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carbon dot

Zhenxing Qin, Wenhai Wang, Xiaozhi Zhan, Xiujuan Du, Qingmei Zhang, Rui Zhang, Kun Li, Jinhong Li, Weiping Xu
Luminescent carbon-based nanoparticles, named often as carbon dots (CDs), were synthesized from citric acid (CA) and guanidine thiocyanate (GITC) via an N and S co-doped hydrothermal procedure. In the present structure characterization, N and S elements could be sufficiently doped by means of the heteroatom or the functional groups bonded on the surface of CDs. The as-prepared CDs solution showed blue color fluorescence under ultraviolet excitation, yet the PL spectra exhibited a repetitive emission process from excitation-independent to excitation-dependent...
October 4, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Huajun Feng, Qiaoqi Guo, Yingfeng Xu, Ting Chen, Yuyang Zhou, Yigang Wang, Meizhen Wang, Dongsheng Shen
The concept of photocatalytic CO2 conversion provides simultaneous solutions for global warming mitigation and fuels generation, which, however, is limited by the unsatisfactory photoconversion efficiency. Despite light harvesting and charge separation, enhancing adsorption of CO2 via surface modification could be an efficient way to improve CO2 photoconversion efficiency. Herein, we doped nonpolar carbon quantum dots (denoted as CQDs) on g-C3N4 to construct a metal-free heterojunction photocatalyst (denoted as CQDs/g-C3N4)...
October 12, 2018: ChemSusChem
Wei Hong, Yan Liu, Ming-Hui Li, Yue-Xiao Xing, Ting Chen, Yong-Hong Fu, Lei Jiang, He Zhao, Ai-Qun Jia, Jun-Song Wang
Owing to the promising applications of C-dots in biomedical engineering, concerns about their safety have drawn increasing attention recently. In this study, mice were intraperitoneally injected at different C-dot concentrations (0, 6.0, 12.0 and 24.0 mg kg-1 ) once every 2 days for 30 days. A 1 H NMR-based metabolic approach supplemented with biochemical analysis and histopathology was used for the first time to explore the toxicity of C-dots in vivo . Histopathological inspection revealed that C-dots did not induce any obvious impairment in tissues...
September 1, 2018: Toxicology Research
Xuetao Hu, Jiyong Shi, Yongqiang Shi, Xiaobo Zou, Muhammad Arslan, Wen Zhang, Xiaowei Huang, Zhihua Li, Yiwei Xu
Gold nanoparticles@Carbon quantum dots nanocomposites (Au@CQDs) were designed for analyzing melamine in milk visually. Fluorescent emission of Au@CQDs enhanced with the increase of melamine concentration. A calibration curve (R2  = 0.9856) and fluorescence standard array were established for detection of melamine in the range of 1 μM-10 μM. Limit of quantification and limit of detection were 12 nM and 3.6 nM, respectively. The approximate concentration of melamine adulterated in milk samples were detected visually by the fluorescence standard array and smartphone...
January 30, 2019: Food Chemistry
Xiaoqiang Chen, Yu Luan, Ningwei Wang, Zhiping Zhou, Xiaoni Ni, Yunfei Cao, GuangShe Zhang, Yufeng Lai, Wenming Yang
Sulfadiazine is an environmental pollutant derived from abuse of antibiotics. Its content in environmental water is closely related to human health. Thus, a novel dual emission surface molecularly imprinted nanosensor is designed for specific adsorption and detection of sulfadiazine. In the system, blue emissive carbon quantum dots wrapped with silica served as the internal reference signal for eliminating background interference while red emissive thioglycolic acid-modified CdTe quantum dots were encapsulated in the imprinted layer to offer recognition signal...
October 11, 2018: Journal of Separation Science
Jinjin Xu, Chaofan Yu, Tao Feng, Mingyue Liu, Fengting Li, Ying Wang, Jingjuan Xu
To date, numerous methods have been reported for the detection of organophosphorus pesticides (OP) due to their severe potential hazard to the environment, public health and national security. However, very few works have ever found that the signal loss of thiocholine (TCh) during electrochemical processing is a key factor leading to the low sensitivity of acetylcholinesterase (AChE)-based OP electrochemical sensing platforms. Herein, we propose an ultrasensitive detection method for multiple OPs including parathion-methyl, paraoxon, dimethoate and O,O-dimethyl-O-2,2-dichlorovinyl-phosphate using N-carbamoylmaleimide-functionalized carbon dots (N-MAL-CDs) as a nano-stabilizer...
October 11, 2018: Nanoscale
Yajun Wang, Juan Chen, Liming Liu, Xiaoxu Xi, Yuming Li, Zhouliang Geng, Guiyuan Jiang, Zhen Zhao
Carbon quantum dots (CDs) are rising stars for photocatalytic applications due to their low toxicity and excellent electron transfer characteristics. Doping with heteroatoms is expected to adjust the band levels and electron transfer properties of CDs, and understanding the effect of doping on CDs can aid the rational preparation of highly efficient CD-based photocatalysts. Herein, we prepared a series of metal atom (Zn, Co, Bi, Cd, or Ti) doped CDs by pyrolysis and explored the photocatalytic application of these metal doped CDs for the first time...
October 11, 2018: Nanoscale
Ziwei Sun, Fang Lu, Jinjun Cheng, Meiling Zhang, Yafan Zhu, Yaxue Zhang, Hui Kong, Huihua Qu, Yan Zhao
Although recent research on intrinsic bioactivities of carbon dots is expanding, it is focused on basic aspects, which creates the need for broadening our knowledge about carbon dots to expand their uses in biomedical sciences and facilitate their application in clinical practice. Jiaosanxian is a charcoal traditional Chinese medicine with a pronounced effect on promoting appetite and digestion that is widely used as dyspepsia therapy in China. To study the underlying mechanism and the material requirements, we investigated carbon dots which was generated in the charcoal processing...
December 1, 2018: Journal of Biomedical Nanotechnology
Kefilwe Vanessa Mokwebo, Oluwatobi Samuel Oluwafemi, Omotayo Ademola Arotiba
We report the preparation of poly (propylene imine) dendrimer (PPI) and CdTe/CdSe/ZnSe quantum dots (QDs) as a suitable platform for the development of an enzyme-based electrochemical cholesterol biosensor with enhanced analytical performance. The mercaptopropionic acid (MPA)-capped CdTe/CdSe/ZnSe QDs was synthesized in an aqueous phase and characterized using photoluminescence (PL) spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, transmission electron microscopy (TEM), X-ray power diffraction (XRD), energy dispersive X-ray (EDX) spectroscopy...
October 9, 2018: Sensors
Azam Akbarnia, Hamid R Zare
The authors describe a DNA based voltammetric assay for the cancer biomarker microRNA-25. A glassy carbon electrode (GCE) was modified with amino-functionalized graphene quantum dots and used as an amplifier of electrochemical signals. p-Biphenol is introduced as a new electroactive probe with a fairly low working potential of 0.3 V (vs. Ag/AgCl). The stages of fabricating the electrode were characterized by cyclic voltammetry and electrochemical impedance spectroscopy. ss-Probe DNA was immobilized on the modified GCE and then exposed to a sample containing microRNA-25...
October 9, 2018: Mikrochimica Acta
Zheng-Long Xu, Shenghuang Lin, Nicolas Onofrio, Limin Zhou, Fangyi Shi, Wei Lu, Kisuk Kang, Qiang Zhang, Shu Ping Lau
Lithium sulfur batteries with high energy densities are promising next-generation energy storage systems. However, shuttling and sluggish conversion of polysulfides to solid lithium sulfides limit the full utilization of active materials. Physical/chemical confinement is useful for anchoring polysulfides, but not effective for utilizing the blocked intermediates. Here, we employ black phosphorus quantum dots as electrocatalysts to overcome these issues. Both the experimental and theoretical results reveal that black phosphorus quantum dots effectively adsorb and catalyze polysulfide conversion...
October 9, 2018: Nature Communications
Fatemeh Ansari, Danial Kahrizi
Herein, green, environmental-friendly and economical synthesize of luminescent carbon dots (CDs) was reported using the plant-based material, Stevia rebaudiana Bertoni, as a herbal bio-sweetener. In this regard, hydrothermal carbonization of Stevia was performed under mild conditions and without any chemical oxidizing agents. Exploring the morphological aspect, surface groups, chemical composition and structure of Stevia-based CDs have been carried out systematically using SEM-EDS, TEM, fluorescence, FT-IR, UV-Vis, and XRD techniques...
September 30, 2018: Cellular and Molecular Biology
Die Ling Zhao, Tai-Shung Chung
Carbon quantum dots (CQDs), which are a fascinating class of nanostructured carbons, have recently attracted extensive attention in the field of membrane technologies for their applications in separation processes. This is because they possess two unique advantages. Their productions are facile and inexpensive, while their physicochemical properties such as ultra-small sizes, good biocompatibility, high chemical inertness, tunable hydrophilicity, rich surface functional groups and antifouling characteristics are highly desirable...
September 27, 2018: Water Research
Joshua O Island, Marvin Ostermann, Lee Aspitarte, Ethan D Minot, Daniele Varsano, Elisa Molinari, Massimo Rontani, Gary A Steele
Carbon nanotubes continue to be model systems for studies of confinement and interactions. This is particularly true in the case of so-called "ultraclean" carbon nanotube devices offering the study of quantum dots with extremely low disorder. The quality of such systems, however, has increasingly revealed glaring discrepancies between experiment and theory. Here, we address the outstanding anomaly of exceptionally large orbital magnetic moments in carbon nanotube quantum dots. We perform low temperature magnetotransport measurements of the orbital magnetic moment and find it is up to 7 times larger than expected from the conventional semiclassical model...
September 21, 2018: Physical Review Letters
Xiaotong Feng, Jon Ashley, Tongchang Zhou, Yi Sun
A fluorometric assay is described for doxycycline detection. It is based on the use of nitrogen-doped carbon quantum dots (NCQDs) coated with molecularly imprinted polymers (MIPs). The NCQDs were prepared by a one-step hydrothermal reaction using citric acid and ethylenediamine (EDA) as the starting materials. Afterwards, the NCQDs were incorporated into the polymer that was molecularly imprinted with doxycycline. It is found that doxycycline quenches the fluorescence of the NCQDs, and that the functional groups on the surface of NCQDs play an important role in terms of quenching efficiency...
October 6, 2018: Mikrochimica Acta
Zihnil Adha Islamy Mazrad, Pham Thi My Phuong, Cheong A Choi, Insik In, Kang Dae Lee, Sung Young Park
In the present study, pH/redox responsive cationic polymer dot (CD) was successfully prepared for a near-infrared (NIR)-mediated simultaneously controllable photothermal temperature guided imaging off/on system to monitor therapeutic delivery. The carbonized disulfide crosslinked branched-polyethyleneimine (bPEI) with a folic acid (FA) conjugation as the targeting moiety and a partially ionic complex between anionic indocyanine green (ICG) and bPEI-based CD (ICG-CD). This was responsive to mild reductive (GSH) and acidic tumor conditions, which enabled the simultaneous biodegradation of those hydrophobic and complex sites...
October 4, 2018: ChemMedChem
Rajendra Prasad, Deepak S Chauhan, Amit S Yadav, Janhavi Devrukhkar, Barkha Singh, Mahadeo Gorain, Mayur Temgire, Jayesh Bellare, Gopal C Kundu, Rohit Srivastava
Specific targeting and phototriggered therapy in mouse model have recently emerged as the starting point of cancer theragnosis. Herein, we report a bioresponsive and degradable nanohybrid, a liposomal nanohybrid decorated with red emissive carbon dots, for localized tumor imaging and light-mediated tumor growth inhibition. Unsaturated carbon dots (C-dots) anchored to liposomes convert near-infrared (NIR) light into heat and also produce reactive oxygen species (ROS), demonstrating the capability of phototriggered cancer cell death and tumor regression...
October 5, 2018: Nanoscale
Shengliang Hu, Wenliang Yang, Ning Li, Huiqi Wang, Jinlong Yang, Qing Chang
A photocatalytic reaction is always governed by energy band configuration of the catalyst, but its modulation is challenging. Here, the adjustment of band-edge positions of Ag3 PO4 through fluorescent carbon dots is reported for the first time. Both Ag3 PO4 and carbon dots which keep the similar sizes constitute a heterojunction. Such heterostructure not only promotes visible light absorption, photogenerated charge separation, and transfer, but it also transforms photocatalytic activity of Ag3 PO4 from photooxidation to photoreduction due to the huge changes of band-edge positions...
October 4, 2018: Small
Yanlei Liu, Xiao Zhi, Wenxiu Hou, Fangfang Xia, Jingpu Zhang, Lexiang Li, Yuping Hong, Hao Yan, Chen Peng, Jesus Martinez de la Fuentea, Jie Song, Daxiang Cui
The development of multifunctional nanoparticles for tumor theranostics has become a research hotspot. Despite the advantages of non-invasive precision diagnostics and efficient drug-delivery, these nanoparticles bring two significant issues: (i) a potential toxic effect and (ii) difficult clearance. To solve these issues, carbon dots (C-dots) are key potential candidates owing to their unique properties, such as excellent biocompatibility and rapid renal clearance. However, their small size leads to a short circulation time in the blood, which causes non-sufficient tumor accumulation for antitumor therapy...
October 4, 2018: Nanoscale
Chun Li, Jianru Zhao, Yanqiu Chen, Xiaoyu Wang, Xiaobo Sun, Wei Pan, Guifeng Yu, Zun Yan, Jinping Wang
In this work, colorimetric and fluorimetric dual mode detection of Al3+ in aqueous solution was achieved using a carbon dots/rutin (CDs/rutin) coexisting system. Upon addition of Al3+, a yellow Al(iii)-rutin complex was formed without any interaction between Al3+ and the carbon dots (CDs). As a result, a new absorption peak of the complex at 430 nm increased while the peak of rutin at 360 nm decreased. Therefore, a ratiometric colorimetric method for the detection of Al3+ was built on a good linear relationship between the absorbance ratio (A430 nm/A360 nm) and the concentration of Al3+ in a wide linear range from 2...
October 4, 2018: Analyst
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