Fluorescent immunosensor based on fluorescence resonance energy transfer between CdSe/ZnS quantum dots and Au nanorods for PRRSV detection

An ultrasensitive and selective sandwich-type fluorescent immunosensor based on fluorescence resonance energy transfer (FRET) between CdSe/ZnS quantum dots (QDs) and Au nanorods (AuNRs) was developed for the rapid detection of porcine reproductive and respiratory syndrome virus (PRRSV). Modified CdSe/ZnS QDs and AuNRs were bioconjugated with primary antibodies M and GP5, respectively. When the target antigen was present, a well-known sandwich-type form CdSe/ZnS QDs-M antibody-antigen-GP5 antibody-AuNRs was produced, and thus reducing the distance between the QDs and NRs. As a result, FRET occurred and the fluorescence intensity of CdSe/ZnS QDs decreased, and this decrease was used to determine the antigen concentration. Ultrasensitive detection of PRRSV at low concentrations in swine serum was achieved with a limit of detection of 0.55 TCID₅₀/mL and a linear detection range of 10¹–3.5 ?× ?10⁴ TCID₅₀/mL. Therefore, the fluorescent immunosensor is selective and highly sensitive; specifically, it can detect PRRSV at low concentrations in swine serum over a large concentration range. This proposed detection method can facilitate the development of high-performance fluorescent immunosensors for the detection of PRRSV and other antigens.     

聚苯乙烯微球中荧光共振能量转移的研究

采用分散共聚合法制备了单分散的负载有1,8-萘酰亚胺染料的荧光微球。利用供体和受体染料间的荧光共振能量转移,荧光微球在激发供体染料时同时实现了供体和受体染料的双重荧光发射信号。结果表明:当微球中染料的浓度相对较低(质量分数小于0.2%)时,荧光共振能量就可以有效地发生转移。聚合过程中增加供体或受体染料的浓度都会提高能量转移效率,这是浓度增加使得染料分子间距离缩短造成的。通过调整微球中染料浓度可以获得不同能量转移效率、具有荧光编码信号的系列荧光微球。这类粒径均一的荧光微球在多元生物分析中有潜在的应用价值。     

基于量子点荧光探针的高灵敏蛋白质检测方法

通过制备量子点荧光检测探针,构建了一种基于量子点探针和免疫磁珠的蛋白质检测方法,实现了对蛋白肿瘤标志物癌胚抗原(carcinoembryonic antigen,CEA)的高灵敏定量检测.在该检测体系中,若存在有靶标蛋白,其与量子点检测探针以及捕获探针之间会发生免疫反应形成三明治结构,利用磁力分离器对免疫复合物进行富集后,通过检测富集在磁珠表面的量子点荧光信号,可实现对靶标蛋白的定量.该方法的检测灵敏度为38 pg/mL,线性范围为0.39~50ng/mL,临床质控样本检验结果表明,该方法准确度高,可重复性好,可应用于临床样本检测.该量子点探针检测体系具有灵敏度高、特异性好、样品消耗量低等优点,在疾病早期诊断方面具有广阔的应用前景.     

量子点作为生物荧光探针的应用研究

量子点作为一种能发射荧光的半导体纳米微晶体,具有独特的光学性质。这决定了它在生物研究中有广阔的诱人的前景:如替代传统的生物荧光探针,具有荧光光谱较窄、量子产率高、不易漂白等优点;进一步讨论了量子点的电泳和微流控芯片的生物应用及其前景。     

石墨烯量子点复合材料的制备及其对抗坏血酸的荧光检测

设计并制备了一种在纯水系中荧光增强识别抗坏血酸(AA)的石墨烯量子点复合材料NB-GQDs@MOF-5,利用TEM、FT-IR和XRD对其形貌和结构进行了表征,结果表明NB-GQDs与MOF-5成功复合.荧光检测结果表明,在纯水体系中,NB-GQDs@MOF-5可在考察的有机小分子及阳离子范围内专一性地识别AA,滴加AA后引起荧光增强8.1倍,检出限为0.039μmol/L.     

基于动态光散射法测量量子点粒径的实验方法

动态光散射技术是进行纳米及亚微米颗粒粒径测量的一种有效方法.通过对量子点特性和动态光散射系统的分析,提出了一种基于动态光散射测量量子点粒径的实验方法,构建实验装置并进行测量与分析.通过CONTIN算法反演量子点粒径,并与电子显微镜和粒径公式得到的粒径数据进行比较,证明动态光散射法是测量量子点粒径的一种有效的方法,为量子点光学特性的快速分析提供了一种新的途径.     

A water-soluble fluorescence resonance energy transfer probe for hypochlorous acid and its application to cell imaging

A water-soluble fluorescence resonance energy transfer (FRET) probe for hypochlorous acid (HOCl), dansyl rhodamine B piperazinoacetohydrazide, was designed, synthesized and characterized. The dansyl moiety in the probe acted as a FRET donor and the rhodamine moiety acted as a FRET acceptor. The two moieties were connected by a HOCl-cleavable active bond, and cleavage of this linker decreased the FRET efficiency and increased the fluorescence intensity of the donor at 501 nm. The water solubility of the prob...     

一维量子点阵列自旋链上多比特态的信息传输

利用演化算符作泰勒展开,作用于初态的信息上;使用湮灭算符和其所产生的算符,作用在单比特态上,使一维量子点阵列自旋链上的多比特态量子信息实现完美传输;通过计算初态演化到末态的概率幅,使保真度达到1时实现信息完美传输．结果表明:当相邻量子点之间的交换相互作用和自旋链长度都相同时,保真度传输的比特数越大,传输时间越短．      

Multipolar model for collisional quantum interference on rotational energy transfer

A theoretical model of collisional quantum interference ( CQI) is developed in a diatom-diatom system based on the first-order Born approximation of time-dependent perturbation theory and the multipolar interaction potential. The transition cross section is obtained. The relations between the differential and integral interference angles are discussed. The key factors on the determination of the differential and integral interference angles are obtained. The changing tendency of the interference angles with the experimental temperatures is obtained.     

量子点层厚度对量子点发光二极管发光特性的影响简

采用湿法旋涂技术制备量子点发光二极管器件（QD-LEDs）。PEDOT作为空穴注入层,TFB作为空穴传输层,量子点作为发光层,采用无机二氧化钛（TiO2）作为电子传输层,在相同的工艺条件下调节量子点层旋涂转速（800～1100 r/min）,制备不同厚度的量子点发光二极管发光器件（QD-LEDs）。实验结果表明,当量子点层的旋涂转速为900 r/min时,此时的量子点层厚度为30 nm,所制备的量子点发光二极管器件（QD-LEDs）的发光性能最好,开启电压最低,只有5．5 V。     

能量转移电化学发光分析法测定金霉素

至今,还未见有关碳质印刷电极上荧光素电化学发光分析的报道。我们发现,碱性介质中的荧光素在碳质印刷电极表面的弱电化学发光信号可被金霉素所增敏。据此,我们首次建立了一种测定金霉素的能量转移电化学发光新方法。在实验所建立的最佳条件下,该方法测定金霉素的线性范围为2.0×10~(-6)～5.0×10~(-4)g/ml,检出限为6×10~(-7)g/ml,相对标准偏差为3.1％(n=11;C=1×10~(-5)g/ml。该方法还被成功地应用于片剂金霉素样品的分析。     

能量转移电化学发光分析法测定金霉素

至今,还未见有关碳质印刷电极上荧光素电化学发光分析的报道.我们发现,碱性介质中的荧光素在碳质印刷电极表面的弱电化学发光信号可被金霉素所增敏.据此,我们首次建立了一种测定金霉素的能量转移电化学发光新方法.在实验所建立的最佳条件下,该方法测定金霉素的线性范围为2.O×1O-6～5.O×10-4g/ml,检出限为6×1O-7g/ml,相对标准偏差为3.1%(n=11;C=1×10-5g/ml.该方法还被成功地应用于片剂金霉素样品的分析.     

花椒碳点荧光探针的制备及对牛奶中溴代乙酰胆碱的检测

以食用花椒为原料,采用热解法制备了荧光碳量子点(CDs),加入β-环糊精修饰CDs.用荧光表征CDs的光学性质,透射电镜观察了CDs的外貌特征.结果表明:荧光激发和发射波长分别为315nm、429nm,荧光量子产率为0.60,碳点平均直径为4.2nm,由于溴代乙酰胆碱(ACH)对碳量子点的荧光具有增敏作用,可以用于牛奶中ACH的分析检测.在pH值为7,25℃条件下,(ACH)的加入量与CDs荧光强度的增加成正比,其线性回归方程为ΔF=314.72c+134.54,线性0.08～1.6μmol/L,相关系数r=0.997 9,标准偏差为1.75,检出限(3σ/K)为1.62×10^-8 mol/L.将此方法用于牛奶和酸奶中ACH含量的测定,回收率为98%～102%.     

基于硫化镉量子点荧光增强测定痕量碘

以水相中制备的羧甲基纤维素钠修饰的硫化镉(CdS)量子点为荧光探针,基于Cu2+离子和I-离子作用后生成的CuI对CMC-CdS量子点荧光的增强作用,建立了测定痕量碘离子的新的分析方法.考察了缓冲体系、量子点浓度、反应时间等因素的影响.实验表明,在0.03 mol/L、pH=7.7的磷酸氢二钠-磷酸二氢钾(PBS)缓冲溶液中,当量子点的浓度为2.0×10-4mol/L、反应时间为25 min时,量子点的相对荧光强度与I-离子的浓度呈很好的线性关系,线性范围为:1.0×10-7～1.0×10-9mol/L,检出限为0.5 nmol/L.该法已用于海带和紫菜中碘含量的测定,结果令人满意.     

磁耦合谐振式无线能量传输效率分析

为分析无线能量传输的效率问题,利用电磁仿真软件HFSS,建立了单个线圈模型,利用单个谐振线圈模型构建了基于磁耦合谐振的能量传输系统。通过S参数曲线直观反映能量传输效率的变化规律,验证了磁耦合谐振式能量传输效率远远大于一般的感应耦合。通过改变模型中两线圈的相对位置,分析了线圈距离、夹角等因素对能量传输效率的影响,依据效率变化曲线,直观展示了频率分裂现象。仿真和分析表明,为实现系统的高效率、远距离能量传输,应尽量减小收发线圈的角度和线圈的错位偏移量,该系统为设计和优化无线电能传输系统提供了一种理论分析方法。     

Evidence for wavelike energy transfer through quantum coherence in photosynthetic systems

Photosynthetic complexes are exquisitely tuned to capture solar light efficiently, and then transmit the excitation energy to reaction centres, where long term energy storage is initiated. The energy transfer mechanism is often described by semiclassical models that invoke 'hopping' of excited-state populations along discrete energy levels. Two-dimensional Fourier transform electronic spectroscopy has mapped these energy levels and their coupling in the Fenna-Matthews-Olson (FMO) bacteriochlorophyll complex, which is found in green sulphur bacteria and acts as an energy 'wire' connecting a large peripheral light-harvesting antenna, the chlorosome, to the reaction centre. The spectroscopic data clearly document the dependence of the dominant energy transport pathways on the spatial properties of the excited-state wavefunctions of the whole bacteriochlorophyll complex. But the intricate dynamics of quantum coherence, which has no classical analogue, was largely neglected in the analyses-even though electronic energy transfer involving oscillatory populations of donors and acceptors was first discussed more than 70 years ago, and electronic quantum beats arising from quantum coherence in photosynthetic complexes have been predicted and indirectly observed. Here we extend previous two-dimensional electronic spectroscopy investigations of the FMO bacteriochlorophyll complex, and obtain direct evidence for remarkably long-lived electronic quantum coherence playing an important part in energy transfer processes within this system. The quantum coherence manifests itself in characteristic, directly observable quantum beating signals among the excitons within the Chlorobium tepidum FMO complex at 77 K. This wavelike characteristic of the energy transfer within the photosynthetic complex can explain its extreme efficiency, in that it allows the complexes to sample vast areas of phase space to find the most efficient path.     

量子点的尺寸效应及声子对激子基态结合能的影响

利用变分法研究了有很小厚度圆盘形GaAs量子点模型中激子的基态结合能,及电子-空穴间距随量子点尺寸变化的规律．考察了电子-空穴的关联明显加强时及完全束缚发生时量子点的横向尺度,初步考虑了体纵光学声子对量子点中激子基态结合能的影响,得出一些定性的结论。     

微波场作用下Fano效应对量子点电子态密度近藤峰的影响

讨论了一个微波场辐照下量子点电极耦合体系,当两边电极间存在非共振直接隧穿时量子．占、上电子态密度的变化情况。用非平衡格林函数方法及吴大琪假设得到了此体系能态密度在相互作用强度U有限情况下的解析表达式。数值计算的结果表明随着背景透射率及库仑相互作用能大小的变化,量子点上电子能态密度共振峰可被增强或减弱,并可能出现新的共振峰结构。     

基于Lamb波无基准方法的裂纹检测

传统的结构健康监测技术容易受到温度、振动噪音等与结构缺陷无关的因素影响.为了克服这一缺陷,发展了一种基于传递阻抗的无基准裂纹检测方法.该方法既不需要基准数据,也不需要损伤阈值,而是利用裂纹导致的Lamb波模式转换效应和PZT极化特性从两组并排的PZT元件间获取传递阻抗,通过比较传递阻抗的能量来判断裂纹是否存在.仿真和实验表明,该方法无需选择最优的激励频率和采样时间即可实现对裂纹的检测,具有较强的鲁棒性和适用性.