Label-free alternating-current plasmonic nanopore sensing of nanoparticles
Label-free alternating-current plasmonic nanopore sensing of nanoparticles
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DOI：
10.1117/12.2607884
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发表时间：
2022-03
期刊：
影响因子：
14
通讯作者：
Scott Renkes;Minjun Kim;G. Alexandrakis
中科院分区：
文献类型：
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作者：
Scott Renkes;Minjun Kim;G. Alexandrakis
我们之前开发的一种等离子体纳米孔传感器——自感应反作用驱动纳米孔电泳（SANE）传感器，通过交流（AC）调制命令电压，可以获得新的数据类型，从而有可能增强纳米颗粒（NPs）和单分子的表征。特别是，交流电压频率响应提供了对通常使用直流命令电压混淆的分析物的电荷和介电常数的见解。我们首先分析了Axopatch 200B数据，绘制了在有和没有等离子体激励的情况下，空SANE传感器在相移和调幅方面的频率响应图。然后，我们测试了20 nm直径的二氧化硅纳米粒子和20 nm金纳米粒子的频率响应，这使得这些粒子悬浮在SANE传感器中心的25 nm纳米孔上。通过施加带有叠加交流频率扫描的直流命令电压，同时将NPs光学捕获在纳米孔入口附近，我们发现二氧化硅和金NPs具有明显不同的电响应。这项试点工作证明了用等离子体纳米孔进行交流测量的可行性，这鼓励我们在未来的工作中对纳米粒子和单分子进行更详细的表征研究。
Alternating current (AC) modulation of command voltage applied across a Self-induced Back Action Actuated Nanopore Electrophoresis (SANE) sensor, a type of plasmonic nanopore sensor that we have developed previously, enables acquisition of new data types that could potentially enhance the characterization of nanoparticles (NPs) and single molecules. In particular, AC voltage frequency response provides insight into the charge and dielectric constant of analytes that are normally obfuscated using DC command voltages. We first analyzed Axopatch 200B data to map the frequency response of the empty SANE sensor in terms of phase shift and amplitude modulation, with and without plasmonic excitation. We then tested the frequency response of 20 nm diameter silica NPs and 20 nm gold NPs trapped optically, which made these particles hover over an underlying 25 nm nanopore at the center of the SANE sensor. By applying a DC command voltage with a superimposed AC frequency sweep while keeping the NPs optically trapped in the vicinity of the nanopores’s entrance, we have found that silica and gold NPs to have distinctly different electrical responses. This pilot work demonstrates the feasibility of performing AC measurements with a plasmonic nanopore, which encourages us to pursue more detailed characterization studies with NPs and single molecules in future work.