Plasmonic Mach-Zehnder Interferometer for Ultrasensitive On-Chip Biosensing
Plasmonic Mach-Zehnder Interferometer for Ultrasensitive On-Chip Biosensing
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DOI：
10.1021/nn2034204
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发表时间：
2011-12-01
期刊：
影响因子：
17.1
通讯作者：
Bartoli, Filbert J.
中科院分区：
文献类型：
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作者：
Gao, Yongkang;Gan, Qiaoqiang;Bartoli, Filbert J.
我们通过实验展示了与微流控芯片集成的等离子体马赫-曾德干涉仪 (MZI)，用于超灵敏光学生物传感。 MZI 是通过在薄金属薄膜中形成两个平行纳米缝图案而形成的，传感器监测由表面生物分子吸附引起的在金属薄膜顶面和底面传播的表面等离子体波之间的相位差。该紧凑型传感平台将纳米等离子体结构与敏感干涉技术相结合，折射率灵敏度超过 3500 nm/RIU，并在可见光区域创下超过 200 的高传感品质因数，大大超越了之前的等离子体传感器，并且仍然具有通过优化器件结构进一步改进的潜力。我们在这种简单、超灵敏、小型化的等离子体生物传感器中展示了对链霉亲和素-生物素特异性结合的实时、无标记、定量监测，具有高信噪比。
We experimentally demonstrate a plasmonic Mach-Zehnder interferometer (MZI) integrated with a microfluidic chip for ultrasensitive optical biosensing. The MZI is formed by patterning two parallel nanoslits in a thin metal film, and the sensor monitors the phase difference, induced by surface biomolecular adsorptions, between surface plasmon waves propagating on top and bottom surfaces of the metal film. The combination of a nanoplasmonic architecture and sensitive interferometric techniques in this compact sensing platform yields enhanced refractive index sensitivities greater than 3500 nm/RIU and record high sensing figures of merit exceeding 200 in the visible region, greatly surpassing those of previous plasmonic sensors and still hold potential for further improvement through optimization of the device structure. We demonstrate real-time, label-free, quantitative monitoring of streptavidin-biotin specific binding with high signal-to-noise ratio in this simple, ultrasensitive, and miniaturized plasmonic biosensor.