Search Results (1,332)

The overuse of pesticides has raised serious food-safety and environmental concerns. Carbon dots (CDs) can act as biostimulants by enhancing photosynthesis, thereby promoting plant growth and stress tolerance. However, their roles in plant pesticide detoxification remain unclear. This study synthesized nitrogen-doped carbon dots (N-CDs) with strong blue fluorescence, excellent biocompatibility, and no cytotoxicity observed in HEK 293T cells. The N-CDs were synthesized from 1.025 g citric acid and 0.379 g urea, producing particles with a size of around 2.42 nm and abundant hydrophilic groups. When applied to tomato plants, N-CDs (especially at 150 mg·L⁻¹) significantly reduced chlorothalonil (CHT) residues affecting tomato, by up to 66%. Importantly, N-CDs also improved tomato plant growth, reversing the negative effects of CHT on key parameters such as height, leaf area, and biomass. Indeed, under CHT conditions, N-CDs significantly reduced the contents of malondialdehyde, superoxide, and hydrogen peroxide. In contrast, N-CDs significantly increased the activities of superoxide dismutase, peroxidases, catalase, and ascorbate peroxidase to 117.57%, 158.53%, 162.79%, and 152.23%, respectively. Notably, N-CDs dramatically changed the glutathione pool for tomato detoxification. Overall, this study synthesized the non-cytotoxic N-CDs that not only promote tomato growth but also alleviate CHT toxicity by strengthening the tomato’s antioxidant defense system. Full article

The widespread presence of antibiotic residues, particularly norfloxacin (NFX), in food products and the environment has raised concern, underscoring the need for sensitive and selective detection methods. In this study, a novel broccoli-derived nitrogen-doped carbon quantum dots (N-CQDs) was synthesized via a green hydrothermal approach, 4-dimethylaminopyridine (DMAP) as both a nitrogen dopant and a functionalizing agent. The synthesized N-CQDs exhibit an average diameter of approximately ~4.2 nm and emit bright blue fluorescence, with a maximum emission at 445 nm upon excitation at 360 nm. A “Turn-ON” response toward NFX was achieved with a detection limit of 0.30 nM, attributed to hydrogen bonding and π–π stacking interactions that suppressed non-radiative decay. Moreover, the sensor demonstrates high selectivity for NFX, effectively distinguishing it from common interfering substances, including other antibiotics, organic acids, and biomolecules. The N-CQDs also exhibit excellent stability under diverse conditions, such as varying pH levels, high ionic strength, and prolonged irradiation. Finally, the practical applicability of the developed sensor was validated by detecting NFX in spiked broccoli extract and milk samples, with recovery rates ranging from 98.2% to 100.1% and relative standard deviations of less than 2.0%. This work presents a sustainable and efficient N-CQD-based fluorescent sensing platform, offering significant potential for rapid and reliable detection of NFX in food safety and environmental monitoring. Full article

Alzheimer’s disease (AD) requires early and accurate identification of affected brain regions, which can be achieved through the detection of specific biomarkers to enable timely intervention. Carbon nanomaterials (CNMs), including graphene derivatives, carbon nanotubes, graphitic carbon nitride, carbon black, fullerenes, and carbon dots, offer high conductivity, large electroactive surface area, and versatile surface chemistry that enhance biosensor performance. While such properties benefit a wide range of transduction principles (e.g., electrochemical, optical, and plasmonic), this review focuses on their role in electrochemical biosensors. This review summarizes CNM-based electrochemical platforms reported from 2020 to mid-2025, employing aptamers, antibodies, and molecularly imprinted polymers for AD biomarker detection. Covered topics include fabrication strategies, transduction formats, analytical performance in complex matrices, and validation. Reported devices achieve limits of detection from the femtomolar to picogram per milliliter range, with linear ranges typically spanning 2–3 orders of magnitude (e.g., from femtomolar to picomolar, or from picogram to nanogram per milliliter levels). They exhibit high selectivity against common interferents such as BSA, glucose, uric acid, ascorbic acid, dopamine, and non-target peptides, along with growing capabilities for multiplexing and portable operation. Remaining challenges include complex fabrication, limited long-term stability and reproducibility data, scarce clinical cohort testing, and sustainability issues. Opportunities for scalable production and integration into point-of-care workflows are outlined. Full article

Traditional Chinese medicine-derived carbon dots (TCM-CDs) are prepared by top-down or bottom-up synthesis methods using TCM or their active ingredients as precursors, and the size of TCM-CDs is usually less than 10 nm. It has the advantages of easy preparation, low toxicity, and high compatibility. Compared with traditional Chinese medicines, it shows more outstanding performance in antioxidant, hemostatic, antibacterial, and other aspects, thus having good development prospects. This paper systematically reviews the synthesis methods of carbon dots, focusing on the influence of different traditional Chinese medicine precursors on the formation of carbon dots during the processing process, and analyzes the performance of carbon dots in enhancing the efficacy of original medicinal materials, exerting multi-target synergistic effects, improving bioavailability, and generating new medicinal effects. It is expected to provide a theoretical basis and reference direction for the in-depth research and development of traditional Chinese medicine carbon dots in the field of medicinal value. Full article

Zibai Jade is a recently identified hydrogrossular-dominant jade originating from Shaanxi Province, China. It constitutes a polymineralic aggregate composed predominantly of hydrogrossular, with minor proportions of vesuvianite, diopside, chlorite, uvarovite, and calcite. A multi-method analytical approach was employed to characterize this jade, incorporating conventional gemological testing, polarizing microscopy, SEM, XRD, BSE, XRF, and EPMA, as well as UV-Vis and infrared (IR). These techniques enabled a detailed examination of its mineralogy, surface features, and color origin. The stone displays a heterogeneous color distribution, featuring a base hue of light green to yellowish-green, accompanied by distinct occurrences of emerald-green spots, dark green spots, mossy green inclusions, white patches, white veinlets, and a black dot with a green ring. Microanalytical results indicate that the emerald-green spots are principally composed of uvarovite; the dark green spots are dominated by hydrogrossular, diopside, and chlorite; fibrous green inclusions consist mainly of chlorite and Cr-bearing grossular; white patches and veinlets are primarily composed of calcite; and the black dot with a green ring predominantly comprises chromite and uvarovite. Coloration is attributed to the combined influence of Fe and Cr³⁺. The formation of Zibai Jade involved three mineralization stages: deposition of a carbonate protolith, high-temperature metasomatism, and retrograde alteration. The metasomatism was driven by hydrothermal fluids derived from granodioritic and ultramafic rocks, which provided Si, Al, and the essential Cr, respectively. The interplay of these processes resulted in the development of Zibai Jade, which exhibits a dense texture and attractive coloration. Full article

The increasing prevalence of antimicrobial resistance and the persistent challenge of infectious diseases highlight the critical necessity for novel approaches that integrate pathogen management with swift detection methods. Carbon dots (CDs) are a versatile class of fluorescent nanomaterials that have garnered increasing attention owing to their tunable surface chemistry, strong photoluminescence, high stability, and biocompatibility. Recent studies demonstrate that CDs possess broad-spectrum antibacterial and antifungal activities via multiple mechanisms, including the generation of reactive oxygen species, disruption of membranes, inhibition of biofilms, and synergistic interactions with conventional antimicrobials. The performance is significantly affected by precursor selection, heteroatom doping, and surface functionalization, with minimum inhibitory concentrations reported to range from highly potent at the microgram level to moderate at elevated concentrations. The intrinsic fluorescence of CDs, in addition to their antimicrobial activity, facilitates their use as sensitive and selective probes for microbial detection, allowing for rapid and real-time monitoring in biomedical, food safety, and environmental settings. This review summarizes recent advancements in the antimicrobial properties of carbon dots (CDs) and their fluorescence-based applications in microbial detection. It emphasizes their theranostic potential and future prospects as multifunctional nanomaterials for combating infectious diseases and ensuring microbial safety. Full article

A surface molecularly imprinted ratiometric fluorescent sensor (Eu/CDs@SiO₂@IIPs) was constructed for the selective and visual detection of Cu²⁺. The sensor integrates blue-emitting carbon dots as an internal reference and a custom-designed Eu(III) complex, Eu(MAA)₂(2,9-phen), as both the functional and fluorescent monomer within a surface-imprinted polymer layer, enabling efficient ratiometric fluorescence response. This structural design ensured that all fluorescent monomers were located at the recognition sites, thereby reducing background fluorescence interference and enhancing the accuracy of signal changes. Under optimized conditions, the sensor exhibited a detection limit of 2.79 nM, a wide linear range of 10–100 nM, and a rapid response time of 3.0 min. Moreover, the uncoordinated nitrogen atoms in the phenanthroline ligand improved resistance to interference from competing ions, significantly enhancing selectivity. Practical applicability was validated by spiked recovery tests in deionized and river water, with results showing good agreement with ICP-MS analysis. These findings highlight the potential of Eu/CDs@SiO₂@IIPs as a sensitive, selective, and portable sensing platform for on-site monitoring of Cu²⁺ in complex water environments. Full article

Titanium and its alloys are the most widely used metallic materials for bone contact implants. However, despite advances in implant technology, these alloys are still susceptible to post-operative clinical complications such as inflammation, which is often joined by infections and biofilm formation. A number of coatings were studied to overcome the drawbacks of these complications, but the controlled release of bioactive molecules over the first few days and the adhesion of the coating to the substrate remain recognized challenges. Carbon dots and the antibacterial potential of chiral carbon dots (CCDs) were recently reported, and their chirality was identified as a major contribution to the bactericidal effect. This study aimed to achieve a stimuli-responsive medium-term controlled release for up to one month. Two types of chiral carbon dots (CCDs) with distinct functional groups were incorporated into a stable and adherent biodegradable polymer coating, i.e., poly(lactic-co-glycolic acid) (PLGA). To enhance the coating adhesion, the titanium alloy surfaces were pre-treated and activated. The wettability, morphology, and surface composition of the coatings were characterized by contact angle, profilometry, SEM, and XPS, respectively. Coating degradation, adhesion, and CCDs release were studied at physiological pH (7.4) and at an acidic pH characteristic of an inflammatory site (pH 3.0) for up to one month. Their biological performances and blood compatibility were assessed as well. Degradation studies conducted over 28 days revealed a slow mass loss of approximately 10%, with maximum release rates for CCDs-OH and CCDs-NH₂ of 67% and 45% at pH 7.4, respectively. At pH 3.0 an inverse trend was observed with 49% and 59% maximum release after 28 days. Furthermore, the coatings did not exhibit any cytotoxic and hemolytic effects. These findings demonstrate the potential of this approach to providing titanium implants with pH-sensitive controlled release of bioactive CCDs lasting up to one month, which could address key challenges in implant-associated complications. Full article

Iron detection is of growing importance in the critical minerals sector, where unwanted iron ions are typically removed during the processing of target critical metals. The ideal sensor should utilize inexpensive, scalable materials along with a low-cost, robust, and easy-to-use analysis platform. Here, we demonstrate a simple acid–base synthesis of luminescent iron-responsive carbon dots by reacting ethanolamine, phosphoric acid, and m-phenylenediamine. The carbon dots exhibit selective, iron-specific emission quenching, with the ability to detect part-per-billion levels of iron ions even in 0.1 M HCl. After benchmarking the purified materials using a commercial spectrometer, a “low-cost” process is demonstrated in which carbon dots with minimal purification are coupled with a portable fiber-optic spectrometer for analyzing iron content. Carbon dot-coated paper strips are also evaluated as another convenient platform for iron analysis. Taken together, the sensing material and platforms demonstrated here are well-suited for detecting trace quantities of iron in environmentally relevant conditions, with potential applications in tracking iron removal processes during critical mineral production as one exciting area of interest. Full article

Background: Temporal lobe epilepsy (TLE), a prevalent refractory focal epilepsy frequently complicated by comorbid anxiety and depression, poses significant therapeutic challenges due to the inadequate efficacy of current antiepileptic drugs in seizure control. Carbon dots (CDs) demonstrate notable biological activities and represent a promising class of nanomedicines for TLE intervention. Methods: This study established an eco-friendly calcination protocol to synthesize a novel suspension of Crinis Carbonisatus-derived carbon dots (CC-CDs) as a candidate therapeutic for TLE. Results: In a TLE mouse model, the CC-CDs suspension significantly inhibited phosphorylation of the MAPK pathway (p-JNK, p-ERK, p-p38; p < 0.01, p < 0.05), leading to reduced levels of pro-inflammatory cytokines (IL-6, IL-1β, TNF-α; p < 0.01, p < 0.05), upregulation of TGF-β1 (p < 0.01, p < 0.05), and restoration of antioxidant enzyme activities (SOD, GSH, CAT; p < 0.01, p < 0.05). These modifications subsequently regulated the Glu/GABA balance, alleviating excitotoxicity (p < 0.05), attenuating neuronal damage and Nissl body loss in hippocampal CA1/CA3 regions, and improving cognitive function alongside reducing anxiety-like behaviors (p < 0.01, p < 0.05). In vitro, the CC-CDs suspension suppressed LPS-induced apoptosis in BV2 cells. Conclusions: The CC-CDs suspension ameliorates TLE by inhibiting MAPK signaling, thereby reducing neuroinflammation and oxidative stress, rectifying Glu/GABA imbalance, attenuating excitotoxicity, and ultimately improving behavioral deficits. These findings underscore the therapeutic potential of CC-CDs suspension for TLE treatment. Full article

The overabundance of Ulva australis (U. australis), a green macroalga widespread along the coastline of Jeju Island, Republic of Korea, presents a growing ecological challenge, as it can cause unpleasant odors and disturb the ecological balance. Hence, we report a sustainable valorization strategy for converting U. australis biomass into marine carbon dots (MCDs) via a facile hydrothermal carbonization process. The synthesis requires no hazardous reagents or complex instrumentation and yields highly water-dispersible MCDs with excitation-dependent fluorescence properties. Comprehensive in vitro and in vivo assessments revealed the multifunctional bioactivity of the synthesized MCDs. Moreover, in vivo fluorescence imaging at seven days post-fertilization revealed the preferential accumulation of MCDs along the vertebral column, implying a possible affinity for mineralized tissues and suggesting their utility in skeletal imaging applications. Collectively, these findings underscore the potential of U. australis-derived MCDs as biocompatible and multifunctional nanomaterials with broad biomedical applications. Full article

Dual-mode fluorescent materials are vital in bioimaging, sensing, displays, and lighting, owing to their efficient emission of visible or near-infrared light. Traditional optimization methods, including empirical experiments and quantum chemical computations, suffer from high costs, high labor intensities, and difficulties capturing complex relationships among molecular structures, synthesis parameters, and key photophysical properties. In this review, fundamental principles, key methodologies, and representative applications of machine learning (ML) in predicting fluorescent material performance are systematically summarized. The core ML techniques covered include supervised regression, neural networks, and physics-informed hybrid frameworks. The representative fluorescent materials analyzed encompass aggregation-induced emission (AIE) luminogens, thermally activated delayed fluorescence (TADF) emitters, quantum dots, carbon dots, perovskites, and inorganic phosphors. This review details the modeling approaches and typical workflows—such as data preprocessing, descriptor selection, and model validation—and highlights algorithmic optimization strategies such as data augmentation, physical constraints embedding, and transfer learning. Finally, prevailing challenges, including limited high-quality data availability, weak model interpretability, and insufficient model transferability, are discussed. Full article

In this study, the applicability of carbon dots (CDs) for the treatment of oral cancer cells in vitro was assessed under laser irradiation. For the study, CDs were synthesized using an amino acid via heat treatment and then combined with a photosensitizer. The absorbance and photoluminescence of CDs were measured. The production of reactive oxygen species (ROS) was evaluated using assay agents. The glutathione (GSH) content of the test solutions was evaluated. The viability of normal and cancer cells was evaluated using CDs at different concentrations under laser irradiation. Live/dead cells and intracellular lipid peroxidation (LPO) were observed after treatment. According to the assays, the production of •OH, •O₂⁻, and ¹O₂ was spectroscopically observed, which was reflected by the change in their peak absorbance. GSH was depleted mostly during light irradiation. Cancer cells were eliminated without leaving visible live cells, whereas normal cells were minimally affected. Intracellular LPO was confirmed in cells by green fluorescence, which was emitted from an oxidized assay dye. Conclusively, the amino acid-based photosensitizer-combined CDs eliminated approximately 70% of the cancer cells in vitro under laser irradiation, with no visible live cells. Based on these assays, ROS production may induce cell death via synergistic apoptosis–ferroptosis therapy. Full article

Lycium barbarum L. (goji berry) undergoes rapid quality deterioration after harvest owing to its high water activity and abundant reactive oxygen species (ROS). Carbon-dot-mediated photodynamic treatment (CD-PDT) has recently been shown to extend shelf life by modulating ROS-scavenging and defense enzymes, yet the global metabolic reprogramming that supports this protection remains unresolved. Here, we applied ultra-high-performance liquid chromatography–tandem mass spectrometry (HPLC-MS/MS)-based untargeted metabolomics to decode the metabolic footprint of CD-PDT in freshly harvested goji berries. Our results revealed a total of 17,603 differentially expressed metabolites between the treatment and control groups under both positive- and negative-ion modes. Principal component analysis indicated that CD-mediated PDT significantly altered the metabolic profile of fresh goji berries. The treatment activated the phenylpropanoid biosynthesis pathway, promoting the accumulation of compounds such as kaempferol-3-sophoroside, kaempferol-3-O-β-D-glucoside, and galactoside, thereby enhancing the antioxidant capacity of the fruit. Furthermore, CD-mediated PDT induced the tricarboxylic acid cycle, providing sufficient energy to support the phenylpropanoid biosynthesis pathway. In conclusion, these findings provide the systems-level evidence that CD-PDT orchestrates a coordinated activation of primary and secondary metabolism in postharvest goji berries, establishing a mechanistic framework for preservation of horticultural products. Full article

Rapid and accurate bacteria identification, particularly Escherichia coli (E. coli), is essential in the monitoring of health, environment, and food safety. E. coli, a prevalent pathogenic bacterium, serves as a key indicator of food and water contamination. Carbon quantum dots (CQDs) have appeared as promising fluorescent probes because of their small size, ease of synthesis, low toxicity, and tunable fluorescence using different carbon-rich precursors. Advances in both bottom-up and top-down synthesis procedures have enabled precise control over CQD properties and surface functionalities, enhancing their capabilities in biosensing. Among the critical factors influencing CQD performance is the strategic selection of precursors, which determines the surface chemistry and recognition potential of the resulting nanodots. The integration with other nanomaterials and the surface modification of CQDs with specific functional groups or recognition elements further improves their sensitivity and selectivity toward E. coli. This review summarizes recent progress in the modification of CQDs for the fluorescent detection of E. coli, highlighting relevant sensing mechanisms and the influence of different precursors, such as antibiotics and sugars, as well as various functionalization and surface modification strategies. The aim is to provide insight into the rational design of efficient, selective, and cost-effective CQD-based biosensors for bacterial detection. Full article