量子点探针测定痕量金属离子

量子点是近几年发展起来的新型纳米材料。因其独特而优良的荧光特性,量子点成为了一种具有很大发展潜力的荧光探针。将量子点作为标记物的荧光分析法也成为国内外研究学者的研究热点。这种新型荧光分析法已经广泛地应用于生物科学、医学、分析化学等领域,并显示出极大的优越性。本文集中叙述了修饰剂对量子点的荧光性质的影响和量子点在分析检测痕量金属离子方面的应用,讨论了金属离子与量子点作用后荧光猝灭或荧光增强的可能的机理。     

巯基乙胺为稳定剂制备水溶性荧光量子点的合成探究

本文用巯基乙胺作为稳定剂分别利用了水相加热回流法、水热法两种方法制备出CdTe水溶性荧光量子点。这种荧光量子点可溶于水,且根据其特性可调控发射波长,发光性能较好。同时本文亦研究了在合成CdTe荧光量子点的过程中其反应温度、反应时间,pH环境等对于CdTe量子点发光性能的影响,以此甄选出最优化的量子点合成条件。     

量子点的制备及其在生物医学中的应用进展

量子点作为一种优良的荧光半导体纳米粒子,已成为纳米技术领域最受关注的研究对象之一,并成功应用于生命科学等领域。随着小粒径的低毒无镉量子点的制备和量子点荧光共振能量转移等新技术的发展,量子点在生命科学领域将展示出更大的应用空间。本文介绍了量子点的基本概念和性质,探讨了近年来在有机溶剂和水溶液两种不同介质中制备量子点的方法,并分析比较了其优缺点;对量子点在生物医学领域(包括蛋白质和核酸研究、组分检测、荧光编码及细胞标记等)的应用进行了综述和展望,指出了目前存在的问题和今后的发展方向。     

谷胱甘肽修饰CdTe量子点应用于二价汞离子检测

应用"一锅法"合成谷胱甘肽修饰的Cd Te量子点。利用荧光分析法检测量子点溶液中的Hg2+含量,分析得到含有不同浓度Hg2+的谷胱甘肽修饰量子点体系荧光强度与Hg2+浓度具有良好的线性关系。根据这一研究建立了一种利用量子点荧光特性对Hg2+进行测定的简便、快速的检测方法。     

碳量子点的光学性质及其应用研究进展

碳量子点是一种由碳原子组成的新型纳米结构,其粒径尺寸一般在10nm以下,具有很好的量子限域效应、荧光性能和光学性能等,有良好的应用前景。碳量子点在光催化反应中的作用主要体现在两个方面：作为电子接收器和用作太阳能电池光阳极的增敏剂。从荧光性能、光激发性、太阳能电池和光催化等方面总结了碳量子的荧光性质和光学性质,分析了碳量子点在光催化、太阳能电池和荧光转换等领域面临的挑战和问题。     

量子点荧光纳米材料的化学合成及其在潜手印显现中的应用

随着纳米科技的发展,将量子点荧光纳米材料作为一种新型显现试剂并应用于潜手印显现技术已引起了研究者的浓厚兴趣。合成出高质量、高荧光性能的量子点是拓展其在手印显现方面广泛应用的前提条件。本文针对量子点荧光纳米材料的化学法合成及其在潜手印显现领域中的应用进展进行了较为详尽的归纳和总结。     

量子点/有机硅树脂光学膜的制备与性能

将量子点分散在透明硅树脂中并添加固化剂,加热交联固化,获得封装有量子点的硅树脂光学薄膜。采用紫外可见光吸收光谱(UV-Vis)、荧光发射光谱(PL)等方法对光学薄膜的性能进行表征。PL结果表明,量子点薄膜的荧光发射光谱较量子点溶液发生少量红移,而半峰宽则保持一致,量子点光学膜总体上保留了量子点在溶液中93%的荧光量子效率值。制备的量子点膜经高温加速老化后仍然保持约50%的荧光量子效率。     

氮掺杂黄色碳荧光量子点的制备与表征

为提高碳量子点的荧光穿透能力,利用邻苯二胺、尿素作为前体,水热合成法制备黄色荧光碳量子点。考察了温度、时间、氮掺杂量对碳量子点荧光性能的影响。通过红外、荧光光谱仪等对所制备荧光碳量子点进行结构和性能的表征。结果表明,温度为160℃、时间为5h、氮掺杂量占60%时,所制备的荧光碳量子点荧光性能最好。其最佳激发波长为373 nm,最佳发射波长为567 nm。     

水热法合成仙人掌荧光碳量子点的研究

以仙人掌为碳源,通过水热法合成了荧光碳量子点,并通过荧光光谱对样品的光学性能进行了表征,同时考察了仙人掌用量、水热反应时间和温度对合成荧光碳量子点的影响。结果显示:以仙人掌为碳源合成的荧光碳量子点在水溶剂30 m L条件下,仙人掌质量为0.5 g时得到的荧光碳量子点发光效率最高;同时,水热反应时间为3 h,反应温度为160℃时得到的荧光碳量子点发光强度最高。荧光碳量子点在紫外灯照射下发出明亮的绿光。     

量子点纳米材料探针及其在肿瘤影像中的应用

针对现有量子点影像探针存在荧光性质不可控、生物毒性强的问题,本研究结合现有的CuInS量子点探针,研究制备出一种掺杂Zn离子可简易合成的ZCIS/ZnS量子点纳米探针,并通过改进其水溶性,得到一种可直接应用于医学肿瘤影像的改进ZCIS/ZnS量子点纳米探针。为提高该量子点纳米探针的靶向性,研究根据EDC偶联的原理,通过将改进ZCIS/ZnS量子点纳米探针与cRGD多肽进行偶联,得到ZCIS/ZnS-cRGD量子点纳米探针,并从结构形态、细胞毒性和离体荧光3个方面重点评估了该量子点纳米探针,并通过实验论证了其有效性和实用性。实验结果证明,本研究制备的ZCIS/ZnS-cRGD量子点纳米探针是一种有效的肿瘤靶向探针,可用于实际肿瘤靶向检测。     

水溶性CdTe量子点的制备和表面修饰及表征

近年来,半导体纳米晶CdTe引起人们越来越多的关注。它具有吸收光谱宽,发射光谱窄而对称,发光颜色可调,荧光强度和光稳定性高等特点,已经广泛用于生物标记,生物传感及生物检测领域。尤其在基于荧光共振能量转移原理的生物传感领域,量子点有望取代有机荧光发色基团作为能量供体。在文章实验中,以巯基丙酸(MPA)作为稳定剂,在水相中合成了CdTe量子点,并考察了回流时间,反应温度,溶液pH对CdTe光学性质的影响。利用透射电子显微镜(TEM),荧光分光光度计(FS)等手段对产物进行分析和表征。结果表明:在pH为9.1,反应温度为30℃,回流5 h,可以实现CdTe的优化合成。在紫外灯(254 nm)照射下,回流时间从1 h到7 h所得到的CdTe量子点,颜色由绿色变到黄色,对应的荧光光谱图的吸收峰位从515 nm(回流1 h)红移到573 nm(回流7 h),证实了CdTe量子点的尺寸随着回流时间的增长而增加。由TEM结果,所合成的CdTe量子点分散性好,且粒径大约在5 nm左右。该本实验制备的CdTe量子点具有较高的荧光强度和量子效率,将在生物标记,生物传感,生物成像等领域有重要作用。     

Temperature dependent synthesis and optical properties of CdSe quantum dots

The CdSe quantum dots (QDs) were synthesized at various temperatures in aqueous solution. The as-synthesized QDs were characterized by X-ray diffraction (XRD) method and transmission electron microscopy (TEM), and their optical properties were assessed via ultraviolet–visible (UV–vis) absorption spectrum and fluorescence spectrum. The results showed that the reaction temperature could significantly influence the band gap, particle size, and spectral behaviors of the QDs. With the increase of the temperature from room temperature to 90 °C, the band gap of the QDs linearly decreased, corresponding to an essential increase of particle size as well as variable spectral behaviors. In particular, the starting temperature had an important effect on the QDs synthesis and their optical properties. From a viewpoint of wide controls of fluorescence color and intensity, a reaction temperature range of 17–90 °C was appropriate for the synthesis of the CdSe QDs.     

Synthesis of CdTe quantum dot-conjugated CC49 and their application for in vitro imaging of gastric adenocarcinoma cells

The purpose of this experiment was to investigate the visible imaging of gastric adenocarcinoma cells in vitro by targeting tumor-associated glycoprotein 72 (TAG-72) with near-infrared quantum dots (QDs). QDs with an emission wavelength of about 550 to 780 nm were conjugated to CC49 monoclonal antibodies against TAG-72, resulting in a probe named as CC49-QDs. A gastric adenocarcinoma cell line (MGC80-3) expressing high levels of TAG-72 was cultured for fluorescence imaging, and a gastric epithelial cell line (GES-1) was used for the negative control group. Transmission electron microscopy indicated that the average diameter of CC49-QDs was 0.2 nm higher compared with that of the primary QDs. Also, fluorescence spectrum analysis indicated that the CC49-QDs did not have different optical properties compared to the primary QDs. Immunohistochemical examination and in vitro fluorescence imaging of the tumors showed that the CC49-QDs probe could bind TAG-72 expressed on MGC80-3 cells.     

Studies on the interaction of CdTe QDs with bovine serum albumin

BACKGROUND: Quantum dots (QDs) have attracted much attention in biological and medical applications. In particular, the interaction of QDs with bovine serum albumin (BSA) is crucial, and has been systematically investigated by various spectroscopic techniques under the physiological conditions. RESULTS: The effects of ionic strength and pH on the interaction of CdTe QDs with BSA were studied by changing NaCl concentration and pH in mixed solution and making fluorescence spectroscopic measurements. The Stern‐Volmer quenching constant (K_a) of different ionic strength and pH were calculated, and information on the structural features of BSA were discussed by means of circular dichroism (CD) spectrum. CONCLUSION: Both fluorescence (FL) and circular dichroism (CD) results indicated that hydrophobic and electrostatic interactions play a major role in the binding reaction, and the nature of quenching is static, resulting in forming QDs‐BSA complexes. Copyright © 2012 Society of Chemical Industry     

CdTe量子点的纯化以及作为pH探针的研究

以巯基乙酸为稳定剂在水相中合成了CdTe量子点,并将合成的CdTe量子点进行表征、纯化。通过用0.05 mol.L-1PBS缓冲溶液调节不同的pH来考察量子点的荧光强度和pH的关系。研究发现,水溶性的CdTe量子点是pH敏感的,随着pH值的降低,量子点荧光强度的下降规律与溶液pH值呈现良好的线性关系。结果表明,CdTe量子点是一个令人满意的pH敏感的探针,有潜在的化学和生物传感能力。     

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.     

N-乙酰-L-半胱氨酸修饰的CdTe量子点与人血清白蛋白的相互作用

以N,乙酰-L-半胱氨酸为修饰剂,制备了水溶性的CdTe量子点（NAc—CdTeQDs）。利用荧光光谱法和等温滴定量热法（11℃）研究了NAC-CdTeQDs与人血清白蛋白（HsA）的相互作用。结果表明,NAC—CdTeQDs对HSA内源荧光具有较强的动态猝灭作用,且猝灭作用是扩散控制的。     

Quantum dot based turn-on fluorescent probes for anion sensing

The design of fluorescent probes for turn-on sensing of anions has been especially significant because it can effectively enhance sensing sensitivity by decreasing the background interference. In the present work, we have systematically studied the potential applications of fluorescent quantum dots (QDs) in turn-on anion sensing. The fluorescence of QDs are firstly quenched by three different mechanisms, i.e. fluorescence resonance energy transfer, electron transfer and surface states modulated fluorescence. The fluorescence of the pre-quenched QDs can then be recovered by various anions due to the modulating effects of added anions on the interaction between QDs and QDs, the interaction between QDs and quenchers, and the surface chemistry of the quenched QDs, respectively. The results described here indicate that turn-on sensing of various anions by QDs-based systems can be achieved by rationally choosing fluorescence modulating strategies, demonstrating the versatility of QDs in the corresponding applications.     

Transparent,fluorescent, and mechanical enhanced elastomeric composites formed with poly (styrene‐butadiene‐styrene) and SiO2‐hybridized CdTe quantum dots

Transparent poly(styrene‐butadiene‐styrene) (SBS)‐quantum dots (QDs) composites (SBS/CdTe QDs) that simultaneously possess strong photoluminescence (PL) and enhanced mechanical properties are presented for the first time based on the facile blending of SiO₂‐hybridized CdTe QDs with SBS. UV–vis spectrum and fluorescence measurement show that SBS/CdTe QDs composites exhibit good optical properties. The results of transmission electron microscopy show good dispersion of CdTe QDs in the SBS matrix. The results of dynamic mechanical thermal analysis indicate that the micro‐phase separated structure of the SBS is exist in the composites, and the presence of CdTe QDs can lead to an decrease of glass transition temperatures of polybutadiene (PB) and polystyrene(PS) domains. In addition, mechanical tests reveal that the addition of CdTe QDs is a useful approach to improve the mechanical properties of SBS. Meanwhile, the fluorescent photographs taken under ultraviolet light prove that SBS/CdTe QDs composites possess strong PL. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

靶向壳聚糖基因载体与水溶性量子点的自组装

将透明质酸(HA)接枝到四种不同分子量的壳聚糖(CS)上,获得了靶向壳聚糖基因载体。将CS及接枝CS分别与水溶性量子点(QDs)自组装,研究发现,相对于纯QDs,CS/QDs复合物及接枝CS/QDs复合物的荧光强度均明显增强,荧光发射峰位发生红移。复合物呈核/壳结构,QDs被包裹在核内。和CS/QDs复合物相比,接枝CS/QDs复合物的尺寸更小,分布更为均一。