Signal Transduction and Amplification for Aptamers

核酸适体是经配体指数富集系统进化技术（SELEX）筛选获得的一类能够 特异性地结合离子、分子，甚至整个细胞的单链DNA或者RNA分子。核酸适 体能够高效、特异地结合小分子、蛋白质等多种目标物质，具有制备、修饰简便 快速，稳定性好，无毒性、无免疫原性等优点，在生物医学基础研究和临床诊断 与治疗方面显示出巨大的应用前景，因此发展基于核酸适体的高灵敏、高选择性 的生物分析方法成为分析化学研究的热点之一。由于核酸适体的本质是一段寡核 苷酸链，本身没有信号输出功能，所以需要将其对靶分子的识别信号转换为可检 测的物理信号。本文选择以可卡因、腺苷和凝血酶等分子作为模型靶物质，设计、 发展了荧...The ability to monitor important molecules with good sensitivity and excellent selectivity offers significant challenge for bio-analytical processes. The key to the successful signaling of these precesses is the use of molecular probes. Aptamers are a new class of nucleic acid probes, which are ssDNA/RNA molecules selected to target a wide range of ions, molecules and even cells through SELEX (Sy...学位：理学硕士院系专业：化学化工学院化学系_化学生物学学号：2052007115099

The Phase Transition of Nematic Liquid Crystal Cells Bounded by Surfactant-Laden Interfaces

National Science Foundation of China [50873083, 10974162]Taking into account the surface-coupling strength effect, we discuss the phase transitions of a finite thickness cell bounded by surfactant-laden interfaces in a magnetic field perpendicular to the substrate and it is compared with that of a semi-infinite system. It is found that the larger the thickness, the closer the three-dimensional phase transition surface of the finite system to that of the semi-infinite one. The simulation also shows that when a magnetic field is applied to a nematic semi-infinite sample, an orientational phase transition first takes place close to the interface and then extends to the inner space as the temperature increases

Application of Aptamers in Biomedicine

Corresponding author e-mail:[email protected]; [email protected][中文文摘]核酸适体是经配体指数富集系统进化技术(SELEX)筛选获得的一类能够特异性地结合离子、分子,甚至整个细胞的单链DNA或者RNA分子。本文介绍了核酸适体及相关筛选技术SELEX;综述了近年来以提高筛选效率和效果为目标的核酸适体筛选技术新进展;列举了核酸适体在无机离子、小分子、生物大分子和肿瘤细胞检测、肿瘤标记物的发现等方面的应用;讨论了基于核酸适体的靶向治疗策略;最后对核酸适体在生物医学上的应用前景进行了展望。[英文文摘]Aptamers are a new class of nucleic acid probes,which are ssDNA /RNA molecules selected to target a wide range of ions,molecules and even cells through SELEX(systematic evolution of ligands by exponential enrichment) technique.This paper presents aptamers and traditional selection approaches;summarizes recent efforts in developing new aptamer selection strategies;reviews new approaches for biomedical analysis,disease biomarker discovery and target therapy.Finally,the potential of aptamers in biomedicine is also discussed.国家重点基础研究发展计划(973)项目(No.2010CB732400); 福建省自然科学基金项目(No.2008J0107)资

Dynamics of a Magnetic Nanowire in Twisted Nematic Liquid Crystal

液晶中的纳米颗粒悬浮体系由于其独特的性质引起了极大的关注.采用保角变换法和等效电容法,对悬浮于扭曲型向列相液晶盒中的磁性纳米金属丝在外加恒定磁场下的动态响应行为进行了研究,并将理论计算结果与实验结果作比较.通过比较发现,理论计算结果与实验结果符合得很好.Systems of nanoparticles suspended in liquid crystal have raised great interest because of their unique property and the potential as novel materials.The dynamic behaviors of a nickel nanowire suspended in a twisted nematic liquid crystal cell under constant magnetic field are analyzed,using the methods of equivalent capacitance and conformal mapping.A comparison with experiments shows that our calculation agrees well with the experimental results.国家自然科学基金项目(50873083;10974162

Application of Aptamers in Food Safety

核酸适体(APTAMEr)是经体外筛选技术(SElEX)筛选出的能特异结合蛋白质或其它小分子物质的寡聚核苷酸片段,对可结合的配体有严格的识别能力和高度的亲和力。经过十几年的发展,SElEX技术已经成为一种重要的研究手段和工具,被广泛应用到分子生物学、基因组学、临床医学等领域。高通量筛选的技术特点与APTAMEr精确识别、易体外合成与修饰等特性,使得APTAMEr在分析化学与生物医药研究方面具有广阔的应用前景。本文对提高筛选效率和效果为目标的核酸适体筛选技术新进展、核酸适体技术在食品安全分析中的应用进行了回顾,展望了核酸适体在食品安全分析上的应用前景。Aptamers are all new ligands with a high affinity for considerably differing molecules ranging from large targets as proteins over peptides,complex molecules to drugs and organic small molecules or even metal ions.These molecules are identified and selected through an in vitro process called systematic evolution of ligands by exponential enrichment(SELEX).Aptamers are widely used,including medical and pharmaceutical basic research,drug development,diagnosis,and therapy.Analytical and separation tools bearing aptamers as molecular recognition and binding elements are another big field of application.The SELEX method was modified over the years in different ways to become more efficient and less time consuming,to reach higher affinities of aptamers selected and higher automation of process.In reviewing this technology,the article covers the topic,following a general introduction,under the headings: the SELEX protocol,the development of aptamers by use of SELEX,and the application of aptamers in food safety.厦门市科技计划项目(No.3502Z20092008);福建省自然科学基金项目(No.2008J0107);国家质检总局科技计划项目(No.2010IK150);国家重点基础研究发展计划(973)项目(No.2010CB732400)资

Numerical evidences for a free energy barrier in starlike polymer brushes

National Science Foundation of China [11074208, 11274258]; Deutsche Forschungsgemeinschaft (DFG) [SPP 1369]The existence of a free energy barrier, which prohibits the upward motion of retracted molecules into the surface region of starlike polymer brushes, is analyzed through molecular dynamics simulations in good solvent. This barrier emerges at moderate and high grafting densities, as a result of a density-discontinuity at the branching points of the highly stretched starlike molecules. The vertical force profiles of brushes of varying densities are taken with the help of a probe-particle that is gradually moved into the brush, and the results are compared with the density profiles and their negative gradients which generate the local osmotic pressures. Chain expulsion simulations, supported by scaling theory, are conducted to understand the dynamics of individual molecules inside the brushes. We prove that the flip-rates between retracted and extended states, being of relevance for the generation of efficiently switchable, environment-responsive brush layers, are determined by the elastic tension of the stretched molecules. (C) 2013 AIP Publishing LLC

Homoleptic tris-cyclometalated iridium(III) complexes with phenylimidazole ligands for highly efficient sky-blue OLEDs

As an extension of our previous study, three sky-blue homoleptic iridium(III) complexes 1-3 with fluorine-free phenylimidazole ligands were synthesized and their photophysical, electrochemical and thermal properties were studied. All the complexes showed high photoluminescence quantum yields ranging from 0.50 to 0.53. The introduction of a bulky isopropyl group at the 2,6-position of N-phenyl of the phenylimidazole ligands increases the quantum yield and the decomposition temperature of the iridium(III) complexes. As the conjugated system of the ligand becomes larger, a very small bathochromic-shift of 1 nm was observed in complex 3 (475 nm) compared with complexes 1 (474 nm) and 2 (474 nm). All the OLED devices showed high current efficiencies of over 20 cd A(-1) at the luminance of 1000 cd m(-2). Devices incorporated with complexes 1-3 all showed longer lifetime in comparison with that of a Flrpic-based device

A printed aluminum cathode with low sintering temperature for organic light-emitting diodes

A printed aluminum cathode with low sintering temperature has been achieved using an aluminum precursor ink, AlH3 center dot O(C3H7)(2), which in the presence of a TiCl4 catalyst can be printed to give the required pattern and then sintered at 80 degrees C for 30 s to form an Al film. The Al cathode of 50 nm thickness has a sheet resistance of 2.09 Omega square(-1) and work function of 3.67 eV. The study demonstrates that the low sintering temperature and work function of the printed film, together with its high conductivity and stability, mean that it is well suited for use as an OLED cathode and that it paves the way for fully printed flexible devices

Sorting of large-diameter semiconducting carbon nanotube and printed flexible driving circuit for organic light emitting diode (OLED)

A novel approach was developed to sort a large-diameter semiconducting single-walled carbon nanotube (sc-SWCNT) based on copolyfluorene derivative with high yield. High purity sc-SWCNTs inks were obtained by wrapping arc-discharge SWCNTs with poly[2,7-(9,9-dioctylfluorene)-alt-4,7-bis(thiophen-2-yl) benzo-2,1,3-thiadiazole] (PFO-DBT) aided by sonication and centrifugation in tetrahydrofuran (THF). The sorted sc-SWCNT inks and nanosilver inks were used to print top-gated thin-film transistors (TFTs) on flexible substrates with an aerosol jet printer. The printed TFTs demonstrated low operating voltage, small hysteresis, high on-state current (up to 10 (3) A), high mobility and on-off ratio. An organic light emitting diode (OLED) driving circuit was constructed based on the printed TFTs, which exhibited high on-off ratio up to 104 and output current up to 3.5 x 10(-4) A at V-scan = -4.5 V and V-dd = 0.8 V. A single OLED was switched on with the driving circuit, showing the potential as backplanes for active matrix OLED applications