Flow-Through vs Flow-Over: Analysis of Transport and Binding in Nanohole Array Plasmonic Biosensors
Flow-Through vs Flow-Over: Analysis of Transport and Binding in Nanohole Array Plasmonic Biosensors
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DOI：
10.1021/ac101654f
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发表时间：
2010-12-15
影响因子：
7.4
通讯作者：
Sinton, David
中科院分区：
文献类型：
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作者：
Escobedo, Carlos;Brolo, Alexandre G.;Sinton, David
通过尺度分析和数值模拟，我们量化了流过纳米孔传感的有效性，与已建立的流过格式相比。纳米孔阵列在基于表面等离子体共振的传感方法中占有越来越重要的地位，利用纳米孔作为纳米通道可以增强传输和分析响应。然而，通过流动操作提供的额外好处是操作参数和特定应用的结合化学的复杂功能。本文比较了具有等效传感区域的流动型传感器和流过型纳米孔阵列传感器，其中纳米孔阵列传感区域作为纳米孔的内壁。传感器的足迹是相似的（例如，一个方形的20pm宽的流量传感器与一个方形的30pm宽的300 nm直径的纳米孔阵列具有相同的传感面积，这些纳米孔在100 nm厚的金膜上具有450 nm的周期性）。仅考虑传输，这里的分析表明，给定等效的传感面积和流速，流过纳米孔格式可以大大增加分析物到传感表面的通量（例如，在Q = 10 nL/min的情况下，通量增加40倍）。通过实验数据验证的计算模型包括传输和结合动力学，为结合时间常数、分析物扩散率和运行参数的性能提供了指导。对于常见的结合动力学和分析物，流过纳米孔阵列的响应时间提高了10倍，对于具有快速动力学的小生物分子，响应时间最多提高了20倍。
We quantify the efficacy of flow-through nanohole sensing, as compared to the established flow-over format, through scaling analysis and numerical simulation. Nanohole arrays represent a growing niche within surface plasmon resonance-based sensing methods, and employing the nanoholes as nanochannels can enhance transport and analytical response. The additional benefit offered by flow-through operation is, however, a complex function of operating parameters and application-specific binding chemistry. Compared here are flow-over sensors and flow-through nanohole array sensors with equivalent sensing area, where the nanohole array sensing area is taken as the inner-walls of the nanoholes. The footprints of the sensors are similar (e.g., a square 20 pm wide flow-over sensor has an equivalent sensing area as a square 30 pm wide array of 300 nm diameter nanoholes with 450 nm periodicity in a 100 nm thick gold film). Considering transport alone, an analysis here shows that given equivalent sensing area and flow rate the flow-through nanohole format enables greatly increased flux of analytes to the sensing surface (e.g., 40-fold for the case of Q = 10 nL/min). Including both transport and binding kinetics, a computational model, validated by experimental data, provides guidelines for performance as a function of binding time constant, analyte diffusivity, and running parameters. For common binding kinetics and analytes, flow-through nanohole arrays offer similar to 10-fold improvement in response time, with a maximum of 20-fold improvement for small biomolecules with rapid kinetics.