流體動力學式之細胞捕捉及磁場刺激微流井微流道晶片

A Microwell Microfluidic Device for Cell Trapping and Magnetic Gradient Stimulation

賴彥廷(Richard Lee Lai)

指導教授 ： 黃念祖

國立臺灣大學/電機資訊學院/生醫電子與資訊學研究所/碩士(2020年)

https://doi.org/10.6342/NTU202003738

摘要

在本論文中，我們提出一個具有多個微流井的微流道晶片進行懸浮型細胞 (單核細胞株，THP-1) 的捕捉及長時間的培養，並觀察它們在不同磁場刺激條件下受到的影響。首先，我們透過數值模擬來最佳化單細胞捕捉的微流井構造。模擬的參數包含刮長寬比 (W/L) 、寬深寬比 (D/W) 以及細胞尺寸跟微流井長度的比例 (R/L) 。初步結果顯示，當W/L越大的時候，捕捉的效率會越高，而當D/W越大時，細胞比較不會被沖走。R/L則是越小越容易被捕捉。接著我們利用細胞進行實驗，證明當 W/L = 2、D/W = 0.5 跟 R/L = 0.125 時，單細胞捕捉效率(細胞捕捉率跟單細胞捕捉率的乘積)是最高的。因此，我們選擇 W/L = 2 微流井構造來行磁場刺激實驗。找到最佳的細胞導植入濃度以後，我們將進行不同種類磁場的刺激並且判斷它們對THP-1細胞的影響。結果顯示，梯度為 2x10^2 T/m 的高磁場梯度的條件下會增加細胞ROS 的分泌，過了36小時甚至比沒有施加磁場的情況多了兩倍。該刺激同時也會造成細胞生長的抑制 (比控制組低了25%) 以及真圓度的下降 (由控制組的0.9下降為0.8)。這是因為有梯度的磁場會對細胞膜造成剪應力，並影響到負責調控ROS濃度的機械感應通道TRPV4。因此，我們的晶片可以用來進行大量單細胞捕捉以及精準的磁場梯度引發之機械刺激。

關鍵字

微流道 ； 單細胞捕捉

並列摘要

We aim to develop a microfluidic platform and the accompanying image processing algorithms for the long-term cultivation and observation of the suspension cell line types (monocytes, THP-1) under different physiological conditions. First, we conduct simulations to determine the optimal microwell geometry for single single-cell trapping. Parameters such as width to cross-sectional length (W/L), width to depth (D/W) and radius to cross-sectional length ratio (R/L) ratios are discussed in our study. Next, we conduct actual experiments to verify our simulations. Triangular microwells with W/L = 1 and W/L = 2 have single cellsingle-cell occupancy rates (given as the product of the single cellsingle-cell trapping rate and well occupancy) of 16.7% and 35.8%, respectively. Therefore, we choose W/L = 2 and D/W=0.5 for our purposes. For these two values, the ideal R/L ratio is found to be around 0.125. After finding the optimal cell loading conditions, we conduct experiments under different magnetic field gradients and determine their effect on THP-1 cell culture. Results show that a high magnetic field gradient on the order of 2x10^2 T/m would increases the concentration of Reactive Oxygen Species (ROS) secretion by 200% over 36 hours. It also results in both decreased cell size (reduction of 25% compared with the control group) and circularity (0.8 compared with 0.9 for control). This is because magnetic field gradients induce shear and pressure forces on the cellular membrane, affecting the mechanosensitive ion channel TRPV4, which is responsible for the regulation of ROS concentrations. Therefore, our chip can be used in high-throughput single cellsingle-cell trapping and provide precise magnetic field gradient induced mechanical stimulus.

並列關鍵字

Microfluidics ； Single cell trapping

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