Yuan Wu, Ho Ho Pui, Lee Rebecca K Y, Kong Siu Kai
Center for Advanced Research in Photonics, Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China.
Appl Opt. 2009 Aug 1;48(22):4329-37. doi: 10.1364/ao.48.004329.
We present a study on the surface-enhanced Raman scattering (SERS) properties of Ag nanoparticle island substrates (NIS) and their applications for target oligonucleotide (OND) detection. It has been found that the surface nanostructure of NIS samples can be controlled with a good degree of reproducibility, and a high SERS enhancement can be achieved when the peak extinction wavelength of NIS is tuned to a spectral window (approximately 60 nm) between the excitation wavelength and the scattered Raman wavelength. The highest SERS enhancement was obtained from the NIS substrates with a nominal thickness of 50 A. Detection of target OND was performed with a sandwich format in which the target OND was hybridized both to a capture OND immobilized on the NIS substrate, and a detection OND conjugated with a Raman-active dye for SERS signal generation. We compare the detection performance of two strategies based on the use of the detection OND with or without the gold nanoparticle (Au-NP). Our results confirm that, when the detection OND is coupled to the Au-NP, a better sensitivity for the target OND detection, in terms of a wider dynamic range and a lower detection limit (0.4 fM versus 1 nM without Au-NP), would be achieved.
我们展示了一项关于银纳米颗粒岛状衬底（NIS）的表面增强拉曼散射（SERS）特性及其在目标寡核苷酸（OND）检测中的应用的研究。已发现NIS样品的表面纳米结构能够以良好的可重复性进行控制，并且当NIS的峰值消光波长被调谐到激发波长和散射拉曼波长之间的一个光谱窗口（约60纳米）时，可以实现高SERS增强。从标称厚度为50埃的NIS衬底获得了最高的SERS增强。目标OND的检测采用夹心形式进行，其中目标OND既与固定在NIS衬底上的捕获OND杂交，又与与拉曼活性染料共轭以产生SERS信号的检测OND杂交。我们比较了基于使用带或不带金纳米颗粒（Au-NP）的检测OND的两种策略的检测性能。我们的结果证实，当检测OND与Au-NP偶联时，在更宽的动态范围和更低的检测限（0.4飞摩尔对无Au-NP时的1纳摩尔）方面，对目标OND检测将实现更好的灵敏度。
