论文标题
交联增加明胶水凝胶的弹性模量和断裂韧性
Crosslinks increase the elastic modulus and fracture toughness of gelatin hydrogels
论文作者
论文摘要
水凝胶具有大变形的能力，但像脆性材料一样失败。在许多应用中，具有高强度和韧性的生物相容性水凝胶的发展是一个持续的挑战。我们使用戊二醛（对照）和甲基乙二醛（MGO）交联牛明胶，并评估了其骨折韧性的变化。肿胀实验表明，MGO水凝胶中的水保留约710％，而对照样品中的水位约为450％。我们使用FTIR来确定可能参与明胶凝胶交联的化学基团的存在。与对照样品相比，冻干MGO水凝胶的扫描电子显微照片显示出大毛孔，这些毛孔具有板状完整壁，可帮助保留水。单调压缩测试证明了两个水凝胶组的非线性应力 - 应变行为。与模量为4.77+-0.73 kPa的对照水凝胶相比，MGO样品的模量高96％（n = 4）。与Mooney-Rivlin和Neo-Hookean模型相比，一阶Ogden模型非常适合应力 - 应变数据。我们使用空化流变学来使用内部半径为75、150、230和320μm的钝针量化水凝胶中气泡破坏的最大压力。气泡内部的压力随时间线性增加，并在临界值之后急剧下降。与对照样品中的大球形气泡相比，MGO凝胶中的气泡小且一分钱形状。我们使用临界压力来量化水凝胶的断裂能。 MGO治疗从13.09 J/m2增加了骨折能量，用于对照凝胶。最后，我们讨论了使用Ogden和Mooney-Rivlin模型来计算明胶水凝胶的衰竭能的挑战。
Hydrogels have the ability to undergo large deformations and yet fail like brittle materials. The development of biocompatible hydrogels with high strength and toughness is an ongoing challenge in many applications. We crosslinked bovine gelatin using glutaraldehyde (control) and methylglyoxal (MGO) and assessed changes in their fracture toughness. Swelling experiments show ~710% retention of water in MGO hydrogels as compared to ~450% in control specimens. We used FTIR to identify the presence of chemical groups that may be involved in the crosslinking of gelatin gels. Scanning electron micrographs of lyophilized MGO hydrogels show large pores with plate-like intact walls that help retain water as compared to control specimens. Monotonic compression tests demonstrate nonlinear stress-strain behaviors for both hydrogel groups. MGO samples had 96% higher moduli as compared to control hydrogels that had moduli of 4.77+-0.73 kPa (n=4). A first order Ogden model fit the stress-strain data well as compared to Mooney-Rivlin and neo-Hookean models. We used cavitation rheology to quantify the maximum pressure for bubble failure in the hydrogels using blunt needles with inner radii of 75, 150, 230, and 320 μm respectively. Pressures inside the bubbles increased linearly with time and dropped sharply following a critical value. Bubbles in MGO gels were small and penny-shaped as compared to large spherical bubbles in control samples. We used the critical pressures to quantify the fracture energies of the hydrogels. MGO treatment increased the fracture energy by 187% from 13.09 J/m2 for control gels. Finally, we discuss the challenges in using the Ogden and Mooney-Rivlin models to compute the failure energy for gelatin hydrogels.
