A microfluidic device enabling surface-enhanced Raman spectroscopy at chip-integrated multifunctional nanoporous membranes
A microfluidic device enabling surface-enhanced Raman spectroscopy at chip-integrated multifunctional nanoporous membranes
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DOI：
10.1007/s00216-019-02228-9
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发表时间：
2019-12-03
影响因子：
4.3
通讯作者：
Belder, Detlev
中科院分区：
文献类型：
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作者：
Krafft, Benjamin;Panneerselvam, Rajapandiyan;Belder, Detlev
开发了一种结合样品操作和片上SERS检测的三维微流控芯片。这是通过纳米多孔聚碳酸酯径迹蚀刻（PCTE）膜的芯片集成成功实现的，该膜将两个不同层面上的微流体通道相互连接。该膜同时履行两种功能。一方面，它可以通过膜的选择性电动传输过程来富集样品。另一方面，同一膜的银纳米粒子涂层背面能够对富集的分析物进行 SERS 检测。使用罗丹明 B (RhB) 通过拉曼显微镜和荧光视频显微镜研究了 SERS 基底性能和动电传输现象。系统验证后，该方法通过复杂食品样品的片上处理得到验证。在一项概念验证研究中，使用带有 SERS 基底膜的微流体装置来检测全脂牛奶中 1 ppm 三聚氰胺 (705 cm(-1)) 的浓度。穿过纳米多孔 SERS 基底的动电传输有助于通过电位梯度将分析物分子从样品通道提取到检测通道中，从而轻松去除样品基质中存在的模糊化合物。通过目标样品干燥可以显着增强分析物的 SERS 信号。这是通过在膜上引导额外的气流来实现的，这进一步扩展了芯片装置的微流体功能。该方法具有在三维微流体装置中结合动电传输快速（15 分钟内）样品净化的优点，非常适合化学和生物分析物的灵敏和选择性 SERS 检测。
A three-dimensional microfluidic chip that combines sample manipulation and SERS detection on-chip was developed. This was successfully achieved by chip integration of a nanoporous polycarbonate track-etched (PCTE) membrane which connects microfluidic channels on two different levels with each other. The membrane fulfills two functions at the same time. On the one hand, it enables sample enrichment by selective electrokinetic transport processes through the membrane. On the other hand, the silver nanoparticle-coated backside of the same membrane enables SERS detection of the enriched analytes. The SERS substrate performance and the electrokinetic transport phenomena were studied using Rhodamine B (RhB) by Raman microscopy and fluorescence video microscopy. After system validation, the approach was attested by on-chip processing of a complex food sample. In a proof-of-concept study, the microfluidic device with the SERS substrate membrane was used to detect a concentration of 1 ppm melamine (705 cm(-1)) in whole milk. Electrokinetic transport across the nanoporous SERS substrate facilitates the extraction of analyte molecules from a sample channel into a detection channel via a potential gradient, thus easily removing obscuring compounds present in the sample matrix. The SERS signal of the analyte could be significantly increased by on-target sample drying. This was achieved by guiding an additional gas flow over the membrane which further extends the microfluidic functionality of the chip device. The proposed method possesses the advantages of combining a rapid (within 15 min) sample clean-up using electrokinetic transport in a three-dimensional microfluidic device which is highly suitable for sensitive and selective SERS detection of chemical and biological analytes.