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A convenient green method to synthesize luminescent carbon dots from edible carrot and its application in bioimaging and preparation of nanocatalyst
摘要： A simple single-stage method, based on refluxing edible carrot with aqueous trisodium phosphate (TSP) has been reported to synthesize blue color luminescent carbon dots (CDs). Transmission electron microscopy (TEM) image showed that CDs are almost spherical in shape and the size is around 3-8 nm. Fourier-transform-infrared (FTIR) and 1H-NMR spectroscopy study revealed that the carbohydrates present in the carrot undergone carbonization to produce luminescent CDs. Optimization study indicate that refluxing 5 g of carrot in 80 mM TSP aqueous solution for 120 min is adequate to produce highly luminescent blue CDs. The CDs produced are used as luminophore to image bacteria through fluorescence microscopy. CDs have membrane good permeability and minimum toxicity against Gram-negative and Gram-positive bacteria. The CDs capability for direct reduction of silver ions to elemental silver (Ag0) and gold ions to elemental gold (Au0) without additional reducing and stabilizing agent was demonstrated. The resulting Ag and Au nanoparticles have a size of 8-22 nm and 5-15 nm, respectively. The catalytic activity of nanoparticles in the hydrogenation reaction was investigated. The results suggest that the nanoparticles had high catalytic activity in the sodium borohydride mediated hydrogenation of nitroaromatic compounds.
关键词： nanoparticles,bioimaging,carrot,trisodium phosphate,nanocatalyst,Carbon dots
更新于2025-09-23 15:22:29
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Tuning of carbon dots emission color for sensing of Fe3+ ion and bioimaging applications
摘要： Herein, we report a facile one-step synthetic strategy for fabrication of three (blue, green and yellow) fluorescent color carbon dots (CDs) from tomato (Solanum lycopersicum). The as-synthesized CDs showed emission peaks at 450, 520 and 560 nm for blue, green and yellow color CDs when excited at 370, 420 and 460 nm, respectively. Using tomato as a carbon source, the fabricated three fluorescent color CDs showed good water dispersity and high quantum yield. The analytical performances of three fluorescent color CDs are evaluated by detecting Fe3+ ion in biofluids and iron tablets. Upon the addition of Fe3+ ion under optimal conditions, the fluorescence intensity of three fluorescent color CDs was quenched linearly over the range of 0.1 to 2.0 μM. This method opens a new analytical strategy to quantify Fe3+ ion in iron tablets and biofluids with high sensitivity. Further, the uptake of three fluorescent color CDs into HeLa cells was confirmed by confocal laser scanning microscopy. Intracellular experiments demonstrated that the three fluorescent color CDs were effectively internalized the cells and show excellent biocompatibility and low toxicity, suggesting that the CDs can be used as good candidates for biomedical applications.
关键词： Fluorescent carbon dots,Fe3+ ion,Cancer cells,Fluorescence spectroscopy and microscopy,Tomato
更新于2025-09-23 15:22:29
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A far-red FRET fluorescent probe for ratiometric detection of l-cysteine based on carbon dots and N-acetyl-l-cysteine-capped gold nanoparticles
摘要： A novel far-red fluorescence resonance energy transfer (FRET) fluorescenct probe for ratiometric detection of L-cysteine (L-Cys) has been designed. The system was established a FRET assembly by positively charged carbon dots (CDs) and negatively charged N-acetyl-L-cysteine capped gold nanoparticles (NAC-AuNPs). The fluorescence of CDs at 539 nm could be effectively quenched in the presence of NAC-AuNPs owing to FRET process, while the emission of NAC-AuNPs at 630 nm was appeared. Subsequently, the interactions between L-Cys and NAC-AuNPs resulted in the decreased emission intensity of NAC-AuNPs, but the emission intensity of CDs kept almost constant due to the continuous FRET efficiency. The ratio of emission intensities at 539 and 630 nm (I539/I630) exhibited a linear correlation to the L-Cys concentration in the range of 1.0-110 μM with the detection limit of 0.16 μM. Moreover, this far-red ratiometric sensor also revealed excellent selectivity toward L-Cys over other amino acids, which showed very high potential in the practical application for diagnosing of cysteine-related disease.
关键词： Fluorescence resonance energy transfer,gold nanoparticles,L-cysteine,Carbon dots
更新于2025-09-23 15:22:29
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Theranostic Carbon Dots with Innovative NIR-II Emission for in Vivo Renal Excreted Optical Imaging and Photothermal Therapy
摘要： Carbon dots (CDs) with low biotoxicity, high photostability, and well-controlled small size are highly desirable imaging agents for optical bioimaging. However, most of the CDs triggered by ultraviolet (UV)/blue light present visible/first near infrared (NIR-I) emissions shorter than 820 nm, impairing their imaging applications in vivo by low penetration depth. Hence, developing novel CDs based materials with second near infrared (NIR-II) emission located in 1000-1700 nm region is an urgent task. Here, a novel NIR-II emitting CDs-based nanoprobe triggered by 808 nm laser is developed. The designed CDs with 900-1200 nm luminescence possess high quantum yield (QY-0.4%), and high biocompatibility, which have proven to be effective probes for in vivo NIR-II bioimaging. Notably, nearly 65% CDs are excreted from mouse urine within 6 h, further demonstrating the rapid renal clearance of CDs. Furthermore, the designed CDs also exhibit high photothermal efficiency (30.6%), making them ideal materials for thermal ablation of cancer. Our findings pave the way of designing multifunctional CDs-based theranostic platform for simultaneously integrating the advanced NIR-II bioimaging and photothermal therapy (PTT) of cancer.
关键词： carbon dots,renal clearance,photothermal therapy of cancer,NIR-II bioimaging,NIR-triggered NIR-II emission
更新于2025-09-23 15:22:29
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Tuning Carbon Dots’ Optoelectronic Properties with Polymers
摘要： Due to their unique properties of photoluminescence, biocompatibility, photostability, ease of preparing, and low cost, carbon dots have been studied extensively over the last decade. Soon after their discovery, it was realized that their main optical attributes may be protected, enhanced, and tuned upon proper surface passivation or functionalization. Therefore, up to date, numerous polymers have been used for these purposes, resulting to higher-quality carbon dots regarding their quantum yield or further emission-related aspects and compared to the primitive, bare ones. Hence, this review aims to clarify the polymers’ role and effect on carbon dots and their features focusing on the quality characteristics of their photoluminescence upon passivation or functionalization. Given in fact the numbers of relevant publications, emphasis is given on recent articles capturing the latest advances for polymers in carbon dots for expanding emission lifetimes, advancing quantum yields, tuning emission wavelengths, enhancing specific spectral range absorption, and tailoring optoelectronic properties in general.
关键词： photoluminescence,functionalization,carbon dots,polymers,optoelectronic properties,surface passivation
更新于2025-09-23 15:22:29
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Rapid cancer diagnosis by highly fluorescent carbon nanodots-based imaging
摘要： Carbon dots (Cdots) with bright green fluorescence were applied to the rapid and selective cell imaging for a variety of cell lines. Different labeling distributions of hepatoma cells (HepG2) and normal human liver cells (LO2) were achieved using Cdots as imaging agents. For HepG2 cells, the Cdots could rapidly permeate the cell membrane and diffuse into the cytoplasm and nucleus within 3 min, and retained their location in the targets for 24 h. However, the Cdots exhibited bright fluorescence only in the cytoplasm of LO2 cell lines. Moreover, the Cdots were almost non-cytotoxic and exhibited superior photostability over a wide range of pH. Therefore, these Cdots have great potential for rapid, luminous and selective bioimaging applications, and are expected to be used as a nucleus-staining agent in cancer diagnosis.
关键词： Selective fluorescence imaging,Rapid nuclear targeting,Carbon dots
更新于2025-09-23 15:22:29
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Influence of molecular fluorophores on the research field of chemically synthesized carbon dots
摘要： Carbon dots (CDs) – small crystalline or amorphous carbon-based nanoparticles – have attracted much attention as promising fluorescent materials for a wide range of applications. One of their widely accepted advantages is the simplicity of the formation of highly luminescent CDs from a wide variety of organic precursors. At the same time, several recent studies on these chemically synthesized CDs raised questions about the nature of the resulting products. Their strong fluorescence can arise due to the presence of molecular organic fluorophores, not necessary CDs, as was assumed in the earlier publications. In this review, we consider fundamental characteristics of CDs and discuss several issues that currently prevent a better understanding of their structure-property correlation. Analysis of recent related studies identifying the presence of organic fluorophores in CDs with an emphasis on the optical properties of the synthesis products shows that their emission characteristics may be a complex interplay of stand-alone molecular fluorophores and their aggregates, possibly embedded in an amorphous carbon/polymer network. The review concludes with an outlook towards the challenges in the field of the bottom-up synthesized CDs, and their proper identification within the variety of the organic side-products eventually formed during the synthesis.
关键词： Luminescence,Chemical synthesis,Carbon dots,Optical properties,Molecular fluorophores,Aggregation
更新于2025-09-23 15:21:21
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Photoinduced Electron Transfer in Carbon Dots with Long Wavelength Photoluminescence
摘要： Carbon dots have often been studied to investigate their unique optical properties such as excitation wavelength-independence emission. Carbon dots have also been shown to undergo electron transfer in different situations. This study endeavors to investigate the properties of carbon dots photoluminescence and electron transfer. Herein, the preparation and characterization of carbon dots which exhibit long wavelength photoluminescence has been reported. These carbon dots exhibit quenching when exposed to metal ions in proportion to the reduction potential of the metal, which experimental evidence has shown for the first time. This property of metal ion reduction potential-dependent quenching has been studied to show the collisional electron transfer from amine groups in carbon dots to the metal ions. Therefore, the photoluminescence in these carbon dots are directly related to organic functional groups on the surface of the carbon dots.
关键词： Quenching,Electron transfer,Photoluminescence,Carbon dots,Metal ions
更新于2025-09-23 15:21:21
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A sensitive and selective triple-channel optical assay based on red-emissive carbon dots for the determination of PFOS
摘要： In this study, a simple, fast and cost-effective triple-channel optical assay for the determination of PFOS has been developed. The carbon quantum dots (CDs) were prepared by one-pot hydrothermal method and employed as probe for sensing PFOS. CDs react with PFOS to form ground-state complex, which brings about the intensity changes of three signals including fluorescence, UV–vis absorption and resonance light scattering (RLS). And the changes of the fluorescence and absorption signals can be used for the visual detection of PFOS. And there is a certain relationship between the three-signal changes with the concentration of PFOS, respectively. The proposed assay exhibits good selectivity and sensitivity with a limit of detection (LOD) of 18.27 nmol/L in the fluorescence signal. Fluorescence lifetime, transmission electron microscopy (TEM) images, Fourier transform infrared (FTIR) and zeta potential were investigated for the mechanism study. Furthermore, this promising approach was also successfully applied to PFOS sensing in real water samples with RSD ≤ 2.09%.
关键词： Perfluorooctane sulfonate (PFOS),Triple-channel,Visualization,Carbon dots
更新于2025-09-23 15:21:21
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Fuel Waste to Fluorescent Carbon Dots and Its Multifarious Applications
摘要： Herein, we report the fluorescent carbon dots (KCDs) from kerosene fuel soot via simple one pot oxidative acid treatment. The obtained KCDs were thoroughly characterized by pivotal techniques. The prepared KCDs are 5 nm sized quasi-spherical particles and exhibited an outstanding stability against pH, NaCl and light irradiation. Intriguingly, the KCDs display an excitation wavelength independent emissive property. Further, the KCDs were successfully utilized for multifarious applications such as photoinduced electron transfer (PET) and sensing studies. For PET studies, charged porphyrins (tetra pyridyl and tetra sulphonato) were selected and the fluorescence of associated porphyrin was quenched and the quenching is due electron transfer. The lower recombination rate obtained from transient absorption spectral studies suggests that KCDs can be used as electron shuttling material in a cascade system of photovoltaic device. On the other hand, the fluorescent nature of KCDs was used for the selective and sensitive detection of explosives and metal ions. The detection limit for picric acid, Cu2+ and Fe3+ is found to be 86 ng/ml, 15.3 ng/ml and 0.36 μg/ml respectively. Moreover, the unreacted soot during the acid treatment has been calcined and used as an affordable filter bed for waste water treatment.
关键词： Explosives,PET,Kerosene Soot,Carbon dots,Metal ion detection
更新于2025-09-23 15:21:21