Array-Assisted SERS Microfluidic Chips for Highly Sensitive and Multiplex Gas Sensing

Abstract

A novel kind of array-assisted surface-enhanced Raman spectroscopy (SERS) microfluidic chip (ArraySERS chip) is demonstrated for gas sensing, which has the advantages of both ultrahigh sensitivity and multiplex sensing ability. On the one hand, the introduction of a microstructured triangular array can greatly increase the multiple collision probability between gas molecules and sensing interfaces in the channel. Compared with traditional gas sensors using sealed boxes, where gaseous molecules move only by diffusion, the ArraySERS chip exhibits significantly improved sensitivity. On the other hand, a composite nanoparticle is fabricated as a SERS probe for reading out the fingerprint spectral data, which consists of metal–organic framework (MOF) materials [Zeolitic Imidazolate framework-8 (ZIF-8)] and Au@Ag nanocubes, as well as cysteamine (CA) that serves as the gas-capturing agent. The experimental results show that such a structure of the SERS probe can further increase the sensing ability because of better adsorption of ZIF-8 for gas and the lower SERS background of CA itself. In addition, the simultaneous detection of multiplex gases was easily performed according to their own intrinsic SERS signals. Taking aldehyde gas as a model of a typical air pollutant, trace and multicomponent detection was realized using the ArraySERS chip. The limit of detection value was as low as 1 ppb, which is 2 magnitudes lower than that obtained by traditional methods. This strategy can be well extended for the detection of universal gases and help unleash the potential of existing gas sensors, especially for samples at low concentrations in air.

Emerging microfluidic chips on medical application

“…extraction and quantitative setting based on chemiluminescence technology [40] . (b) Schematic diagram of a novel array assisted surface-enhanced Raman spectroscopy microfluidic chip for gas sensing [41] . (c)A real-time pressure monitoring diagram of microfluidic equipment based on colloid crystal film chromaticity change [42] .…”

Understanding the Role of Metal–Organic Frameworks in Surface‐Enhanced Raman Scattering Application

“…Cui and coworkers introduced the MOF-SERS composite material into a microfluidic chip with a triangular array microstructure, which can further increase the probability of multiple collisions between the target gas molecules to be detected and the SERS hotspot interface. [47] This array-assisted SERS microfluidic chip has good adsorption capacity and ultrahigh sensitivity for target gas and can realize multichannel trace multicomponent detection. Sim et al found that the Ag@ZIF-8 substrate can drive the reaction of aniline and CO 2 at ambient conditions.…”

Recent advances in surface-enhanced Raman spectroscopy for the detection of tumor markers

“…Koh等人 [78] 设计了一种"等离子体鼻"结构, 其由MOF 包覆的Ag纳米立方体(Ag@ZIF)组成, 以将气体分子 和电磁场集中在该结构三维空间的纳米尺度上, 检测 低至ppm(parts per million)级的VOCs. Yang等人 [79] 提 出了一种新型阵列辅助SERS微流控芯片(ArraySERS 芯片), 用于气体传感分析, 三角形阵列结构可增加通 道中气体分子与传感界面之间的碰撞概率, 以提高检 图 4 (网络版彩色)SERS技术在气体类和其他类肿瘤标志物检测中的应用. 基于GSPs@ZIF-8核壳结构的SERS传感器用于VOCs的定量检 测 [76] : (a) 自组装GSPs@ZIF-8核壳结构及SERS检测VOCs的示意图; (b) 检测不同浓度4-乙基苯甲醛的SERS光谱及标准曲线; (c) SERS基底的 选择性; (d) 健康和肺癌患者模拟呼出气的主成分分析.…”