Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Nat Commun. 2013;4:1636. doi: 10.1038/ncomms2590.
Various nanostructured sensor designs currently aim to achieve or claim single molecular detection by a reduction of the active sensor size. However, a reduction of the sensor size has the negative effect of reducing the capture probability considering the diffusion-based analyte transport commonly used. Here we introduce and apply a localized programmable electrodynamic precipitation concept as an alternative to diffusion. The process provides higher collection rates of airborne species and detection at lower concentration. As an example, we compare an identical nanostructured surfaced-enhanced Raman spectroscopy sensor with and without localized delivery and find that the sensitivity and detection time is improved by at least two orders of magnitudes. Localized collection in an active-matrix array-like fashion is also tested, yielding hybrid molecular arrays on a single chip over a broad range of molecular weights, including small benzenethiol (110.18 Da) and 4-fluorobenzenethiol (128.17 Da), or large macromolecules such as anti-mouse IgG (~150 kDa).
目前，各种纳米结构传感器设计旨在通过减小传感器的有效尺寸来实现或声称能够实现单分子检测。然而，考虑到通常使用的基于扩散的分析物传输，传感器尺寸的减小会产生降低捕获概率的负面影响。在这里，我们引入并应用了局部可编程电动沉淀概念作为扩散的替代方法。该过程提供了更高的空气传播物种收集率和更低浓度的检测。例如，我们将相同的纳米结构化表面增强拉曼光谱传感器与带有和不带有局部输送的传感器进行了比较，发现灵敏度和检测时间至少提高了两个数量级。还以类似于有源矩阵阵列的方式进行了局部收集，从而在单个芯片上生成了包括小分子巯基苯（110.18Da）和 4-氟苯硫醇（128.17Da）以及大分子如抗小鼠 IgG（~150 kDa）在内的广泛分子量范围内的混合分子阵列。
