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carbon dot

Yaoping Hu, Zhijin Gao, Jie Yang, Hui Chen, Lei Han
The increasing production of waste polyethylene terephthalate (PET) is a growing problem worldwide. Environmentally benign conversion of waste PET to valuable materials remains a substantial challenge. In this paper, we developed a green route to reuse waste PET for low-cost synthesis of fluorescent carbon dots (CDs) via air oxidation followed by hydrothermal treatment in aqueous H2 O2 solution. No expensive, corrosive, or toxic reagents, or severe conditions were required in the synthetic process. The resultant CDs possessed abundant oxygenous groups and unique photoluminescence (PL) properties, which showed a highly selective and sensitive detection of ferric ion (Fe3+ ) through a PL quenching effect (on-off)...
December 4, 2018: Journal of Colloid and Interface Science
Yingping Li, Yong Jia, Qi Zeng, Xiaohui Jiang, Zhengjun Cheng
We used thiamine nitrate (TN) as single material to fabricate nitrogen and sulfur co-doped carbon quantum dots (N,S-CQDs) with a quantum yield of 10.4% through one-pot hydrothermal method, and its properties were characterized by TEM, XPS, FTIR, fluorescence (FL) and UV-vis spectrophotometer, respectively. The fluorescence of N,S-CQDs was effectively quenched in the presence of vitamin B12 (VB12)/tartrazine due to Förster resonance energy transfer (FRET). Moreover, the rate (KT ) and efficiency (E%) of energy transfer from N,S-CQDs (as a donor) to VB12/tartrazine (as an acceptor) enhanced with increasing the concentrations of acceptor, and the KT and E% were also varied with the change of excitation wavelengths (from 338 to 408 nm)...
December 4, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Ji-Shi Wei, Chen Ding, Peng Zhang, Hui Ding, Xiao-Qing Niu, Yuan-Yuan Ma, Chao Li, Yong-Gang Wang, Huan-Ming Xiong
Hybrid supercapacitors generally show high power and long life spans but inferior energy densities, which are mainly caused by carbon negative electrodes with low specific capacitances. To improve the energy densities, the traditional methods include optimizing pore structures and modifying pseudocapacitive groups on the carbon materials. Here, another promising way is suggested, which has no adverse effects to the carbon materials, that is, constructing electron-rich regions on the electrode surfaces for absorbing cations as much as possible...
December 9, 2018: Advanced Materials
Hongzhi Lu, Chunwei Yu, Shuai Quan, Shoufang Xu
Based on the inner filter effect and charge transfer dual response mechanism, a dual response ratiometric fluorescent probe (D-RFP) with two reversible signal changes for sensing H2O2 and glucose was developed. The D-RFP was proposed by embedding glycine-derived carbon dots (CDs) (λem = 400 nm) into silica nanoparticles and covalently linking CdTe quantum dots (QDs) (λem = 600 nm) onto the surface of silica nanoparticles. When silver nanoparticles (Ag NPs) were mixed with D-RFP, the fluorescence intensity of CDs can be quenched by Ag NPs via the inner filter effect...
December 11, 2018: Analyst
Dipankar Bain, Subarna Maity, Amitava Patra
This feature article highlights the recent advances of luminescent metal nanoclusters (MNCs) for their potential applications in healthcare and energy-related materials because of their high photosensitivity, thermal stability, low toxicity, and biocompatibility. Current studies reveal that metal cluster based hybrid systems could pave the way for energy harvesting and sensing applications. To begin with, we illustrate general synthesis methodologies for atomically precise metal nanoclusters and discuss the origin of photoluminescence properties and the electronic transitions of nanoclusters...
December 10, 2018: Physical Chemistry Chemical Physics: PCCP
Naama Massad-Ivanir, Susanta Kumar Bhunia, Raz Jelinek, Ester Segal
Carbon dots (C-dots) exhibit unique fluorescence properties, mostly depending upon their physical environments. Here we investigate the optical properties and nanostructure of Carbon dots (C-dots) which are synthesized in situ within different porous Silicon (PSi) Bragg reflectors. The resulting hybrids were characterized by photoluminescence, X-ray photoelectron, and Fourier Transform Infrared spectroscopies, as well as by confocal and transmission electron microscopy. We show that by tailoring the location of the PSi Bragg reflector photonic bandgap and its oxidation level, the C-dots emission spectral features can be tuned...
2018: Frontiers in Chemistry
Yanchun Deng, Yong Sik Ok, Dinesh Mohan, Charles U Pittman, Xiaomin Dou
Carbon dot- and magnetite-modified magnetic carbon nanotubes (CMNTs) were synthesized and evaluated for carbamazepine removal from water. The adsorbent was characterized by multiple modern surface and microstructure analyzing techniques. CMNTs were composed of three components including carbon dots (CDs), carbon nanotubes (CNTs) and magnetite. CDs and CNTs introduce abundant carboxyl groups onto CMNTs and magnetite allows rapid magnetic separation of the adsorbent realizable after batch adsorption. This adsorbent has a moderately high adsorption capacity of 65 mg-carbamazepine/g-adsorbent at pH 7...
November 22, 2018: Environmental Research
J Plácido, S Bustamante-López, K E Meissner, D E Kelly, S L Kelly
This research seeks a coupled solution for managing the large amounts of biochar produced by microalgae biofuel production, and the necessity for novel, economic and accurate heavy metal sensing methods. Therefore, this study evaluated the transformation of microalgae biochar (MAB) into carbon dots (Cdots) and their subsequent application as heavy metal ion sensors in aqueous systems. The experimental phase included the transformation of MAB into microalgae biochar-derived carbon dots (MAB-Cdots), MAB-Cdot characterisation and the evaluation of the MAB-Cdots as transducers for the detection of four heavy metal ions (Pb2+ , Cu2+ , Cd2+ , and Ni2+ )...
November 27, 2018: Science of the Total Environment
Piumi Y Liyanage, Regina M Graham, Raja R Pandey, Charles C Chusuei, Keenan J Mintz, Yiqun Zhou, James K Harper, Wei Wu, Athula H Wikramanayake, Steven Vanni, Roger M Leblanc
In contrast to the recent immense attention in carbon nitride quantum dots (CNQDs) as a heteroatom-doped carbon quantum dot (CQD), their biomedical applications have not thoroughly investigated. The targeted cancer therapy is a prominently researched area in biomedical field. Here, the ability of CNQDs as a selective bioimaging nanomaterial was investigated to assist the targeted cancer therapy. CNQDs were first synthesized using four different precursor sets, involving urea derivatives and the characteristics were compared to select the best candid material for bioapplications...
December 10, 2018: Bioconjugate Chemistry
Dejian Chen, Caiyan Cui, Na Tong, Haifeng Zhou, Xinchen Wang, Ruihu Wang
Nanodots are attractive stimuli-responsive luminescence materials for anti-counterfeiting and information encryption. However, their applications are limited by low water solubility and single-mode information identification by naked eyes under UV light illumination. Herein, we report one type of new nanodots, main-chain imidazolium-based ionic polymer dots (IPDs). There is no edge effect in IPDs, the ionic groups are homogenously distributed in the entire dot. IPDs exhibit high water solubility, good stability, narrow size distribution, low toxicity and exceptional optical performance without the additional modification...
December 10, 2018: ACS Applied Materials & Interfaces
Qiang Guo, Fanglong Yuan, Bing Zhang, Shijie Zhou, Jin Zhang, Yiming Bai, Louzhen Fan, Tasawar Hayat, Ahmed Alsaedi, Zhan'ao Tan
Organic-inorganic hybrid perovskites are prone to defect formation due to iodine and methylamine ion/defect migration, leading to the formation of lots of defects at the perovskite surface and grain boundaries. Passivation of the defects is an effective method to improve the power conversion efficiency (PCE) and stability of perovskite solar cells (PSCs). To achieve stable passivation, the interaction between the perovskite and additive materials should be taken into consideration. In this work, we for the first time introduced carbon quantum dots (CQDs) as an additive for the stabilization of MAPbI3 via passivation of the grain boundaries of the perovskite...
December 7, 2018: Nanoscale
Sena Ghayem, Farnoush Faridbod
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...
November 14, 2018: Methods and Applications in Fluorescence
Zhifeng Zhu, Hongbin Sun, Juan Jin, Menglin Wang, Yan Zhang, Dabin Yu, Yang Jiang
For nanomaterials, it is a new stage to be utilized in bio-applications with low-toxicity, good stability and fine dissolvability. Herein, we present a pulsed laser assisted carbon coating method for nanocrystals, and gadolinium carbide/carbon shell (GC/CS) dots with face-centered cubic structured gadolinium carbide core have been synthesized in toluene. Good stability of GC/CS dots was observed not only in ethanol but also in the immunoconjugates. The MTT assay had revealed the immunoconjugates with non-/low- cytotoxicities...
December 6, 2018: Nanotechnology
Yanting Xie, Jingxia Zheng, Yaling Wang, Junli Wang, Yongzhen Yang, Xuguang Liu, Yong Kang Chen
A one-step hydrothermal synthesis of nitrogen and silicon co-doped fluorescence carbon
 quantum dots (N,Si-CQDs) from citric acid monohydrate and silane coupling agent KH-792
 with high product yield (PY) of 52.56% and high quantum yield (QY) of 97.32% was
 developed. This greatly improves both PY and QY of CQDs and provides a new approach for a
 large-scale production of high-quality CQDs. Furthermore, N,Si-CQDs were employed as
 phosphors without dispersants to fabricate white light-emitting diodes (WLEDs) with the
 color coordinates at (0...
November 26, 2018: Nanotechnology
Vijay Bhooshan Kumar, Raj Kumar, Aharon Gedanken, Orit Shefi
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...
November 22, 2018: Ultrasonics Sonochemistry
Shou-Yuan Sung, Yu-Lin Su, Wei Cheng, Pei-Feng Hu, Chi-Shiun Chiang, Wen-Ting Chen, Shang-Hsiu Hu
Dual targeted delivery of drugs and energy by nanohybrids can potentially alleviate side effects and improve the unique features required for precision medicine. To realize this aim, however, the hybrids which are often rapidly removal from circulation and piled up tumors periphery near the blood vessels must address the difficulties in low blood half-lives and tumor penetration. In this study, a sponge-inspired carbon composites-supported red blood cell (RBC) membrane that doubles as a stealth agent and photolytic carrier that transports tumor-penetrative agents (graphene quantum dots and docetaxel (GQD-D)) and heat with irradiation was developed...
December 6, 2018: Nano Letters
Tianli Yang, Ren He, Guihua Nie, Wenlei Wang, Gui Zhang, Yunchu Hu, Lichao Wu
In this work, carbon quantum dots were first prepared through one-pot hydrothermal route of the propyl aldehyde and sodium hydroxide via an aldol condensation reaction, and a novel solid-phase extraction adsorbent of hollow calcite single crystals was prepared via the precipitation of metal nitrates by the CO2 diffusion method in the presence of CQDs and further applied for excessive Cd(II) ions removal from water. The spectra and morphologies of the etched calcite were investigated by X-ray diffraction, Fourier transform infrared spectrometry, Scanning electron microscope, and Transmission electron microscopy...
December 4, 2018: Scientific Reports
Janjira Praneerad, Nichaphat Thongsai, Preeyanuch Supchocksoonthorn, Sumana Kladsomboon, Peerasak Paoprasert
A recent trend in the preparation of carbon dots, optically unique nanomaterials, revolves around the use of readily-available, low-cost natural resources as precursors and their multipurpose applications. In this work, a hydrothermal method for preparing biocompatible carbon dots from radish was developed. The carbon dots were then tested for sensing of Cu2+ and acetic acid vapor. The carbon dots exhibited blue emission under UV illumination with, a quantum yield of 15%. The fluorescence emission was selectively quenched when Cu2+ ions were added, giving a detection limit of 0...
November 20, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Qin Wang, Yanfeng Zhou, Rong Fu, Yi Zhu, Bin Song, Yiling Zhong, Sicong Wu, Yu Shi, Yanyan Wu, Yuanyuan Su, Huimin Zhang, Yao He
Nanomaterial-induced autophagy has raised increasing concerns. A variety of nanomaterials, conventional or recently emerged, have the capability of inducing autophagy. As a consequence, it is becoming a popular belief that induction of autophagy is a common response of cells upon exposure to nanoscale materials. In order to clarify whether the "nanoscale" size is the determining factor for the nanomaterials to induce autophagy, we utilized in vitro cultured cells and an in vivo Caenorhabditis elegans (C...
December 4, 2018: Nanoscale
Neil Hammond
Retraction of 'The next generation cell-penetrating peptide and carbon dot conjugated nano-liposome for transdermal delivery of curcumin' by Santanu Patra et al., Biomater. Sci., 2016, 4, 418-429.
December 3, 2018: Biomaterials Science
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