Visualization and mechanical manipulations of individual fibrin fibers suggest that fiber cross section has fractal dimension 1.3
Visualization and mechanical manipulations of individual fibrin fibers suggest that fiber cross section has fractal dimension 1.3
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DOI：
10.1529/biophysj.104.042333
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发表时间：
2004-12-01
影响因子：
3.4
通讯作者：
Superfine, R
中科院分区：
文献类型：
--
作者：
Guthold, M;Liu, W;Superfine, R
我们报告的协议和技术，图像和机械操纵个别纤维蛋白纤维，这是血凝块的关键结构组成部分。使用基于原子力显微镜的侧向力操纵，我们确定了纤维蛋白纤维的断裂力，F-R，作为其直径的函数，D，在环境条件下。正如预期的那样，破裂力随着直径的增加而增加;然而，有点出乎意料的是，它随着F-R的增加而增加，类似于D1.30 +/- 0.06。此外，使用组合的原子力显微镜-荧光显微镜仪器，我们确定了由荧光标记的纤维蛋白原形成的单纤维的光强度I作为其直径D的函数。与力的数据类似，我们发现光强度以及每个横截面的分子数量随着I的增加而增加，类似于D1.25 +/- 0.11。基于这些研究结果，我们提出，纤维蛋白纤维是分形的分子数量每横截面增加约D-1.3。这意味着分子密度随rho（D）变化，类似于D-0.7，即，较细的纤维比较粗的纤维更致密。这样的模型将与纤维蛋白纤维由70 - 80%的水和仅20 - 30%的蛋白质组成的观察结果一致，这也表明纤维蛋白纤维是非常多孔的。
We report protocols and techniques to image and mechanically manipulate individual fibrin fibers, which are key structural components of blood clots. Using atomic force microscopy-based lateral force manipulations we determined the rupture force, F-R, of fibrin fibers as a function of their diameter, D, in ambient conditions. As expected, the rupture force increases with increasing diameter; however, somewhat unexpectedly, it increases as F-R similar to D1.30 +/- 0.06. Moreover, using a combined atomic force microscopy-fluorescence microscopy instrument, we determined the light intensity, I, of single fibers, that were formed with fluorescently labeled fibrinogen, as a function of their diameter, D. Similar to the force data, we found that the light intensity, and thus the number of molecules per cross section, increases as I similar to D1.25 +/- 0.11. Based on these findings we propose that fibrin fibers are fractals for which the number of molecules per cross section increases as about D-1.3. This implies that the molecule density varies as rho(D) similar to D-0.7, i.e., thinner fibers are denser than thicker fibers. Such a model would be consistent with the observation that fibrin fibers consist of 70 - 80% water and only 20 - 30% protein, which also suggests that fibrin fibers are very porous.