School of Chemical and Environmental Engineering, Shanghai Institute of Technology, No. 100 Haiquan Road, Shanghai 201418, People's Republic of China.
Beijing Research Center for Agricultural Standards and Testing, Beijing Academy of Agricultural and Forestry Science, No. 9 Middle Road of Shuguanghuayuan, Haidian District, Beijing 100097, People's Republic of China.
Anal Chem. 2021 Jan 19;93(2):946-955. doi: 10.1021/acs.analchem.0c03652. Epub 2020 Nov 18.
Nonspecific binding and weak spectral discernment are the main challenges for surface-enhanced Raman scattering (SERS) detection, especially in real sample analysis. Herein, molecularly imprinted polymer (MIP)-based core-shell AuNP@polydopamine (AuNP@PDA-MIP) nanoparticles (NPs) are designed and immobilized on an electrochemically reduced MoS-modified screen-printed electrode (SPE). This portable electrochemical-Raman interface offers the dual functions of electrokinetic preseparation (EP) and MIP trapping of charged molecules so that a reliable SERS recognition with molecular selectivity and high sensitivity can be achieved. Core-shell AuNP@PDA-MIP NPs can be controllably synthesized, possess predesigned specific recognition, and provide "hot spots" at the junction of NPs. The introduction of an electric field enables the autonomous exclusion and separation of similarly charged molecules as well as attraction and concentration of the oppositely charged molecules by electrostatic attraction. Subsequently, the specific MIP recognition cavities allow selective adsorption of targets on the interface without the interference of analogues. Owing to the distinctive design of the multiple coupling separation, trapping, and enrichment strategies, the MIP-based SERS-active interface can be used for label-free detection of charged molecules in real samples without pretreatment. As a proof-of-concept study, label-free SERS detection of charged phthalate plasticizers (PAEs) was demonstrated with a detection limit as low as 2.7 × 10 M for dimethyl phthalate (DMP) and 2.3 × 10 M for di(2-ethylhexyl) phthalate (DEHP). This sensing strategy for SERS analysis of charged pollutants or toxins holds vast promises for a wide range of in-field applications.
非特异性结合和弱光谱分辨是表面增强拉曼散射（SERS）检测的主要挑战，尤其是在实际样品分析中。在此，设计并固定了基于分子印迹聚合物（MIP）的核壳 AuNP@聚多巴胺（AuNP@PDA-MIP）纳米粒子（NPs）在电化学还原 MoS 修饰的丝网印刷电极（SPE）上。这种便携式电化学-Raman 接口具有电动预分离（EP）和带电荷分子的 MIP 捕获的双重功能，从而可以实现具有分子选择性和高灵敏度的可靠 SERS 识别。核壳 AuNP@PDA-MIP NPs 可以进行可控合成，具有预定的特异性识别，并在 NPs 的连接处提供“热点”。引入电场可以实现类似带电荷分子的自主排斥和分离，以及通过静电吸引吸引和浓缩带相反电荷的分子。随后，特定的 MIP 识别腔允许目标在界面上选择性吸附，而不受类似物的干扰。由于采用了多种耦合分离、捕获和富集策略的独特设计，基于 MIP 的 SERS 活性界面可用于无需预处理的实际样品中带电荷分子的无标记检测。作为概念验证研究，对带电荷的邻苯二甲酸酯增塑剂（PAEs）进行了无标记 SERS 检测，邻苯二甲酸二甲酯（DMP）的检测限低至 2.7×10 M，邻苯二甲酸二（2-乙基己基）酯（DEHP）的检测限低至 2.3×10 M。这种用于带电荷污染物或毒素的 SERS 分析的传感策略为广泛的现场应用提供了广阔的前景。
