Department of Mechanical Engineering, McGill University, Montreal, QC, Canada H3A 0C3.
Acta Biomater. 2013 Aug;9(8):7957-67. doi: 10.1016/j.actbio.2013.04.044. Epub 2013 May 3.
Collagen fibrils are believed to control the immediate deformation of soft tissues under mechanical load. Most extracellular matrix proteins remain intact during frozen sectioning, which allows them to be scanned using atomic force microscopy (AFM). Collagen fibrils are distinguishable because of their periodic roughness wavelength. In the present study, the shape and organization of collagen fibrils in dissected porcine vocal folds were quantified using nonlinear laser scanning microscopy data at the micrometer scale and AFM data at the nanometer scale. Rope-shaped collagen fibrils were observed. The geometric characteristics for the fibrils were fed into a hyperelastic model to predict the biomechanical response of the tissue. The model simulates the micrometer-scale unlocking behavior of collagen bundles when extended from their unloaded configuration. Force spectroscopy using AFM was used to estimate the stiffness of collagen fibrils (1±0.5MPa). The presence of rope-shaped fibrils is postulated to change the slope of the force-deflection response near the onset of nonlinearity. The proposed model could ultimately be used to evaluate changes in elasticity of soft tissues that result from the collagen remodeling.
胶原纤维被认为可以控制软组织在机械载荷下的瞬时变形。大多数细胞外基质蛋白在冷冻切片过程中保持完整，这使得它们可以使用原子力显微镜（AFM）进行扫描。胶原纤维因其周期性的粗糙度波长而具有可分辨性。在本研究中，使用非线性激光扫描显微镜在微米尺度上和 AFM 在纳米尺度上的数据，对分离的猪声带中的胶原纤维的形状和组织进行了定量分析。观察到绳状胶原纤维。将纤维的几何特征输入超弹性模型，以预测组织的生物力学响应。该模型模拟了胶原束从无负载状态拉伸时的微观尺度解锁行为。使用 AFM 进行力谱分析以估计胶原纤维的刚度（1±0.5MPa）。假设绳状纤维的存在会改变非线性起始附近力-挠度响应的斜率。该模型最终可用于评估由于胶原重塑而导致的软组织弹性变化。
