‡Division of Synchrotron Radiation Research, Department of Physics, Lund University, Box 118, 221 00 Lund, Sweden.
§Division of Solid State Physics, Department of Physics, Lund University, Box 118, 221 00 Lund, Sweden.
Anal Chem. 2015;87(10):5056-61. doi: 10.1021/acs.analchem.5b00774. Epub 2015 Apr 30.
Molecularly imprinted polymers (MIPs) have a predesigned molecular recognition capability that can be used to build robust chemical sensors. MIP-based chemical sensors allow label-free detection and are particularly interesting due to their simple operation. In this work we report the use of thiol-terminated MIP microspheres to construct surfaces for detection of a model organic analyte, nicotine, by surface enhanced Raman scattering (SERS). The nicotine-imprinted microspheres are synthesized by RAFT precipitation polymerization and converted into thiol-terminated microspheres through aminolysis. The thiol groups on the MIP surface allow the microspheres to be immobilized on a gold-coated substrate. Three different strategies are investigated to achieve surface enhanced Raman scattering in the vicinity of the imprinted sites: (1) direct sputtering of gold nanoparticles, (2) immobilization of gold colloids through the MIP's thiol groups, and (3) trapping of the MIP microspheres in a patterned SERS substrate. For the first time we show that large MIP microspheres can be turned into selective SERS surfaces through the three different approaches of assembly. The MIP-based sensing surfaces are used to detect nicotine to demonstrate the proof of concept. As synthesis and surface functionalization of MIP microspheres and nanoparticles are well established, the methods reported in this work are handy and efficient for constructing label-free chemical sensors, in particular for those based on SERS detection.
分子印迹聚合物（MIPs）具有预定的分子识别能力，可用于构建坚固的化学传感器。基于 MIP 的化学传感器允许无标记检测，由于其操作简单而特别有趣。在这项工作中，我们报告了使用巯基封端的 MIP 微球来构建用于通过表面增强拉曼散射（SERS）检测模型有机分析物尼古丁的表面。尼古丁印迹微球是通过 RAFT 沉淀聚合合成的，并通过氨解转化为巯基封端的微球。MIP 表面上的巯基基团允许微球固定在金涂覆的基底上。研究了三种不同的策略来实现印迹部位附近的表面增强拉曼散射：（1）金纳米粒子的直接溅射，（2）通过 MIP 的巯基基团固定金胶体，以及（3）将 MIP 微球捕获在图案化的 SERS 基底中。我们首次表明，通过三种不同的组装方法，大的 MIP 微球可以变成选择性的 SERS 表面。基于 MIP 的传感表面用于检测尼古丁，以证明概念验证。由于 MIP 微球和纳米粒子的合成和表面功能化已经成熟，因此本工作中报道的方法对于构建无标记化学传感器非常方便和有效，特别是对于基于 SERS 检测的传感器。
