Tang Jingyuan, Chen Xi, Liu Fengkai, Zeng Liangsong, Suo Zhigang, Tang Jingda
State Key Laboratory for Strength and Vibration of Mechanical Structures, Department of Engineering Mechanics, Xi'an Jiaotong University, Xi'an 710049, China.
John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA.
Sci Adv. 2025 Jun 20;11(25):eadw0808. doi: 10.1126/sciadv.adw0808. Epub 2025 Jun 18.
Bovine pericardium is the tissue of choice for replacing heart valves of human patients in minimally invasive surgery. The tissue has an extraordinarily high toughness of ~100 kilojoules per square meter. Here, we investigate the origin of the toughness through mechanical tests and microscopic observations. In the tissue, crimped, long, strong collagen fibers are embedded in a soft matrix. As a crack grows in the matrix, the fibers decrimp, reorient, slip, and bridge the crack. These microscopic processes enable the fibers to transmit high tension over a long distance. Using two types of experiments, we measure the bridging traction as a function of crack separation, σ(δ). The peak traction is σ ~ 60 megapascals. The maximum separation is δ ~ 6 millimeters, two to four orders of magnitude higher than that of hard tissues. Both the high traction and large separation of the bovine pericardium contribute to its high toughness.
牛心包是微创手术中替代人类患者心脏瓣膜的首选组织。该组织具有极高的韧性，约为每平方米100千焦。在此，我们通过力学测试和微观观察来研究其韧性的来源。在该组织中，卷曲的、长而坚韧的胶原纤维嵌入柔软的基质中。当裂纹在基质中扩展时，纤维展开、重新定向、滑动并跨越裂纹。这些微观过程使纤维能够在长距离上传递高张力。通过两种类型的实验，我们测量了桥接牵引力随裂纹间距σ(δ)的变化。峰值牵引力为σ ~ 60兆帕斯卡。最大间距为δ ~ 6毫米，比硬组织高两到四个数量级。牛心包的高牵引力和大间距共同促成了其高韧性。
