水溶性的高荧光CdTe/CdSeⅡ型核壳量子点的合成与表征

用L-半胱氨酸(L-cysteine)作为稳定剂,以制备的CdTe量子点为核模板,水相合成了具有近红外发光的Ⅱ型核壳CdTe/CdSe半导体量子点。实验考察了合成温度,核模板的尺寸和组分比等因素对合成高质量的CdTe/CdSe量子点的影响。用紫外-可见吸收和荧光光谱研究了合成的量子点的光学性质。在优化的合成条件下,荧光发射光谱在586～753nm范围连续可调,荧光量子产率高达68%;通过X-射线衍射(XRD),X射线光电子能谱(XPS)和透射电镜(TEM)对合成的Ⅱ型核壳CdTe/CdSe量子点进行了结构和形貌表征。     

超声电化学快速制备近红外CdTe量子点与细胞成像

针对当前水溶性量子点合成路线复杂、量子产率低的现状,在无需N2保护的条件下,采用简便的超声电化学方法快速合成了CdTe量子点前驱体;并对不同条件下制得的前驱体加热回流,得到水溶性、高质量的近红外CdTe量子点。产物的形貌、结构和组成通过高分辨透射电子显微镜(HRTEM)、X-射线粉末衍射(XRD)等手段进行了表征。考察了超声电化学参数和回流条件对量子点荧光性质的影响。通过控制电流脉冲宽度、反应时间、反应温度等参数,实现了CdTe量子点前驱体的可控制备;通过调节加热回流条件得到不同荧光发射波长的量子点;选用602 nm近红外发射波长的CdTe量子点标记了子宫颈癌细胞(Hela),并采用共聚焦技术实现了肿瘤细胞的显微成像观察。和传统的量子点合成方法相比,超声电化学方法具有合成路线简单、参数易调可控的特点;为高品质量子点的快速制备提供了新的思路,拓展了超声电化学在纳米材料制备领域的应用。     

超声电化学快速制备近红外CdTe量子点与细胞成像

针对当前水溶性量子点合成路线复杂、量子产率低的现状, 在无需N₂保护的条件下, 采用简便的超声电化学方法快速合成了CdTe量子点前驱体;并对不同条件下制得的前驱体加热回流, 得到水溶性、高质量的近红外CdTe量子点。产物的形貌、结构和组成通过高分辨透射电子显微镜(HRTEM)、X-射线粉末衍射(XRD)等手段进行了表征。考察了超声电化学参数和回流条件对量子点荧光性质的影响。通过控制电流脉冲宽度、反应时间、反应温度等参数, 实现了CdTe量子点前驱体的可控制备;通过调节加热回流条件得到不同荧光发射波长的量子点;选用602 nm近红外发射波长的CdTe量子点标记了子宫颈癌细胞(Hela), 并采用共聚焦技术实现了肿瘤细胞的显微成像观察。和传统的量子点合成方法相比, 超声电化学方法具有合成路线简单、参数易调可控的特点;为高品质量子点的快速制备提供了新的思路, 拓展了超声电化学在纳米材料制备领域的应用。     

一步水热法合成硫、氮掺杂碳量子点高效检测柠檬黄和pH

采用D-生物素为碳源,通过一步水热法合成硫、氮掺杂荧光碳量子点(S,N-CDs)。其量子产率达61.7%,并且具有荧光强度高、水溶性好和抗光漂白等特点。透射电镜表征的结果表明,合成的碳量子点呈球形且分散性好。在水溶液中,该碳量子点作为荧光探针对柠檬黄和p H表现出选择性猝灭效果,基于此,建立了一种新型检测柠檬黄和p H的方法。     

川木香水热法一步合成荧光碳量子点及光学性能研究

以中药材川木香原药为碳源，采用水热法一步合成了荧光碳量子点。通过水热法实验条件优化，获得制备荧光碳量子点的最佳实验参数，通过透射电镜(TEM)对荧光碳量子点进行形貌表征，通过X射线光电子能谱分仪(XPS)对荧光碳量子点进行元素组成分析，通过荧光光谱和紫外-可见吸收光谱对荧光碳量子点进行了光学性能研究。结果表明：川木香用量1.00 g,水热反应温度180℃,水热反应时间2.0 h时，制备得到的荧光碳量子点光学性能最佳。荧光碳量子点平均粒径为5 nm,主要含有C元素和O元素，最大激发波长为360 nm,对应的发射波长为420 nm,特征吸收峰为280 nm,量子产率为12.9%。     

荧光量子点的水相合成及其在化学和生物分析中的应用

荧光量子点(又称为半导体纳米晶体)是一种新兴的无机发光材料, 由于其具有独特的结构和光电性能, 在发光二极管、太阳能电池及生命科学等领域有广泛的应用. 目前, 有机相合成法和水相合成法已被成功地用于荧光量子点的合成. 与有机相合成法相比, 水相合成量子点方法简单、绿色且廉价, 合成的量子点水溶性好, 在生物医学等领域具有很好的应用前景. 本文主要介绍荧光量子点的水相合成方法及其在化学和生物分析中的应用, 并对其发展趋势进行了展望.     

石墨烯/CdTe量子点复合物的合成及在克伦特罗检测方面的应用（英文）

成功地合成了石墨烯/CdTe量子点复合物,并采用透射电镜、紫外吸收光谱、荧光发射光谱、荧光衰减曲线和X射线光电子能谱对产物进行了表征。透射电镜结果显示CdTe量子点被修饰于石墨烯的表面;X射线光电子能谱结果表示石墨烯在合成过程中被还原,还表明在所合材料的表面具有羧基和羟基;荧光发射光谱和荧光衰减曲线的结果显示将CdTe量子点修饰于石墨烯表面显著提高了CdTe量子点的荧光性能。此外,基于克伦特罗和石墨烯/CdTe量子点复合物之间形成的氢键,所合成材料可用于定量分析克伦特罗。克伦特罗对石墨烯/CdTe量子点复合物具有显著的猝灭作用,荧光强度的降低(F0/F)与克伦特罗之间存在良好的线性关系,线性范围为7.22~108.30μmol·L-1,检出限为4μmol·L-1。     

多功能两亲梳状聚合物的合成及包覆荧光量子点

利用溶液聚合和成酰胺反应合成了多功能梳状两亲性共聚物,聚(甲基丙烯酸-co-甲基丙烯酸十八酯)-(乙醇胺-乙二胺叶酸)(PSM-EE-FA).用红外光谱(FTIR),核磁共振(1H-NMR)及凝胶渗透色谱(GPC)表征了该聚合物的结构及分子量分布.实验结果证明合成了该聚合物,其数均分子量(Mn)为28600,多分散性为1.375.用该两亲梳状聚合物包覆油溶性CdSe/ZnS量子点,通过相转移作用,得到水溶性靶向量子点(PSM-EE-FA-QDs).该水溶性量子点溶液具有较好的稳定性.通过紫外-可见(UV-Vis)及荧光发射光谱分析对该量子点的光学性质进行研究.结果表明,PSM-EE-FA-QDs的紫外-可见光谱及荧光发射光谱峰形与原量子点基本一致.由于量子点表面聚合物层的形成,峰位发生少量红移.该量子点水溶液的荧光强度是原量子点氯仿溶液的98%,荧光产率是原量子点氯仿溶液的95%.动态光散射(DLS)及透射电镜(TEM)测试结果表明水溶性量子点分布均匀.合成的水溶性量子点不但光学性能稳定,而且聚合物及水溶性量子点的合成方法较为简便.     

葡萄糖酸碳量子点的合成及其光学性能的研究

以葡萄糖酸为碳源,采用微波法、热解法和水热溶液法合成了水溶性较好的蓝色荧光碳量子点。用透射电镜(TEM)观察其形貌,荧光光谱(FL)和紫外可见光谱(UV)探究其激发和发射光谱,用时间分辨光谱(TRF)测其荧光寿命值。微波和热解法制备的碳量子点粒径在2.5~7.5 nm之间,激发波长为360 nm,发射波长为450 nm,荧光发射依赖激发波长,有三个荧光寿命,表面状态不均一。水热法制备的碳量子点,粒径在3.0~8.5 nm之间,激发波长为350 nm,发射波长为430 nm,荧光发射不依赖激发波长,只有一个荧光寿命值,表面状态均一。水热法合成的碳量子点荧光量子产率高为6.01%,为进一步研究葡萄糖酸制备碳量子点提供参考。     

温敏性碳量子点的快速制备、荧光性质及细胞成像应用

以草酸和尿素为碳源,超纯水为溶剂,采用微波方法快速合成了具有热敏性的氮掺杂碳量子点,对其形貌、结构、荧光性质和荧光强度的影响因素,以及细胞毒性进行了测试和讨论,并用于小鼠结肠癌细胞(CT26.WT)成像。结果表明,制备的碳量子点近似球形,粒径约3.8 nm。碳量子点具有良好的温度响应的荧光性质。在10~80℃温度范围内,相对荧光强度与温度之间存在良好的线性关系。随着温度的增加,碳量子点的荧光强度减小,温度从10℃升至80℃,相对荧光强度减少了25%,当温度反向降低时,其荧光强度恢复到原始值。碳量子点温度与荧光强度之间的线性关系,使之在温度响应的荧光传感领域具有潜在的应用价值。对碳量子点进行氮掺杂能有效提高其荧光量子产率,当草酸和尿素质量比为3∶1时,荧光量子产率最高,为9.5%。另外,合成的碳量子点还具有优异的抗盐性能、强稳定性等特点,不仅能有效被CT26.WT细胞吞噬,还显示出低毒性和生物相容性,MTT分析结果表明,在1 000μg·mL~(-1)的碳量子点存在下,CT26.WT细胞存活率达85%,荧光碳量子点有望作为温敏性的荧光纳米探针在细胞研究领域得到应用。     

Study on the interaction of CdTe quantum dots with coumaric acid and caffeic acid based on fluorescence reversible tune

This paper describes the synthesis of CdTe quantum dots (QDs) together capped by glutathione and thioglycolic acid (GSH and TGA) in aqueous solution. The narrow photoluminescence (fwhm ≤ 40 nm) CdTe QDs, whose emission spans most of the visible spectrum from green through red, has a quantum yield (QY) of 68% at room temperature. GSH/TGA-CdTe QDs are characterized by various experimental techniques such as optical absorption, photoluminescence and AFM measurements. Coumaric acid and caffeic acid is able to quench the fluorescence of GSH/TGA-CdTe QDs, and the fluorescence intensity is linearly proportional to the concentration of quenchers. The addition of bovine serum albumin (BSA) restores the fluorescence intensity of GSH/TGA-CdTe QDs-coumaric acid system and GSH/TGA-CdTe QDs-caffeic acid system. The fluorescence recovery was due to the interaction of BSA with coumaric acid and caffeic acid, leading to the freeing of the GSH/TGA-CdTe QDs. The fluorescence quenching mechanism of GSH/TGA-CdTe QDs was discussed. The binding constant and thermodynamics parameters of BSA-coumaric acid and BSA-caffeic acid during the binding process were calculated in the paper.     

The preparation of glutathione-capped CdTe quantum dots and their use in imaging of cells

In this paper, different sizes of glutathione-capped CdTe (GSH/CdTe) quantum dots (QDs) have been prepared directly in aqueous solution. The QDs have tunable fluorescence in the range of 510-670 nm, and they also have high photoluminescence quantum yield (PLQY) without any postpreparative treatment. Furthermore, the QDs have strong resistance to photobleaching, and they also have to be considered as cytocompatible. In addition, for the first time, folic acid was covalently conjugated to the GSH/CdTe QDs for imaging of cancer cells, demonstrating their potentially broad application as biolabels.     

CdTe量子点荧光猝灭法测定奥沙利铂中微量银

以谷胱甘肽作为稳定剂,100℃恒温回流,直接合成水溶性CdTe量子点。基于Ag+对合成的CdTe量子点的荧光猝灭效应,建立了测定抗癌药物奥沙利铂中微量银的方法。考察了量子点浓度、缓冲液种类、缓冲液浓度、缓冲液pH和反应时间对银离子测定的影响。当量子点浓度为0.004 g/L时,在0.10 mmol/LpH7.4的磷酸缓冲溶液中,反应时间为5 min,体系的相对荧光强度与Ag+的质量浓度呈良好的线性关系,其线性范围为16.42～98.50μg/L,线性相关系数为0.9975,检出限为0.12μg/L。     

配体对CdTe量子点与BSA的选择性相互作用的影响

以巯基乙酸(TGA)、巯基丙酸(MPA)、巯基甘油(TG)、L-半胱氨酸(L-cys)和谷胱甘肽(GSH)等5种巯基分子为稳定剂, 水相合成了5种CdTe量子点. 以牛血清白蛋白(BSA)作为靶分子, 通过吸收光谱、荧光光谱和时间分辨荧光动力学等手段研究了各种配体分子稳定的CdTe量子点与BSA的直接相互作用. 结果表明, 5种量子点均能有效猝灭BSA的荧光, 其猝灭程度按配体次序为GSH>L-cys>TGA>TG>MPA; 而BSA对不同配体稳定的CdTe量子点的荧光光谱的影响则具有明显的选择性. BSA对TGA-CdTe和MPA-CdTe量子点的荧光先敏化增强而后猝灭下降; L-cys分子由于同时具有氨基和羧基而与BSA的相互作用较强, 因此BSA能显著猝灭L-cys-CdTe量子点的荧光; 而BSA对TG-CdTe量子点的荧光猝灭程度较小; GSH分子的空间效应使GSH-CdTe量子点的荧光被BSA猝灭的程度最小. 吸收光谱和时间分辨荧光动力学研究表明, 5种量子点与BSA之间的相互作用均为静态过程. 探讨了量子点的配体分子结构与蛋白质的相互作用机理.     

Simple and sensitive detection method for chromium(VI) in water using glutathione—capped CdTe quantum dots as fluorescent probes

Water-soluble and stable CdTe quantum dots (QDs) were synthesized in aqueous solution with glutathione (GSH) as the stabilizer. GSH is employed by nature to detoxify heavy metal ions. As a result of specific interaction, the fluorescence intensity of GSH-capped QDs is selectively reduced in the presence of Cr(VI). Under the optimum conditions, the relative fluorescence intensity decreases linearly with the Cr(VI) concentration in the range from 0.01 to 1.00?µg mL^?1, and the detection limit is 0.008?µg mL^?1. The luminescence response of the QDs to ions markedly depended on the particle size, and a new strategy for tuning the selectivity of luminescent QDs to certain ions without changing the capping layer of the QDs can be achieved by changing the crystallite size of the QDs.     

Direct Synthesis of High-Quality Water-Soluble CdTe:Zn(2+) Quantum Dots

The synthesis of water-soluble and low-cytotoxicity quantum dots (QDs) in aqueous solution has received much attention recently. A one-step and convenient method has been developed for synthesis of water-soluble glutathione (GSH)-capped and Zn(2+)-doped CdTe QDs via a refluxing route. Because of the addition of Zn ions and the epitaxial growth of a CdS layer, the prepared QDs exhibit superior properties, including strong fluorescence, minimal cytotoxicity, and enhanced biocompatibility. The optical properties of QDs are characterized by UV-vis and fluorescence (FL) spectra. The structure of QDs was verified by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectrometry (XPS), energy dispersive spectroscopy (EDS), atomic absorption spectrometry (AAS), and Fourier transform infrared spectroscopy (FTIR). Furthermore, the low cytotoxicity of the prepared QDs was proved by the microcalorimetric technique and inductively coupled plasma-atomic emission spectrometry (ICP-AES).     

量子点比率荧光探针研究进展

量子点(QDs)是一种纳米发光粒子,具有优异的发光性能,在太阳能利用、荧光检测等方面具有广阔的应用前景。QDs与另一荧光团复合可构建比率荧光探针,实现可视化检测目标物并且提高了检测灵敏度。本文主要对QDs比率荧光探针的种类、构建方法和应用领域的研究进展进行综述,并对其中的不足进行分析,以期为研发具有优异性能的比率荧光探针提供借鉴。     

Biomimetic Synthesis of Ag2Se Quantum Dots with Enhanced Photothermal Properties and as “Gatekeepers” to Cap Mesoporous Silica Nanoparticles for Chemo–Photothermal Therapy

Ag₂Se quantum dots (QDs) with near‐infrared (NIR) fluorescence have been widely utilized in NIR fluorescence imaging in vivo because of their narrow bulk band gap and excellent biocompatibility. However, most of synthesis methods for Ag₂Se QDs are expensive and the reactants are toxic. Herein, a new protein‐templated biomimetic synthesis approach is proposed for the preparation of Ag₂Se QDs by employing bovine serum albumin (BSA) as a template and dispersant. The BSA‐templated Ag₂Se QDs (Ag₂Se@BSA QDs) showed NIR fluorescence with high fluorescence quantum yield (≈21.2 %), excellent biocompatibility and good dispersibility in different media. Moreover, the obtained Ag₂Se@BSA QDs exhibited remarkable photothermal conversion (≈27.8 %), which could be used in photothermal therapy. As a model application in biomedicine, the Ag₂Se@BSA QDs were used as “gatekeepers” to cap mesoporous silica nanoparticles (MSNs) by means of electrostatic interaction. By taking the advantages of NIR fluorescence and photothermal property of Ag₂Se@BSA QDs, the obtained MSN‐DOX‐Ag₂Se nanoparticles (MDA NPs) were employed as a nanoplatform for combined chemo‐photothermal therapy. Compared with free DOX and MDA NPs without NIR laser, the laser‐treated MDA NPs exhibited lower cell viability in vitro, implying that Ag₂Se@BSA QDs are highly promising photothermal agents and the MDA NPs are potential carriers for chemo–photothermal therapy.     

基于GSH-CdTe/CdS量子点的荧光变化研究hsDNA与盐酸洛美沙星-Cu(Ⅱ)配合物的相互作用

采用水相法合成了谷胱甘肽(GSH)修饰的CdTe/CdS量子点(GSH-CdTe/CdS QDs). 透射电子显微镜表征结果表明, GSH-CdTe/CdS QDs的粒径分布均匀, 分散性好. 在Tris-HCl(pH=7.6)缓冲液中, 由于静电引力作用, 带正电的盐酸洛美沙星(LMFH)-Cu(Ⅱ)配合物[LMFH-Cu(Ⅱ)]吸附到带负电的GSH-CdTe/CdS QDs表面形成基态复合物, 导致GSH-CdTe/CdS QDs的荧光猝灭. 随后, 向GSH-CdTe/CdS QDs-LMFH-Cu(Ⅱ)配合物体系中加入鲱鱼精DNA(hsDNA), hsDNA可诱导LMFH-Cu(Ⅱ)配合物从GSH-CdTe/CdS QDs表面脱落而嵌入到hsDNA的双螺旋结构中, 使GSH-CdTe/CdS QDs的荧光恢复. 通过对GSH-CdTe/CdS QDs荧光的可逆调控, 利用荧光光谱、 紫外-可见吸收光谱和共振瑞利散射光谱研究了hsDNA与LMFH-Cu(Ⅱ)配合物的相互作用. 通过对比GSH-CdTe/CdS QDs与LMFH相互作用的光谱性质, 讨论了GSH-CdTe/CdS QDs-LMFH-Cu(Ⅱ)-hsDNA的相互作用机理, 模拟了作用过程, 从而建立了一种研究氟诺喹酮类药物的金属配合物与核酸相互作用机制的光谱方法.     

Biomimetic interactions of proteins with functionalized cadmium sulfide quantum dots

Interactions between various modified semiconductor nanocrystal, cadmium sulfide quantum dots (CdS QDs) and bovine serum albumin (BSA) and lysozyme (LZY) were investigated. CdS QDs capped with mercaptoethanol (MPA), l-cysteine (Lcys) and glutathione (GSH) were synthesized in aqueous solution and characterized by UV-vis and fluorescence spectrum. Circular dichroism (CD) and fluorescence spectrum were used to detect the interactions between as-prepared CdS QDs and protein molecules. The interaction parameters, including binding constant (K_b), binding site number (n) and quench constant (K_q), were determined by fluorescence spectrum. The changes of secondary structures of the proteins were detected by CD. The results imply that CdS QDs modified by different agents have dramatically different binding strength with protein molecules. The results obtained here analyze the biosafety of CdS QDs in terms of the biological behavior of biomolecules and could serve as basis for the application of CdS QDs to bioscience.