基于微流控系统太赫兹超材料传感器对水体中重金属离子检测研究

Many molecules would exhibit strong absorptions or transmittances in terahertz spectrum and have distinctive spectroscopic “fingerprints”. This enables the development of terahertz sensing technologies. Terahertz metamaterials have drawn attentions in the field of solid-state sample detections, because they exhibit enhancements of electromagnetic fields and high sensitivity to the changes in dielectric properties around the structure. However, due to the strong absorption of terahertz waves by water molecules and the relative low sensitivity to the trace concentration samples, terahertz metamaterials have not been applied in heavy metal ions detections in the water. This project proposes a terahertz metamaterial integrated with microfluidic system for heavy metal ions detections in water. The micro-channel would reduce the absorption of terahertz wave by water. By coating a chelating agent within the designed micro-channel, the heavy metal ions will be captured and clustered in the sensitive area. In addition, the micro-channel structure is fabricated in the metamaterial substrate, to avoid the terahertz wave attenuation by the micro-channel material. This special structure improves the sensitivity of the sensor. The terahertz metamaterial sensor will realized the detection of heavy metal ions in water and the minimum detectable concentration is expected to be ng/L level This project focus on the research, such as the design and optimization of metamaterial unit cell and micro-channel structure, the fabrication of the sensor and the mechanism of chelating agents react with heavy metal ions. The metamaterial sensor is expected to show a relative shift of the resonant frequency or peak in the transmittance spectrum greater than 10% with and without the sample. It is believed that the metamaterial sensor is capable to detect the heavy metal ions and distinguish the various concentrations of heavy metal ions in the water.

许多生物分子和材料在太赫兹频段存在“指纹特征谱”，从而促进了太赫兹传感检测技术的发展。太赫兹超材料对电磁场的局域增强性和对周围环境介电性质变化的高敏感性，令其在固态样品检测领域备受关注。但由于水对太赫兹波的强吸收，以及传感器对痕量样品的灵敏性制约着这一技术在水体中重金属离子检测领域的发展。本项目提出基于微流控系统的太赫兹超材料传感器。利用微流控技术降低水对太赫兹波的吸收。在微管道中涂覆螯合剂，达到快速捕捉和富集痕量重金属离子的效果。此外，优化超材料衬底兼微管道结构，在衬底中直接制备微管道，从而提高传感器灵敏度，实现对水体中ng/L级别重金属离子的检测。本项目将重点研究太赫兹超材料单元和微管道结构的优化设计、超材料和微管道的加工以及螯合剂工作机理等内容。预期在有无待测样品时，超材料结构透射特性的谐振峰频率或幅度的变化量大于10%，以期实现对水体中痕量重金属离子及重金属离子浓度的检测。

生物分子和材料在太赫兹频段存在的“指纹特征谱”，促进了太赫兹传感检测技术的发展。太赫兹超材料对电磁场的局域增强性和对周围环境介电性质变化的高敏感性，令其在固态样品检测领域备受关注。但是由于水对太赫兹波的强吸收，以及传感器对痕量样品的灵敏性，制约着太赫兹超材料传感器对液态样品的检测。本项目将太赫兹超材料传感器与微流控技术相结合，有别于传统的基于太赫兹超材料的微流控检测技术，本研究将微流控管道直接设计在超材料衬底中，减少太赫兹波在器件层中的衰减，从而提高传感器的灵敏度。本项目重点研究太赫兹超材料单元结构和微管道结构的优化设计、衬底兼微管道结构的加工工艺等内容，从而实现对痕量样品在溶液中的高灵敏度检测。本项目的研究成果在痕量液态样品检测，以及环境污染检测等领域具有广阔的应用前景。