Surface-Enhanced Raman Spectroscopic Detection of a Bacteria Biomarker Using Gold Nanoparticle Immobilized Substrates
Surface-Enhanced Raman Spectroscopic Detection of a Bacteria Biomarker Using Gold Nanoparticle Immobilized Substrates
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使用金纳米颗粒固定基质对细菌生物标志物进行表面增强拉曼光谱检测
DOI：
10.1021/ac9014275
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发表时间：
2009-12-15
影响因子：
7.4
通讯作者：
Yu, Ru-Qin
中科院分区：
文献类型：
--
作者：
Cheng, Han-Wen;Huan, Shuang-Yan;Yu, Ru-Qin
开发用于检测吡啶二羧酸 (DPA) 的超灵敏和快速方法变得越来越重要，DPA 是包括炭疽杆菌在内的细菌孢子的生物标志物。本文报道了使用金纳米颗粒/聚乙烯吡咯烷酮/金基质（AuNPs/PVP/Au）对 DPA 进行超灵敏检测的表面增强拉曼光谱 (SERS) 的研究结果。该基底的强 SERS 效应利用了粒子-粒子和粒子-基底等离子体耦合，通过操纵纳米粒子的直径 (50-70 nm) 进行优化。诊断带的 SERS 强度与 DPA 浓度（0.1 ppb 至 100 ppm）之间的相关性显示出两个线性区域，即低（1 ppm）区域，其间有一个中间区域。在DPA的SERS检测中首次观察到低浓度区域存在线性关系。从具有 60 nm 尺寸的 Au NP 的基材中获得了 0.1 ppb 的检测限，据我们所知，这是使用此类 SERS 基材的 DPA 报告的最低检测限。这一发现也得到了估计的增强因子（类似于 10(6)）和低浓度区域的大吸附平衡常数（1.7 x 10(7) M-1）的支持。通过单层和多层吸附等温线分析 DPA 在 SERS 基底上的吸附特性，以深入了解 SERS 强度与 DPA 浓度之间的相关性。发现观察到的从低浓度线性区域到高浓度线性区域的转变对应于从单层到多层吸附等温线的转变，这与单层覆盖的估计最小 DPA 浓度（类似于 0.01 ppm）一致。
The development of ultrasensitive and rapid methods for the detection of dipicolinic acid (DPA), a biomarker for bacterial spores including Bacillus anthracis, is increasingly important. This paper reports the results of an investigation of surface enhanced Raman spectroscopy (SERS) based ultrasensitive detection of DPA using a gold nanoparticle/polyvinylpyrrolidone/gold substrate (AuNPs/PVP/Au). The strong SERS effect of this substrate exploits the particle-particle and particle-substrate plasmonic coupling, which is optimized by manipulating the diameter of the nanoparticles (50-70 nm). The correlation between the SERS intensity of the diagnostic band and the DPA concentration (0.1 ppb to 100 ppm) was shown to exhibit two linear regions, i.e., the low- (1 ppm) regions, with an intermediate region in between. The presence of a linear relationship in the low-concentration region was observed for the first time in SERS detection of DPA. A detection limit of 0.1 ppb was obtained from the substrates with 60 nm sized Au NPs, which is, to our knowledge, the lowest detection limit reported for DPA using this type of SERS substrate. This finding was also supported by the estimated enhancement factor (similar to 10(6)) and a large adsorption equilibrium constant for the low-concentration region (1.7 x 10(7) M-1). The adsorption characteristics of DPA on the SERS substrates were analyzed in terms of monolayer and multilayer adsorption isotherms to gain insights into the correlation between the SERS intensity and the DPA concentration. The observed transition from the low- to high-concentration linear regions was found to correspond to the transition from a monolayer to multilayer adsorption isotherm, which was in agreement with the estimated minimum DPA concentration for a monolayer coverage (similar to 0.01 ppm).