Kim Kwan, Kim Nam Hoon, Park Hyoung Kun
Laboratory of Intelligent Interfaces, School of Chemistry, Seoul National University, Seoul 151-742, Republic of Korea.
Biosens Bioelectron. 2007 Jan 15;22(6):1000-5. doi: 10.1016/j.bios.2006.04.010. Epub 2006 May 22.
In this study, we demonstrate that powders of commercially available 2-microm-sized Ag (microAg) can be used as a core material for constructing molecular sensing/recognition units operating via surface-enhanced Raman scattering (SERS). This is possible because microAg powders are very efficient substrates for both the infrared and Raman-spectroscopic characterization of molecular adsorbates prepared in a similar manner on silver surfaces. The Raman spectrum of organic monolayers on powdered silver is a SERS spectrum. The agglomeration of microAg particles in a highly concentrated buffer solution could be prevented by the deposition of polar molecules like 1,4-phenylenediisocyanide (1,4-PDI), and mixed self-assembled monolayers of 1,4-PDI and N-(+)-biotinyl-6-aminocaproic acid on microAg particles were then confirmed via the SERS of 1,4-PDI to selectively recognize the avidin arrays formed on a separate biotinylated substrate. According to a dose response curve, avidin at >10(-6)g/mL could be easily identified by the present method. In addition, the non-specific adsorption of microAg particles was found to be negligibly small, probably because the Ag particles were too heavy to be retained on organic substrates solely by non-specific interaction.
在本研究中，我们证明市售的2微米大小的银粉（微银）可作为构建通过表面增强拉曼散射（SERS）运行的分子传感/识别单元的核心材料。这是可行的，因为微银粉对于以类似方式在银表面制备的分子吸附物的红外和拉曼光谱表征而言是非常有效的基底。粉末状银上有机单分子层的拉曼光谱就是一种SERS光谱。通过沉积1,4-苯二异氰酸酯（1,4-PDI）等极性分子，可以防止微银颗粒在高浓度缓冲溶液中团聚，然后通过1,4-PDI的SERS证实微银颗粒上1,4-PDI和N-(+)-生物素基-6-氨基己酸的混合自组装单分子层能够选择性识别在单独的生物素化基底上形成的抗生物素蛋白阵列。根据剂量响应曲线，本方法能够轻松识别浓度大于10(-6)g/mL的抗生物素蛋白。此外，发现微银颗粒的非特异性吸附极小，这可能是因为银颗粒太重，无法仅通过非特异性相互作用保留在有机基底上。
