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【论文题目】Cationic Conjugated Polymers for Optical Detection of DNA Methylation, Lesions, and Single Nucleotide Polymorphisms
【作者】Xinrui Duan, Libing Liu, Fude Feng and Shu Wang
【发表时间】Acc. Chem. Res., Article ASAP
DOI: 10.1021/ar9001813
【发表期刊】Acc. Chem. Res.
【论文闪光点或简单介绍】见下面
【论文链接】（指出所属数据库）【ACS】http://pubs.acs.org/doi/abs/10.1021/ar9001813
相关介绍：
http://oslweb.iccas.ac.cn/html/2009-10-27/20091027153643.htm
共轭聚合物具有强的光捕获能力，可用来放大荧光传感信号，在医疗诊断、基因检测、环境监测等方面具有广泛的应用。在国家自然科学基金委、科技部以及中国科学院“百人计划”项目的支持下，中国科学院化学研究所有机固体重点实验室的研究人员以水溶性共轭聚合物作为新型荧光探针，实现了对疾病相关生物大分子（DNA与酶）的高灵敏与高选择性检测，建立了体外药物筛选的新体系。
核酸酶作用下的DNA水解在DNA复制与修复生物过程中起着重要作用。研究人员构建了阳离子聚芴/三种染料标记Y－DNA复合体系，通过调控该体系的多重能量转移过程，调控聚芴以及荧光染料的荧光逻辑输出信号，实现了三种核酸酶的同时检测。研究结果发表在Angew. Chem. Int. Ed.（2009，48，5316－5321）上，该研究工作为多种物质的同时检测提供了新思路。基因组DNA中单核苷酸多态性位点的分析和测定在遗传病诊断、药物设计以及基因联合研究等方面具有重要意义。他们与北京蛋白质组研究中心以及河北大学的科研人员合作，利用水溶性共轭聚合物荧光探针，通过控制能量转移过程，实现了76例病人基因样品中两个SNP位点基因分型的灵敏分析（Nature Protocols，2009，4，984－991）。该方法既利用了单碱基引物延伸反应具有特异性的优势，又利用了共轭聚合物具有放大荧光传感信号所产生的高敏感性的独特优点，大幅提高了SNP基因型分辨的特异性和敏感性。
同时，研究人员在水溶性共轭聚合物探针用于药物筛选的研究工作也取得了系列进展。他们与美国加州大学圣巴巴拉分校的科研人员合作，利用水溶性共轭聚合物荧光探针，发展了以RNA－蛋白质复合物为靶点的药物筛选新体系，实现了抗HIV－1药物的高灵敏度筛选，研究结果发表在Angew. Chem. Int. Ed.（2009，48，4372－4375）上。并应邀在Chem. Asian J.杂志发表综述文章，对近年来共轭聚合物作为探针在药物筛选中的新应用进行了综述，重点介绍了以核酸、酶、RNA－蛋白质复合物为靶点的药物筛选研究进展（Chem. Asian J. ，2009, 4, 1196-2006）。他们还在DNA模板下通过PPV前体的原位聚合获得了新型荧光水溶胶，控制反应物比例实现了对水溶胶性质的调控，该体系可用于药物的释放监测研究,研究工作被选作“Hot Article”并以内封面的形式发表在Chem. Commun.（2009, 641-643）上。最近，他们设计合成了新型水溶性聚噻吩与卟啉分子并构建了聚噻吩－卟啉复合物，通过聚合物的强光捕获能力以及到卟啉分子的高效能量转移，提高了卟啉分子的活性氧产生效率以及对革兰氏阴性菌与阳性菌的抗菌活性，为发展新型的高效抗菌光敏剂提供了新方法，研究结果发表在J. Am. Chem. Soc.（2009, 131,13117-13124）上。
论文摘要：
Simple, rapid, and sensitive technologies to detect nucleic acid modifications have important applications in genetic analysis, clinical diagnosis, and molecular biology. Because genetic modifications such as single nucleotide polymorphisms (SNP), DNA methylation, and other lesions can serve as hallmarks of human disease, interest in such methods has increased in recent years. This Account describes a new strategy for the optical detection of these DNA targets using cationic conjugated polymers (CCPs).
Because of their unique signal amplification properties, researchers have extensively investigated conjugated polymers as optical transducers in highly sensitive biosensors. Recently, we have shown that cationic polyfluorene can detect SNPs within the DNA of clinical samples. When we incorporated deoxyguanosine triphosphate (dGTP-Fl) into the DNA chain at an SNP site where the target/probe pair is complementary, we observed higher fluorescence resonance energy transfer (FRET) efficiency between cationic polyfluorene and fluorescein label on the dGTP. By monitoring the change in emission intensity of cationic polyfluorene or fluorescein, we identified the homozygous or heterozygous SNP. The high sensitivity of this assay results from the 10-fold enhancement of fluorescein emission intensity by the FRET from polyfluorene. This method can detect allele frequencies (the proportion of all copies of a gene that is made up of a particular gene variant) as low as 2%. Using this novel method, we clearly discriminated among the SNP genotypes of 76 individuals of Chinese ancestry.
Improving on this initial system, we designed a method for multicolor and one-tube SNP genotyping assays based on cationic polyfluorene using fluorescein-labeled deoxyuridine triphosphate (dUTP-Fl) and Cy3-labeled deoxycytidine triphosphate (dCTP-Cy3) in extension reactions. We also developed a one-step method for direct detection of SNP genotypes from genomic DNA by combining allele-specific PCR with CCPs. In 2008, we developed a new method for DNA methylation detection based on single base extension reaction and CCPs. Treatment of DNA with bisulfite followed by PCR amplification converts unmethylated DNA into a C/T polymorphism, which allows us to characterize the methylation status of the target DNA. Furthermore, we used CCPs to detect DNA lesions caused by ultraviolet light irradiation for the first time. By monitoring the color change of cationic polythiophene before and after DNA cleavage, we also detected oxidative damage to DNA by hydroxyl radical.
These CCP-based new assays avoid primer labeling, cumbersome workups, and sophisticated instruments, leading to simpler procedures and improved sensitivity. We expect that these features could lead to major advances in human disease diagnostics and genomic study in the near future. |
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a) S-2;(b) TOZ-2
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