Label-Free Detection of Nanomolar Unmodified Single- and Double-Stranded DNA by Using Surface-Enhanced Raman Spectroscopy on Ag and Au Colloids
Label-Free Detection of Nanomolar Unmodified Single- and Double-Stranded DNA by Using Surface-Enhanced Raman Spectroscopy on Ag and Au Colloids
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DOI：
10.1002/chem.201103520
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发表时间：
2012-04-01
影响因子：
4.3
通讯作者：
Bell, Steven E. J.
中科院分区：
文献类型：
--
作者：
Papadopoulou, Evanthia;Bell, Steven E. J.
通过表面增强拉曼光谱检测到浓度 =10-9?M 的未标记单链和双链 DNA（分别为 ssDNA 和 dsDNA）。在适当的条件下，序列通过其核碱基自发吸附到Ag和Au胶体的表面；这使得在完全未修改的样品上记录具有良好信噪比的高度可重复的光谱。这消除了通过引入外部连接体（例如硫醇）来促进吸收的需要。模型 ssDNA 序列的光谱包含所有存在的碱基的条带，并且当整体碱基组成改变时显示出系统变化。初步测试还表明，相同碱基以不同顺序排列的寡核苷酸之间可以检测到微小但可重复的变化。研究发现，对应于不同大肠杆菌菌株的 5 个 ssDNA 序列的光谱具有足够的成分依赖性，因此无需任何先进的多变量数据分析技术即可区分它们。
Unlabelled single- and double-stranded DNA (ssDNA and dsDNA, respectively) has been detected at concentrations =10-9?M by surface-enhanced Raman spectroscopy. Under appropriate conditions the sequences spontaneously adsorbed to the surface of both Ag and Au colloids through their nucleobases; this allowed highly reproducible spectra with good signal-to-noise ratios to be recorded on completely unmodified samples. This eliminated the need to promote absorption by introducing external linkers, such as thiols. The spectra of model ssDNA sequences contained bands of all the bases present and showed systematic changes when the overall base composition was altered. Initial tests also showed that small but reproducible changes could be detected between oligonucleotides with the same bases arranged in a different order. The spectra of five ssDNA sequences that correspond to different strains of the Escherichia coli bacterium were found to be sufficiently composition-dependent so that they could be differentiated without the need for any advanced multivariate data analysis techniques.