Tang Tao, Liu Xun, Kiya Ryota, Shen Yigang, Yuan Yapeng, Zhang Tianlong, Suzuki Kengo, Tanaka Yo, Li Ming, Hosokawa Yoichiroh, Yalikun Yaxiaer
Division of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama-cho Ikoma, Nara, 630-0192, Japan.
Center for Biosystems Dynamics Research (BDR), RIKEN, 1-3 Yamadaoka Suita, Osaka, 565-0871, Japan.
Biosens Bioelectron. 2021 Dec 1;193:113521. doi: 10.1016/j.bios.2021.113521. Epub 2021 Aug 2.
In this work, we investigated the ability of impedance flow cytometry to measure the shape of single cells/particles. We found that the impedance pulses triggered by micro-objects that are asymmetric in morphology show a tilting trend, and there is no such a tilting trend for symmetric ones. Therefore, we proposed a new metric, tilt index, to quantify the tilt level of the impedance pulses. Through simulation, we found that the value of tilt index tends to be zero for perfectly symmetrical objects, while the value is greater than zero for asymmetrical ones. Also, this metric was found to be independent on the trajectories (i.e., lateral, and z-direction shift) of the target micro-object. In experiments, we adopted a home-made lock-in amplifier and performed experiments on 10 μm polystyrene beads and Euglena gracilis (E. gracilis) cells with varying shapes. The experimental results coincided with the simulation results and demonstrated that the new metric (tilt index) enables the impedance cytometry to characterize the shape single cells/particles without microscopy or other optical setups.
在这项工作中，我们研究了阻抗流式细胞术测量单个细胞/颗粒形状的能力。我们发现，形态不对称的微物体触发的阻抗脉冲呈现倾斜趋势，而对称微物体则没有这种倾斜趋势。因此，我们提出了一种新的度量指标——倾斜指数，以量化阻抗脉冲的倾斜程度。通过模拟，我们发现对于完美对称的物体，倾斜指数的值趋于零，而对于不对称物体，该值大于零。此外，还发现该度量指标与目标微物体的轨迹（即横向和z方向偏移）无关。在实验中，我们采用了自制的锁相放大器，并对不同形状的10μm聚苯乙烯珠和纤细裸藻（E. gracilis）细胞进行了实验。实验结果与模拟结果一致，表明新的度量指标（倾斜指数）使阻抗流式细胞术无需显微镜或其他光学装置就能表征单个细胞/颗粒的形状。
