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Facile synthesis of fluorescent carbon quantum dots from Betel leafs (Piper betle) for Fe3+sensing
摘要： In this study green synthesis of Fluorescence Carbon quantum dots from betel leafs (piper betle) via hydrothermal method. The characterization of CQDs was carried out and their feasible development mechanism was also discussed. This carbon dots selectively detects Fe3+ in aqueous medium in the presence of other metal ions like (Ca2+, Cu2+, Mg2+, Ag+, Hg2+, Fe2+, Fe3+, Cd2+ and Pb2+) at same concentration and also very sensitivity it will detect 50–150 nM concentration with R2 = 0.9944 value.
关键词： Betel leafs,Sensitivity,Fluorescence,Fe3+ detection,Carbon quantum dots
更新于2025-09-23 15:21:01
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A novel ECL sensor based on a boronate affinity molecular imprinting technique and functionalized SiO2@CQDs/AuNPs/MPBA nanocomposites for sensitive determination of alpha-fetoprotein
摘要： In this work, a boronate-affinity sandwich electrochemiluminescence (ECL) sensor was constructed to detect alpha-fetoprotein (AFP) based on a multiple signal amplification strategy. Gold nanoparticles (AuNPs) were utilized and modified on the surface with chitosan in order to facilitate electron transfer. The composite of the molecularly imprinted polymer (MIP) enhanced the selectivity of alpha-fetoprotein detection. 4-mercaptophenylboronic acid (MPBA) was used as the tracing tag for capture of alpha-fetoprotein. SiO2 nanoparticles carried carbon quantum dots (CQDs) labeled with gold nanoparticles and produced an ECL signal. Under the optimum experimental conditions, the linear range for alpha-fetoprotein was between 0.001 and 1000 ng/mL with a correlation coefficient of 0.9952, and the detection limit was 0.0004 ng/mL (S/N=3). This proposed ECL sensor displayed several advantages, including outstanding selectivity, fine reproducibility, high sensitivity, low detection limit and wide linear range. Furthermore, the newly constructed boronate-affinity sandwich ECL sensor was successfully applied to the determination of alpha-fetoprotein in serum samples, indicating great potential for application in clinical diagnostics.
关键词： Alpha-fetoprotein,Molecular imprinting,Boronate-affinity,Carbon quantum dots,ECL sensor
更新于2025-09-23 15:21:01
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Carbon and graphene quantum dots: a review on syntheses, characterization, biological and sensing applications for neurotransmitter determination
摘要： Neuro-transmitters have been considered to be essential biochemical molecules, which monitor physiological and behavioral function in the peripheral and central nervous systems. Thus, it is of high pharmaceutical and biological significance to analyze neuro-transmitters in the biological samples. So far, researchers have devised a lot of techniques for assaying these samples. It has been found that electro-chemical sensors possess features of robustness, selectivity, and sensitivity as well as real-time measurement. Graphene quantum dots (GQDs) and carbon QDs (CQDs) are considered some of the most promising carbon-based nanomaterials at the forefront of this research area. This is due to their characteristics including lower toxicity, higher solubility in various solvents, great electronic features, inertness, high specific surface areas, plenty of edge sites for functionalization, and strong chemical versatility, in addition to their ability to be modified via absorbent surface chemicals and the addition of modifiers or nano-materials. Hence in the present review, the synthesis methods of GQDs and CQDs has been summarized and their characterization methods also been analyzed. The applications of carbon-based QDs (GQDs and CQDs) in biological and sensing areas, such as biological imaging, drug/gene delivery, antibacterial and antioxidant activity, photoluminescence sensors, electrochemiluminescence sensors and electrochemical sensors, have also been discussed. This study then covers sensing features of key neurotransmitters, including dopamine, tyrosine, epinephrine, norepinephrine, serotonin and acetylcholine. Hence, issues and challenges of the GQDs and CQDs were analyzed for their further development.
关键词： Carbon quantum dots,Graphene quantum dots,Neurotransmitters,Biological applications,Sensing applications,Electrochemical sensors
更新于2025-09-23 15:19:57
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Co2+a??coordinated NH2a??carbon quantum dots hybrid precursor for the rational synthesis of Coa??CoOX/Coa??Na??C ORR catalyst
摘要： For the goal of practical industrial development of fuel cells, design and synthesis of electrocatalysts for oxygen reduction reactions (ORR) with sustainable and high performance are of great significance. In this work, the coordination of NH2-carbon quantum dots (NCQDs) with Co2+ on carbon black was reasonably achieved via one-pot and low-cost hydrothermal treatment for the first time. Citric acid (CA) and urea (UA) were taken as carbon and nitrogen sources for NCQDs, respectively. The coordination of Co2+ and NCQDs were well-characterized using spectroscopic techniques such as FTIR, UV-visible absorption and fluorescence. Carbonization of carbon black-supported Co/NCQDs at 800 oC under N2 atmosphere endows the pyrolysis products with high catalytic activity. The Co-CoOX/Co-N-C possesses enhanced ORR performance in terms of positive onset-potential (～-0.079 V vs. SCE) and half wave potential (E1/2) (～-0.201 V vs. SCE), high stability, as well as the accelerated reaction kinetics.
关键词： urea (UA),Citric acid (CA),oxygen reduction reactions (ORR),NH2-carbon quantum dots (NCQDs)
更新于2025-09-23 15:19:57
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Carbon quantum dots assisted strategy to synthesize Co@NC for boosting photocatalytic hydrogen evolution performance of CdS
摘要： Photocatalytic water splitting accompanied by the hydrogen production as a prospective method has been placed on solving the double issues of the energy crisis and environment pollution. Therefore, the development of stable and efficient hydrogen evolving photocatalysts is pretty important and urgent. Herein, the Co@NC (Co nanoparticles wrapped by nitrogen doped carbon layers) derived from the mixture of carbon quantum dots (CQDs) and Co2+ as the cocatalyst is loaded on the surfaces of the CdS nanorods (NRs) for photocatalytic hydrogen production. The results show a hydrogen evolution activity of 21.8 mmol g-1 h-1 for CdS with 3 wt % loading amount of Co@NC (CdS-3) and 29.8 times higher than that of CdS alone. In addition, an apparent quantum efficiency (AQE) of 41.8 % at 420 nm over the CdS-3 is obtained. The enhanced photocatalytic performance of the hybrid nanostructure is largely ascribed to the effective electron transfer (ET) between the CdS NRs and Co@NC, which is confirmed by the electrochemical experiments and photoluminescence (PL) spectra. In all, this work supplies a novel strategy to synthesize universal photocatalytic cocatalyst.
关键词： Carbon quantum dots,1D CdS,Synergistic effect,Hydrogen evolution reaction,Photocatalysis
更新于2025-09-23 15:19:57
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Green Synthesis of Highly Fluorescent Graphene Oxide/Carbon Quantum Dot Colloid from Rice
摘要： Carbon quantum dot–graphene oxide hybrids have been synthesized from rice precursor using a ball-milling-assisted hydrothermal method. The structure of the quantum dots and graphene oxide was studied using x-ray diffraction analysis, energy-dispersive x-ray spectroscopy, and elemental mapping. The size and morphology of the nanostructures were studied using ?eld-emission scanning electron microscopy and transmission electron microscopy, revealing that the product was composed of spherical nanoparticles and nanosheets. We argue that the presence of some metals in the rice precursor can catalyze the synthesis of graphene oxide. The structure of the product was studied by Fourier-transform infrared spectroscopy. Investigation of the optical properties of the quantum dots and graphene oxide by ultraviolet–visible spectroscopy and photoluminescence (PL) spectroscopy revealed strong PL properties. The PL quantum yield could be improved by surface modi?cation using polyethylene glycol, polyvinylpyrrolidone, ethylenediaminetetraacetic acid, and acetylacetone. The photocatalytic properties of the carbon nanomaterial (CNM) were investigated based on the decomposition of Eriochrome Black-T and Eosin Y dyes, revealing strong photocatalytic activity. The thermal stability of the product was examined by thermogravimetric analysis. Furthermore, atomic absorption spectroscopy showed that CNM could be used to eliminate cations of heavy metals such as lead and cadmium from toxic water.
关键词： Carbon quantum dots,photocatalyst,graphene oxide,photoluminescence,rice,surface adsorption
更新于2025-09-23 15:19:57
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Optical properties and zeta potential of carbon quantum dots (CQDs) dispersed nematic liquid crystal 4a?2- heptyl-4-biphenylcarbonitrile (7CB)
摘要： In this work, carbon quantum dots (CQDS) of three concentrations 0.1, 0.2 and 0.5 wt% have been dispersed in nematic liquid crystal 4-Heptyl-4-biphenylcarbonitrile (7CB). The results on the optical properties and zeta potential of pure and CQDs dispersed nematic 7CB have been reported. It has been observed that the dispersion of CQDs in host nematic matrix induces quenching of photoluminescence and reduces the Ultra-Violet-Visible (UV–Vis) absorbance of pure nematic at a lower wavelength. From the result of fluorescence decay profile, the fluorescence life time of pristine and dispersed nematic systems have been obtained. No remarkable changes in nematic lifetime in the presence of CQDs have been observed, which confirm that no energy is transferred from nematic to CQDs. Further, it has been found that due to dispersion of CQDs the numerical values of zeta potential are increased for the dispersed systems with 0.1 and 0.2 wt% concentrations of CQDs as compared to pure 7 CB. This result demonstrates that the study of zeta potential provides useful information on the stability and aggregation of the CQDs dispersed nematic systems.
关键词： Carbon quantum dots,UV–Vis absorbance,Zeta potential,Nematic liquid crystal,Time resolved fluorescence
更新于2025-09-23 15:19:57
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Fluorescent-Nitrogen-Doped Carbon Quantum Dots Derived from Citrus Lemon Juice: Green Synthesis, Mercury(II) Ion Sensing, and Live Cell Imaging
摘要： In this study, we report a green and economical hydrothermal synthesis of fluorescent-nitrogen-doped carbon quantum dots (NCQDs) using citrus lemon as a carbon source. The prepared NCQDs possess high water solubility, high ionic stability, resistance to photobleaching, and bright blue color under ultraviolet radiation with a high quantum yield (～31%). High-resolution transmission electron microscopy (HRTEM) results show that the prepared NCQDs have a narrow size distribution (1?6 nm) with an average particle size of 3 nm. The mercury ion (Hg2+) sensing efficiency of the NCQDs was studied, and the result indicated that the material has high sensitivity, high precision, and good selectivity for Hg2+. The limit of detection (LOD) is 5.3 nM and the limit of quantification (LOQ) is 18.3 nM at a 99% confidence level. The cytotoxicity was evaluated using MCF7 cells, and the cell viabilities were determined to be greater than 88% upon the addition of NCQDs over a wide concentration range from 0 to 2 mg/mL. Based on the low cytotoxicity, good biocompatibility, and other revealed interesting merits, we also applied the prepared NCQDs as an effective fluorescent probe for multicolor live cell imaging.
关键词： mercury(II) ion sensing,citrus lemon juice,green synthesis,live cell imaging,fluorescent-nitrogen-doped carbon quantum dots
更新于2025-09-23 15:19:57
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S, N-doped carbon quantum dots enhanced Luminol-Mn(IV) chemiluminescence reaction for detection of uric acid in biological fluids
摘要： Herein, S, N doped carbon quantum dots (S, N- CQDs) were prepared by a simple hydrothermal method and characterized by transmission electron microscopy (TEM), Energy-dispersive X-ray spectroscopy (EDS) and Fourier transform infrared (FTIR) analysis. The influence of as-prepared CQDs was studied on the luminol- Mn(IV) CL reaction. The results indicated that S, N-CQDs remarkably increase the CL intensity of this reaction (about 13 fold). Furthermore, it was found that the CL intensity of S,N-CQDs–luminol-Mn(IV) system was significantly declined by uric acid. We exploited the amplified CL system to design a novel probe for the detection of uric acid. The CL intensity of S,N-CQDs–luminol-Mn(IV) reaction was proportional to the logarithm of uric acid concentration in the range of 0.05 to 1.5 μM, with a limit of detection of 17 nM. Based on these results, a sensitive and straightforward CL method was developed for the analysis of uric acid in biological fluids with satisfactory results.
关键词： Uric acid,sulfur-nitrogen doped carbon quantum dots,Chemiluminescence,Mn (IV)
更新于2025-09-23 15:19:57
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Preparation of molecularly imprinted fluorescence sensor based on carbon quantum dots via precipitation polymerization for fluorescence detection of tetracycline
摘要： A facile and effective method was proposed to prepare the molecularly imprinted fluorescence sensor with carbon quantum dots, which were modified vinyl groups by acrylic acid on the surface. The obtained fluorescence composite material was investigated by transmission electron microscope and Fourier transform infrared spectra. After the experimental conditions were optimized, a linear range of 1.0–60 μmol L?1 was obtained and the detection limit was 0.17 μmol L?1. The novel fluorescence sensor can be successfully used to detect tetracycline in real samples. This study provides a convenient strategy for selective recognition and rapid detection of tetracycline in the complex environment.
关键词： precipitation polymerization,tetracycline,carbon quantum dots,molecularly imprinted polymers,fluorescence detection
更新于2025-09-23 15:19:57