Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering; International Joint Research Center of Aerospace Biotechnology and Medical Engineering, Ministry of Science and Technology of China, Beihang University, Beijing, People's Republic of China.
Invest Ophthalmol Vis Sci. 2014 Apr 28;55(4):2739-46. doi: 10.1167/iovs.13-12633.
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.
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.
The parameters were derived using a fitting method that included the expectation for the distribution of fibril crimping degrees, μ = 1.063; the standard deviation, σ = 0.0781; the elastic modulus of collagen fibrils, E = 52.74 MPa; and the fibril ultimate strain, εb = 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.
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.
建立一个力学模型，以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。
对角膜条带进行单轴拉伸实验，以测试其力学性能。基于胶原原纤维卷曲的高斯分布形态构建了一个本构模型。通过将实验数据拟合到本构模型来确定代表胶原原纤维微观特征的参数。采用透射电子显微镜（TEM）观察基质中胶原原纤维的卷曲形态。对 TEM 图像中纤维卷曲度进行定量分析，以验证本构模型预测的参数。
采用拟合方法得出参数，其中纤维卷曲度分布的期望为 μ=1.063，标准差为 σ=0.0781，胶原原纤维的弹性模量为 E=52.74 MPa，纤维极限应变 εb=0.1957。TEM 图像显示，当角膜受到不同拉伸载荷时，纤维卷曲形态发生变化。本构模型得出的参数与 TEM 图像量化数据之间具有良好的一致性。
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。这些发现有望指导与胶原原纤维微观结构异常相关的角膜病变的进一步研究。
