細胞阻抗分析被廣泛地應用於監測生物與藥物反應，而本研究利用微影、電鑄技術製備一個高靈敏度、高深寬比的立體指叉式微電極於聚對苯二甲酸乙二醇酯軟式電路板上，用以不同細胞混合檢測。立體指叉式微電極可使微粒子與細胞排列於電極間隙，而不在電極上，可避免由微粒子、細胞位置所造成的干擾。
而再確認立體指叉式微電極能以阻抗辨別不同微粒子顆數後，將此電極以多細胞電阻抗傳感器做應用，藉以回推細胞的電特性做之後混合分析的依據。細胞電特性，如細胞膜電容與細胞質電阻，可提供許多訊息來研究細胞膜與細胞質所發生的變化，且不需複雜的生化檢測。以量測的結果來看，兩細胞間存在明顯的阻抗差異因此可進行後續的混合分析來推斷各自的顆數。經由等校電路模型計算出初期乳癌細胞(MCF-7)與侵略性乳癌細胞(MDA-MB-231)之細胞質電阻與細胞膜電容後，最後再進行不同比例的混合量測並藉由模型和PET的透明特性來回推兩種不同細胞的顆數。
本研究提供一個分析方法以此多細胞電阻抗傳感器配合等效電路來提取細胞電特性，兩種不同的乳癌細胞可快速、簡單地被此立體指叉式微電極與SU-8做成的柱子捕捉並排列於電極間隙，無細胞定位上的困擾。實驗結果證明了等效電路的準確性與有效性，藉由所呈現的細胞電特性提取方法，成功地從42顆侵略性乳癌細胞和72顆初期乳癌細胞中得到各自的細胞膜電容與細胞質電阻，並且將其值代入等效電路模型中，來模擬預測兩種細胞於不同比例(1:1, 1:9)間的電阻抗。模擬預測的阻抗與實際量測值之間最大誤差在阻抗振幅只有8.1%，這證明了可由細胞電特性來辨別細胞數量，也同時證明了用多細胞傳感器與等效電路來求得細胞電特性的可行性。

Cell impedance analysis is widely used for monitoring biological and medical reactions. In this study, a highly sensitive three-dimensional (3D) interdigitated microelectrode (IME) with a high aspect ratio was fabricated on a flexible and transparent substrate polyethylene terephthalate (PET). It was made for cell detection using electroforming and lithography technology. With the 3D IME, the cells were arranged in the gap not on the electrode which would avoid the noise due to cell position.
This study proposes the use of electric cell-substrate impedance sensing (ECIS) to detect the electrical properties of cells by the 3D-IME. The membrane capacitance (Cc) and cytoplasm resistance (Rc) can provide the information required to investigate changes in the membrane and cytoplasm without the need for complex chemical biochemical detection. In this case, the membrane capacitance and cytoplasm resistance of MCF-7 and MDA-MB-231 could provide the data that the model need in order to calculate the numbers of each cell type.
After confirming that 3D IME could use the impedance to identify different numbers of particles, various quantities of MDA-MB-231 cells and MCF-7 cells were captured in Dulbecco’s modified Eagle medium (DMEM) until the electrodes were full of capacity. Their impedances were then measured. From the measured results, it was clear that MCF-7 cells and MDA-MB-231 cells are significant different on impedance magnitudes.
This allowed us to study further on their individual electrical properties for further applications. The proposed method was used to analyze the electrical properties of a multiple-cells impedance biosensor (MCIB) and the application of an ECM by using the 3D IME. MDA-MB-231 and MCF-7 cells were quickly captured at the gap of the electrodes without cellular localization because of the presence of SU-8 columns and the 3D IME. In order to understand the impedance measured with the 3D IME, the ECM was used to analyze the impedance spectrum. The experimental results validated the accuracy and validity of the model. The normalized Rc, Rc1, Cc and Cc1 were calculated by measuring 42 MDA-MB-231 cells and 72 MCF-7 cells. The simulation results using Rc, Rc1, Cc, Cc1 and the ECM successfully forecasted the impedance magnitudes for the ratio of 1:1 and 1:9 of those two cell types. The comparison of the simulation results and the measurement results showed that the maximum average errors in magnitude was only 8.1%, which suggested that the number of MDA-MB-231 cells and MCF-7 cells could be classified based on their electrical properties. It also validates the feasibility for using the proposed multiple-cells sensor and the ECM to evaluate the cellular electrical properties.

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