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。     

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.     

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量子点荧光探针测定氯霉素含量的研究

在水溶液体系中制备出了具有高质量荧光性能,巯基乙酸(TGA)修饰的CdTe量子点(QDs),基于量子点与氯霉素混合后发生荧光猝灭作用,建立CdTe量子点作为荧光探针测定氯霉素的新方法。在Tris-HCl缓冲液(pH 7.00,0.10 mol·L-1)中,反应时间为10min时,氯霉素浓度在10～70μg·mL-1范围内与CdTe量子点的荧光猝灭程度呈良好的线性关系,相关系数为0.9981,检出限为0.799μg.mL-1。方法简便快速,灵敏度高,可用于实际样品中氯霉素的检测。     

一种新型铜离子荧光探针——CdTe量子点

探讨了髙量子产率CdTe量子点作为铜离子探针的可能性,发现铜离子对碲化镉量子点的荧光有猝灭效应,且量子点溶液的荧光强度与铜离子浓度成良好的负相关线性关系.由于CdTe量子点比CdS具有更为优良的光学性质和稳定性,有望成为一种新型纳米离子探针.     

CdTe量子点荧光探针测定盐酸四环素含量的研究

研究了CdTe量子点(QDs)荧光猝灭法测定盐酸四环素含量的分析方法。以3-巯基丙酸(3-MPA)修饰的CdTe QDs为荧光探针,考察了缓冲液体系及pH值、反应时间等不同条件下盐酸四环素对CdTe QDs的荧光猝灭作用。结果表明在pH 7.5的0.10mol·L-1磷酸盐缓冲溶液(PBS)中,反应时间5min时,盐酸四环素浓度在20~180μg·mL-1范围内呈良好的线性关系(r=0.9978),检测限(S/N=3)为1.3μg·mL-1,对盐酸四环素胶囊中盐酸四环素含量进行定量测定,相对标准偏差(RSD)在1.2%~2.7%之间,加标回收率在96.5%~101.1%之间。该方法快速、简便、灵敏、准确,可用于实际样品中盐酸四环素含量的测定。     

CdTe量子点-罗丹明6G荧光共振能量转移体系的构建及其应用研究

采用巯基化合物修饰的CdTe量子点构建了量子点(供体)-罗丹明6G(受体)荧光共振能量转移体系, 研究了CdTe量子点与牛血清白蛋白(BSA)的相互作用. 结果表明, CdTe量子点与BSA相互作用后提高了CdTe量子点-罗丹明6G 体系的荧光共振能量转移(FRET)效率, 减小了CdTe量子点和罗丹明6G分子间的距离(r), 证实BSA是通过其色氨酸(Trp)残基与CdTe量子点表面金属发生配位作用而直接结合到量子点表面的.     

CdTe/CdS量子点-蛋白质与头孢曲松钠的相互作用

以3-巯基丙酸为稳定剂,采用水热法合成了具有优异光学性质的CdTe/CdS核壳型量子点,量子产率为13.8%。量子点与牛血清白蛋白(BSA)偶联后荧光强度明显增大。通过测定荧光强度确定了偶联的最佳反应条件:pH7.4,反应温度37℃,反应时间40min。研究了溶液pH值和NaCl浓度对量子点及量子点-BSA溶液荧光强度的影响。对牛血清白蛋白测定的线性范围为1.1~19.5mg/L;检出限为0.47mg/L。头孢曲松钠对量子点-BSA的荧光有明显猝灭作用,荧光猝灭程度与其浓度有良好的线性关系。实验结果表明为静态猝灭,头孢曲松钠与BSA按1∶1结合,结合常数为6.31×103L/mol。用圆二色光谱技术探讨了其对BSA构象的影响。     

One-pot synthesis of strongly luminesencing CdTe quantum dots and their conjugation with mouse antibody to alpha-fetoprotein

In this paper, strongly luminescent CdTe quantum dots (QDs) were synthesized in aqueous solution by a facile one-pot method. The CdTe QDs were synthesized in a weakly acidic or neutral buffer solution composed of sodium borate (Na₂B₄O₇) and sodium citrate (C₆H₅Na₃O₇). The pH of buffer solution and the ratio of the precursors were systematically optimized; the high-quality CdTe QDs with progressively increasing fluorescence during 60 days storage were obtained. As-prepared QDs can be conjugated with a mouse antibody alpha-fetoprotein via the reaction mediated by N-hydroxysuccinimide and 1-ethyl-3(3-dimethylaminopropyl) carbodiimide hydrochloride. The conjugate showed a red shift of 9 nm for the emission position.     

MAA修饰ZnO量子点及其发光特性

以ZnAc2·2H2O为原料,在乙醇中通过70℃回流4h,得到ZnO前驱物,与LiOH·H2O反应,制备出ZnO.采用巯基乙酸(mercaptoacetic acid,MAA)对所合成的ZnO进行表面修饰,修饰后的产物经SEM和XRD表征,证明获得了物相单一、近似球状、粒径为4.6nm的ZnO量子点.借助紫外-可见和荧光分析,研究了MAA对该量子点的修饰效果,探讨了设置条件下ZnO的发光机理和性质.发现该实验体系之所以产生荧光表面缺陷发射峰消失和激子发射峰明显增加的光学现象,是因为MAA有效地覆盖了ZnO的表面缺陷,并稳定包裹住ZnO粒子.同时还研究了MAA加量、温度、电解质对修饰产物发光性能的影响,发现经MAA修饰后的ZnO量子点具有较强的荧光发光性能、良好的长期陈放稳定性,以及一定的抗电解质影响能力.研究结果对ZnO量子点应用于生物分析具有重要参考价值.     

CdTe quantum dots as a highly selective probe for prion protein detection: colorimetric qualitative, semi-quantitative and quantitative detection

CdTe quantum dots (QDs) were used as a highly selective probe for the detection of prion protein. Orange-emitting precipitates appeared within 30 s of the addition of recombination prion protein (rPrP) to a solution of green-emitting CdTe QDs. This allowed colorimetric qualitative and semi-quantitative detection of rPrP. The decrease in fluorescence intensity of the supernatant could be used for quantitative detection of rPrP. The fluorescence intensity of the supernatant was inversely proportional to the rPrP concentration from 8 to 200 nmol L⁻¹ (R² = 0.9897). Transmission electron microscopy results showed that fibrils existed in the precipitates and these were partly transformed to amyloid plaques after the addition of rPrP.     

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.     

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.     

水热法快速合成绿色到近红外发光CdTe量子点

以3-巯基丙酸(MPA)和柠檬酸钠为稳定剂,Na2TeO3为碲源,利用水热法成功制备了从绿色到近红外发射的CdTe量子点,并详细探讨了影响CdTe量子点体系的荧光发射波长和量子产率的因素,如反应前驱液的pH值,反应物的浓度比和反应时间等实验条件.分别用X射线粉末衍射、透射电镜、紫外-可见光谱和荧光光谱对CdTe量子点进行了表征.     

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.     

CdTe量子点同步荧光法测定人血清白蛋白

以巯基乙酸(HS-CH2COOH)为稳定剂,水相中合成了CdTe量子点.在pH 6.40的0.002 mol/L KH2PO4-Na2HPO4缓冲溶液中,固定波长差为220 nm时一定量蛋白质的加入能明显增强量子点的同步荧光强度,并且荧光峰强度增加值与血清白蛋白浓度间存在良好的线性关系,据此建立了一种高灵敏度的测定微量蛋白质的方法.该方法测定人血清白蛋白的线性范围为0.08～2.80 μg/mL,检出限为0.032 μg/mL,10次重复测定1.80 μg/mL的血清白蛋白相对标准偏差为1.1%,已用于实际样品的测定.