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首页> 外文会议>Conference on plasmonics in biology and medicine XII >Amplifying the SERS signal of DNA bases via the chemical resonances
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Amplifying the SERS signal of DNA bases via the chemical resonances

机译：通过化学共振扩增DNA碱的SERS信号

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Label-free detection methods of DNA bases using surface-enhanced Raman spectroscopy (SERS) have yet to be successfully utilized due to inconsistent signal readouts. We have identified the primary reason for the discrepancies in the SERS signals of nucleic acids as being caused by the charge-transfer chemical resonance of the base silver system which is dependent on excitation wavelength. Time-dependent density functional theory (TD-DFT) methods to calculate the electronic transitions and resonance Raman spectra of base silver complexes are performed, and the optimal excitation wavelength for the charge-transfer electronic transition is found for each base silver complex. The enhancement caused by the chemical resonance is then experimentally measured for adenine, cytosine, guanine and thymine at multiple excitation wavelengths. The dependence of the Raman intensity on excitation wavelength shows good agreement with the TD-DFT calculations. In order to fully achieve the maximum Raman intensity, both the electromagnetic and chemical resonance must be enhanced by the appropriate wavelength selection. Based on the optimal chemical resonance Raman wavelength, we design a SERS substrate which has an electromagnetic maximum wavelength that matches the chemical resonance wavelength. By aligning both resonances, the highest Raman intensity can be found for each base silver system. We have proven that the variance in DNA bases' Raman intensities are caused by chemical enhancement. By incorporating the chemical resonance and optimizing both the chemical and electromagnetic resonance, we believe a label-free DNA SERS based detection method can be realized.
机译：使用表面增强拉曼光谱（SERS）的DNA碱基的无标签检测方法尚未被成功地利用由于信号读数不一致。我们已经确定了核酸的SERS信号中的差异的主要原因，因为由依赖于激发波长的基础银系统的电荷转移化学共振引起。进行时间依赖性密度函数理论（TD-DFT）来计算基础银色复合物的电子转换和谐振拉曼光谱，并且针对每个基础银色复合物找到电荷转移电子转换的最佳激发波长。然后在多个激发波长下通过化学共振引起的增强进行实验测量腺嘌呤，胞嘧啶，鸟嘌呤和胸腺嘧啶。拉曼强度对激发波长的依赖性显示出与TD-DFT计算的良好一致性。为了充分实现最大拉曼强度，必须通过适当的波长选择来提高电磁和化学共振。基于最佳化学共振拉曼波长，我们设计具有与化学共振波长匹配的电磁最大波长的SERS基板。通过对齐两个共振，可以为每个基础银系统找到最高的拉曼强度。我们已经证明，DNA基础的差异的拉曼强度是由化学增强引起的。通过掺入化学共振和优化化学和电磁共振，我们认为可以实现基于标记的DNA SERS的可标检测方法。

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