Gergely Csilla, Hemmerlé Joseph, Schaaf Pierre, Hörber J K Heinrich, Voegel Jean-Claude, Senger Bernard
Institut National de la Santé et de la Recherche Médicale, Unité 424, UFR d'Odontologie, Université Louis Pasteur, 67085 Strasbourg Cedex, France.
Biophys J. 2002 Aug;83(2):706-22. doi: 10.1016/s0006-3495(02)75202-8.
This article deals with the detachment of molecules (fibrinogen) from a surface studied experimentally with an atomic force microscope. The detachment (or rupture) forces are measured as a function of the retraction velocity and exhibit a clear dependence on this parameter, even though the interaction between the molecules and the surface are nonspecific. To interpret these data, a mechanical multi-bead-and-spring model is developed. It consists of one to several parallel, "molecular" springs connected to an extra spring representing the cantilever that is moved at constant velocity. The free end of each molecular spring terminates with a particle that interacts with the surface through a Lennard-Jones potential. This Brownian dynamics model is used to analyze the experimental findings. In the framework of this model, it appears that the fibrinogen molecule must be ascribed a stiffness much smaller than that of the cantilever. In addition, several bonds between the molecule and the surface must be taken into account for the range of the molecule-surface interaction not to be unrealistically small. In future work, this model will be extended to more complex mechanisms such as the detachment of cells from a surface.
本文探讨了用原子力显微镜通过实验研究分子（纤维蛋白原）从表面的脱离情况。脱离（或破裂）力作为回缩速度的函数进行测量，即使分子与表面之间的相互作用是非特异性的，这些力也明显依赖于该参数。为了解释这些数据，建立了一个机械多珠弹簧模型。它由一到几个平行的“分子”弹簧连接到一个代表以恒定速度移动的悬臂的附加弹簧组成。每个分子弹簧的自由端终止于一个通过 Lennard-Jones 势与表面相互作用的粒子。该布朗动力学模型用于分析实验结果。在该模型的框架内，似乎必须赋予纤维蛋白原分子比悬臂小得多的刚度。此外，为了使分子与表面相互作用的范围不至于小到不切实际，必须考虑分子与表面之间的几个键。在未来的工作中，该模型将扩展到更复杂的机制，如细胞从表面的脱离。
