碳点的研究进展

碳点具有优良的光学特性、良好的生物相容性和低毒等优点,被广泛用于生物检测、药物传输和生物成像等领域,是极具发展潜力的碳基质材料.近年来,碳点的新型制备方法、性质探索及应用研究引起广泛关注.本文根据碳源和制备方法的不同,将碳点分为石墨烯纳米点和碳纳米点两类,综述了碳点的制备方法,剖析了碳点的发光机理,总结了碳点在生物传感、药物传输和生物成像中的应用;最后分析了碳点存在的问题及应对策略.     

碳量子点上转换材料的制备及其应用研究进展

碳量子点(CQD)具有化学惰性,生物相容性和低毒性等优势,可能在能源、生物医药等领域得到广泛的应用. CQD可通过表面被聚合物(例如PEG)钝化而表现出很强的光致发光特性.在生物成像,疾病检测和药物输送中使用表面钝化后的功能化生物分子更为有效.并且碳材料由于其优异的电化学性能还展现出在催化、电子器件等许多领域广泛的应用前景.我们将对近年来碳量子点发光材料的研究进行总结,并讨论碳量子点在能源、环境和其他一些领域的应用.     

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.     

硅硼掺杂碳点的制备及其在血红蛋白传感中的应用

杂原子掺杂是提高碳点荧光性能的有效手段.本研究以柠檬酸(C6 H8 O7)、硼酸(H3 BO3)、3-氨丙基三乙氧基硅烷(APTES)为原料,采用微波法一步制备硅和硼掺杂的碳点(SiBCDs);在SiBCDs前驱体中加入聚丙烯酸钠(PAAS),微波法制备了水溶性好、量子产率高的PAAS-SiBCDs.采用X射线衍射(XRD)、X射线光电子能谱(XPS)及红外光谱(FT-IR)对制备的碳点进行了表征.SiBCDs粒径约4~8 nm,PAAS-SiBCDs平均粒径5.2 nm,两者最大激发波长和发射波长分别为350和445 nm,荧光量子产率(QY)分别为20.1%和34.6%.基于血红蛋白对PAAS-SiBCDs的荧光猝灭效应,建立了全血样品中血红蛋白(Hb)的检测方法,线性范围为0.21~5.22μmol/L,检出限为0.06μmol/L(S/N=3).     

氮掺杂碳点的制备及在定量分析中的应用

碳点具有化学稳定性好、毒性低、易于功能化等突出优势而备受关注,然而其仍存在荧光量子产率低、活性位点少等不足。氮掺杂碳点因N的钝化效应表现出更为优异的光电性能,在很大程度上弥补了碳点的这些缺陷,因而在生化传感、环境检测等诸多领域中得到了广泛应用。经过近五年来的发展,氮掺杂已成为碳点改性的主要方法之一,制备方法逐渐多样化,合成过程更加绿色、简便,但其形成机制仍没有明确的统一解释。为了更好地研究氮掺杂碳点的形成机理及扩展其应用领域,本文简述了氮掺杂碳点的发展历程、制备方法及光学特性,重点介绍了氮掺杂碳点在定量分析中的应用,并展望了其发展和应用前景,以期为氮掺杂碳点在分析化学中的发展提供一定的参考。     

电化学方法在荧光碳点研究中的应用

作为以碳为骨架结构的新型纳米材料,碳点具有许多优良的性能,如发射波长可调、良好的光稳定性、抗光漂白、良好的水溶性以及易于生物偶联等. 正是因为这些优点,碳点和其它碳质纳米材料（富勒烯、碳纳米管、石墨烯）一样受到了广泛的关注. 电化学方法制备碳点具有条件温和、费用低廉、后处理简单等特点. 另外,电化学方法在材料的表面结构分析以及发光机理的研究中也有其独特的优势. 本文即就电化学方法在荧光碳点的制备以及发光机理探讨中的应用作了综述,并简略介绍了碳点在传感器中的应用,提出了优化电化学方法制备碳点的某些设想.     

微波一步法制备氮掺杂碳点及其用于多巴胺的检测研究

以柠檬酸为碳源,尿素为氮源,采用微波一步法制备得到稳定性高,水溶性好的蓝色荧光的氮掺杂碳点。并将该氮掺杂碳点经透射电子显微镜(TEM)、原子力显微镜(AFM)、X-射线光电子能谱(XPS)和红外光谱(IR)表征,发现其粒径为0.5～5 nm,平均粒径2.6 nm,富含羟基、羧基和氨基等官能团。在优化实验条件下,多巴胺浓度在2.5～37.5μmol/L范围内与N-CDs的荧光猝灭效率(I_F/I_(F0))呈良好的线性关系,方法的检出限为0.08μmol/L。采用该方法对正常人尿液中的多巴胺进行测定,其加标回收率为99.5%～106%,RSD为1.8%～2.3%,方法准确度高,结果满意。     

基于上转换发光的碳量子点制备及应用研究

碳量子点具有易制备、低毒性、化学惰性高、荧光特性稳定等特点,和其他碳纳米材料(如富勒烯、碳纳米管和石墨烯等)一样引起了研究者的广泛关注。本文将从碳量子点的合成、特性、改性和应用等方面进行阐述,并对其受长波长光激发后可发出短波长光的这一上转换发光特性进行重点综述,为今后碳量子点的合成、改性以及应用提供一定的参考。     

掺杂型碳量子点的制备及其在重金属离子检测中的应用

碳量子点(CQDs)具有独特的荧光性质、制备原料来源广泛、合成过程绿色简便、水溶性和生物相容性良好等优点,因而受到广泛关注。CQDs与特定的重金属离子结合后,荧光强度会出现不同程度的增强或减弱,基于此可实现重金属离子的荧光检测。然而,传统的CQDs受限于自身荧光强度不高以及在重金属离子检测中的灵敏度与选择性较差等不足,应用效果并不理想。对CQDs进行杂原子掺杂可调节CQDs中碳原子的电荷密度和自旋密度,提供更多的活性位点,丰富CQDs的能级结构,从而提升其荧光强度。此外,杂原子掺杂可为CQDs引入丰富的官能团,构建易与重金属离子结合的功能界面,从而提高荧光检测的灵敏度。本文综述了近年来氮、硫、磷、锌和铜等原子掺杂CQDs的制备及在重金属离子检测中的研究进展,分析了原子掺杂对CQDs荧光检测性能的影响、原子掺杂CQDs的检测机理、检测应用效果,并展望了其未来的发展方向。     

一步水热法制备铜掺杂纳米碳点及其在白光器件中的应用

以一水合乙酸铜和苯胺为原料, 合成了铜掺杂纳米碳点(Cu-CDs). 通过优化实验参数, 确定了合成Cu-CDs的最佳反应时间、 反应温度和原料摩尔比分别为5 h, 210 ℃和1∶1. 与相同条件下的对照实验相比, Cu的掺杂使碳点(CDs)的荧光强度明显提高, 并实现了良好的多色发光性能. 在365 nm紫外光激发下, Cu-CDs可直接发射强烈的白光. 进一步与紫外发光二极管(LED)芯片结合, 得到白色发光器件, 色坐标为(0.337, 0.337), 非常接近纯白光的色坐标(0.33, 0.33). 这种制备Cu-CDs材料的方法及突出的白光发射性能, 拓宽了碳点在发光器件中的应用.     

Highly luminescence manganese doped carbon dots

Heteroatom doped carbon dots(CDs) with distinct merits are of great attractions in various fields such as solar cells, catalysis, trace element detection and photothermal therapy. In this work, we successfully synthesized blue-fluorescence and photostability manganese-doped carbon dots(Mn-CDs) with a quantum yield up to 7.5%, which was prepared by a facile one-step hydrothermal method with sodium citrate and manganese chloride. The Mn-CDs is the high mono-dispersity, uniform spherical nanoparticles. The Mn element plays a critical role in achieving a high quantum yield in synthesis of carbon dots, which was confirmed by the structure analysis using XPS and FTIR. Spectroscopic investigations proved that the decent PLQY and luminescence properties of Mn-CDs are due to the heteroatom doped, oxidized carbon-based surface passivation. In addition, the Mn-CDs are demonstrated as promising fluorescent sensors for iron ions with a linear range of 0–500 mmol/L and a detection limit of2.1 nmol/L(turn-off), indicating their great potential as a fluorescent probe for chemical sensing.     

Synthesis and bioimaging application of red-emissive carbon dots

Fluorescent red-emissive carbon dots (RCDs) were synthesized using the solvothermal method with citric acid as a carbon source, N,N-dimethylformamide as a nitrogen source, and formamide as a solvent. The as-synthesized RCDs show red fluorescence in an aqueous solution and have an excellent stability towards photobleaching as well as extremely low cytotoxicity and are successfully used for cell and zebrafish imaging. The results indicate that RCDs have potential applications in both in vitro and in vivo bioimaging.     

Lanthanide doped carbon dots as a fluorescence chromaticity-based pH probe

A colorimetric and fluorescent pH probe was designed by doping carbon dots (C-dots) with Eu(III), Tb(III) and 2,6-pyridinedicarboxylic acid (DPA). The resulting nanoparticles were applied as fluorescent indicators for pH values (best detected at excitation/emission wavelengths of 272/545, 614 nm). The pH induced optical effects are due to pH induced variations in energy transfer. The fluorescence of the probe shows a continuous color variation, and a linear change with pH values in the range from 3.0 to 10.0 can be established by using a Commission Internationale de L’Eclairage (CIE) chromaticity diagram. This new kind of pH nanoprobe is more accurate than previously reported pH indicator probes because the pH value can be calculated by using chromaticity coordinates that only depend on the chromaticity. The pH nanoprobe was applied to visualize pH values in human breast adenocarcinoma cells (MCF-7).

Open image in new window

Graphical abstract Carbon dots modified with Eu(III) and Tb(III) complexes of 2,6-pyridinedicarboxylic acid (DPA) were prepared. The doped carbon dots were used as a pH-sensitive nanosensor. The fluorescence chromaticity of the nanoparticles changes with the variation of pH value.

     

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...     

Determination of DNA based on fluorescence quenching of terbium doped carbon dots

This work describes the preparation of carbon dots doped with terbium(III) (Tb-CDs) via a hydrothermal method, starting from terbium ion and ethylenediamine. The size, composition and spectral properties of the Tb-CDs were characterized by transmission electron microscopy, infrared spectra, and fluorescence spectra. The results show that doping of the CDs with Tb(III) reduces the particle size and results in more uniform particles, while fluorescence (at excitation/emission peaks of 380/475 nm) is strongly enhanced. The interaction between Tb-CDs and ct-DNA results in fluorescence quenching of Tb-CDs. The findings were exploited to design a quenchometric method for the determination of ct-DNA. The signal drops linearly in the 80 ng·mL^?1 to 50 μg·mL^?1 ct-DNA concentration range, and the detection limit is 53 ng·mL^?1. The method was applied to the determination of ct-DNA in spiked samples and gave satisfactory results. The possible fluorescence quenching mechanism (which is mainly static) was investigated using the Stern–Volmer equation and thermodynamic equations.

Open image in new window

Graphical abstract A kind of carbon dots doped with terbium(III) (Tb-CDs) were prepared via a hydrothermal method, using terbium ion and ethylenediamine as precursor. Doping with Tb(III) reduced the particle size of CDs and results in uniform particle size and stronger fluorescence. The interaction between the Tb-CDs and dsDNA results in quenching of the fluorescence of Tb-CDs and can be applied to determination of dsDNA.

     

Electrochemical preparation of luminescent graphene quantum dots from multiwalled carbon nanotubes

Green luminescent, graphene quantum dots (GQDs) with a uniform size of 3, 5, and 8.2(±0.3)?nm in diameter were prepared electrochemically from MWCNTs in propylene carbonate by using LiClO(4) at 90?°C, whereas similar particles of 23(±2)?nm were obtained at 30?°C under identical conditions. Both these sets of GQDs displayed a remarkable quantum efficiency of 6.3 and 5.1?%, respectively. This method offers a novel strategy to synthesise size-tunable GQDs as evidenced by multiple characterisation techniques like transmission and scanning electron microscopy, atomic force microscopy, Raman spectroscopy and X-ray diffraction (XRD). Photoluminescence of these GQDs can be tailored by size variation through a systematic change in key process parameters, like diameter of carbon nanotube, electric field, concentration of supporting electrolyte and temperature. GQDs are promising candidates for a variety of applications, such as biomarkers, nanoelectronic devices and chemosensors due to their unique features, like high photostability, biocompatibility, nontoxicity and tunable solubility in water.     

Synthesis of multicolor luminescent adjustable carbon dots and their application in anti-counterfeiting

A novel approach for fabricating color-adjustable carbon dots (CDs) is proposed via hydrothermal treatment of p-aminobenzenesulfonic acid and o-, m-, or p-phenylenediamines, respectively. The as-synthesized CDs can emit blue, green, and orange fluorescence and are named b-CDs, g-CDs, and o-CDs, respectively. All of them have strict excitation independence and excellent photostability. Variations of photoluminescence emitting them are attributed to the difference in their particle size, the degree of oxidation, and the content of N-related states on their surface. Furthermore, these multicolor CDs have been used as fluorescents inks, which perform well in anti-counterfeiting and information security.     

甲基丙烯酸酯类功能化微球的制备及应用研究进展

甲基丙烯酸酯类功能化聚合物微球具有毒副作用小、与生物样品相容性好等优点,在免疫分析、抗体纯化等诸多领域具有重要应用。本文综述了近5年来此类微球常用的制备方法,对每种制备方法进行举例分析,并总结了此类微球在色谱填料、分子印迹聚合物、固定化酶、药物载体、水处理等领域的最新研究进展,最后对此类微球的发展趋势进行了展望,为研究者根据不同的应用目的选择合适的制备方法及分析手段提供一定的参考。     

Barium charge transferred doped carbon dots with ultra-high quantum yield photoluminescence of 99.6% and applications

Long-emission carbon dots(CDs) is triggering immense enthusiasm on account of their intrinsic merits of high chemical stability and excellent optical properties.In this study,a facile and rapid approach was developed for the preparation of barium-doped carbon dots(Ba-CDs) with yellow fluo rescence emission and high quantum yields.Surface chemistry and the chemical architecture of the Ba-CDs was revealed under various spectroscopic methods.This work provides more insights into the effects of charge transfer caused by Ba heteroatoms,which is considered as the most challenging step in the investigation on luminescence mechanism.Remarkably,the prepared Ba-CDs were successfully applied as fluorescent probes in the detection of trace water in organic solvents(ethanol,isopropanol,acetone,tetrahydrofuran).Comparing with traditional fluorescent probes for water detection in organic solvents,Ba-CDs detection provides a more sensitive,much faster and more economical approach.     

Tetraphenylethylene and N-isopropylacrylamide block polymer-grafted carbon dots with their application in cellular imaging

Carbon dots (CDs) grafted with block polymer of tetraphenylethylene (TPE) and N-isopropylacrylamide (CD-g-poly(TPE-block-NIPAM)) were synthesized, which are aggregation-induced emission (AIE) nanoparticles. The CD-g-poly(TPE-block-NIPAM) exhibited different fluorescence behaviors in tetrahydrofuran (THF) and water. In THF, the CD-g-poly(TPE-block-NIPAM) could fluoresce, but only from CDs, and the TPE block showed no fluorescence. The fluorescence of CDs was quenched ,and the TPE block showed AIE, when the CD-g-poly(TPE-block-NIPAM) were dispersed in water. The CD-g-poly(TPE-block-NIPAM) showed no cytotoxicity, which could be easily internalized by human breast cancer cells and human embryonic kidney cells with high fluorescence, and they can be used as fluorescent tracers for living cells.