Microwave Devices for Biosensors and Single Cell Dielectric Spectroscopy

研究生物细胞的生理特性，监测它们对不同刺激或药物的反应，是生物过程和生物医学研究中必不可少的。许多目前使用的细胞分析仪器利用化学标记物、复杂的设备和耗时的制备技术。采用介电分析的微流体装置是一种有前途的替代方案，因为它们是无标记的，可以小型化，并使用纳升流体体积。拟议的研究计划的目标是开发集成微波介电传感器和致动器的微流体设备，用于流动单细胞分析，使用这些来研究细胞对不同类型的应力的响应，开发新的细胞介电模型，并将细胞介电特性与生理学联系起来。 组织、细胞和其他生物介质具有独特的介电特性，可用于提供丰富的信息，例如细胞的生长阶段，是健康的还是癌变的，或者是否发生了药物诱导的变化。目前大多数用于测量单细胞介电特性的方法采用仅使用一个或两个频率的低频下的阻抗或介电电泳。通过测量完整的光谱并将其扩展到微波频率，可以获得更多的信息，在这种情况下，场可以穿透细胞内部，并且可以检测大分子的极化率。单细胞的介电谱是非常困难的，由于它们的小尺寸。我们将探索新的微波介电电泳传感技术，以测量单细胞在一个很宽的频谱，并使用它来开发多参数的细胞介电模型。 微流体装置将用于研究细胞对饥饿、热休克和微波电穿孔（EP）的反应。饥饿诱导细胞凋亡的检测在生物制药和生物医学研究中具有重要意义。饥饿条件下细胞的介电变化将与细胞生理学相关，开发的细胞模型将用于理解散装悬浮液介电测量。热休克和暴露于高强度电场（诱导EP）可以永久或暂时渗透细胞膜。这被用于转染，增强癌症治疗中的药物摄取，诱导细胞凋亡，或在极端情况下，裂解。微流控装置将被开发用于应用并同时测量与这两种应激源相关的细胞的介电变化。特别感兴趣的是CW微波EP，我们将探索使用低强度场诱导EP效应。 该研究的成果将是新的微流控单细胞介电光谱工具与刺激功能相结合，提供新的非侵入性无标记单细胞分析仪器。该研究计划将在跨学科环境中为高素质的人才提供理论和实验培训。

Studying the physiology of biological cells and monitoring their response to different stimuli or drugs is essential in bioprocess and biomedical research. Many currently used instruments for cellular analysis utilize chemical markers, sophisticated equipment and time-consuming preparation techniques. Microfluidic devices employing dielectric analysis are a promising alternative as they are label-free, can be miniaturized and use nanoliter fluid volumes. The objectives of the proposed research program is to develop microfluidics devices integrated with microwave dielectric sensors and actuators for in-flow single cell analysis, use these to study cell response to different types of stress, develop new cell dielectric models, and relate cell dielectric properties to physiology. Tissues, cells and other biomedia have unique dielectric properties that can be used to provide a wealth of information, such as a cell's growth phase, whether it is healthy or cancerous, or if drug-induced changes have occurred. Most current methods for measuring single cell dielectric properties employ impedance or dielectrophoresis at low frequencies using only one or two frequencies. Much additional information can be gained by measuring the complete spectrum and extending this to microwave frequencies, a regime where fields can penetrate the cell interior and the polarizability of large molecules can be detected. Dielectric spectroscopy of single cells is extremely difficult due to their small size. We will explore new microwave dielectrophoresis sensing techniques to measure single cells over a wide frequency spectrum and use this to develop multi-parameter cell dielectric models. Microfliudic devices will be used to study cell response to starvation, heat shock and microwave electroporation (EP). Detection of starvation-induced apoptosis is important in biopharmaceutical bioprocessing and biomedical research. Dielectric changes to cells under starvation will be related to cell physiology and the developed cell models will be used to understand bulk-suspension dielectric measurements. Heat shock and exposure to high-intensity electric fields (inducing EP) can permanently or temporarily permeabilize cell membranes. This is employed for transfection, enhancing drug uptake in cancer therapy, inducing apoptosis, or in the extreme case, lysis. Microfluidic devices will be developed to apply and simultaneously measure the dielectric changes to cells associated with these two stressors. Of particular interest is CW microwave EP, where we will explore use of low-intensity fields to induce EP effects. The outcomes of the research will be new microfluidic single cell dielectric spectroscopy tools integrated with stimulus capabilities, providing new non-invasive label-free single cell analysis instruments. The research program will provide both theoretical and experimental training to highly qualified personnel in an interdisciplinary environment.