| Summary: | 碩士 === 國立成功大學 === 醫學工程研究所碩博士班 === 95 === 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).
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