A Mechanical Model of the Cornea Considering the Crimping Morphology of Collagen Fibrils
A Mechanical Model of the Cornea Considering the Crimping Morphology of Collagen Fibrils
复制标题
考虑胶原原纤维卷曲形态的角膜力学模型
DOI：
10.1167/iovs.13-12633
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发表时间：
2014-04-01
影响因子：
4.4
通讯作者：
Fan, Yubo
中科院分区：
文献类型：
--
作者：
Liu, Xiaoyu;Wang, Lizhen;Fan, Yubo
目的。建立一种力学模型，用于研究胶原原纤维卷曲形态与角膜非线性力学行为之间的关系。用角膜条进行单轴拉伸实验，测试角膜条的力学性能。基于卷曲胶原原纤维的高斯分布形态，建立了本构模型。通过将实验数据拟合到本构模型中，确定了代表胶原原纤维微观特征的参数。透射电镜观察基质中胶原原纤维的卷曲形态。定量分析了TEM图像中纤维的卷曲程度，以验证本构模型预测的参数。参数的拟合方法包括对纤维卷曲度分布的期望，mu = 1.063；标准差，sigma = 0.0781；胶原原纤维弹性模量，E = 52.74 MPa；而原纤维极限应变ε (b) = 0.1957。透射电镜图像显示，在不同的拉伸载荷作用下，角膜纤维卷曲形态发生了变化。本构模型得到的参数与TEM图像量化的数据吻合较好。角膜的非线性力学行为与胶原原纤维的卷曲形态密切相关。这一发现有望指导与胶原原纤维异常显微结构相关的角膜病理的进一步研究。
PURPOSE. To develop a mechanical model with which to investigate the relationship between the crimping morphology of collagen fibrils and the nonlinear mechanical behavior of the cornea.METHODS. Uniaxial tensile experiments were performed with corneal strips to test their mechanical behavior. A constitutive model was constructed based on the Gaussian-distributed morphology of crimped collagen fibrils. The parameters that represent the micro characteristics of collagen fibrils were determined by fitting the experimental data to the constitutive model. Transmission electron microscopy (TEM) was used to visualize the crimping morphology of collagen fibrils in the stroma. A quantitative analysis of fibril crimping degrees in the TEM images was conducted to test the parameters predicted by the constitutive model.RESULTS. The parameters were derived using a fitting method that included the expectation for the distribution of fibril crimping degrees, mu = 1.063; the standard deviation, sigma = 0.0781; the elastic modulus of collagen fibrils, E = 52.74 MPa; and the fibril ultimate strain, epsilon(b) = 0.1957. TEM images showed a variation of the fibril crimping morphology when the cornea was subjected to different tensile loads. A good agreement was found between the parameters derived by the constitutive model and the data quantified from the TEM images.CONCLUSIONS. The nonlinear mechanical behavior of the cornea is closely correlated with the crimping morphology of collagen fibrils. The findings are expected to guide further research of corneal pathologies related to the abnormal microstructure of collagen fibrils.