In age-related macular degeneration, the retinal pigment epithelium can be damaged by light acting on photosensitizers like N-retinylidene-N-retinylethanolamine (A2E). In this paper, the underlying cellular mechanism of lesion at the cell layer scale is analyzed by impedance spectroscopy. Retinal pigment epithelium (RPE) cells are cultured on top of custom-made electrodes capable of taking impedance measurements, with the help of a custom-made electronic setup but without the use of any chemical markers. An incubator is used to house the cells growing on the electrodes. An electrical model circuit is presented and linked to the constituents of the cell layer in which various electrical elements have been defined including a constant phase element (CPE) associated to the interface between the cell layer and the electrolyte. Their values are extracted from the fitted model of the measured impedance spectra. In this paper, we first investigate which parameters of the model can be analyzed independently. In that way, the parameter's evolution is examined with respect to two different targeted changes of the epithelium: 1. degradation of tight junctions between cells by extracellular calcium sequestration with Ethylenediaminetetraacetic acid (EDTA); 2. application of high amplitude short length electric field pulses. Based on the results obtained showing a clear relation between the model and the physiological state of the cell layer, the same procedure is applied to blue light exposure experiment. When A2E-loaded cells are exposed to blue light, the model parameters indicate, as expected, a clear degradation of the cell layer opposed to a relative stability of the not loaded ones.

中文翻译：

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视网膜色素上皮的阻抗光谱研究：在监测蓝光照射对A2E体外细胞培养的影响中的应用。

在与年龄相关的黄斑变性中，视网膜色素上皮会受到作用于光敏剂（例如N-视黄基-N-视黄基乙醇胺（A2E））的光的损害。在本文中，通过阻抗谱分析了在细胞层尺度上病变的潜在细胞机制。视网膜色素上皮（RPE）细胞在能够进行阻抗测量的定制电极上培养，无需借助任何化学标记，即可进行定制的电子设置。孵化器用于容纳在电极上生长的细胞。提出了电模型电路并将其链接到电池层的组成部分，其中已定义了各种电气元件，包括与电池层和电解质之间的界面关联的恒定相元件（CPE）。它们的值是从测量阻抗谱的拟合模型中提取的。在本文中，我们首先研究可以独立分析模型的哪些参数。以这种方式，针对上皮的两种不同的靶向变化来检查参数的演变：1.通过用乙二胺四乙酸（EDTA）进行细胞外钙螯合来降解细胞之间紧密连接。2.施加高振幅短长度电场脉冲。基于显示模型与细胞层生理状态之间明确关系的所得结果，将相同步骤应用于蓝光暴露实验。当加载A2E的电池暴露在蓝光下时，模型参数将按预期指示：