水相合成CdX (X＝Te, Te/CdS, Te/ZnS)红色量子点及毒性效应

分别以巯基乙酸(Mercaptoacetic Acid, MA)、还原型谷胱甘肽(Glutathione, GSH)为稳定剂在水相中直接合成了巯基乙酸CdTe (CdTe-MA)、红色巯基乙酸CdTe/CdS (CdTe/CdS-MA)、巯基乙酸CdTe/ZnS (CdTe/ZnS-MA)及谷胱甘肽CdTe (CdTe-GSH)量子点. 其中, CdTe-GSH量子点的量子产率可达47.3%. 体外溶血实验证实CdTe/ZnS-MA和CdTe-GSH量子点的溶血率较CdTe-MA和CdTe/CdS-MA低, 浓度为0.05 mmol/L的量子点溶血率＜5%, 达到了生物医用材料的要求. 活体实验证实: 通过尾静脉方式把量子点注入小鼠体内后, 荧光显微镜观察发现高剂量的量子点(0.4 mmol/10 g)在体内主要在心、肝、脾、肾组织中分布较多, 且引起不同程度的组织病变.     

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.     

CdX(X=Se,Te,Te/ZnS)量子点脂质体的制备及毒性比较

在水相中以巯基乙酸(mercaptoacetic acid, MA)为稳定剂合成了CdSe、CdTe、CdTe/ZnS量子点及谷胱甘肽(glutathione, GSH)为稳定剂合成了CdTe量子点,然后通过卵磷脂和胆固醇修饰制得相应的量子点脂质体。溶血实验证实GSH修饰量子点的溶血率低于MA修饰的量子点45%;脂质体修饰后,量子点的溶血率＜5%,达到生物医用材料要求。不同表面修饰的量子点对小鼠毒性存在明显差异,荧光显微镜观察组织切片证实量子点在小鼠体内主要分布在肺、肾、胸腺等组织中,而脂质体量子点在脑组     

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。     

Study the damage of DNA molecules induced by three kinds of aqueous nanoparticles

In this paper, the interaction of DNA molecules with aqueous CdTe quantum dots (CdTe QDs), CdTe/SiO₂ composite nanoparticles (CdTe/SiO₂ NPs), and Mn-doped ZnSe quantum dots (Mn:ZnSe d-dots) was studied with ethidium bromide as a probe. The purpose of this work was to study the damage of DNA molecules induced by these three kinds of water-soluble nanoparticles. It was found that ionic strength, pH value and UV irradiation influenced the PL emission properties of CdTe QDs, CdTe/SiO₂ NPs and Mn:ZnSe d-dots, and also influenced the interaction of DNA molecules with them. Among the three kinds of nanoparticles, DNA molecules were most easily damaged by CdTe QDs whether in the dark or under UV irradiation. The CdTe/SiO₂ NPs led to much less DNA damage when compared with CdTe QDs, as a silica overcoating layer could isolate the QDs from the external environment. Mn:ZnSe d-dots as a new class of non-cadmium doped QDs demonstrated almost no damage for DNA molecules, which have great potentials as fluorescent labels in the applications of biomedical assays, imaging of cells and tissues, even in vivo investigations.     

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.     

CdTe量子点与蛋白质相互作用的荧光猝灭效应

本文在水热法合成水溶性CdTe及核壳结构CdTe/CdS量子点的基础上,分别研究了细胞色素c对CdTe量子点及CdTe/CdS核壳量子点荧光的猝灭效应和CdTe量子点对牛血清白蛋白荧光的猝灭效应,并阐述了猝灭机理。结果显示,细胞色素c对CdTe量子点的荧光猝灭效应具有一定的粒径依赖性,粒径越小,猝灭效应越强;细胞色素c对CdTe/CdS核壳量子点的猝灭效应比对CdTe量子点的更强,揭示了受激电子的表面传递机理。CdTe量子点通过松散牛血清白蛋白的螺旋结构而猝灭其荧光。     

CdTe/CdSe核壳量子点的合成及其在指纹显现中的应用

以CdCl2和Te粉为原料,在水相中合成了CdTe量子点核;通过外延生长在CdTe量子点核上包覆一层CdSe量子点,得到具有良好荧光性能的CdTe/CdSe核壳量子点;采用X射线衍射仪、透射电镜、高分辨透射电镜分析了不同反应条件下合成的CdTe/CdSe核壳量子点的晶体结构和微观结构,并对其进行了荧光光谱等测试和指纹显现分析.结果表明,合成的CdTe和CdTe/CdSe量子点粒径在3～5nm之间,粒径分布窄,水分散性良好;可以通过控制反应时间和Te/Se比等得到在500～700nm显示荧光发射峰的CdTe/CdSe核壳量子点.此外,核壳CdTe/CdSe量子点可以有效地和指纹物质结合,可应用于对铝合金油潜指纹的鉴别.     

水热法合成巯基乙胺稳定的CdTe量子点

提出了一种以水热法合成巯基乙胺稳定的CdTe量子点的简单制备路线. 在优化的反应条件下, 产物的荧光量子效率最高达到19.7%, 接近已报道的其它方法的2倍. 考察了反应条件对产物的荧光性能的影响及产物在不同pH溶液中的稳定性.     

Effect of CdS Interlayer on Properties of CdTe Based Quantum Dots

Highly luminescent thioglycolic acid-capped CdTe-based core/shell quantum dots (QDs) were synthesized through encapsulating CdTe QDs in various inorganic shells including CdS, ZnS and CdZnS. CdTe/CdS core/shell QDs exhibited a significant redshift of emission peaks (a maximum emission peak of 652 nm for the core/shell QDs and 575 nm for CdTe cores) with increasing shell thickness. In contrast, the redshift of photoluminescence (PL) peak wavelength of CdTe/ZnS QDs was less than 15 nm. The PL peak wavelengths of the core/shell QDs depended strongly on core size and shell thickness. The PL quantum yields (QYs) of the CdTe/CdS core/shell QDs are up to 67 % while that of CdTe/ZnS core/shell QDs is 45 %. A composite CdZnS shell made CdTe cores a high PL QY up to 51 % and broadly adjusted PL spectra (a maximum PL peak wavelength of 664 nm). The epitaxial growth of the shell was confirmed by X-ray powder diffraction analysis and luminescence decay experiments. Because of high PL QYs, tunable PL spectra, and low toxicity from a ZnS surface layer, CdTe/CdZnS core/shell QDs will be great potential for bioapplications.     

不同环境因子作用下水溶性CdTe量子点的生长动力学研究

以硫普罗宁为稳定剂,水热法制备了水溶性CdTe量子点,系统研究了回流时间、反应物配比、pH值、反应温度和电解质种类等环境因子对量子点生长动力学及光物理性质的影响。结果表明,溶液的pH值及反应物配比对CdTe量子点的光物理性质均有重要影响。优化条件后,回流5 h可得到发射峰位于550 nm的CdTe量子点,其荧光量子效率高达52%;在氯化钠作用下,量子点生长加快,即高浓度氯化钠会减弱溶液中粒子间静电排斥,促进离子扩散,有利于量子点的生长;添加苯磺酸钠会抑制量子点的生长,有利于制备高荧光量子效率的小尺寸CdTe量子点。     

碲化镉/马来酰亚胺三嗪纳米杂化材料的制备及其光性能研究

利用低温水相法, 以巯基丙酸(MPA)作为稳定剂制备了碲化镉(CdTe)量子点, 通过马来酰亚胺三嗪(TMT)中的三嗪基团与CdTe量子点表面富含的羧基之间的氢键作用, 得到了分散性能优良的纳米杂化材料. 利用紫外-可见吸收光谱、荧光光谱以及透射电子显微镜等手段对产物的光物理性质和形貌进行了表征. 结果表明, 马来酰亚胺三嗪与CdTe量子点杂化后, CdTe量子点的荧光发射峰有明显的蓝移, 在CdTe量子点和马来酰亚胺三嗪之间存在着能量转移, 并且纳米杂化材料的分散性也有明显的改善.     

3-巯基异丁酸衍生物对碲化镉量子点水相合成的影响

为探索适宜制备粒径分布窄、荧光量子产率高、发光区域在红光至近红外光区段的量子点的巯基酸的条件, 我们研究了三类3-巯基异丁酸(MIBA)衍生物在以亚碲酸钠为碲源的水相法水热制备CdTe量子点中的影响. 这三类衍生物包括设计合成的主链亲水性衍生物3-巯基异丁酰甘氨酸(MIBGly)、3-巯基异丁酰-3-氨基丙酸(MIBAPA)和3-巯基异丁酰天冬氨酸(MIBAsp), 支链亲水性衍生物N-乙酰基半胱氨酸(ACys)和支链疏水性衍生物3-巯基-2-甲基丁酸(MMBA)和3-巯基-2,2-二甲基丙酸(MDMPA). 以这三类MIBA 衍生物为修饰剂时,CdTe量子点均能够保持MIBA体系较窄的荧光半峰宽. 采用亲水性的MIBA衍生物(MIBGly、MIBAPA、MIBAsp和ACys)比采用疏水性的MIBA衍生物(MMBA和MDMPA)更有利于制备发射波长较长的量子点. 采用支链亲水性的MIBA衍生物((ACys)比采用主链亲水性的MIBA衍生物(MIBGly、MIBAPA和MIBAsp)更容易获得高荧光量子产率的量子点.     

颜色可调的高荧光CdTe量子点的水相合成

以亚碲酸钠为碲源,硼氢化钠为还原剂,一步合成了巯基丁二酸(MSA)稳定的CdTe量子点.研究了反应液pH值、镉与碲的摩尔比及镉与巯基丁二酸的摩尔比等实验条件对CdTe量子点体系荧光量子产率的影响,并用荧光光谱、X射线粉末衍射及透射电子显微镜等对其进行了表征.结果表明,CdTe量子点具有闪锌矿结构,形貌呈球状;在pH=1...     

Preparation of giant unilamellar CdTe quantum dot vesicles and their metabolic pathway in vivo

Glutathione (GSH) capped CdTe quantum dots (QDs) with photoluminescence quantum yields of 61% and the maximum emitting at 601.2 nm were prepared in water phase. Giant unilamellar CdTe quantum dot vesicles (GUVs-CdTe), with diameters larger than 1.5 μm, were obtained using lower-pressure evaporation techniques with soybean lecithin. Compared with other QD liposomes, the entrapment efficiency of GUVs-CdTe for QDs has been significantly improved to 86.3%. After GUVs-CdTe were injected into mice through the tail vein, the fluorescence microscopy of tissue sections showed that GUVs-CdTe could not pass through the blood-brain barrier and air-blood barrier, which were removed mostly by the reticuloendothelial system and were widely distributed in the spleen and the liver. This behavior is the same as the character of the metabolic pathway of giant unilamellar vesicles by intravenous injections in mice.     

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。     

One-pot synthesis of CdTe quantum dots using tellurium dioxide as a tellurium source in aqueous solution

A novel route has been developed for the synthesis of l-cysteine (Cys)-capped CdTe quantum dots (QDs) in an aqueous medium. Compared with previous reports, this synthesis was carried out in air atmosphere with one pot by using TeO₂ to replace Te or Al₂Te₃ as tellurium source. The mechanism for the formation of CdTe QDs is elucidated. The influences of various experimental variables on the luminescent properties of the obtained CdTe QDs have been systematically investigated, including refluxing time, pH value, Cd/Cys and Cd/Te molar ratios. Furthermore, the obtained QDs were characterized by Fourier transform infrared spectra, X-ray powder diffraction, and transmission electron microscopy, respectively. The results demonstrate that the obtained QDs have zincblende crystal structure with a sphere-like shape. Under the optimized experimental conditions, green- to yellow-emitting CdTe QDs with a maximum photoluminescence quantum yield of 14.6 % can be obtained.     

基于聚合物多齿配体的高性能CdTe量子点的微波水相合成

针对当前水相合成的量子点(QDs)光性能与稳定性等方面存在的不足,发展了基于聚合物多齿配体的水相制备策略.利用巯基修饰的聚丙烯酸(PAA-SH)作为多齿配体代替常用的巯基丙酸等单齿配体,结合微波辅助加热制备了CdTe量子点,研究了多齿配体对量子点的生长机制与荧光性能的影响.以PAA-SH为配体制备的CdTe量子点荧光性能优异(荧光量子效率(PLQY)可达75%),流体力学直径较小(~10 nm),稳定性也有明显提高.基于聚合物多齿配体的量子点制备技术有助于实现生物医学研究中急需的兼具高亮度、高稳定性、小尺寸等特征的高性能量子点生物探针的制备.     

Temperature-dependent photoluminescence of highly luminescent water-soluble CdTe quantum dots

Highly luminescent water-soluble CdTe quantum dots(QDs) have been synthesized with an electrogenerated precursor.The obtained CdTe QDs can possess good crystallizability,high quantum yield(QY) and favorable stability.Furthermore,a detection system is designed firstly for the investigation of the temperature-dependent PL of the QDs.     

Synthesis of CdTe Quantum Dots with Tunable Photoluminescence Using Tellurium Dioxide as Tellurium Source

A simple and convenient method has been developed for synthesis of water‐soluble CdTe quantum dots (QDs) under ambient atmospheric conditions. In contrast to the traditional aqueous synthesis, green to red emitting CdTe QDs were prepared by using TeO₂ to replace Te or Al₂Te₃ as tellurium source in this method. The influences of experimental variables, including pH value, 3‐mercaptopropionic acid (MPA)/Cd and Te/Cd molar ratios, on the emission peak and photoluminescence (PL) quantum yield (QY) of the obtained CdTe QDs have been systematically investigated. Experimental results indicate that green to red emitting CdTe QDs with a maximum photoluminescence quantum yield of 35.4% can be prepared at pH 11.3 and n_(Cd):n_(Te):n_(MPA)=1:0.1:1.7.