體外細胞培養的生理活性可從其貼附、延長、生長、移動等生理特性來加以評估，然一般將細胞培養在L-Lysine修飾之Petri dish上，細胞底下所貼附的平面堅硬環境不易量化其生理特性的變化。為此，本研究以聚二甲基矽氧烷(PDMS)為基材，透過微機電製程製作出具彈性之微柱陣列結構(MPAs)，並以此具彈性的立體環境頂端上進行細胞培養。在細胞培養時細胞移動，特別是於其爬行過程中所產生的牽引力會使微柱起微小的形變，此可經由影像技術軟體求得與力學公式量化細胞力學。單一微柱的K值是由微懸臂探針固定於玻璃棒上，並藉微小操作儀來控制位移，對微柱上端之中心施予一已知力量，可藉由微柱之形變量量測得知，而細胞牽扯微柱後所產生的位移改變量，乃由顯微鏡觀察並配合影像軟體求得。當細胞貼附於MPAs後，約經5 hrs，部分的微柱受細胞牽引會有明顯之形變，於是細胞四周各部位之牽引力即可被量化得知。相較Autoclave與酒精滅菌處理方法，由於UV光照射法(254 nm)來進行滅菌處理後之PDMS的彈性係數改變量最少（8%），因此，本研究採UV光照射法來進行MPAs滅菌。將滅菌處理後的MPAs，浸於DMEM培養液中進行細胞培養，微柱表面經過collagen修飾後，有助細胞攤開並生長於微柱頂端，可提高攤開面積1.5 ~ 2倍。最後，將MDCK細胞、MDCK DDR DN細胞與MDCK DDR 1b細胞培養於微柱上，經過24小時培養後，於顯微鏡下拍攝觀察，紀錄2小時的力量表現，發現其牽引力分別為4~14, 2~9, 4~8 nN。本研究已初步可供立體式擬自然生長下細胞牽扯力量化之探求，相信在更多的經驗累積，此細胞力學量測平台應可發展成另一評估細胞相關反應所造成的微力學之生理應答上。

In order to evaluate the traction force of the cultured cell, the elastic micro-pillars array system (MPAs) was fabricated with poly-dimethylsiloxane (PDMS) by Micro-Electro-Mechanical- System technology. The MPAs provides a non-rigid 3D environment for the attachment, growth, spread of the cell. The purpose of the MPAs is to quantify the cell traction force during cell culture. The specific aim of this study is to evaluate the effects of layout parameters and manufacturing process of various MPAs designs on the cellular force quantification. The traction force evaluation was based on the Beam deflection theory, therefore the spring constant and the displacement of a signle pillar must be evaluated. Two approaches were used to determine the deflection constant. First, the Young’s modulus was measured by dynamic mechanical analyzer; the Young’s modulus was then used to calculate the deflection constant by appling the known geometry of snigle pillar. Second, micro-cantilever was pressed on the end of the single pillar. From the known spring constant of cantilever and deflection of pillar after loading the deflection constant of pillar can be measured. To evaluate the sterilization effect on the mechanical property of the pillar, three sterilization methods were used including autoclave at 121C, 75% ethanol immersion, and UV light (254 nm) radiation. The spring constants demonstrated a changing of ±25%, ±16%, and ±8% after sterilization, respectively. The MDCK cells were cultured in the DMEM medium by MPAs. After 24 hrs culture, recording to the MDCK, MDCK DDR DN, MDCK DDR 1b cells for 2 hrs by microscope that the traction force were about 4 ~ 14, 2 ~ 9, 4 ~ 8 nN, respectively. The spreading area of the cells can be enhancing about 1.5 ~ 2 folds after collagen coating on the MPAs. In conclusion, the displacement of the micro-pillars caused by the cell traction forces could be measured by this system. This system provides a convenient measurement platform for cell mechanics environment.

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