Facile synthesis and application of highly luminescent CdTe quantum dots with an electrogenerated precursor

An electrogenerated precursor has been developed for green synthesis of highly luminescent aqueous CdTe quantum dots (QDs) with unique quantum yield and strong electrogenerated luminescence, which can access cellular targets via specific binding and have potential application as biolabels in highly sensitive biosensing and cell imaging.     

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.     

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。     

Ultrafast synthesis of near-infrared-emitting aqueous CdTe/CdS quantum dots with high fluorescence

The traditional aqueous route to synthesis CdTe/CdS Core/shell (c/s) quantum dots (QDs) via decomposition of Cd-thiol complexes is usually time consuming. Herein, an ultrafast and facile aqueous synthetic approach under atmospheric pressure for CdTe/CdS c/s QDs with emission from the green to the near-infrared window (535–820 nm) is reported. With purified CdTe core QDs diluted in solution of Cd-3-mercaptopropionic acid (MPA) complexes, CdTe/CdS c/s QDs with emission wavelengths at 700 and 800 nm can be obtained within 20- and 45-min refluxing under the optimized experimental conditions, respectively. This is the most rapid way to prepare CdTe/CdS c/s QDs in aqueous phase, and the obtained QDs were highly luminescent without postsynthesis treatment. The influences of various experimental factors, including Cd²⁺ concentration, MPA-to-Cd ratio, pH value, and dilution ratio on the growth rate and luminescent properties of the obtained CdTe/CdS c/s QDs, have been taken into consideration. The three processes “purification-dilution-addition” ensure the synthesis environment with high pH value and low core concentration and have a marked impact on the rapid synthesis rate and the resulting high fluorescence of CdTe/CdS c/s QDs.     

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...     

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.     

一锅合成绿色到近红外发射的CdTe量子点

以3-巯基丙酸(MPA)为稳定剂,采用水相合成法制备了从绿色到近红外发射的CdTe量子点。系统研究了反应液pH值、镉和碲的物质的量之比及镉和3-巯基丙酸的物质的量之比等实验条件对CdTe量子点体系的发射波长和荧光量子产率的影响。在pH值为10.5,且nCd2+∶nTe2-∶nMPA=1∶0.05∶1.1的条件下,回流0.5 h,CdTe量子点体系在569 nm波长处的荧光量子产率达到30.8%;在7 h的回流时间内,制备的量子点的波长覆盖范围为525～730 nm。分别用X射线粉末衍射、透射电镜和红外光谱对CdTe量子点的晶体结构、形貌及表面基团进行表征。     

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.     

Aqueous one-pot synthesis of bright and ultrasmall CdTe/CdS near-infrared-emitting quantum dots and their application for tumor targeting in vivo

CdTe/CdS core(small)/shell(thick) quantum dots (QDs) with tunable near-infrared fluorescence were directly synthesized in aqueous phase through a facile one-step strategy. The QDs possessed bright fluorescence, ultrasmall size, excellent photostability and good biocompatibility. Their applicability for biological imaging was demonstrated with the in vivo active tumor targeting of nude mice.     

水溶性CdTe量子点的合成及其用于荧光猝灭法测定肌红蛋白

以3-巯基丙酸为稳定剂,合成了具有特殊光学性质的水溶性CdTe量子点,其最大发射波长位于544 nm.利用荧光光谱、紫外可见光谱及圆二色光谱法系统的研究了CdTe量子点与肌红蛋白(Mb)二者结合前后体系光谱的变化,从而证实了CdTe量子点与Mb之间静电结合反应的特征.在pH 7.0的PBS缓冲液中,用CdTe量子点作为荧光探针研究了肌红蛋白与量子点的相互作用,并基于肌红蛋白对CdTe量子点有显著的荧光猝灭作用,建立了肌红蛋白的快速检测方法.在最佳实验条件下,该体系荧光强度的猝灭程度(△F)与肌红蛋白质量浓度呈良好的线性关系,线性范围为0.3～24 μg/mL,检出限为0.13 μg/mL.该方法已对合成样品中肌红蛋白进行检测,并用于人体尿样中肌红蛋白的测定.     

双靶向CdTe量子点的制备及其在细胞标记中的应用

以巯基乙酸和巯基乙酰肼为稳定剂,制备了酸度敏感型CdTe量子点。经与抗体链接,该量子点具备酸度敏感、免疫识别双重靶向功能。经荧光光谱分析、透射电镜图像及细胞免疫成像证明,抗体已成功链接于量子点表面,且该量子点具有酸度敏感及抗体识别的双重靶向功能,可以实现对肿瘤细胞的特异性标记。     

Formation of luminescent nanocomposite assemblies via electrostatic interaction

A novel luminescent nanocomposite assembly was prepared in aqueous solutions, via the electrostatic interaction between poly(ethylene glycol)-b-poly(N,N-dimethylaminoethyl methacrylate) (PEG-b-PDMAEMA) double hydrophilic block copolymer (DHBC) and thioglycolic acid (TGA)-stabilized CdTe quantum dots (QDs). By tuning the molar ratios of QDs to DHBC, the nanocomposite assemblies could be well controlled and the dimension of these regular spherical QDs/PEG-b-PDMAEMA assemblies ranged from 40 to 75 nm in aqueous media. As the periphery of QDs/PEG-b-PDMAEMA nanocomposite assembly was composed of PEG segments when the PDMAEMA blocks and QDs were immobilized inside the assembly, the cytotoxicity of the assembly was significantly reduced, compared with that of pure PEG-b-PDMAEMA and QDs. The nanocomposite assembly also exhibited superior stability in salt solutions and remained strongly photoluminescent even when free radicals existed. Thus, the QDs/PEG-b-PDMAEMA nanocomposite assembly is potentially useful for a number of applications in biolabeling and imaging.     

水合肼还原二氧化碲水相合成CdTe量子点

以巯基乙酸为稳定剂, 氯化镉为镉源, 二氧化碲为碲源, 水合肼为还原剂, 一步合成了CdTe量子点. 研究了反应时间、 碲与镉的摩尔比及巯基乙酸与镉的摩尔比等实验条件对CdTe量子点生长过程的影响. 采用荧光光谱、 X射线粉末衍射和透射电子显微镜等对量子点的性能进行了表征. 结果表明, 反应时间及反应物的相对用量对量子点的生长和荧光光谱有明显影响, 所得CdTe量子点具有立方晶型, 发光颜色从绿色到红色连续可调, 荧光量子产率可达26%.     

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.     

碲化镉量子点光催化降解溴化乙锭的研究

以巯基乙酸为稳定剂, 水相合成出不同粒径的碲化镉量子点, 对其进行适当的光照处理, 以提升其光学性质和稳定性. 将其用作光催化剂, 以紫外灯为光源, 降解具有强诱变作用的常用核酸荧光染料——溴化乙锭. 考察了光照时间和溶液 pH 对降解率的影响. 以溴化乙锭在620 nm处的特征荧光发射峰为参数表征降解率, 在反应4 h后, 对15 mg/L溴化乙锭水溶液的降解率近90%, 同时, 对琼脂糖凝胶中的溴化乙锭也有降解作用.     

Substance P conjugated to CdTe quantum dots triggers cytosolic calcium concentration oscillations and induces quantum dots internalization in the pancreatic carcinoma cell line AR4-2J

Highly fluorescent CdTe quantum dots (QDs) stabilized by 3-mercaptopropionic acid were prepared by an aqueous solution approach and used as a fluorescent label to link substance P (SP) in studying the interaction of SP with NK-1 receptor, which was expressed on the AR4-2J cell line. Nonspecific adsorptions of CdTe QDs on the AR4-2J cell membrane were observed, whereas the QD-SP conjugates successfully crossed the cell membrane and entered the cytosol. SP is a neurotransmitter, and neurotransmitter-induced calcium concentration oscillation is a common phenomenon in diverse cells especially of secretory type. Cytosolic calcium concentration responses were studied in the AR4-2J cell line during stimulation with SP and QD-SP conjugates. The oscillations triggered by SP and QD-SP conjugates were dose-dependent and very similar. Such QD-SP conjugates readily internalized into the cytosol as would be expected of an active NK-1 ligand. Therefore QD-SP conjugates could be used successfully to study ligand and NK-1 receptor interactions in live cells. Our research may provide a meaningful reference for congener research.     

量子点荧光探针检测抗坏血酸

以巯基丙酸（MPA）为稳定剂水相合成了高荧光CdTe量子点. 向量子点溶液中加入Mn2+,由于量子点表面状态发生改变而使其荧光淬灭,加入抗坏血酸后量子点荧光又得以恢复,且荧光恢复程度与抗坏血酸的浓度线性相关,从而建立了基于量子点的荧光“开关”探针检测抗坏血酸的新方法. 当CdTe量子点的浓度为1.67 uM（量子点的尺寸为1.91nm）,加入的Mn2+浓度为0.25 mM时,在优化的实验条件下,检测抗坏血酸的线性范围为0.25~16 uM,检出限为36 nM. 相对标准偏差为2.5%(10 uM, n=11). 该探针可用于维生素C药片和人血浆中抗坏血酸的快速、灵敏和选择性检测.     

水溶性CdTe量子点荧光探针检测肠癌相关T抗原

直接合成性能优良的水溶性CdTe量子点,然后在其表面成功修饰花生凝集素,经过凝胶柱的分离纯化获得功能化的量子点荧光探针.基于T抗原选择性与花生凝集素(PNA)结合的特性,利用该探针对肠癌中高表达的T抗原进行检测,且与传统的荧光染料标记的免疫荧光分析进行了比较.实验结果表明:该功能化的荧光探针能够有效地识别肠癌的相关T抗原,从而为T抗原的检测以及肠癌的临床诊断与愈后判断提供了一种新的方法.     

表面修饰CdTe量子点的合成及其光学特性

在水相中合成高发光性能的CdTe量子点,研究以巯基乙酸(TGA)为稳定剂对CdTe表面进行修饰,制备在水中分散性良好的纳米晶,通过对CdTe量子点合成反应条件的摸索,掌握了其合成的反应规律.同时用紫外分光光度计、荧光分光光度计和透射电子显微镜对其进行了表征.结果表明,回流时间、n(Cd²⁺):n(HTe^-)、反应物浓度、TGA用量、反应体系pH值,对纳米晶的光学性质具有显著影响.回流2 h制得的CdTe纳米粒子直径约为5 nm,其发射峰窄且对称,表现出良好稳定的光学性质.