在生物體的形態產生過程中，全功能性的幹細胞是藉由啟動某些基因和抑制某些基因的表現，來達成轉化為各種多功能性的細胞系，再進一步轉變為各種完全分化的細胞。但決定細胞分化類型與生物體內各種細胞的空間組織的機制，到目前為止仍未被釐清。 另一方面，細胞的行為不僅可以藉由生物化學信號來調控，也可以藉由生物物理信號來控制，尤其是來自細胞外基質的信號。眾所皆知細胞外基質的最主要組成成分是膠原蛋白微纖維束，它所具備的分子識別和結構特徵可能在控制例如分化等細胞行為和生物體形態生成上扮演關鍵的角色。尤其是，過去已有研究發現，膠原蛋白微纖維束的特殊 67 奈米周期橫紋結構，對於細胞在膠原蛋白基板上的型態與遷移方向，扮演著決定性的控制因素。 有鑑於上述這些研究的發現，我們認為可能可以利用有 67 奈米周期橫紋結構且具特定微米圖案的膠原蛋白基板來控制細胞內動蛋白纖維束的空間分佈，進而以機械作用去對細胞核內染色質的組蛋白的密度進行空間分佈上的調節，以達到對細胞表現型的控制。我們認為這可能是生物體內控制在形態生成與及腫瘤生成中細胞類型轉化的機制。而我們的研究成果顯示出利用膠原蛋白纖維束可以使幹細胞分化成神經細胞，然而有67奈米周期橫紋結構的膠原蛋白纖維束更可以提高其分化的能力。 ;It is known that during morphogenesis, totipotent stem cells become the various pluripotent cell lines of the embryo, which in turn become fully differentiated cells, by activating some genes while inhibiting the expression of others. However, the mechanisms underlying the cell type commitment and the cells’ spatial organization in an organism are still largely unknown. On the other hand, cellular behaviors can be modulated not only by biochemical signals but also by biophysical cues, especially those from extracellular matrix (ECM). It is well known that cell ECM is actually made of most importantly collagen microfibrils, which possess specific molecular identity and structural characteristics that may be crucial for controlling cell behaviors such as cell phenotype and coordinating organism morphogenesis. In particular, it has been reported that the characteristic 67-nm-period D-banding of collagen. Microfibrils is required in order to observe the elongation and motional directionality of cells on a collagen substrate. Based on these observations, we hypothesize that the cell phenotype could be controlled by spatial modulation of the chromatin in the cell nucleus through mechanical action from actin filament bundles, which in turn could be controlled by integrin clustering and activation triggered by a micropatterned collagen substrate/scaffold with D-banding. We propose that this could be what dominate cell type commitment in morphogenesis and tumorigenesis. Our result indicated that collagen microfibril could make stem cell differentiate into neuron cell, moreover, collagen microfibril with 67 nm D-banding could enhance the ability of stem cell differentiate into neuron cell.
