Synthesis of cell-penetrated nitrogen-doped carbon dots by hydrothermal treatment of eggplant sepals

Novel nitrogen doped carbon quantum dots were successfully fabricated by a hydrothermal method with eggplant sepals as carbon source. The carbon materials were characterized by transmission electron microscopy (TEM), UV-Vis adsorption, Fourier-transformed infrared spectroscopy (FTIR), fluorescence and the X-ray photoelectron spectroscopy (XPS) measurements, respectively. The carbon quantum dots showed excellent photoluminescence property with high stability in phosphate buffer solution with different pH values from 5 to 9, even in the cell culture medium supplied with the fetal bovine serum. Meanwhile, we also studied the interaction of carbon quantum dots with living HeLa cells with confocal microscopy. Our results indicated that the carbon quantum dots can enter the living HeLa cells by cellular penetration.     

Highly selective detection of phosphate in very complicated matrixes with an off-on fluorescent probe of europium-adjusted carbon dots

A simple method for phosphate (Pi) detection is established by developing an off-on fluorescence probe of europium-adjusted carbon dots (CDs), which has been successfully applied to the detection of Pi in very complicated matrixes such as artificial wetlands system.     

Electrochemiluminescence of CdSe Quantum Dots Composited with Nitrogen‐Doped Carbon Nanotubes

A nanocomposite of CdSe quantum dots with nitrogen‐doped carbon nanotubes was prepared for enhancing the electrochemiluminescent (ECL) emission of quantum dots. With hydrogen peroxide as co‐reactant, the nanocomposite modified electrode showed a cathodic ECL emission with a starting potential of ?0.97 V (vs. Ag/AgCl) in phosphate buffer solution, which was five‐times stronger than that from pure CdSe quantum dots and three‐times stronger than that from CdSe quantum dots composited with carbon nanotubes. The latter showed a starting potential of ?1.19 V. This result led to a sensitive ECL sensing of hydrogen peroxide with good stability, acceptable reproducibility and a detection limit down to 2.1×10^?7 mol L^?1. Nitrogen‐doped carbon nanotubes could be used as a good material for the construction of sensitive ECL biosensors for chemical and biochemical analysis.     

新型荧光碳点的制备及其在Hg2+检测中的应用

以中药材川佛手为碳源,通过高温热解产生的烟制备了平均粒径为6 nm的新型荧光碳点,其最大激发波长285 nm,最大荧光发射波长340 nm。 基于碳点良好的荧光性能及Hg²⁺对碳点荧光的猝灭作用,建立了检测Hg²⁺的新方法。 结果表明,在0.2 mol/L磷酸盐缓冲溶液(pH=7.0)中,响应时间为2 min时,该方法具有良好的选择性和抗干扰能力,检测Hg²⁺浓度的线性范围为0.2~40 μmol/L,相关系数为r=0.9996,检出限为0.052 μmol/L。 当加入2.0和40.0 μmol/L Hg²⁺到实际水样后,相对标准偏差(RSD)和加标回收率分别为0.3%~2.4%和99.5%~101.1%,可用于实际水样中Hg²⁺的分析检测。     

Matrix‐Free and Highly Efficient Room‐Temperature Phosphorescence Carbon Dots towards Information Encryption and Decryption

Designing efficient room‐temperature phosphorescence (RTP) carbon dots (C‐dots) without the need of an additional matrix is important for various applications. Herein, matrix‐free and highly efficient C‐dots with yellow‐green RTP emission have been successfully synthesized towards information encryption and decryption. Phytic acid (PA) and triethylenetetramine are used as molecular precursors, and a facile microwave‐assisted heating method is selected as synthesis method. The obtained C‐dots exhibit a maximum phosphorescence emission at around 535 nm under an excitation wavelength of 365 nm and a long average lifetime up to 750 ms (more than 9 s to the naked eye). PA containing six phosphate groups and serving as P source plays a significant role in producing the RTP C‐dots. Furthermore, potential applications of the RTP C‐dots in the field of information encryption and decryption are successfully demonstrated.     

碳点/β-环糊精复合物的制备及其用于尿酸检测的研究

以柠檬酸三钠为碳源,采用微波辅助制备碳点,用β-环糊精(β-CD)和碳点复合制备出碳点/β-CD复合物,并用荧光、紫外、红外光谱等进行表征.在pH=6.6的磷酸盐缓冲溶液中,尿酸可使碳点/β-CD复合物的荧光增强,探讨了反应时间、反应温度、缓冲溶液及pH对荧光增强程度的影响,建立了测定尿样中尿酸含量的方法.碳点/β-C...     

反相高效液相色谱法同时测定多种头孢菌素的研究(I)

 建立了同时分离测定６种头孢菌素（头孢米诺、头孢羟氨苄、头孢克罗、头孢氨苄、头孢拉定和头孢西丁）的高效液相色谱法。流动相为Ｖ（５０ｍｍｏｌ／Ｌ的磷酸二氢钾缓冲液,ｐＨ３．４）ｖＶ（乙腈）＝８７．５ｖ１２．５的混合液,色谱柱为ＨｙｐｅｒｓｉｌＯＤＳＣ１８５μｍ,２００ｍｍ×４．６ｍｍｉ．ｄ．,紫外检测波长为２５４ｎｍ,流速为１．０ｍＬ／ｍｉｎ。各个组分的线性范围：头孢米诺为１６４ｎｇ～１６．４μｇ,头孢羟氨苄为９９ｎｇ～９．９３４μｇ,头孢克罗为１０４ｎｇ～１０．３５８μｇ,头孢氨苄为１２２ｎｇ～１２．２２４。     

Enhancing the luminescence of carbon dots with a reduction pathway

Blue luminescent reduced state carbon dots were prepared by reducing carbon dots with NaBH(4). The quantum yield of the reduced state carbon dots increased from 2% to 24% and the maximum emission wavelength shifted from 520 to 450 nm. This offers a simple pathway to enhance the luminescence of carbon dots.     

磷酸盐改性对TS-1分子筛及其丙烯液相环氧化性能的影响

丙烯和过氧化氢在钛硅沸石TS-1上的液相环氧化反应是合成环氧丙烷HPPO新工艺的核心.首先比较了 3种酸性磷酸盐溶液(磷酸二氢铵、磷酸二氢钾和磷酸二氢钠)和两种碱性磷酸盐溶液(磷酸氢二钠和磷酸三钠)浸渍改性对TS-1沸石及其环氧化性能的影响,发现酸性磷酸盐溶液改性可以明显提高TS-1的过氧化氢转化率和环氧丙烷选择性,但...     

氟化修饰显著提高碳点的抗菌活性

本文采用支化聚乙烯亚胺和乙醇制备阳离子碳点,并在其表面接枝含氟烷基链,得到一种氟化修饰的碳点材料,其对革兰氏阳性菌金黄色葡萄球菌以及革兰氏阴性菌大肠杆菌和绿脓杆菌都表现出了优异的抗菌活性,而对哺乳动物细胞具有较低的毒性。通过构效关系研究发现,氟化修饰对于碳点的抗菌活性至关重要,将含氟烷基链替换成烷烃基链会极大削弱碳点的抗菌性能。本文的结果为阳离子抗菌材料的设计提供了新的思路。     

Hydrothermal Synthesis of Luminescent Carbon Dots from Glucose and Birch Bark Soot

Carbon dots were prepared by the method of hydrothermal synthesis from carbon precursors of glucose and birch bark soot in aqueous ammonia. The distribution of lateral sizes of carbon dots testifies their average size to be 10–12 nm for glucose and 20–22 nm for soot. Infrared absorption spectra indicate oxygen groups on the surfaces of obtained carbon dots. Aqueous suspensions with glucose-based carbon dots exhibit strong absorption in the visible region from 300 nm to 500 nm. Soot-based carbon dots demonstrate strong absorption in the ultraviolet region, but are transparent in the visible region. The luminescence spectra exhibit that carbon dots synthesized from glucose and soot are luminescent in the same spectral region, their wavelengths of radiation depend on the wavelengths of excitation, and the intensity of luminescence depends on the presence of oxygen groups on the surface of carbon dots. Carbon dots synthesized from glucose and soot have great prospects in terms of their application in biology and medicine.     

碳点荧光探针的制备及其在食品分析中的应用

碳点作为一种新型荧光碳纳米材料,具有优良的光学性能和小尺寸特性,以及良好的生物相容性、低毒性以及易于实现表面功能化等特点,是潜在的可以代替传统半导体量子点等荧光探针的良好选择.基于其独特的荧光特性和高灵敏度,碳点荧光探针在食品分析领域具有很好的应用潜力.本文对近年来荧光碳点的研究进展进行了综述,简述碳点的性能并对碳点的制备方法进行总结对比,重点介绍了碳点荧光探针在食品分析领域的应用,对目前碳点应用的限制进行了分析,对其发展前景和展望.     

三种不同元素掺杂的碳点与DNA相互作用及其机制研究

碳点(carbon dots,CDs)在材料学及生物医学相关领域的研究已引起科研人员的广泛关注.本文采用一步水热法,制备了三种具有不同元素掺杂的CDs、N-CDs、N,S-CDs,并结合多种光谱法、熔链温度法和黏度法,系统地研究了三种不同元素掺杂的碳点与ctDNA结合模式以及结合能力的差异.荧光实验证明三种不同性质的碳...     

Preparation of carbon quantum dots with tunable photoluminescence by rapid laser passivation in ordinary organic solvents

A simple approach to prepare carbon quantum dots is presented in this communication by laser rapid passivation of nano carbon particles in ordinary organic solvent. The as-prepared carbon dots exhibited visible, tunable and stable photoluminescence (PL). XPS analysis showed that the increased oxygen concentration might be concerned with the origin of PL.     

Tunable Photoluminescence Across the Entire Visible Spectrum from Carbon Dots Excited by White Light

Although reports have shown shifts in carbon dot emission wavelengths resulting from varying the excitation wavelength, this excitation‐dependent emission does not constitute true tuning, as the shifted peaks have much weaker intensity than their dominant emission, and this is often undesired in real world applications. We report for the first time the synthesis and photoluminescence properties of carbon dots whose peak fluorescence emission wavelengths are tunable across the entire visible spectrum by simple adjustment of the reagents and synthesis conditions, and these carbon dots are excited by white light. Detailed material characterization has revealed that this tunable emission results from changes in the carbon dots’ chemical composition, dictated by dehydrogenation reactions occurring during carbonization. These significantly alter the nucleation and growth process, resulting in dots with either more oxygen‐containing or nitrogen‐containing groups that ultimately determine their photoluminescence properties, which is in stark contrast to previous observations of carbon dot excitation‐dependent fluorescence. This new ability to synthesize broadband excitable carbon dots with tunable peak emissions opens up many new possibilities, particularly in multimodal sensing, in which multiple analytes and processes could be monitored simultaneously by associating a particular carbon dot emission wavelength to a specific chemical process without the need for tuning the excitation source.     

1,2-dithioglycol functionalised carbon nitride quantum dots as a “turn – off” fluorescent sensor for mercury ion detection

A kind of 1,2-dithioglycol (DTG) functionalised carbon nitride quantum dots (DTG-CNQDs) was designed for the first time by modifying DTG on the surface of carbon nitride quantum dots (CNQDs). The as-prepared DTG-CNQDs exhibit strong blue fluorescence under ultraviolet light and have a high quantum yield of 27%. Experiments show that Hg²⁺ has a good quenching effect on the fluorescence of DTG-CNQDs. In phosphate buffer (PBS, 10 mM, pH 6.0), the fluorescence quenching rate (F₀/F) has a good linear relationship with the concentration of Hg²⁺ in the range of 0.020–0.50 μM with detection limit of 0.63 nM. This fluorescent probe possesses high sensitivity and good selectivity, which can be applied in the rapid detection of Hg²⁺ in tap and lake water samples.     

Quantum-sized carbon dots for bright and colorful photoluminescence

We report that nanoscale carbon particles (carbon dots) upon simple surface passivation are strongly photoluminescent in both solution and the solid state. The luminescence emission of the carbon dots is stable against photobleaching, and there is no blinking effect. These strongly emissive carbon dots may find applications similar to or beyond those of their widely pursued silicon counterparts.     

基于氮掺杂碳量子点荧光猝灭效应检测Fe3+

碳量子点光致发光性质取决于尺寸大小和表面官能团的性质.本研究以还原冶炼过程产生的生物质焦油为前驱体,采用小分子乙二胺进行氮掺杂,通过一步水热法合成荧光产率高、分散性能好的氮掺杂碳量子点,基于Fe3+对氮掺杂碳量子点选择性荧光猝灭效应,实现了对Fe3+快速准确检测.合成的氮掺杂碳量子点为规则的球形,尺寸均一,平均粒径为2.64 nm,晶面间距为0.25 nm,具备石墨碳晶格(100)晶格结构,其荧光量子产率为26.1%;Fe3+与N-CQDs表面官能团配位络合致使N-CQDs荧光猝灭,Fe3+浓度在0.23~600μmol/L范围内,与氮掺杂碳量子点荧光猝灭程度呈良好的线性关系,Fe3+的检出限为230 nmol/L.     

异元素掺杂碳点的制备及其在生物成像中的应用

荧光碳点具有良好的生物相容性和优良的抗光漂白能力,因此碳点在生物荧光成像方面的应用潜力受到广泛关注,但是碳点相对较低的荧光量子产率和缺乏近红外荧光发射的缺陷限制了碳点在荧光成像分析中的应用.随着异元素掺杂对碳点结构和荧光性质的改善,碳点被越来越广泛地用于生物成像.本文对近年来元素掺杂碳点的合成方法、异元素掺杂对碳点光学性质的影响和元素掺杂碳点在成像分析中的进展进行了综述,并对其应用前景进行了展望.     

Controllable Photoelectric Properties of Carbon Dots and Their Application in Organic Solar Cells

Organic solar cells are a current research hotspot in the energy field because of their advantages of lightness,translucency,roll to roll printing and building integration.With the rapid development of small molecule acceptor materials with high-performance,the efficiency of organic solar cells has been greatly improved.Further improving the device efficiency and stability and reducing the cost of active layer materials will contribute to the industrial development of organic solar cells.As a novel type of carbon nanomaterials,carbon dots gradually show great application potential in the field of organic solar cells due to their advantages of low preparation cost,non-toxicity and excellent photoelectric performance.Firstly,the synthesis and classification of carbon dots are briefly introduced.Secondly,the photoelectric properties of carbon dots and their adjusting,including adjustable surface energy level structure,good film-forming performance and up/down conversion characteristics are summarized.Thirdly,based on these intrinsic properties,the feasibility and advantages of carbon dots used in organic solar cells are discussed.Fourthly,the application progress of carbon dots in the active layer,hole transport layer,electron transport layer,interface modification layer and down-conversion materials of organic solar cells is also reviewed.Finally,the application progress of carbon dots in organic solar cells is prospected.Several further research directions,including in-depth exploration of the controllable preparation of carbon dots and their application in the fields of interface layer and up/down conversion for improving efficiency and stability of device are pointed out.