Pensalfini Marco, Ehret Alexander E, Stüdeli Silvia, Marino Daniela, Kaech Andres, Reichmann Ernst, Mazza Edoardo
Institute for Mechanical Systems, Department of Mechanical and Process Engineering, ETH Zurich, Leonhardstrasse 21, 8092 Zurich, Switzerland.
Institute for Mechanical Systems, Department of Mechanical and Process Engineering, ETH Zurich, Leonhardstrasse 21, 8092 Zurich, Switzerland; Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland.
J Mech Behav Biomed Mater. 2017 May;69:85-97. doi: 10.1016/j.jmbbm.2016.12.004. Epub 2016 Dec 9.
The effect of the production factors yielding a functional dermal substitute was investigated by means of monotonic and cyclic uniaxial tensile tests, as well as electron microscopy visualizations. The role of (i) plastic compression, (ii) product incubation, and (iii) cell permanence in the collagenous matrix in order to achieve a skin-like behavior were characterized in terms of material and structural stiffness, in-plane kinematics, and cyclic response, as well as pore size and network density. The plastic compression resulted in a denser and stiffer material, while no corresponding change was observed in the behavior of the entire structure. This was related to the progressive reduction in product thickness and amount of excess water, rather than to formation of new crosslinks between fibers. Contrary, irrespective of the presence of human fibroblasts, the product incubation induced both material and structural stiffening, indicating the formation of a denser network. These results were confirmed by similar evolutions in the construct in-plane kinematics and cyclic stress reduction. Finally, comparison of constructs incubated in different culture media indicated a determinant contribution of the biochemical environment, rather than of the seeded cells, to the achieved mechanical properties. The observed features are relevant in terms of mechanical biocompatibility of the implant and might direct future optimizations of the production process in order to rapidly attain the desired mechanical properties.
通过单调和循环单轴拉伸试验以及电子显微镜观察，研究了产生功能性真皮替代物的生产因素的影响。为了实现类似皮肤的行为，从材料和结构刚度、平面内运动学、循环响应以及孔径和网络密度等方面，对（i）塑性压缩、（ii）产品孵育和（iii）细胞在胶原基质中的持久性的作用进行了表征。塑性压缩导致材料更致密、更坚硬，而整个结构的行为未观察到相应变化。这与产品厚度和过量水分的逐渐减少有关，而不是与纤维之间形成新的交联有关。相反，无论是否存在人成纤维细胞，产品孵育都会导致材料和结构变硬，表明形成了更致密的网络。构建体平面内运动学和循环应力降低的类似演变证实了这些结果。最后，在不同培养基中孵育的构建体的比较表明，生化环境而非接种细胞对所实现的力学性能起决定性作用。观察到的特征在植入物的机械生物相容性方面具有相关性，并且可能指导未来生产工艺的优化，以便快速获得所需的机械性能。
