Enhanced Quality Factor Label-free Biosensing with Micro-Cantilevers Integrated into Microfluidic Systems
Enhanced Quality Factor Label-free Biosensing with Micro-Cantilevers Integrated into Microfluidic Systems
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DOI：
10.1021/acs.analchem.7b01174
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发表时间：
2017-11-21
影响因子：
7.4
通讯作者：
Knowles, Tuomas P. J.
中科院分区：
文献类型：
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作者：
Kartanas, Tadas;Ostanin, Victor;Knowles, Tuomas P. J.
微机电系统（MEMS）使得新一代传感器平台的开发成为可能。然而，在液体（生物分子的天然环境）中的声传感器操作由于粘性阻力而导致感测性能的显著退化，并且依赖于捕获分子的可用性以将感兴趣的分析物结合到传感器表面。在这里，我们描述了一种通过气溶胶喷雾将MEMS传感器与微流体平台连接的策略。我们的传感平台包括一个微流控喷嘴和一个在闭环振荡器内以动态模式操作的微控制杆阵列。含有分析物的溶液通过皮升液滴均匀地喷洒到微悬臂梁表面上;微米级的液滴迅速蒸发并留下溶质，增加了悬臂梁的质量。与在液体中操作相比，这种感测方案导致品质因数增加50倍，但允许将分析物从溶液相引入感测系统中。它实现了370毫微微克的检测限，我们证明了无机盐和模型蛋白质的定量无标记分析。这些结果表明，在动态模式下的悬臂梁感测的标准分辨率极限可以克服与集成的喷雾微流体与MEMS。
Microelectromechanical systems (MEMS) have enabled the development of a new generation of sensor platforms. Acoustic sensor operation in liquid, the native environment of biomolecules, causes, however, significant degradation of sensing performance due to viscous drag and relies on the availability of capture molecules to bind analytes of interest to the sensor surface. Here, we describe a strategy to interface MEMS sensors with microfluidic platforms through an aerosol spray. Our sensing platform comprises a microfluidic spray nozzle and a microcanti-lever array operated in dynamic mode within a closed loop oscillator. A solution containing the analyte is sprayed uniformly through picoliter droplets onto the microcantilever surface; the micrometer-scale drops evaporate rapidly and leave the solutes behind, adding to the mass of the cantilever. This sensing scheme results in a 50-fold increase in the quality factor compared to operation in liquid, yet allows the analytes to be introduced into the sensing system from a solution phase. It achieves a 370 femtogram limit of detection, and we demonstrate quantitative label-free analysis of inorganic salts and model proteins. These results demonstrate that the standard resolution limits of cantilever sensing in dynamic mode can be overcome with the integration of spray microfluidics with MEMS.