此研究是延續去年正在進行的國科會計畫(99/04/01 100/ 04/31: Cell Traction Forces on a Viscoelastic Gel, contract number: NSC 992218E008006) 。主要目標係在針對老鼠骨髓間葉幹細胞(RM1)發展一個新的實驗設計，同時結合分析模擬來進行在化學趨向性(chemotaxis)中有關細胞遷移的定量研究。以下議題將是本研究的重點： 明膠(gelatin)基材的化學製備； 明膠(gelatin)基材的熱及機械性質； 簡易的化學趨向性實驗設計； 建立RM1細胞培養流程； 在細胞培養液和基材中之化學擴散特性的定量量測； 細胞在化學趨向性之遷移特性的定量量測；此提案主要在延續去年的研究計畫─細胞在凝膠材料上的作用力。今年將持續結合實驗和基本的數值模擬來進行研究。不過分析凝膠基材將由Gelatin 取代PAG，這是因其製造成本較低，含水量控制容易和更為簡易的製作過程。然而此項變更將幾乎不會改變細胞與基材間之生物力學的作用以及細胞內外化學訊號之傳遞。這是由於控制細胞表面貼附、細胞化學訊號內外部傳遞及細胞遷移的基本理論並無二致。因此過去的研究經驗和結果仍然可作為引導今年的計畫明確依據。此項研究計劃亦將透過與國內大型醫院的生物醫學團隊合作以期更進一步了解哺乳類動物細胞之機械特性與凝膠以及細胞變形之間的關聯性。目前本實驗室已有的實驗技術與方法已成功應用於數項生物細胞(紅血球、白血球和老鼠肌肉細胞)及人造的薄膜之研究，且其可行性已被證明。同時，由PI 個人藉由hyperelasticity 所發展出的數值模擬亦已被用於模擬與比對相關實驗量測以了解凝膠與細胞之間的交互作用。這些研究在未來針對免疫或藥物傳遞的設計是至關重要，因為細胞表面貼附乃是保護重要細胞機制和細胞生命的第一線機制。此外，如在有限時間及資源允許下，這項計畫的最後一小部分將藉由蛋白體分析方法如聚合酶鏈反應（PCR）技術，嘗試了解基本細胞貼附力, 細胞膜肌動蛋白(trans-membrane proteins)和細胞內的相關肌動蛋白(actins)之間的化學訊號傳遞途徑。This proposed research is a continuing work from last year’s ongoing project (99/04/01 ‐ 100/04/31: Cell Traction Forces on a Viscoelastic Gel, contract number: NSC 99‐2218‐E‐008‐006). Our main goals are aimed to develop a novel experimental procedure for rat bone marrow cells, combined with simulation to quantitatively investigate the correlation among cell migration, mechanical responses of substratum and chemical diffusion in chemotaxis. Following issues will be the focuses of this study: chemically fabrication of gelatin substratum; thermal and mechanical properties of gelatin substratum; design of simple chemotaxis experiment; establishment of RM1 cell culture procedure; experimental measure and quantitative characterization of chemical diffusion in culture media and in substratum; the measurement and quantitative characterization of cell migration under chemotaxis. This proposal aims to continue from last year’s project. It is still a combined experimental and basic numerical study on characterizing the cell traction on soft materials. This year, the gelatin is chosen instead of PAG for the substratum in that we can fabricate gelatin lower cost with more freedom to control its moisture content and simpler fabrication process. However, such change only alters the cellular mechno‐transduced deformation and bio‐mechanical interactions between cells and substratum marginally. Such minor difference is due to the fact that the same underlying principle governs focal adhesion and cell traction together to trig a cascading of chemo‐mechanical responses of cells and beyond. Thus, the past experience and results are still available as very precise guideline for this year’s project. This project aims to advance our understanding and combine two continuous developments in the mechanical characterizations on mammalian tissues and hydrogels, cellular deformation through collaborations with biomedical research groups in hospitals. A general prototype approach of the characterizing technique has been developed to investigate several biological and artificial soft membranes with proved feasibility. In parallel, a numerical modeling by the PI has been developed based on the theory of hyperelasticity in order to simulate the experimental work and comprehend the material responses of hydrogels in the virtue world by correlating with the experimental measures. These studies are crucial for the future design of immunization or drug delivery because focal adhesion on cell surface serves as the first and foremost mechanism for the life and protection of cells. In addition, a smaller portion of this proposal shall be protein analysis by methods from proteomics such polymerase chain reactions (PCR) in an attempt to decipher the relation between adhesion and trans‐membrane proteins and associated actins inside cells. 研究期間：10008 ~ 10107
