monitoring progesterone in real samples with acceptable recoveries. The methodology developed here offers a promising direction for the detection of clinical biomarkers that are closely related to human health. [ABSTRACT FROM AUTHOR]