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氡衰变形成稳定的子体铅只需约3.82 d,且衰变产生的~(210)Pb非常稳定,其半衰期为21年。基于氡辐射衰变最终形成稳定的子体铅的特点,探讨了子体铅诱导富鸟嘌呤核苷酸序列形成G-四链体的特性,建立了一种基于子体铅诱导T30695构象改变的荧光传感器。氡的子体铅诱导T30695形成的G-四链体结构能与N-甲基卟啉二丙酸Ⅸ(NMM)荧光染料结合发出较强荧光,在一定范围内,荧光强度与Pb~(2+)的浓度和氡累积辐射剂量浓度成正相关。Pb~(2+)离子浓度在5.13×10~(-9)~1.25×10~(-7)mol/L范围内与体系的ΔI_F值呈现良好的线性关系,回归方程为ΔI_F=77.30+5.05c,r=0.995 0,对铅的检出限为1.54×10~(-9)mol/L,对氡的检出限为1.07×10~4 Bq·h/m~3。 相似文献
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Since 1970s, electrochemistry is enthusiastically used for studies of severe neurodegenerative disorders, including Alzheimer's disease, Parkinson's disease, or prion-associated transmissible spongiform encephalopathies, associated with the neuronal death in the brain. The existing electrochemical sensors can be used both for direct neurotransmitter analysis in the brain and for detection of both proteins/amyloid peptides and the extent of their aggregation/oligomerisation. However, these sensors' application in body fluids or certain brain areas of interest may be restricted by the presence of structurally or electrochemically related species interfering with electroanalysis. Thus, recent efforts are refocusing on bioelectroanalysis with the apatmer- and antibody-modified electrodes, enabling obtaining more specific, interference-free results that allow better correlations with the disease state. In this opinion, I consider these recent efforts aimed at deeper studies and better understanding of neurotransmitter and protein/peptide patterns linked to neurodegenerative disorders. 相似文献
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A solid-state electrochemiluminescence sensing platform based on ferrocene-labeled structure-switching signaling aptamer (Fc-aptamer) for highly sensitive detection of small molecules is developed successfully using adenosine as a model analyte. Such special sensing platform included two main parts, an electrochemiluminescence (ECL) substrate and an ECL intensity switch. The ECL substrate was made by modifying the complex of Au nanoparticle and Ruthenium (II) tris-(bipyridine) (Ru(bpy)32+-AuNPs) onto Au electrode. An anti-adenosine aptamer labeled by ferrocene acted as the ECL intensity switch. A short complementary ssDNA for the aptamer was applied to hybridizing with the aptamer, yielding a double-stranded complex of the aptamer and the ssDNA on the electrode surface. The introduction of adenosine triggered structure switching of the aptamer. As a result, the ssDNA was forced to dissociate from the sensing platform. Such structural change of the aptamer resulted in an obvious ECL intensity decrease due to the increased quenching effect of Fc to the ECL substrate. The analytic results were sensitive and specific. 相似文献
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A chiral stationary phase derived from an L-RNA aptamer is evaluated for the enantiomer separation of a series of herbicide molecules (aryloxypropionic, aryloxyphenoxypropionic, and aminopropionic acid) by CEC after binding to biotin and grafting upon streptavidin-modified porous glass beads. We demonstrated that the aptamer capillary was stable in term of efficiency and retention during a long period. The influences of the mobile phase constitution and its flow-velocity on the enantioseparation were also investigated. The results suggest that the interactions of the enantiomer during CEC are solely based on chromatographic mechanisms and that the electrophoresis plays only a minor role. The separation efficiency and peak shape could be improved by Mg2+ divalent cation that stabilized the aptamer secondary structure and thus enhanced the mass transfer kinetics during the ligand-aptamer binding process. In addition, it was demonstrated that the determination of the enantiomerization barrier of flamprop was possible using this chiral stationary phase. 相似文献
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将巯基修饰的核酸适配子(aptmer)偶联到金纳米粒子(AuNPs)表面,制备出朊蛋白特异性的Apt-AuNPs纳米光学探针,并成功应用到细胞表面朊蛋白的光散射成像和电子透射显微成像分析.通过对Apt-AuNPs探针进入细胞的途径及其在细胞内命运的进一步研究表明,窖蛋白介导的内吞作用可能是其进入细胞的一个重要途径.Apt-AuNPs纳米探针制备简单、成本低廉,可能被广泛应用于生物医学成像领域. 相似文献
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It has been hypothesized that selections for aptamers with high affinity for a given target molecule will of necessity identify aptamers that have high specificity for that target. We have attempted to assess this hypothesis by selecting aptamers that can bind to MS2 coat protein or to single- or double-substitution variants of the coat protein. Some aptamers selected to bind MS2 coat protein or its variants were mildly specific for their cognate targets, discriminating by two- to fourfold against closely related proteins. Specificity determinants on both the coat proteins and the aptamers could be identified. However, many aptamers could readily bind to each of the different coat proteins. The identification of such aptamer 'generalists belies the proposed relationship between the affinities and specificities of selected RNA ligands. These results imply that, while aptamers may not finely discriminate between closely related targets, neither will their binding be negated by mutations in targets. Aptamer pharmaceuticals may therefore better resist the evolution of resistance. 相似文献
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By taking advantage of recent advances in aptamer biology and nanotechnology, a general approach was developed for the design and fabrication of bioresponsive controlled delivery system. It utilized the structure-switchable aptamer directed assembly and disassembly of gold nanoparticles from mesoporous silica supports, which enables the control of cargo release from the inside of the mesoporous nanoparticles specifically in the presence of target molecule. 相似文献
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核酸适配体是指通过体外筛选技术从核酸文库中筛选出来,能够高特异性、高亲和力识别靶标物的寡核苷酸序列,具有靶标类型广泛、合成简单、相对分子质量小、化学稳定性高、易于进行生物化学修饰等优点。 核酸适配体能够通过折叠成特定的二维或三维构型与靶标物特异性结合,加上合适的信号转导机制,为重要靶标物的研究提供理想的分子识别与分子检测探针。 荧光检测技术具有高灵敏、高分辨率、易于实现多元分析等优点。 将核酸适配体的分子识别特性与荧光优异的光学检测性能相结合,在生命科学研究领域有着广泛的应用空间。 本文主要综述了核酸适配体荧光探针常见的分子设计和信号响应方式,及其在细胞成像、亚细胞成像中的应用研究,并对核酸适配体探针目前面临的一些挑战进行了讨论,最后对其未来的发展方向进行了展望。 相似文献