†Microsystems Laboratory, Institute of Microengineering, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
‡ICFO-Institut de Ciencies Fotoniques, Mediterranean Technology Park, 08860 Castelldefels, Barcelona, Spain.
Nano Lett. 2015 Jun 10;15(6):4176-82. doi: 10.1021/acs.nanolett.5b01335. Epub 2015 May 7.
We present a novel blurring-free stencil lithography patterning technique for high-throughput fabrication of large-scale arrays of nanoaperture optical antennas. The approach relies on dry etching through nanostencils to achieve reproducible and uniform control of nanoantenna geometries at the nanoscale, over millimeter-sizes in a thin aluminum film. We demonstrate the fabrication of over 400 000 bowtie nanoaperture (BNA) antennas on biocompatible substrates, having gap sizes ranging from (80 ± 5) nm down to (20 ± 10) nm. To validate their applicability on live cell research, we used the antenna substrates as hotspots of localized illumination to excite fluorescently labeled lipids on living cell membranes. The high signal-to-background afforded by the BNA arrays allowed the recording of single fluorescent bursts corresponding to the passage of freely diffusing individual lipids through hotspot excitation regions as small as 20 nm. Statistical analysis of burst length and intensity together with simulations demonstrate that the measured signals arise from the ultraconfined excitation region of the antennas. Because these inexpensive antenna arrays are fully biocompatible and amenable to their integration in most fluorescence microscopes, we foresee a large number of applications including the investigation of the plasma membrane of living cells with nanoscale resolution at endogenous expression levels.
我们提出了一种新颖的无模糊模板光刻图形化技术，可用于高通量制造大规模纳米孔径光天线阵列。该方法依赖于通过纳米模板进行干法刻蚀，以在毫米尺寸的薄铝膜上实现纳米级的纳米天线几何形状的可重复和均匀控制。我们展示了在生物相容性衬底上制造超过 40 万个蝶形纳米孔（BNA）天线，其间隙尺寸从（80±5）nm 缩小到（20±10）nm。为了验证它们在活细胞研究中的适用性，我们将天线衬底用作局部照明的热点，以激发活细胞膜上荧光标记的脂质。BNA 阵列提供的高信噪比允许记录单个荧光爆发，这些爆发对应于自由扩散的单个脂质通过热点激发区域的通过，激发区域小至 20nm。爆发长度和强度的统计分析以及模拟表明，测量信号来自天线的超限制激发区域。由于这些廉价的天线阵列完全生物相容且易于集成到大多数荧光显微镜中，我们预计会有许多应用，包括以内源表达水平对活细胞膜进行纳米级分辨率的研究。
