水热法制备稳定的发光CdTe材料

采用水热合成技术将表面修饰有羧基的纳米CdTe微粒与表面活性剂和硅源进行自组装,得到了一种与氧化硅复合的稳定的CdTe发光材料.通过一系列表征手段(如TG-DTA,EDX,TEM,荧光光谱和N₂吸附)证实了CdTe微粒复合在氧化硅中.进一步通过烧结的方法除去表面活性剂,用稀酸除去金属氧化物,即得到多孔的氧化硅材料.     

CdTe量子点DNA荧光纳米探针的合成及表征

采用水相合成法合成了巯基乙酸(TGA)修饰的水溶性CdTe量子点,通过反相微乳液法制备了二氧化硅及壳聚糖修饰的核壳型复合荧光纳米粒子,将其与DNA吸附连接,得到CdTe量子点DNA荧光纳米探针.用扫描电镜、透射电镜、荧光光谱、红外光谱、紫外光谱、ζ电位等测试方法对产物的理化性质进行了分析表征.结果表明制备了表面富含氨基的复合荧光纳米粒子,其对DNA具有良好的吸附作用.     

CdTe量子点DNA荧光纳米探针的合成及表征

采用水相合成法合成了巯基乙酸(TGA)修饰的水溶性CdTe量子点,通过反相微乳液法制备了二氧化硅及壳聚糖修饰的核壳型复合荧光纳米粒子,将其与DNA吸附连接,得到CdTe量子点DNA荧光纳米探针。用扫描电镜、透射电镜、荧光光谱、红外光谱、紫外光谱、ζ电位等测试方法对产物的理化性质进行了分析表征。结果表明制备了表面富含氨基的复合荧光纳米粒子,其对DNA具有良好的吸附作用。     

CdTe纳米晶-BaSO4复合荧光微球的制备

利用表面活性剂双层修饰技术在水溶性荧光CdTe纳米晶表面先后包覆了双十八烷基二甲基溴化铵和十二烷基硫酸钠, 从而在纳米晶外表面引入—SO-4反应位点, 以—SO-4为活性中心进一步制备了包覆CdTe纳米晶的BaSO4复合荧光微球. 通过扫描电子显微镜、透射电子显微镜、共聚焦荧光显微镜和X射线粉末衍射等方法确定了复合微球的尺寸及组成. 由于BaSO4的保护, CdTe-BaSO4复合微球荧光的耐酸性比CdTe原液的提高明显.     

CdTe/CdS量子点的Ⅰ-Ⅱ型结构转变与荧光性质

制备了壳层厚度可以精确控制的CdTe/CdS核壳量子点, 利用紫外-可见吸收光谱、光致发光光谱、透射电镜和时间分辨光谱等技术, 分析了CdS壳层厚度对CdTe量子点的荧光量子产率和光谱结构的影响规律. 发现了不同于CdSe/CdS, CdSe/ZnS, CdTe/ZnS等核壳量子点的荧光峰展宽、大幅度红移以及荧光寿命大幅度增加现象. 根据能带的位置关系, 随着CdS厚度的增加, CdTe从Ⅰ型结构逐渐过渡到Ⅱ型核壳结构. 对于Ⅱ型CdTe/CdS核壳量子点, 不仅存在CdTe核区导带电子与价带空穴间的直接复合, 还存在CdS壳层导带电子与CdTe核价带空穴界面处的间接复合, 发光机制的变化导致荧光峰的展宽、明显红移和荧光寿命的增加. 当壳层过厚时, 壳层表面新引入的缺陷会阻碍荧光寿命和量子产率的进一步提高.     

水热法合成CdTe量子点及其与蛋白质连接作为生物荧光探针的研究

以巯基丙酸为稳定剂,采用水热法合成了CdTe量子点.吸收光谱和荧光光谱表明,所合成的CdTe量子点具有优异的发光特性.透射电子显微境(TEM)表征了纳米微粒的结构和粒径分布.并以牛血清白蛋白(BSA)为代表,通过测定CdTe量子点与BSA偶联(QDs-BSA)后溶液的荧光强度确定CdTe量子点与蛋白质偶联的最佳反应条件为pH 9～10,反应温度37 ℃,反应时间2 h.通过荧光发射光谱研究了溶液pH和NaCl浓度对QDs-BSA溶液和QDs溶液荧光强度的影响.在优化的反应条件下,用制备的QDs-BSA荧光探针对BSA进行了定量测定,线性范围是0.06～0.48 μg/mL,对0.24 μg/mL QDs-BSA样品7次测定的相对标准偏差是2.2%.     

CdTe/Mn3 O4/SiO2荧光/磁共振双模成像纳米球的制备与表征

成功地制备了CdTe/Mn_3O_4/SiO_2核壳结构的荧光/磁共振成像双功能纳米球,并用透射电镜(TEM)、能谱分析(EDXA)、磁共振成像(MRI)、红外、荧光光谱等对其结构、磁共振成像和发光性能进行了表征。TEM照片显示所合成的纳米球具有明显的球形核壳结构。EDXA分析显示所制备的CdTe/Mn_3O_4/SiO_2纳米球表面只检测到Si和O元素,证明CdTe量子点和Mn_3O_4纳米立方体被成功地包被于二氧化硅纳米球之内。荧光发射光谱显示相对于CdTe量子点,CdTe/Mn_3O_4/SiO_2纳米球荧光发射光谱虽然发生了一定的蓝移,但是仍具有良好的荧光性能。MRI分析可知CdTe/Mn_3O_4/SiO_2纳米球的弛豫参数(r_1)为3.88 s~(-1)(mg·L~(-1))~(-1),说明所合成的CdTe/Mn_3O_4/SiO_2纳米球可用于T_1-加权磁共振成像。细胞毒性实验表明,当CdTe/Mn_3O_4/SiO_2溶液浓度达到300μg·mL~(-1)时,细胞活力仍可达到90%以上,表明此浓度对细胞的毒性作用较弱。     

罗丹明类染料-磷钼酸复合纳米微粒的合成、表征及应用

本文合成了罗丹明6G-磷钼酸(R6G-PMA)和罗丹明B-磷钼酸(RhB-PMA)两种复合纳米微粒,并用扫描电镜(SEM)、紫外-可见(UV-Vis)吸收光谱、荧光光谱、共振光散射(RLS)光谱对复合纳米微粒进行了表征。合成的RhB-PMA复合纳米微粒的平均粒径为343±144nm。R6G-PMA和RhB-PMA复合纳米微粒具有优异的光学性能,最大吸收波长分别为562nm和555nm,其荧光峰分别位于581nm和580nm。复合纳米微粒的吸收波长和荧光峰波长与相应的罗丹明染料相比发生红移,且表现出强烈的RLS增强效应,R6G-PMA和RhB-PMA的最大RLS峰波长分别为581nm和654nm,这表明在复合纳米微粒中相邻的罗丹明染料分子之间存在强烈的电子耦合效应。制备了R6G-PMA修饰玻碳电极(R6G-PMA/GCE),研究了H2O2在R6G-PMA/GCE上的电化学行为。结果表明,该修饰电极对H2O2有着明显的电化学响应,且在其浓度为3.3×10-6~5.6×10-5 mol/L的范围内呈线性响应,相关系数r2为0.9921,检出限(3σ)为2.0×10-8 mol/L。R6G-PMA/GCE对尿酸(UA)和抗坏血酸(AA)有较好的抗干扰能力,可以在UA和AA共存的情况下测定H2O2。     

半胱胺包被的碲化镉量子点的直接水相制备及其与DNA链接

用半胱胺作为表面修饰剂,在水相中制备了稳定的CdTe纳米量子点。吸收光谱和荧光光谱表明,所合成的CdTe量子点具有优异的发光特性。透射电子显微境(TEM)表征了纳米微粒的结构和粒径分布。与目前较为普遍的用巯基羧酸等其它稳定剂在水相中合成的CdTe量子点相比,半胱胺包被的CdTe量子点的前驱体不需要加热就能受激发出荧光,在100℃加热20min后,荧光明显增强;而巯基羧酸包被的CdTe量子点前驱体受激不能发光。本工作还利用量子点上包被的半胱胺上的氨基,实现了与单链DNA分子的直接链接,链接后溶液的发射峰位红移19nm,荧光强度增强。     

CdS/TiO2复合纳米微粒的原位合成及性质研究

采用一种新方法,在TiO₂表面原位合成CdS纳米微粒,并用红外光谱跟踪了CdS/TiO₂复合纳米微粒的形成过程.紫外吸收光谱研究表明TiO₂对CdS纳米微粒的形成有很好的稳定作用,荧光光谱研究结果表明,这种纳米异质结构有着良好的电荷分离.     

Silica Coating of Water-Soluble CdTe/CdS Core-Shell Nanocrystals by Microemulsion Method

"Using Te powder as a tellurium source and Na2S as a sulfur source, core-shell CdTe/CdS NPs were synthesized at 50 oC. UV-visible and photoluminescence (PL) spectra were used to probe the effect of CdS passivation on the CdTe quantum dots. As the thickness of CdS shell increases, there is a red-shift in the optical absorption spectra, as well as the PL spectra. The broadening absorption peaks and PL spectra indicate that the size distributions of CdTe/CdS NPs widen increasingly with the increase of CdS coverage. The PL spectra also show that the fluorescence intensity of CdTe QDs will increase when the particles are covered with CdS shell with ratio of S/Te less than 1.0, otherwise it will decrease if the ratio of S/Te is larger than 1.0. Furthermore, the (CdTe/CdS)@SiO2 particles were prepared using a water-in-oil microemulsion method at room temperature in which hydrolysis of tetraethyl orthosilicate leads to the formation of monodispersed silica nanospheres. The obtained (CdTe/CdS)@SiO2 particles show bright photoluminescence with their fluorescence intensity being enhanced 18.5% compared with that of CdTe NPs. TEM imaging shows that the diameter of these composite particles is 50 nm. These nanoparticles are suitable for biomarker applications since they are much smaller than cellular dimensions."     

Synthesis of aqueous CdTe quantum dots embedded silica nanoparticles and their applications as fluorescence probes

This paper presents the synthesis of aqueous CdTe QDs embedded silica nanoparticles by reverse microemulsion method and their applications as fluorescence probes in bioassay and cell imaging. With the aim of embedding more CdTe QDs in silica spheres, we use poly(dimethyldiallyl ammonium chloride) to balance the electrostatic repulsion between CdTe QDs and silica intermediates. By modifying the surface of CdTe/SiO₂ composite nanoparticles with amino and methylphosphonate groups, biologically functionalized and monodisperse CdTe/SiO₂ composite nanoparticles can be obtained. In this work, CdTe/SiO₂ composite nanoparticles are conjugated with biotin-labeled mouse IgG via covalent binding. The biotin-labeled mouse IgG on the CdTe/SiO₂ composite nanoparticles surface can recognize FITC-labeled avidin and avidin on the surface of polystyrene microspheres by protein-protein binding. Finally, the CdTe/SiO₂ composite nanoparticles with secondary antibody are used to label the MG63 osteosarcoma cell with primary antibody successfully, which demonstrates that the application of CdTe/SiO₂ composite nanoparticles as fluorescent probes in bioassay and fluorescence imaging is feasible.     

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.     

巯基乙胺稳定的水溶性CdTe纳米粒子的合成与表征

用巯基乙胺(cysteamine，CA)作为稳定剂，在水相中合成了发光可调的CdTe半导体纳米粒子。这些巯基乙胺稳定的CdTe纳米粒子表面带有大量的正电荷。实验结果表明，稳定剂与Cd的比例以及pH等实验条件对CdTe纳米粒子体系的荧光发射强度影响较大。在pH为6.1时，纳米粒子体系在橙红波段的荧光量子产率达到了9%左右。控制实验条件，合成了各种尺寸的CdTe纳米粒子，荧光发射光谱在520～600 nm范围连续可调。分别用X射线光电子能谱(XPS)，透射电子显微镜(TEM)，X射线衍射仪(XRD)，红外吸收     

利用水相合成的量子点标记木瓜蛋白酶的研究

利用半导体纳米粒子 (也称半导体量子点 ,Quantum Dots,以下简称 QDs)和表面修饰技术制备的半导体荧光探针具有极其优良的光谱特征和光化学稳定性 [1] .自 1 997年以来 ,随着量子点制备技术的不断提高 ,量子点在生物医学方面已有应用 . 1 998年 ,Alivisatos[1] 和 Nie[2 ] 两个研究小组分别将结合了生物分子的 QDs作为荧光探针应用于生物体系 ,开创了纳米粒子应用的新领域 .最近 Nie等 [3 ]在利用量子点编码生物分子的研究中取得了突破性进展 .目前 ,纳米粒子与生物分子的连接以共价键方式相结合最为常见 [1,2 ,4 ,5] ,而且在这些应用中…     

Transferring CdTe Nanoparticles from Liquid Phase to Polyvinylpyrrolidone Nanofibers by Electrospinning and Detecting Its Photoluminesccnce Property

The major aim of this work was to synthesize thio-stabilized CdTe nanoparticles（NPs） in an aqueous solution, which was then enwrapped with cetyltrimethylammonium bromide（CTAB）, and finally transferred to the polyvinylpyrrolidone（PVP） matrix by electrospinning. The PVP nanofibers containing CdTe NPs were characterized by scanning electron microscopy（SEM） and transmission electron microscopy（TEM）, to observe the morphology of the nanofibers and the distribution of CdTe NPs. The selective area electronic diffraction（SAED） pattern verified that CdTe NPs were cubic lattice. The photoluminescence（PL） spectrum indicated that CdTe NPs existed in an optical style in PVP nanofibers. Moreover, X-ray photoelectron spectra（XPS） revealed that thiol-stabilized CdTe NPs were enwrapped by CTAB, and PVP acted as a dispersant in the process of electrospinning.     

Transferring CdTe Nanoparticles from Liquid Phase to Polyvinylpyrrolidone Nanofibers by Electrospinning and Detecting Its Photoluminescence Property

The major aim of this work was to synthesize thio-stabilized CdTe nanoparticles(NPs) in an aqueous solution,which was then enwrapped with cetyltrimethylammonium bromide(CTAB),and finally transferred to the polyvinylpyrrolidone(PVP) matrix by electrospinning,The PVP nanofibers containing CdTe NPs were characterized by scanning electron microscopy(SEM) and transmission electron microscopy(TEM),to observe the morphology of the nanofibers and the distribution of CdTe NPs,The selective area electronic diffraction(SAED) pattern verified that CdTe NPs were cubic lattice,The photoluminescence(PL) spectrum indicated that CdTe NPs existed in an optical style in PVP nanofibers,Moreover,X-ray photoelectron spectra(XPS) revealed that thiol-stabilized CdTe NPs were enwrapped by CTAB,and PVP acted as a dispersant in the process of electrospinning.     

用水溶液中合成的量子点作为生物荧光标记物的研究

以巯基丙酸(HS-CH₂CH₂COOH)为稳定剂,在水溶液中合成了具有窄而对称(FWHM=40nm)的荧光发射带且尺寸为3nm的CdTe半导体纳米粒子,并用此纳米粒子成功地标记了生物分子胰蛋白酶.与单独的CdTe纳米粒子的溶液相比较,CdTe-胰蛋白酶溶液的吸收光谱在400～600nm范围内较为平坦,其发射光谱蓝移8nm,但发射峰的半峰宽不变.实验证明,CdTe-胰蛋白酶溶液吸收和发射光谱的变化是由CdTe纳米粒子与胰蛋白酶之间的结合反应引起的,而不是由空气中的O₂所引起的,加热可促进CdTe纳米粒子与胰蛋白酶之间的结合反应.     

半导体CdTe纳米晶的合成及其光学性能

半导体CdTe纳米晶的合成及其光学性能;CdTe;纳米晶;光学性能     

Modification of CdTe quantum dots as temperature-insensitive bioprobes

CdTe quantum dots (QDs) were synthesized in aqueous solution with 3-mercaptopropionic acid (MPA) as the stabilizer. The photoluminescence (PL) of CdTe QDs (3.5nm) is found to be temperature-dependent: as the temperature arising from 278K to 323K, the PL intensity declines to 50.2% of its original and PL emission peak shows obvious red-shift ( approximately 7nm). After modification of the QDs surface with denatured ovalbumin, the PL is more temperature-insensitive than before. The PL intensity retains more than 70% of its original and the emission peak shows less red-shift ( approximately 2nm). Moreover, it is found that the PL intensity and wavelength of denatured ovalbumin coated CdTe QDs are reversible during heating (323K)-cooling (278K) cycles. All the studies provide an important theoretical basis for searching temperature-insensitive bioprobes.