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Multifunctional N,S co-doped carbon dots for sensitive probing of temperature, ferric ion, and methotrexate
摘要： In this paper, we have presented a facile method to fabricate nitrogen and sulfur co-doped carbon dots (N,S-CDs) for blood methotrexate (MTX) sensing applications. The N,S-CDs with quantum yield up to 75% were obtained by one-step hydrothermal carbonization, using reduced glutathione and citric acid as the precursors. With this approach, the formation and the surface passivation of N,S-CDs were carried out simultaneously, resulting in intrinsic fluorescence emission. Owing to their pronounced temperature dependence of the fluorescence emission spectra, resultant N,S-CDs can work as versatile nanothermometry devices by taking advantage of the temperature sensitivity of their emission intensity. In addition, the obtained N,S-CDs facilitated high selectivity detection of Fe3+ ions with a detection limit as low as 0.31 μM and a wide linear range from 3.33 to 99.90 μM. More importantly, the added MTX selectively led to the fluorescence quenching of the N,S-CDs. Such fluorescence responses were used for well quantifying MTX in the range of 2.93 to 117.40 μM, and the detection limit was down to 0.95 μM. Due to Binert^ surface, the N,S-CDs well resisted the interferences from various biomolecules and exhibited excellent selectivity. The proposed sensing system was successfully used for the assay of MTX in human plasma. Due to simplicity, sensitivity, selectivity, and low cost, it exhibits great promise as a practical platform for MTX sensing in biological samples.
关键词： Hydrothermal carbonization,Doped carbon dots,Excitation-independent emission,Multifunctional probe,Methotrexate,Surface passivation
更新于2025-11-19 16:46:39
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Tunable luminescence and morphological evolution of facile synthesized zinc borate/carbon dots composites for NUV-WLEDs
摘要： A series of zinc borate/carbon dots composites (ZBH/yNCDs) were successfully synthesized under hydrothermal conditions. The influences of yellow N-doped carbon dots (yNCDs) content on the structure, morphologies and luminescence properties of the zinc borate (4ZnO·B2O3·H2O, ZBH) were investigated. With increasing yNCDs content, ZBH in the ZBH/yNCDs composites gradually lost water and eventually became ZB/yNCDs (4ZnO·B2O3, ZB) composites. Meanwhile, the tunable luminescence of ZBH/yNCDs composites and the morphological evolution from rod-like to blocks to sphere-like were achieved by varying the yNCDs content in the zinc borate matrix. The results revealed that the ZBH/yNCDs composite with sphere-like morphology has the strongest white light emission at 395 nm excitation wavelength. Therefore, the ZBH/yNCDs composites may be used as phosphors in the near-ultraviolet (NUV) excitation white-light illumination field. The discovery of this work may also provide new inspirations for solving the self-quenching effect of carbon dots in the solid-state display applications.
关键词： N-doped carbon dots,White light-emitting diodes,Morphology,Zinc borate
更新于2025-09-23 15:21:01
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Silver nanosol SERS quantitative analysis of ultratrace biotin coupled N-doped carbon dots catalytic amplification with affinity reaction
摘要： Highly catalytic and stable N-doped carbon dots (N-CDs) were prepared rapidly by microwave procedure using glucose as precursor and ammonium sulfite as N-dopant. The reduction of AgNO3 by trisodium citrate (TCA) was slow to form nanosilver (AgNP), and the N-CDs exhibited strong catalysis of the AgNP reaction. The formed AgNPs were used as indicator in the presence of Vitoria blue B (VBB) molecule probe with a SERS peak at 1615 cm?1. With the increase of nanocatalyst N-CDs concentration, the AgNP reaction speed up, and the SERS peak of VBB enhanced linearly due to formation of more AgNPs as substrate. In the presence of avidin (Ad), the SERS peak weakened. Upon addition of biotin, the SERS peak enhanced due to turn on the indicator nanoreaction. The enhanced SERS signal had a good linear relationship with the biotin concentration in range of 0.0006–0.021 ng/mL, with a detection limit of 0.3 pg/mL.
关键词： Nanocatalysis,N-doped carbon dots,SERS,Affinity reaction,Biotin
更新于2025-09-23 15:19:57
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Determination of chondroitin sulfate in synovial fluid and drug by ratiometric fluorescence strategy based on carbon dots quenched FAM-labeled ssDNA
摘要： Chondroitin sulfate (CS) plays an increasingly important role in clinical settings and pharmacy quality control. However, sensitive and simple methods for CS detection remain limited. In this work, positively charged nitrogen doped carbon dots (P-NCDs) with internal luminescence and quenching property to FAM-labeled random-sequence ssDNA (F-ssDNA) were prepared by a simple heating method. P-NCDs attached and quenched F-ssDNA through electrostatic interaction to form the system of P-NCDs and F-ssDNA (P-NCDs/F-ssDNA) with retained fluorescence intensity of P-NCDs. The highly negatively charged CS reacted electrostatically with P-NCDs and then replaced F-ssDNA in P-NCDs/F-ssDNA to recover the fluorescence intensity of the original quenched F-ssDNA while retaining the internal fluorescence intensity of P-NCDs. Thus, by using restored F-ssDNA as the signal controlled by adding CS to P-NCDs/F-ssDNA, a ratiometric fluorescence strategy based on the retained fluorescence of P-NCDs as reference signal was fabricated through synchronous fluorescence spectrometry for the sensitive detection of CS. Under the optimal experimental conditions, a linear equation for CS was obtained for CS concentration within the range of 0.05–2.0 μg/mL. The method was also successfully applied for the accurate determination of CS in joint fluid samples of arthritic patients, chondroitin sulfate tablets, and chondroitin sulfate eye drops, suggesting its appreciable application potential in the clinic.
关键词： Positively charged nitrogen doped carbon dots (P-NCDs),Chondroitin sulfate,Synchronous fluorescence spectrometry,Ratiometric fluorescence strategy,Synovial fluid
更新于2025-09-23 15:19:57
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Ratiometric fluorometric determination of silver(I) by using blue-emitting silicon- and nitrogen-doped carbon quantum dots and red-emitting N-acetyl-L-cysteine-capped CdTe quantum dots
摘要： A ratiometric fluorometric assay for silver(I) is described. The method makes use of a dually emitting quantum dot hybrid, which is composed of (a) blue-fluorescent silicon- and nitrogen-doped carbon quantum dots (CQDs), and (b) of red-emitting CdTe quantum dots (QDs) capped with N-acetyl-L-cysteine. The red-emitting CdTe QDs undergo strong and specific quenching by Ag(I), whereas the blue-emitting N,Si-CQDs are not quenched. The two kinds of QDs are mixed and used as a ratiometric fluorescent probe. A linear relationship is found between the log of intensities [(I608/I441)0/(I608/I441)] and the concentration of Ag(I) in the range from 5.0–1000 nM, and the limit of detection (at S/N = 3) is 1.7 nM. Possible interferents (including 17 general metal ions, 12 anions and fulvic acid) do not interfere with the determination. The assay was successfully used for the determination of Ag(I) in surface water and wastewater samples. The fluorescence quenching mechanism of the ratiometric assay system was also discussed in detailed.
关键词： Fluorescence quenching mechanism,Surface water,Nitrogen-doped carbon dots,Silver ions,Silicon-doped carbon dots,Wastewaters,3-Aminopropyltriethoxysilane functionalized carbon dots,Quenching efficiency,Dual-emission quantum dots hybrid,Fluorescent probe
更新于2025-09-19 17:13:59
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N,S-self-doped carbon quantum dots from fungus fibers for sensing tetracyclines and for bioimaging cancer cells
摘要： In this work, nitrogen and sulfur dual-doped carbon quantum dots (N,S-CDs) from naturally renewable bio-material fungus fibers were prepared by a biosynthesis and hydrothermal method. The N,S-CDs displayed good water solubility, excellent stability, high quantum yield (QY = 28.11%) as well as remarkable features for fluorescence quenching-based detection and cellular imaging of cancer cells. It was worth mentioning that the heteroatoms doped carbon quantum dots made from the fungus fibers had a satisfactory QY and could be used as a selective, efficient, and sensitive fluorescent probe to determine tetracyclines by the synergistic effects of static quenching and internal filtration effect. The probe demonstrated a wide linear range and low detection limit. For tetracycline, the linear range was 0.5 μM to 47.6 μM, and the corresponding detection limit was 15.6 nM. Significantly, the test papers prepared by using N,S-CDs could detect tetracyclines in aquiculture wastewater rapidly. The produced N,S-CDs did not affect the cell viability and showed great promises for cellular imaging.
关键词： Biosynthesis,Cellular imaging,Tetracyclines,Fungus fibers,N,S-self-doped carbon dots
更新于2025-09-19 17:13:59
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Optimization and performance of nitrogen-doped carbon dots as a color conversion layer for white-LED applications
摘要： In this study, green-emitting nitrogen-doped carbon dots (N-CDots) were synthesized and incorporated into drop-cast composite films for use as color conversion layers in a white-LED configuration to generate white light. In order to resolve the red deficiency of this configuration, a commercial red phosphor was integrated into the system. Moreover, the N-CDots were also processed into polymer/N-CDot composite fibers, for which we determined the amount of N-CDots that yielded adequate white-light properties. Finally, we showed that white light with excellent properties could be generated by employing both of the fabricated N-CDot composites either as drop-cast films or composite fibers. Hence, N-CDots provide a promising alternative to inorganic phosphors that are commonly employed in white-LED configurations.
关键词： PVP,nitrogen-doped carbon dots,color conversion layer,electrospinning,white-light generation,white LED,solid-state lighting
更新于2025-09-11 14:15:04
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N Doped Carbon Dot Modified WO <sub/>3</sub> Nanoflakes for Efficient Photoelectrochemical Water Oxidation
摘要： It is a serious challenge to develop photoanodes with fast charge separation efficiency and surface reaction kinetics. Herein, the N doped carbon dot modified WO3 nanoflake (NCDs/WO3) is constructed by impregnation method. The resulting NCDs/WO3 exhibits an excellent photocurrent density of 1.42 mA cm?2 (1.0 V vs saturated calomel electrode, SCE) in 1 m H2SO4 solution under AM 1.5 G irradiation, which is 2.25 times higher than that of the pristine WO3. In addition, the onset potential of NCDs/WO3 photoanode represents a cathodic shift of 70 mV, indicating the charge separation and transfer process are both promoted. These results demonstrate N doped CD modified WO3 can further enhance the conductivity and electrochemical activity surface area, which contributes to the higher photoelectrochemical (PEC) performance. This work provides an efficient strategy for the development of doping carbon material with heteroatoms to increase the charge transfer and charge separation efficiency in PEC water oxidation.
关键词： WO3 nanoflakes,photoelectrochemical,N doped carbon dots,water oxidation
更新于2025-09-10 09:29:36
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A ratiometric fluorescent and colorimetric dual-signal sensing platform based on N-doped carbon dots for selective and sensitive detection of copper(II) and pyrophosphate ion
摘要： A simple ratiometric fluorescent and colorimetric dual-signal sensing system for Cu2+ and pyrophosphate ion (PPi) detection is established based on N-doped carbon dots (N-CDs) which are synthesized via one-step hydrothermal approach. In the strategy, 2,3-diaminophenazine (oxOPD), the oxidation product of o-phenylenediamine (OPD), can be adsorbed on the surface of N-CDs through electrostatic interaction, which efficiently quenches the fluorescence of N-CDs, meanwhile, oxOPD provides a new emission peak at 553 nm. In virtue of the selective oxidative and chromogenic reaction of OPD with Cu2+, a dual-readout sensing system for Cu2+ is achieved. In addition, the redox and chromogenic reaction among them can be inhibited by PPi, which protects effectively the fluorescence of N-CDs from quenching. This sensing system exhibits good selectivity and sensitivity toward Cu2+ and PPi over other analytes with a low detection limit of 23 nM and 0.7 μM, respectively. Furthermore, the proposed sensing system displays a prospective application for quantitative assay of Cu2+ and PPi in practical samples.
关键词： N-doped carbon dots,ratiometric fluorescence,PPi,colorimetric detection,Cu2+
更新于2025-09-10 09:29:36
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Fluorescent Metal-Doped Carbon Dots for Neuronal Manipulations
摘要： There is a growing need for biocompatible nanocomposites that may efficiently interact with biological tissues through multiple modalities. Carbon dots (CDs) could serve as biocompatible fluorescence nanomaterials for targeted tissue/cell imaging. Important goals toward this end are to enhance the fluorescence quantum yields of the CDs and to increase their targetability to cells. Here, sonochemistry was used to develop a one-pot synthesis of CDs, including metal-doped CDs (M@CDs), demonstrating how various experimental parameters, such as sonication time, temperature, and power of sonication affect the size of the CDs (2–10 nm) and their fluorescence properties. The highest measured quantum yield of emission was ~16%. Similarly, we synthesized CDs doped with different metals (M@CDs) including Ga, Sn, Zn, Ag, and Au. The interaction of M@CDs with neuron-like cells was examined and showed efficient uptake and low cytotoxicity. Moreover, the influence of the M@CDs on the improvement of neurites during initiation and elongation growth phases were compared with pristine CDs. Our research demonstrates the use of M@CDs for imaging and for neuronal interactions. The M@CD nanocomposites are promising due to their biocompatibility, photo-stability and potential selective affinity, paving the way for multifunctional biomedical applications.
关键词： sonication,neurite outgrowth,biocompatibility,metal-doped carbon dots,neural tissue engineering,fluorescence
更新于2025-09-09 09:28:46