Carbon nanotube-quenched fluorescent oligonucleotides: Probes that fluoresce upon hybridization
Carbon nanotube-quenched fluorescent oligonucleotides: Probes that fluoresce upon hybridization
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DOI：
10.1021/ja800604z
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发表时间：
2008-07-02
影响因子：
15
通讯作者：
Tan, Weihong
中科院分区：
文献类型：
--
作者：
Yang, Ronghua;Jin, Jianyu;Tan, Weihong
我们报道了一种有效的、新型的带有寡核苷酸的自组装单壁碳纳米管(SWNT)复合体，并证明了它在均相溶液中一步识别和检测特定DNA序列的可行性。这种复合体的关键成分是发夹结构的荧光寡核苷酸，它使SWNT既能作为寡核苷酸的“纳米支架”，又能作为荧光团的“纳米猝灭剂”。鉴于这种功能，这种碳纳米管复合体代表了一种新的通用荧光猝灭剂，它与有机猝灭剂有很大的不同，因此在分子工程和生物传感器开发中应该有很多应用。DNA靶标和单壁碳纳米管与寡核苷酸的竞争性结合导致相对于没有靶标的荧光信号增加，以及明显的荧光猝灭。与常见的分子信标(MBS)的环茎结构不同，这种新型的荧光寡核苷酸只需要一个标记的荧光团，而且可以在几乎没有背景干扰的情况下测量发射。与传统的MB相比，这一特性大大提高了信号与背景的比率，同时MB仍然保持了DNA结合的特异性。通过热力学分析和荧光各向异性测量，研究了荧光寡核苷酸与单壁碳纳米管和靶DNA的相互作用机理。结果表明，MB/SWNT探针可以作为核酸研究和分子传感的良好平台。
We report an effective, novel self-assembled single-wall carbon nanotube (SWNT) complex with an oligonucleotide and demonstrate its feasibility in recognizing and detecting specific DNA sequences in a single step in a homogeneous solution. The key component of this complex is the hairpin-structured fluorescent oligonucleotide that allows the SWNT to function as both a "nanoscaffold" for the oligonucleotide and a "nanoquencher" of the fluorophore. Given this functionality, this carbon nanotube complex represents a new class of universal fluorescence quenchers that are substantially different from organic quenchers and should therefore have many applications in molecular engineering and biosensor development. Competitive binding of a DNA target and SWNTs with the oligonucleotide results in fluorescence signal increments relative to the fluorescence without a target as well as in marked fluorescence quenching. In contrast to the common loop-and-stem configuration of molecular beacons (MBs), this novel fluorescent oligonucleotide needs only one labeled fluorophore, yet the emission can be measured with little or no background interference. This property greatly improves the signal-to-background ratio compared with those for conventional MBs, while the DNA-binding specificity is still maintained by the MB. To test the interaction mechanisms of the fluorescent oligonucleotide with SWNTs and target DNA, thermodynamic analysis and fluorescence anisotropy measurements, respectively, were applied. Our results show that MB/SWNT probes can be an excellent platform for nucleic acid studies and molecular sensing.