Effect of corneal collagen crosslinking on viscoelastic shear properties of the cornea
Effect of corneal collagen crosslinking on viscoelastic shear properties of the cornea
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DOI：
10.1016/j.jmbbm.2022.105300
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发表时间：
2022-09-01
影响因子：
3.9
通讯作者：
Emu, Md Esharuzzaman
中科院分区：
文献类型：
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作者：
Hatami-Marbini, Hamed;Emu, Md Esharuzzaman
角膜负责眼睛中的大部分屈光力，并充当眼睛内部内容物的保护层。角膜需要机械强度来保持其精确形状并承受外部和内部力。角膜胶原交联（CXL）是改善角膜机械性能的一种治疗选择。本研究的主要目的是表征CXL对作为压缩应变函数的猪角膜粘弹性剪切特性的影响。为此目的，制备角膜扣并将其分为三组：对照组（n = 5）、假交联组（n = 5）和交联组（n = 5）。利用流变仪对角膜圆盘在不同压缩应变水平（0%-40%）下进行动态扭转剪切实验。具体地，进行应变扫描实验和频率扫描测试，以分别确定线性粘弹性和频率依赖性剪切特性的范围。结果发现，所有样品的剪切性能取决于剪切应变的大小，加载频率，和压缩应变。随着施加的剪切应变的增加，所有样品都表现出非线性粘弹性响应。此外，样品的剪切模量随着施加的剪切应变的频率的增加和/或增加的压缩应变。最后，当压缩应变从0%变化到30%时，CXL处理显著增加了剪切储能模量和损失模量（p < 0.05）;在压缩40%应变下观察到更大的剪切模量，但差异不显著（P = 0.12）。
The cornea is responsible for most of the refractive power in the eye and acts as a protective layer for internal contents of the eye. The cornea requires mechanical strength for maintaining its precise shape and for withstanding external and internal forces. Corneal collagen crosslinking (CXL) is a treatment option to improve corneal mechanical properties. The primary objective of this study was to characterize CXL effects on viscoelastic shear properties of the porcine cornea as a function of compressive strain. For this purpose, corneal buttons were prepared and divided into three groups: control group (n = 5), pseudo-crosslinked group (n = 5), and crosslinked group (n = 5). A rheometer was used to perform dynamics torsional shear experiments on corneal disks at different levels of compressive strain (0%-40%). Specifically, strain sweep experiments and frequency sweep tests were done in order to determine the range of linear viscoelasticity and frequency dependent shear properties, respectively. It was found that the shear properties of all samples were dependent on the shear strain magnitude, loading frequency, and compressive strain. With increasing the applied shear strain, all samples showed a nonlinear viscoelastic response. Furthermore, the shear modulus of samples increased with increasing the frequency of the applied shear strain and/or increasing the compressive strain. Finally, the CXL treatment significantly increased the shear storage and loss moduli when the compressive strain was varied from 0% to 30% (p < 0.05); larger shear moduli were observed at compressive 40% strain but the difference was not significant (P = 0.12).