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Abstract：
Cell dielectric property measurement holds significant potential for application in cell detection and diagnosis due to its label-free and noninvasive nature. In this study, we developed a biosensor designed to measure the permittivity of liquid samples, particularly cell suspensions at the nanoliter scale, utilizing microwave and millimeter wave coplanar waveguides in conjunction with a microchannel. This biosensor facilitates the measurement of scattering parameters within a frequency domain ranging from 1 GHz to 110 GHz. The obtained scattering parameters are then converted into dielectric constants using specific algorithms. A cell capture structure within the microchannel ensures that cell suspensions remain stable within the measurement zone. The feasibility of this biosensor was confirmed by comparison with a commercial Keysight probe. We measured the dielectric constants of three different cell suspensions (HepG2, A549, MCF-7) using our biosensor. We also counted the number of cells captured in multiple measurements for each cell type and compared the corresponding changes in permittivity. The results indicated that the real part of the permittivity of HepG2 cells is 0.2-0.8 lower than that of the other two cell types. The difference between A549 and MCF-7 was relatively minor, only 0.2-0.4. The fluctuations in the dielectric spectrum caused by changes in cell numbers during measurements were smaller than the differences observed between different cell types. Thus, the sensor is suitable for measuring cell suspensions and can be utilized for label-free, noninvasive studies in identifying biological cell suspensions.
摘要：
由于其无标记和非侵入性，细胞介电特性测量在细胞检测和诊断中具有重要的应用潜力。在这项研究中,我们开发了一种生物传感器，用于测量液体样品的介电常数，特别是纳升尺度的细胞悬浮液，利用微波和毫米波共面波导结合微通道。该生物传感器有助于在1GHz至110GHz的频域内测量散射参数。然后使用特定算法将获得的散射参数转换为介电常数。微通道内的细胞捕获结构确保细胞悬浮液在测量区内保持稳定。通过与商业Keysight探针比较,证实了该生物传感器的可行性。我们使用我们的生物传感器测量了三种不同细胞悬浮液（HepG2，A549，MCF-7）的介电常数。我们还计算了每种细胞类型在多次测量中捕获的细胞数量，并比较了相应的介电常数变化。结果表明，HepG2细胞的介电常数的实部比其他两种细胞类型的介电常数低0.2-0.8。A549和MCF-7之间的差异相对较小，只有0.2-0.4。测量过程中细胞数量变化引起的介电谱波动小于不同细胞类型之间观察到的差异。因此，该传感器适用于测量细胞悬浮液，可用于无标签，鉴定生物细胞悬液的非侵入性研究。
