細胞黏著是細胞生理重要的功能行為，影響細胞型態、細胞攤附、細胞移動、運動及分化等。黏著行為會受到細胞本身生理調控及外界環境的影響，而區域黏著增加細胞與基材間的黏著能力，也是大部分力量來源，它可調節細胞骨架結構與胞外基質的連結進而改變細胞內張力，甚至觸發訊息傳遞路徑改變細胞功能。
　　本研究欲探討不同硬度基材與細胞黏著的關係。每種細胞對基材軟硬度的感知或反應皆有不同，目前已知在軟基材上細胞凋亡反應的差異：極性細胞有明顯的凋亡反應，纖維母細胞則不明顯。因此本實驗量化此兩種細胞的細胞黏著，並分析在不同硬度基材上此兩種細胞的面積、黏著力，及黏著應力的表現。實驗中選用極性上皮細胞－LLC-PK1與纖維母細胞－NIH-3T3，在三種不同硬度（1000 Pa、10000 Pa、玻璃基材）並塗佈第一型膠原蛋白的基材上，經過六小時的培養，利用細胞刮取機構量測單顆細胞的細胞黏著力，計算出細胞面積並求得單位面積的細胞黏著力－黏著應力。
　　實驗結果顯示，種植培養六小時後，隨著基材硬度的增加，細胞面積及細胞黏著力都有增加的趨勢。細胞黏著應力在1000 Pa、10000 Pa及玻璃基材上，3T3的應力大小分別是825.23±215.97、991.97±368.26、1231.86±359.70 Pa；而PK1的大小為911.32±254.79、920.36±173.87、960.83±321.14 Pa。同樣的，黏著應力也會隨基材硬度增加而增加。利用“單因子變異數分析”統計方法分析在三種不同硬度細胞的變異性：兩種細胞在細胞攤附面積與黏著力上都有顯著差異；而黏著應力方面，3T3有顯著差異，PK1則沒有。
　　另外，利用黏著力量－位移曲線圖，計算曲線下面積，求得細胞與基材分離的刮取能量－功，並計算單位面積的功。在1000 Pa、10000 Pa及玻璃基材上，3T3的做功量與單位面積功分別是3.83±1.24、5.09±1.12、5.55±1.84（10-12J）；11.55±4.39、16.66±4.66、12.14±3.74（10-3 J/m2）。PK1的大小為11.37±2.42、16.70±6.56、18.97±7.22（10-12J）；23.10±8.75、22.38±12.22、30.65±13.58（10-3 J/m2）。

　Cell adhesion plays a critical role in cell physiology functions, which influences morphology, spreading, migration, and differentiation, etc. The adhesion is affected by intracellular regulations and extracellular environment. Most of the adhesion to extracellular matrix is derived from focal adhesions, which enhance adhesion, functioning as structural links between the extracellular matrix and the cytoskeleton that regulates intracellular tension, and direct cell function by triggering signaling pathways.
　In this study, the relationship between different substratum rigidity and cell adhesion was investigated. The sensibility and reaction to different substratum rigidity differ from kinds of cells. Several studies have shown that apoptosis would be induced while certain kinds of polarized cells were seeded on soft substrate, but not fibroblasts. To understand effects of the substrate rigidity on cell behaviors, the adhesion force was measured quantitatively between cells and collagen-coated substrates with different rigidity in two types of cells, and also cell spreading area, adhesion force, and adhesion stress were analyzed. In the experiments, the epithelia cell, (LLC-PK1), and fibroblast, (NIH-3T3), were seeded on collagen-coated polyacrylamide substrates with rigidity 1000, 10000Pa and glass surface (control group), respectively. After 6 hours of seeding, the adhesion force was measured by cytodetachment technique, and cell area was also detected. Therefore, the cell adhesion force per unit area, defined as adhesion stress, was figured out.
　The results show that the cell spreading area and adhesion force increased with increasing rigidity. The cell adhesion stress at 6 hour seeding was 825.23±215.97, 991.97±368.26, and 1231.86±359.70 Pa on substratum rigidity 1000, 10000Pa, and glass, respectively, for 3T3, and they are 911.32±254.79, 920.36±173.87, and 960.83±321.14 Pa for PK1. Also, the adhesion stress increased with increasing rigidity. The one-way ANOVA analysis shows significant differences in spreading area and adhesion force among three different rigidity substrates for 3T3 and PK1. However, the cell adhesion stress has significant difference in 3T3 but not for pk1 among different substrate.
　Besides, the detachment energy (work) was obtained by integrating the area of the adhesion force-distance curve, and the normalized work was also found by dividing cell area. For 3T3, the detachment work and the work per unit area was 3.83±1.24, 5.09±1.12, 5.55±1.84 (10-12J) and 11.55±4.39, 16.66±4.66, 12.14±3.74 (10-3 J/m2) on substratum rigidity 1000, 10000Pa, and glass. For PK1, they are 11.37±2.42, 16.70±6.56, 18.97±7.22 (10-12J) and 23.10±8.75, 22.38±12.22, 30.65±13.58 (10-3 J/m2).

Anselme, K. "Osteoblast adhesion on biomaterials." Biomaterials 21(7): 667-81. (2000).
Choquet, D., D. P. Felsenfeld, et al. "Extracellular matrix rigidity causes strengthening of integrin-cytoskeleton linkages." Cell 88(1): 39-48. (1997).
Civelekoglu-Scholey, G., A. W. Orr, et al. "Model of coupled transient changes of Rac, Rho, adhesions and stress fibers alignment in endothelial cells responding to shear stress." J Theor Biol 232(4): 569-85. (2005).
Discher, D. E., P. Janmey, et al. "Tissue cells feel and respond to the stiffness of their substrate." Science 310(5751): 1139-43. (2005).
Engler, A. J., S. Sen, et al. "Matrix elasticity directs stem cell lineage specification." Cell 126(4): 677-89. (2006).
Galbraith, C. G., K. M. Yamada, et al. "The relationship between force and focal complex development." J Cell Biol 159(4): 695-705. (2002).
Gallant, N. D., K. E. Michael, et al. "Cell adhesion strengthening: contributions of adhesive area, integrin binding, and focal adhesion assembly." Mol Biol Cell 16(9): 4329-40. (2005).
Geiger, B. and A. Bershadsky "Assembly and mechanosensory function of focal contacts." Curr Opin Cell Biol 13(5): 584-92. (2001).
Hoben, G., W. Huang, et al. "Quantification of varying adhesion levels in chondrocytes using the cytodetacher." Ann Biomed Eng 30(5): 703-12. (2002).
Huang, W., B. Anvari, et al. "Temporal effects of cell adhesion on mechanical characteristics of the single chondrocyte." J Orthop Res 21(1): 88-95. (2003).
Lo, C. M., H. B. Wang, et al. "Cell movement is guided by the rigidity of the substrate." Biophys J 79(1): 144-52. (2000).
Pelham, R. J., Jr. and Y. Wang "Cell locomotion and focal adhesions are regulated by substrate flexibility." Proc Natl Acad Sci U S A 94(25): 13661-5. (1997).
Pettit, E. J. and F. S. Fay "Cytosolic free calcium and the cytoskeleton in the control of leukocyte chemotaxis." Physiol Rev 78(4): 949-67. (1998).
Sagvolden, G., I. Giaever, et al. "Cell adhesion force microscopy." Proc Natl Acad Sci U S A 96(2): 471-6. (1999).
Sung, K. L., M. K. Kwan, et al. "Adhesion strength of human ligament fibroblasts." J Biomech Eng 116(3): 237-42. (1994).
Van Vliet, K. J., G. Bao, et al. "The biomechanics toolbox: experimental approaches for living cells and biomolecules." Acta Materialia 51: 5881-5905. (2003).
Walker, J. L., A. K. Fournier, et al. "Regulation of growth factor signaling and cell cycle progression by cell adhesion and adhesion-dependent changes in cellular tension." Cytokine Growth Factor Rev 16(4-5): 395-405. (2005).
Wang, H. B., M. Dembo, et al. "Focal adhesion kinase is involved in mechanosensing during fibroblast migration." Proc Natl Acad Sci U S A 98(20): 11295-300. (2001).
Wang, H. B., M. Dembo, et al. "Substrate flexibility regulates growth and apoptosis of normal but not transformed cells." Am J Physiol Cell Physiol 279(5): C1345-50. (2000).
Wang, Y. H., W. T. Chiu, et al. "Deregulation of AP-1 proteins in collagen gel-induced epithelial cell apoptosis mediated by low substratum rigidity." J Biol Chem 282(1): 752-63. (2007).
Welch, D. R., T. Sakamaki, et al. "Transfection of constitutively active mitogen-activated protein/extracellular signal-regulated kinase kinase confers tumorigenic and metastatic potentials to NIH3T3 cells." Cancer Res 60(6): 1552-6. (2000).
Yamamoto, A., S. Mishima, et al. "A new technique for direct measurement of the shear force necessary to detach a cell from a material." Biomaterials 19(7-9): 871-9. (1998).
Yeung, T., P. C. Georges, et al. "Effects of substrate stiffness on cell morphology, cytoskeletal structure, and adhesion." Cell Motil Cytoskeleton 60(1): 24-34. (2005).
李真甄 "細胞黏著力的量測技術, A New Technique for Measurement of Cell Adhesion." (2003).