Green synthesis of orange emissive carbon dots for the detection of Ag+and their application via solid-phase sensing and security ink.
TL;DR: In this article, O-phenylenediamine and melamine were used as precursors for the one-step hydrothermal synthesis of novel orange emissive CDs (O-CDs) in an aqueous solution.
Abstract: Fluorescent carbon dots (CDs) have attracted considerable interest due to their superior optical properties and facile preparation. In this work, O-phenylenediamine and melamine were used as precursors for the one-step hydrothermal synthesis of novel orange emissive CDs (O-CDs) in an aqueous solution. The fluorescence intensity (580 nm) of the O-CDs exhibited a good linear relationship with Ag+in the range of 0.0-50.0μM with the detection limit of 0.289μM. Moreover, the O-CDs were successfully used to determine Ag+in biological samples (Hela cells) because of their low cytotoxicity, and good biocompatibility. Besides, the O-CDs-doped solid-phase detection materials (test paper and hydrogel) were employed to monitor Ag+qualitatively and quantitatively, indicated that the O-CDs had a great capacity for the detection of Ag+in biological and environmental areas. Based on their extraordinary fluorescence property, the O-CDs could also be used as security ink. Overall, based on their excellent fluorescent performance, the CDs in this study have significant potential for practical application toward solid-phase sensing and security ink.
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TL;DR: In this paper , fluorescent copper nanoclusters (Cu NCs) have been efficiently synthesized in a novel strategy via sonochemical method, using N-acetyl-L-cysteine (NAC) as reducing and stabilizing reagent.
12 citations
TL;DR: In this article , the effect of sp2 conjugated domain on the fluorescence wavelength of multicolor carbon dots (CDs) was explored through theoretical calculation and experimental verification, through regulation of the structure size and the introduction of amide bonds.
Abstract: Multicolor carbon dots (CDs) possess tremendous potential applications, especially in optoelectronic devices. However, further applications of multicolor light-emitting diode (LED) have been constrained due to the very limited researches concerning the wavelength control mechanism of multicolor CDs. In this work, through theoretical calculation and experimental verification, the regulatory effects of sp2 conjugated domain on the fluorescence wavelength of CDs were explored. Through the regulation of the structure size and the introduction of amide bonds, four kinds of structures were designed in density functional theory (DFT) calculation to explore the influence of sp2 conjugated domain on the fluorescence wavelength of CDs. Using thiourea and p-phenylenediamine as the precursors and regulating the reaction solvents, multicolor CDs with blue, green, and red fluorescence emission were prepared to experimentally verify the emission mechanism. It was confirmed that the increasing structure size and the introduction of amide bond would induce an increasing size of the sp2 conjugated domain, leading to the red shift of the CDs fluorescence wavelength. Furtherly, in order to suppress the self-quenching performance, the CDs@polyvinylpyrrolidone (CDs@PVP) fluorescent film possessing bright solid-state fluorescence was constructed for a better application in light-emitting diodes. The approach provided an effective strategy to realize the programmed regulation on the fluorescence wavelength of CDs, offering us wide potential applications of CDs in the photoelectric device fields.
3 citations
02 Mar 2023
TL;DR: In this paper , the photoluminescence of CDs was found selectively quenched by Fe3+ in a linear manner in the range of 0.05-0.45 mM.
Abstract: Carbon dots (CDs) or CDs/polymer composites have been applied in numerous fields. Here, novel CDs were synthesized by carbonization of egg yolk, and characterized by TEM, FTIR, XPS and photoluminescence spectra. The CDs were found to be approximate sphere in shape with an average size of 4.46 ± 1.17 nm, and emitted bright blue photoluminescence under UV irradiation. The photoluminescence of CDs was found selectively quenched by Fe3+ in a linear manner in the range of 0.05-0.45 mM, meaning they could be applied for Fe3+ detection in solution. Moreover, the CDs could be uptaken by HepG2 cells to exhibit bright blue photoluminescence. The intensity could reflect the level of intracellular Fe3+, indicating they could be further used for cell imaging and intracellular Fe3+ monitoring. Next, dopamine was polymerized on the surface of CDs to obtain the polydopamine (PDA)-coated CDs (CDs@PDA). We found PDA coating could quench the photoluminescence of CDs via inner filter effect, and the degree of quenching was linearly related to the logarithm of DA concentration (Log CDA). Also, the selectivity experiment indicated the method had a high selectivity for DA over a number of possible interfering species. This indicated the CDs in combination with Tris buffer could be potentially applied as the assay kit of dopamine. At last, the CDs@PDA exhibited excellent photothermal conversion capability, and they could efficiently kill HepG2 cells under NIR laser irradiation. Overall, the CDs and CDs@PDA in this work exhibited many excellent advantages, and could be potentially used for multi-applications, such as Fe3+ sensor in solution and cellular, cell imaging, dopamine assay kit, as well as photothermal agents for cancer therapy.
1 citations
TL;DR: In this article , a new off-on fluorescence strategy for determination of Ag+ and S2O32− has been presented, using Nitrogen doped carbon dots (N-CDs) synthesized using oxalic acid dihydrate and ethylenediamine.
Abstract: In this work, a new “off-on” fluorescence strategy for determination of Ag+ and S2O32− has been presented. Nitrogen doped carbon dots (N-CDs) were synthesized using oxalic acid dihydrate and ethylenediamine...
1 citations
02 Dec 2022
TL;DR: In this paper , the influence of sp 2 conjugated domain on the fluorescence wavelength of CDs was explored through theoretical calculation and experimental verification, and it was confirmed that the increasing structure size and the introduction of amide bond would induce an increasing size of the sp 2 convolutional domain, leading to the red shift of the CDs fluorescence wavelengths.
Abstract: Abstract Multicolor carbon dots (CDs) possess tremendous potential applications, especially in optoelectronic devices. However, further applications of multi-color LED have been constrained due to the very limited researches concerning the wavelength control mechanism of multi-color CDs. In this work, through theoretical calculation and experimental verification, the regulatory effects of sp 2 conjugated domain on the fluorescence wavelength of CDs were explored. Firstly, through a regulation on the structure size and the introduction of amide bonds, four kinds of structures were designed in DFT theoretical calculation to explore the influence of sp 2 conjugated domain on the fluorescence wavelength of CDs theoretically. Then, using thiourea and p -phenylenediamine as the precursors and by regulating the reaction solvents, multicolor CDs with blue, green and red fluorescence emission were prepared to experimentally verify the emission mechanism. It was confirmed that the increasing structure size and the introduction of amide bond would induce an increasing size of the sp 2 conjugated domain, leading to the red shift of the CDs fluorescence wavelength. Finally, in order to suppress the self-quenching performance, the CDs@PVP fluorescent film possessing bright solid-state fluorescence was constructed for a better application in light-emitting diodes. The approach provided an effective strategy to realize the programmed regulation on the fluorescence wavelength of CDs, offering us full of potentials for the applications of CDs in the photoelectric device fields.
References
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TL;DR: A facile, catalyst-free thermal annealing approach for large-scale synthesis of NG using low-cost industrial material melamine as the nitrogen source is proposed, which can completely avoid the contamination of transition metal catalysts, and thus the intrinsic catalytic performance of pure NGs can be investigated.
Abstract: The electronic and chemical properties of graphene can be modulated by chemical doping foreign atoms and functional moieties. The general approach to the synthesis of nitrogen-doped graphene (NG), such as chemical vapor deposition (CVD) performed in gas phases, requires transitional metal catalysts which could contaminate the resultant products and thus affect their properties. In this paper, we propose a facile, catalyst-free thermal annealing approach for large-scale synthesis of NG using low-cost industrial material melamine as the nitrogen source. This approach can completely avoid the contamination of transition metal catalysts, and thus the intrinsic catalytic performance of pure NGs can be investigated. Detailed X-ray photoelectron spectrum analysis of the resultant products shows that the atomic percentage of nitrogen in doped graphene samples can be adjusted up to 10.1%. Such a high doping level has not been reported previously. High-resolution N1s spectra reveal that the as-made NG mainly contai...
2,242 citations
TL;DR: CPDs are revealed as an emerging class of CDs with distinctive polymer/carbon hybrid structures and properties, and critical insights into facilitating their potential in various application fields are proposed.
Abstract: Despite the various synthesis methods to obtain carbon dots (CDs), the bottom-up methods are still the most widely administrated route to afford large-scale and low-cost synthesis. However, as CDs are developed with increasing reports involved in producing many CDs, the structure and property features have changed enormously compared with the first generation of CDs, raising classification concerns. To this end, a new classification of CDs, named carbonized polymer dots (CPDs), is summarized according to the analysis of structure and property features. Here, CPDs are revealed as an emerging class of CDs with distinctive polymer/carbon hybrid structures and properties. Furthermore, deep insights into the effects of synthesis on the structure/property features of CDs are provided. Herein, the synthesis methods of CDs are also summarized in detail, and the effects of synthesis conditions of the bottom-up methods in terms of the structures and properties of CPDs are discussed and analyzed comprehensively. Insights into formation process and nucleation mechanism of CPDs are also offered. Finally, a perspective of the future development of CDs is proposed with critical insights into facilitating their potential in various application fields.
631 citations
TL;DR: Sulfur-doped carbon dots were synthesized using a simple and straightforward hydrothermal method in this article, and as-prepared S-Doped C-dots exhibit significant fluorescence quantum yield (67%) and unique emission behavior.
Abstract: Sulfur-doped carbon dots (S-doped C-dots)were synthesized using a simple and straightforward hydrothermal method. The as-prepared S-doped C-dots exhibit significant fluorescence quantum yield (67%) and unique emission behavior. The spherical S-doped C-dots have an average diameter of 4.6 nm and the fluorescence of S-doped C-dots can be effectively and selectively quenched by Fe3+ ions. Thus, S-doped C-dots were applied as probes toward Fe3+ detection, exhibiting a limit of detection of 0.1 μM.
527 citations
TL;DR: This study shows that it is important to understand in detail how silver and silver nanoparticles exert their toxicity and to understand how bacteria acquire silver resistance, to lead to a better understanding of the impact on human health and ecosystems.
Abstract: This review gives a comprehensive overview of the widespread use and toxicity of silver compounds in many biological applications. Moreover, the bacterial silver resistance mechanisms and their spread in the environment are discussed. This study shows that it is important to understand in detail how silver and silver nanoparticles exert their toxicity and to understand how bacteria acquire silver resistance. Silver ions have shown to possess strong antimicrobial properties but cause no immediate and serious risk for human health, which led to an extensive use of silver-based products in many applications. However, the risk of silver nanoparticles is not yet clarified and their widespread use could increase silver release in the environment, which can have negative impacts on ecosystems. Moreover, it is shown that silver resistance determinants are widely spread among environmental and clinically relevant bacteria. These resistance determinants are often located on mobile genetic elements, facilitating their spread. Therefore, detailed knowledge of the silver toxicity and resistance mechanisms can improve its applications and lead to a better understanding of the impact on human health and ecosystems.
424 citations
TL;DR: The present work reports the first probe to image the endogenous generated SO2 without incubation of the SO2 donors and with reversible fluorescent responses toward Cys, the probe could image the enzymatic conversion of Cys to SO2 in living A549 cells in a ratiometric manner.
Abstract: Fluorescent probes, as noninvasive tools for visualizing the metabolism of biomolecules, hold great potential to explore their physiological and pathological processes. For cysteine (Cys), however, none of the reported fluorescent probes could image the metabolic processes in living cells. To achieve this goal, we developed a coumarin derivative based on rational design of the dual recognition sites for Cys and its metabolite, SO2. The probe displayed distinct two channels with turn-on fluorescent emission toward Cys and SO2, which were successfully applied for imaging both A549 cells and zebrafish. Further, with reversible fluorescent responses toward Cys, the probe could image the enzymatic conversion of Cys to SO2 in living A549 cells in a ratiometric manner. The present work reports the first probe to image the endogenous generated SO2 without incubation of the SO2 donors.
399 citations