Department of Metallurgy & Ceramics Science, Tokyo Institute of Technology, O-okayama 2-12-1, Tokyo 152-8550, Japan.
Langmuir. 2011 Jun 21;27(12):7635-44. doi: 10.1021/la200008z. Epub 2011 May 19.
The adhesion process of osteoblast-like cells on hydroxyapatite (HAp) and oxidized polystyrene (PSox) was investigated using a quartz crystal microbalance with dissipation (QCM-D), confocal laser scanning microscope (CLSM), and atomic force microscope (AFM) techniques in order to clarify the interfacial phenomena between the surfaces and cells. The interfacial viscoelastic properties (shear viscosity (η(ad)), elastic shear modulus (μ(ad)), and tan δ) of the preadsorbed protein layer and the interface layer between the surfaces and cells were estimated using a Voigt-based viscoelastic model from the measured frequency (Δf) and dissipation shift (ΔD) curves. In the ΔD-Δf plots, the cell adhesion process on HAp was classified as (1) a mass increase only, (2) increases in both mass and ΔD, and (3) slight decreases in mass and ΔD. On PSox, only ΔD increases were observed, indicating that the adhesion behavior depended on the surface properties. The interfacial μ(ad) value between the material surfaces and cells increased with the number of adherent cells, whereas η(ad) and tanδ decreased slightly, irrespective of the surface. Thus, the interfacial layer changed the elasticity to viscosity with an increase in the number. The tan δ values on HAp were higher than those on PSox and exceeded 1.0. Furthermore, the pseudopod-like structures of the cells on HAp had periodic stripe patterns stained with a type I collagen antibody, whereas those on PSox had cell-membrane-like structures unstained with type I collagen. These results indicate that the interfacial layers on PSox and HAp exhibit elasticity and viscosity, respectively, indicating that the rearrangements of the extracellular matrix and cytoskeleton changes cause different cell-surface interactions. Therefore, the different cell adhesion process, interfacial viscoelasticity, and morphology depending on the surfaces were successfully monitored in situ and evaluated by the QCM-D technique combined with other techniques.
为了阐明表面与细胞之间的界面现象，使用石英晶体微天平（QCM-D）、共聚焦激光扫描显微镜（CLSM）和原子力显微镜（AFM）技术研究了成骨细胞样细胞在羟基磷灰石（HAp）和氧化聚苯乙烯（PSox）上的附着过程。使用基于 Voigt 的粘弹性模型，从测量的频率（Δf）和耗散变化（ΔD）曲线估算了预吸附蛋白质层和表面与细胞之间界面层的界面粘弹性特性（剪切粘度（η（ad））、弹性剪切模量（μ（ad））和 tan δ）。在ΔD-Δf 图中，HAp 上的细胞附着过程分为（1）仅质量增加，（2）质量和ΔD 都增加，以及（3）质量和ΔD 略有减少。在 PSox 上，仅观察到ΔD 的增加，表明附着行为取决于表面特性。材料表面与细胞之间的界面μ（ad）值随附着细胞数量的增加而增加，而η（ad）和 tanδ略有降低，与表面无关。因此，随着数量的增加，界面层将弹性变为粘性。HAp 上的 tan δ值高于 PSox 上的值，超过 1.0。此外，用 I 型胶原抗体染色的 HAp 上的伪足状细胞结构具有周期性条纹图案，而 PSox 上的细胞具有未用 I 型胶原染色的细胞膜样结构。这些结果表明，PSox 和 HAp 上的界面层分别表现出弹性和粘性，这表明细胞外基质和细胞骨架的重新排列会导致不同的细胞-表面相互作用。因此，通过 QCM-D 技术与其他技术相结合，成功地原位监测了不同表面的细胞附着过程、界面粘弹性和形态。
