State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University, Beijing, 100871, China.
Nanoscale. 2014 Aug 7;6(15):9103-9. doi: 10.1039/c4nr01407c.
We designed a heterogeneous optical slot antenna (OSA) that is capable of detecting single molecules in solutions at high concentrations, where most biological processes occur. A heterogeneous OSA consists of a rectangular nanoslot fabricated on heterogeneous metallic films formed by sequential deposition of gold and aluminum on a glass substrate. The rectangular nanoslot gives rise to large field and fluorescence enhancement for single molecules. The near-field intensity inside a heterogeneous OSA is 170 times larger than that inside an aluminum zero-mode waveguide (ZMW), and the fluorescence emission rate of a molecule inside the heterogeneous OSA is about 70 times higher than that of the molecule in free space. Our proposed heterogeneous optical antenna enables excellent balance between performance and cost. The design takes into account the practical experimental conditions so that the parameters chosen in the simulation are well within the reach of current nano-fabrication technologies. Our results can be used as a direct guidance for designing high-performance, low-cost plasmonic nanodevices for the study of bio-molecule and enzyme dynamics at the single-molecule level.
我们设计了一种异质光学缝隙天线（OSA），能够在高浓度溶液中检测单分子，而大多数生物过程都发生在高浓度溶液中。异质 OSA 由在玻璃衬底上依次沉积金和铝形成的异质金属膜上制作的矩形纳米缝隙组成。矩形纳米缝隙会引起单分子的强场和荧光增强。异质 OSA 内的近场强度比铝零模波导（ZMW）内的近场强度大 170 倍，异质 OSA 内分子的荧光发射率比自由空间内的分子高约 70 倍。我们提出的异质光学天线在性能和成本之间实现了出色的平衡。该设计考虑了实际的实验条件，因此模拟中选择的参数在当前的纳米制造技术范围内是可行的。我们的研究结果可为设计高性能、低成本等离子体纳米器件提供直接指导，用于在单分子水平上研究生物分子和酶的动力学。
