Noble Christopher, Kamykowski Michael, Lerman Amir, Young Melissa
Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55905 USA.
IEEE Open J Eng Med Biol. 2020;1:197-202. doi: 10.1109/ojemb.2020.3002450. Epub 2020 Jun 15.
This work evaluates the rate-dependent and relaxation properties of native porcine heart valves, glutaraldehyde fixed porcine pericardium, and decellularized sterilized porcine pericardium.
Biaxial tension testing was performed at strain-rates of 0.001 s, 0.01 s, 0.1 s, and 1 s. Finally, relaxation testing for 300 s was performed on all heart valve biomaterials.
No notable rate-dependent response was observed for any of the three biomaterials with few significant differences between any strain-rates. For relaxation testing, native tissues showed the most pronounced drop in stress and glutaraldehyde the lowest drop in stress although no tissues showed anisotropy in the relaxation.
Increasing the strain-rate of the three biomaterials considered does not increase the stress within the tissue. This indicates that there will not be increased fatigue from accelerated wear testing compared to loading at physiological strain-rates as the increase strain-rates would likely not significantly alter the tissue stress.
本研究评估天然猪心脏瓣膜、戊二醛固定猪心包和脱细胞灭菌猪心包的应变率依赖性和松弛特性。
在应变率为0.001 s、0.01 s、0.1 s和1 s的条件下进行双轴拉伸试验。最后，对所有心脏瓣膜生物材料进行300 s的松弛试验。
三种生物材料中的任何一种均未观察到明显的应变率依赖性反应，不同应变率之间几乎没有显著差异。对于松弛试验，天然组织的应力下降最为明显，戊二醛固定组织的应力下降最低，尽管没有组织在松弛过程中表现出各向异性。
在所考虑的三种生物材料中，增加应变率不会增加组织内的应力。这表明，与生理应变率加载相比，加速磨损试验不会增加疲劳，因为增加应变率可能不会显著改变组织应力。
