Department of Applied Physics, Chalmers University of Technology, SE-41296 Gothenburg, Sweden.
Anal Chem. 2010 Mar 1;82(5):2087-94. doi: 10.1021/ac902925e.
Nanoplasmonic sensors based on short-range ordered nanoholes in thin metal films and discrete metal nanoparticles are known to provide similar sensing performance. However, a perforated metal film is unique in the sense that the holes can be designed to penetrate through the substrate, thereby also fulfilling the role of nanofluidic channels. This paper presents a bioanalytical sensing concept based on short-range ordered nanoplasmonic pores (diameter 150 nm) penetrating through a thin (around 250 nm) multilayer membrane composed of gold and silicon nitride (SiN) that is supported on a Si wafer. Also, a fabrication scheme that enables parallel production of multiple (more than 50) separate sensor chips or more than 1000 separate nanoplasmonic membranes on a single wafer is presented. Together with the localization of the sensitivity to within such short-range ordered nanoholes, the structure provides a two-dimensional nanofluidic network, sized in the order of 100 x 100 microm(2), with nanoplasmon active regions localized to each individual nanochannel. A material-specific surface-modification scheme was developed to promote specific binding of target molecules on the optically active gold regions only, while suppressing nonspecific adsorption on SiN. Using this protocol, and by monitoring the temporal variation in the plasmon resonance of the structure, we demonstrate flow-through nanoplasmonic sensing of specific biorecognition reactions with a signal-to-noise ratio of around 50 at a temporal resolution below 190 ms. With flow, the uptake was demonstrated to be at least 1 order of magnitude faster than under stagnant conditions, while still keeping the sample consumption at a minimum.
基于短程有序纳米孔的纳米等离子体传感器和离散金属纳米粒子在提供类似的传感性能方面是已知的。然而，具有穿孔的金属膜是独特的，因为这些孔可以被设计为穿透基底，从而也满足纳米流道的作用。本文提出了一种基于短程有序纳米等离子体孔（直径 150nm）的生物分析传感概念，这些孔穿透由金和氮化硅（SiN）组成的约 250nm 厚的多层膜，该膜支撑在 Si 晶片上。此外，还提出了一种能够在单个晶片上并行生产多个（超过 50 个）单独的传感器芯片或超过 1000 个单独的纳米等离子体膜的制造方案。与将灵敏度定位在这种短程有序纳米孔内相结合，该结构提供了一个二维纳米流网络，尺寸约为 100x100μm^2，纳米等离子体活性区域定位于每个单独的纳米通道。开发了一种材料特异性的表面修饰方案，以促进仅在光活性金区域上的目标分子的特异性结合，同时抑制 SiN 上的非特异性吸附。使用此方案，并通过监测结构的等离子体共振的时间变化，我们展示了具有约 50 的信噪比的特定生物识别反应的流动纳米等离子体传感，时间分辨率低于 190ms。在流动条件下，摄取速度至少比静态条件快一个数量级，同时仍将样品消耗保持在最低水平。
