适用于光流控传感器件的新型表面等离激元材料的研究

Optofluidics is the synergistic integration of photonics and microfluidics, which is a new analytical field that provides a number of unique characteristics for enhancing the sensing performance and simplifying the design of microsystems. The optofluidic sensing devices that based on the surface plasmon resonance (SPR) are well-suited for biological/chemical detection and analysis in extremely small detection volumes, which is benefited from the integration of the sensing chip with the microfluidics system for the sample preparation and delivery. However, this promising technology is still limited by the bottleneck problems of both SPR sensor and the integrated optofluidic system. Firstly, the sensitivity of the optofluidic system should be maintained and further improved. Secondly, the development of multimodal and high through-put detection is significant. Thirdly, the optofluidic system should be conveniently used to the commercial optical instruments. Finally, the cost should be reduced as much as possible for real applications. We aim to propose the research of novel sensing chip for optofluidic system for the ultrasensitive sensing applications. The design of the chip is guided by the mechanism of plasmonics and special requirements for real applications. The fabrication of the designed optofluidic system is based on the holographic lithography method and micro-electro-mechanical system (MEMS). The proposed optofluidic system here is significant for the development of the portable sensing device.

光流控（optofluidic）传感是将光学传感的方法与微流控技术相结合的新型分析、检测技术。其中，基于表面等离激元共振 (surface plasmon resonance, SPR)传感的光流控技术，因其在灵敏的传感检测的基础上集成了样品的准备、输运功能，所以特别适合于对痕量生物和化学样品的分析和检测。但是，该技术的广泛应用仍然受到传感芯片性能、构造和材料的制约。本项目旨在从物理本质上分析影响芯片性能的关键因素，并基于表面等离激元的理论来调控传感芯片的形貌、构造；再进一步结合光流控传感器件的实际使用需求，设计并制备适用于光流控传感的性能优异的传感芯片。拟实现的光流控传感系统的优势包括: 1、超高灵敏度和稳定性；2、多通道、高通量的检测模式；3、光流控器件能方便地与常规实验室已有的仪器兼容或是联用；4、低成本。本项目对于传感仪器的便携式、小型化也具有十分重要的基础意义。

基于表面等离激元共振（surface plasmon resonance，SPR）的光流控检测集合了微流控对溶液控制的优势和SPR传感检测方法的高灵敏度的特点，是一种新型的多功能的技术。适用于光流控系统的表面等离激元材料的研制是指设计和制备满足光流控系统的新型表面等离激元材料的研究。在过去的三年中，我们主要从表面等离激元结构的光学性质调控、结构构型改善以及材料优化这三个方面入手，开展了适用于光流控系统的表面等离激元材料的研制，并取得了一些列重要的成果：（1）SPR光谱宽度和深度的可控调节，以及超深超窄SPR共振模式的获得；（2）基于PDMS的柔性衬底上表面等离激元结构的制备，及其在超稳定的光流控系统中的应用；（3）高通量的SPR-RI光流控的系统的建立及其在SPR半峰宽对灵敏度影响中的研究。经过反复的实验研究，已经证实了所得到的表面等离激元结构以及进一步获得的光流控系统的优势。此外，半峰宽小于等于5 nm，反射率仅为10%的SPR光谱，可以从550 nm连续调节到950 nm。这种超高品质因子的表面等离激元结构的科学意义在于实验上获得了理论上能够得到的表面等离激元共振模式。除了在超高灵敏度生物化学传感中发挥重要作用以外，在对超高品质因子SPR模式有需求的纳米激光器，非线性光学等研究领域也将产生重要的应用前景。