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A Fluorescent Aptamer/Carbon Dots based Assay for Cytochrome c Protein Detection as a Biomarker of Cell Apoptosis
摘要： Cytochrome c (Cyt c), a heme protein, can be a potential biomarker for cell-apoptosis or even cancer diagnosis. In this work, a simple, rapid, sensitive and selective label-free assay for Cytochrome c (Cyt c) detection is introduced based on an interaction between nucleic acid aptamer biomolecules and surfaces of Carbon Dots (CDs). CDs are used as a fluorescent probes and Cyt c-aptamers as a sensing materials. Interactions of aptamers with CDs quench the fluorescent intensity of CDs. By addition of Cyt c biomolecule as an analyte to the solution and binding to the aptamers, CDs fluorescence turns on. Stronger binding affinity of the aptamers toward Cyt c than CDs, causes they leave the CDs surfaces and the fluorescence is recovered. The amount of recoveries corresponds linearly to the concentration of Cyt c and be used as the basis of detection. The method exhibited high sensitivity to Cyt c with a detection limit of 25.90 nM and a linear range from 40 nM to 240 nM.
关键词： Fluorimetric Detection,Aptamer,Cytochrome c,Carbon dots
更新于2025-09-10 09:29:36
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Solid Acids Accelerate the Photocatalytic Hydrogen Peroxide Synthesis over a Hybrid Catalyst of Titania Nanotube with Carbon Dot
摘要： Photocatalytic synthesis of hydrogen peroxide (H2O2) from water and oxygen is an alternative route for clean energy storage and chemical synthesis, but still having problems with insufficient H2O2 productivity and solar-to-chemical energy conversion efficiency. Herein, we reported a hybrid catalyst of proton-form titania nanotube with carbon dot (HTNT-CD) that is highly efficient for the production of H2O2 under visible-light irradiation (λ>420 nm, H2O2 productivity at 3.42 mmol gcat-1·h-1), outperforming the titania catalysts containing noble metals and the carbon nitride catalysts reported previously. Multiple studies demonstrate that the protons on the HTNT-CD are crucial for the production of H2O2 by efficiently accelerating the half reaction of molecular oxygen reduction to form H2O2, and effectively hindering H2O2 decomposition under the irradiation conditions. This HTNT-CD catalyst gives solar-to-H2O2 apparent energy conversion efficiency at 5.2%, which is even 4.9 times of that (1.06%) over the catalyst derived from commercial P25 and CDs. More importantly, the HTNT-CD is stable, giving high H2O2 productivity in the continuous recycle tests.
关键词： photocatalyst,carbon dots,TiO2 nanotubes,H2O2 synthesis
更新于2025-09-10 09:29:36
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Carbon dots as a dual sensor for the selective determination of d-penicillamine and biological applications
摘要： Dual mode Nanosensors gained tremendous interest in recent years because of their facile synthesis and dual applications. Herein we have synthesized highly fluorescent carbon dots (CDs) from Mahogany fruit shell by chemical oxidation method. The as prepared CDs exhibited selective and sensitive quenching of fluorescence by Fe3+ and also accompanied by a dramatic increase in absorption intensity. Hence these two processes led to fabricate CDs-Fe3+ system as a dual probe. D-Penicillamine (D-PA) has much affinity toward Fe3+ which resulted in recovery of almost 75% fluorescence intensity and decrease in absorption of the CDs-Fe3+ system. Thus, this tendency has been exploited for the selective detection of D-PA by both Spectrofluorimetrically and UV-Visible spectroscopically and showed a wide linear range of detection 0-48 μg mL?1 respectively. This developed probe offered low cost, high selectivity, repeatability, facile operation and excellent recovery ratio in detection of D-PA in pharmaceutical samples. Moreover, biological applications CDs were investigated using Saccharomyces cerevisiae strain with confocal microscopy. We found that CDs were a biocompatible and ideal candidate for differential staining of yeast cells.
关键词： D-penicillamine detection,Cell imaging,Carbon dots (CDs),Dual sensor,Biocompatibility,UV-Visible and spectrofluorimetrically
更新于2025-09-10 09:29:36
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Photoinduced charge transfer from Carbon Dots to Graphene in solid composite
摘要： The emission in solid phase of Carbon Dots (CDs) deposited by drop-casting technique is investigated by means of micro-photoluminescence. Graphene and SiO2 are used as substrates, and the influence of their different nature – conductive or insulating – on the emission of CDs is highlighed. In particular, a systematic loss of efficiency in the emission of CDs on graphene is found, suggesting a CD-graphene interaction possibly due to a photoinduced electron transfer between the surface states of CDs and the conduction band of graphene. Finally, thanks to the negligible influence on CDs emission, SiO2 substrate is used as support to perform thermal processing of CDs in solid phase, showing the possibility to modulate the CDs surface composition, and therefore, their emission.
关键词： carbon dots,thermal processing,graphene,photoluminescence,charge transfer
更新于2025-09-10 09:29:36
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Controllable Synthesis of Carbon Dots with Excitation-Wavelength-Dependent or Independent Photoluminescence for the Selective and Sensitive Detection of Co <sup>2+</sup> Ions
摘要： Fluorescent carbon dots (CDs) with excitation-wavelength-dependent and excitation-wavelength-independent emission have been prepared with varying amounts citric acid (CA), ethylenediamin end-capped polyethylenimine (PEI-EC) and sodium borohydride (NaBH4), structure, optical and chemical sensing properties have been also systematically investigated. The varying of NaBH4 and PEI-EC renders the structure and surface state change as well as photoluminescence (PL) properties. The results indicated that NaBH4 made the CDs sensitive to Co2 + ions, whilst the PEI-EC served to increase their sensitivity. The synergistic roles that both NaBH4 and PEI-EC played on the selective and sensitive detection of Co2 + were achieved via a simple adjustment of the mass ratios during synthesis. Furthermore, the PL intensity was gradually recovered until completely restored with the addition of chelating agent ethylenediaminetetraacetic acid (EDTA) to the Co2 + quenched CDs solutions. This work provided quantitatively preparation and controllable synthesis of excitation-wavelength-dependent or independent CDs for the development of PL based sensors.
关键词： Photoluminescence intensity,Selective detection,XPS analysis,Surface modification,Carbon dots
更新于2025-09-10 09:29:36
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Surface Molecularly Imprinted Carbon Dots Based Core-Shell Material for Selective Fluorescence Sensing of Ketoprofen
摘要： In this work, we report an environment friendly core-shell material based on Carbon Dot core and Molecularly Imprinted Polymer shell as sensor for highly selective fluorescence detection of ketoprofen. The Carbon Dots (CDs) were prepared by a hydrothermal method and the polymer layer around the CDs core was synthesised by sol-gel polymerisation. The prepared material was characterized by Fluorescence Spectroscopy, FT-IR Spectroscopy and Transmission Electron Spectroscopy (TEM). Fluorescence from the Carbon Dots- Molecularly Imprinted Polymer (CDs-MIP) was found to quench selectively in the presence of ketoprofen and quenching effect was found to be greater than for Non-Imprinted Polymer (CDs-NIP) which indicated the potential of CDs-MIP as a fluorescence sensing material for ketoprofen. The imprinting factor was obtained to be 2.35. Under optimized conditions, a linear response was obtained in the concentration range from 0.039 to 3.9 μM with a detection limit of 0.01 μM. The correlation coefficient was 0.999. The developed sensor was applied to determination of ketoprofen in human serum and urine samples with good recoveries ranging from 96 to 104% indicating successful application of the proposed sensor in biological fluids.
关键词： Molecularly imprinted polymer,Fluorescence determination,Carbon dots,Ketoprofen
更新于2025-09-10 09:29:36
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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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Gold Conjugated Carbon Dots Nano Assembly: FRET Paired Fluorescence Probe for Cysteine Recognition
摘要： The detection and discrimination of Cys amino acid from numerous other related biomolecules has great importance in clinical field for diagnosis of various diseases. Herein, to detect the Cys, we embedded the carbon dots (CDs), gold, and naphthalimide (L1) into a single ratiometric fluorescence sensor assembly. Sensor assembly works on the principle of FRET mechanism between CDs and naphthalimide when CDs and L1 adhered on gold nanoparticles surface. Gold metal was turned into solid support by in situ reduction of HAuCl4 in the presence of CDs and L1. When the assembly was excited at 360 nm, emission maxima at 568 nm corresponded to naphthalimide emission was emerged that signifies the existence of a FRET between the CDs and naphthalimide fluorophores. With the addition of Cys, the FRET mechanism eliminated and the change in the fluorescence emission at two different wavelengths (450 nm and 568 nm) was recorded. The endogenous images of Cys was recorded by collecting the fluorescence images of HeLa cells under fluorescence microscope and also applied for the assay of Cys in blood serum. Cytotoxicity studies of CDs and sensor assembly were evaluated by performing the MTT assay.
关键词： Cell Imaging,Fluorescence,Carbon dots
更新于2025-09-10 09:29:36
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AIP Conference Proceedings [Author(s) 6TH INTERNATIONAL CONFERENCE ON PRODUCTION, ENERGY AND RELIABILITY 2018: World Engineering Science & Technology Congress (ESTCON) - Kuala Lumpur, Malaysia (13–14 August 2018)] - Hydrothermal synthesis of carbon dots and their luminescence
摘要： The synthesis of carbon dots by hydrothermal method with external heating from precursors such as glucose, citric acid, birch bark soot, cowberry, blueberry, redcurrant, and blackbird cherry are investigated. The photoluminescence studies of these carbon dots at di?erent excitation wavelengths was held. It is shown that there is an e?ect of the shift of luminescence spectra intensity peaks with the increasing of excitation wavelengths. The presence of this e?ect open new perspectives for development of composite materials from carbon dots, starch, and epoxy, which can convert the light of the blue LED into the green.
关键词： composite materials,luminescence spectra,hydrothermal synthesis,carbon dots,photoluminescence
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