Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, China.
University of Chinese Academy of Sciences , Beijing 100049, China.
Anal Chem. 2017 Feb 7;89(3):1416-1420. doi: 10.1021/acs.analchem.6b05117. Epub 2017 Jan 13.
Surface-enhanced Raman scattering (SERS) is expected as a technique that even theoretically detected chemicals at the single molecule level by surface plasmon phenomena of noble metal nanostructures. Insensitivity of detecting Raman weak-intensity molecules and low adsorptivity of gaseous molecules on solid substrates are two main factors hindering the application of SERS in gas detectors. In this manuscript, we demonstrated an operational SERS strategy to detect gaseous Raman weak-intensity aldehydes that have been considered as a biomarker of lung cancer for abnormal content was measured in volatile organic compounds (VOCs) of lung cancer patients. To enhance the adsorption of gaseous molecules, dendritic Ag nanocrystals mimicking the structural feature (dendritic) of moth's antennae were formed, wherein the existence of numerous cavity traps in Ag dendritic nanocrystals prolonged reaction time of the gaseous molecules on the surface of solid surface through the "cavity-vortex" effect. By the nucleophilic addition reaction with the Raman-active probe molecule p-aminothiophenol (4-ATP) pregrafted on dendritic Ag nanocrystals, the gaseous aldehyde molecules were sensitively captured to detect at the ppb (parts per billion) level. Additionally, the sensitivity of this operational SERS strategy to detection of lung cancer biomarkers was not affected by the humidity, which represented a great potential in fast, easy, cost-effective, and noninvasive recognition of lung malignancies.
表面增强拉曼散射（SERS）有望成为一种技术，通过贵金属纳米结构的表面等离子体现象，甚至从理论上检测到单分子水平的化学物质。检测拉曼弱强度分子的不灵敏性和气体分子在固体基底上的低吸附性是阻碍 SERS 在气体探测器中应用的两个主要因素。在本文中，我们展示了一种用于检测气态拉曼弱强度醛的 SERS 策略，这些醛被认为是肺癌的生物标志物，因为在肺癌患者的挥发性有机化合物（VOCs）中测量到了异常含量。为了增强气体分子的吸附，形成了模仿蛾触角结构特征（树枝状）的树枝状 Ag 纳米晶体，其中 Ag 树枝状纳米晶体中的许多腔陷阱通过“腔-涡旋”效应延长了气体分子在固体表面上的反应时间。通过与预接枝在树枝状 Ag 纳米晶体上的拉曼活性探针分子对氨基苯硫酚（4-ATP）的亲核加成反应，灵敏地捕获气态醛分子进行检测，检测限达到 ppb（十亿分之一）水平。此外，这种操作 SERS 策略对肺癌生物标志物的检测灵敏度不受湿度的影响，这在快速、简便、经济高效和非侵入性识别肺癌方面具有很大的潜力。
