A robust impedance microscopy technique is presented. This optical tool enables high resolution imaging of electrical properties with promising biophysical applications. The underlying principle is that surface plasmon resonance (SPR) sensors are able to measure perturbations of surface charge density and therefore can be used to compute the impedance of surface-adhered cells. However, the ability to perform reliable quantitative impedance imaging is affected by the optical heterogeneity of the cell-sensor interface. To address this issue, a novel method for quantitative time-resolved resonance angle tracking is developed and applied to correct for the effect of the optical properties. To demonstrate the capability of this technique, impedance microspectroscopy of bovine serum albumin (BSA) patterns was performed enabling measurements of capacitance with submicroscopic resolution. The work presented offers an impedance microspectroscopy method that will create new avenues in studying the electrical properties of single cells and biomolecules as well as bio-electrical currents.

中文翻译：

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光学异质样品的基于等离子体的阻抗显微技术

提出了一种鲁棒的阻抗显微镜技术。该光学工具可以在有前途的生物物理应用中实现电特性的高分辨率成像。基本原理是表面等离子体共振（SPR）传感器能够测量表面电荷密度的扰动，因此可用于计算表面粘附细胞的阻抗。然而，执行可靠的定量阻抗成像的能力受细胞-传感器界面的光学异质性影响。为了解决这个问题，开发了一种用于定量时间分辨共振角跟踪的新方法，并将其用于校正光学特性的影响。为了演示这项技术的功能，进行了牛血清白蛋白（BSA）模式的阻抗显微光谱分析，从而能够以亚显微分辨率测量电容。提出的工作提供了一种阻抗显微光谱法，它将为研究单细胞和生物分子的电特性以及生物电流创造新的途径。